Title of Invention

"PROCESS FOR THE PREPARATION OF STABILISED COMPOSITIONS".

Abstract

Compositions comprising one or mors olefin polymers functionalized by at least one functionaliza-tion agent chosen fron carboxylic acic.s, their esters, their anhydrides and their metal salts and one or more stabilizing agents comprising one or mora sterically hindered pheno. groups and at most one ester functional group. Process for their preparation and use of these compositions for compatibilizing olefin polymers with polymers, fillers and metal substrates which are incompatible with olefin polymers,

Full Text

Compositions _formed of polyolefins precess for their preparation and use of these compositions The present invention relates to stabilized compositions formed of functionalized polyolefins and in particular stabilized .compositions formed of polyolefins functionalized by carboxyiic acic. groups, their esters their anhydrides or thair metal salts, it also relates to a process for their preparation and -;o their use . Fur.ctionalized polyolefins are widely used/ in particular as adhesive between a polyethylene (PE) layer and a layer of epoxy resin, for example for the coating of pipes. In practice, all plastics are subject to oxidation phenomena commonly described using the terminology "ageing phenomenon". The most widely used method for slowing down these phenomena i;3 the addition cf antioxidizing or stabilizing agents. Phenolic antioxidants are used as stabilizing agants for polyethylanes. However, their combination with stabilizing agents of phosphite type is generally more effective; sea US 4,250,941. A frequently used combination is for example, a blend of pentaerythrityl tetrakis (3, 5-di--t~butyl-4-hydroxyphenylpropionate) and of tris (2, 4-di-t:-butylphanyl) phosphite. The problem which is posad in the case of adhesives stabilized in this way, basec on polyolefins functionalized by acid or anhydride groups, for example maleic-anhydride-functionalized polyethylene is a long-term loss In adhesion. Furthermore, these compositions are subject to a loss in thermal stability and to en increase in the viscosity in the prssnance of- moisture (less in rheological stability), this phenomenon further being accelerated by an increase in the temperature. The present invention is targeted at overcoming these disadvantages by novel compositors forned of functionalized polyolefins exhibiting better thermal stability and better rheological stability and giving beter long-term adhesion. One aspect of the present invention consequently relates to compositions comprising one or more olefin polymers functionalized by at least one functionalization agent chosen from carboxylic acids their asters, their anhydrides and their metal salts and one or more stabilizing agens comprising one or more sterically hindered phenol groups and at most one ester functional group. These fur.ctionalized compositions exhibit better Theological stability and give better Icng-tarm adhesion. Furthermore, these compositions are no longer subject to a loss in thermal stability nor to an increase in the viscosity in the presence of moisture. The stabilising agents comprising one or more sterically hindered phenol groups and at; most one ester functional group are chosen from stabilizing agents comprising one or more sterically hindered phenol groups which comprise an ester functional group and from stabilizing agents comprising one or more sterically hindered phenol groups which do not; comprise an eater functional group. The term "ester functional group" is understood to denote, for the purposes of the present invention/ the ester functional group derived from the carboxylic acid, functional group within the conventional meaning of organic chemistry (R-CO-O-R1)- Mention may be made, among stabilizing agents comprising one or mora sterically hindered phenol groups which comprisa an ester functional group, of, for example, staaryl β- (3,5-d.i-t-butyl-4-hydroxy~ phenyl)propionate. Mention may be made, among stabilizing agents comprising one or more sterically hindered phenol groups which do r.ot comprise an ester group, of for example, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphe- 2, 2 -mathylerebis (6-t-butyl-4-methylphanoi) 2, 6-bis (a-iaethylbenzyl) -4-rcethylphenol, 4, 4 '-thiobis-(6-t-butyl-n-cresol) 2,2'-methylenebis(4-methyl-6-nonylphenol), diisobutylnonylphenol, tris(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris-(4-t-butyl-3-hydroxy-2, 6-dimethylbenzyl) -1, 3, 5-tri-azine-2, 4, 6- (1H, 3H, 6H) -trione, 1, 3, 5-triBiethyl-2, 4, 6-tris(3,5-di-t~butyl-4-hydroxyben2yl)berzene and their mixtures. Preferably, at least one ox the stabilizing agents dees not comprise an ©star functional group. In a particularly preferred way, at least one of the stabilizing agents is 1,3,5™trinmethyl-2,4,, 6-tris-(3, 5-di-t-butyl-4-hydroxybenzyl) benzene (Irganox191 133C) . In a very particularly praferred way, tha compositions according to the invention comprise 1,3,S-trimethyl-2, 4, 6-tris (3 5-di-t-butyl-4-hydroxybenayl)benzene as sole stabilizing agent. The amounts of stabilising agent aciployed in the compositions of the present invention depend on various factors, for example on the an .cunt of radical initiator used, on the application intended for the compositions and on the nature of the functionalization agent. The amount of stabilizing agsr.t is generally between 0.001 and 1% by weight. Generally, the amount of stabiliaing agent is greater than or equal to 0.001%, preferably greater than or equal to 0.01%, in a particularly preferred way grea.ter than or equal to 0.1% by weight. Genarally, the amount of stabilizing agent is less than or equal to IS, preferably less than or equal to C.75%, in a particularly preferred way less than or equal to 0.55 by weight. The olafin polymers functionalised by func-tionalization agents chosen from carlsoxylic acids, their • esters their anhydrides and their metal salts can be obtained by known techniquas, or example by copolymerization or, preferably, by grafting. They are derivatives of polymers formed of linear olefins comprising from 2 to 3 carbon atoms, such as ethylene, propylene, 1-butene, l-pentena l-hexene and 1-octena. The lir.ear olefins preferably comprise from 2 to 6 carbon atoms, more particularly fron. 2 to 4 carbon atoms. The olafin polymers (polyolefins) car. be selected from homopolymers of the abovementioned olefins or from copolymers of thase oiefins, in particular copoly-mers cf ethylene or of propylene with one or more comcromers. The constituent comonome.rs are advantageously chosen from the abovedescribed oiefins and from diolafins comprising from 4 to 16 carbcn atoms, such as 4-vinylcyclohaxena, dic1, 3-butadian.e, isoprere and 1,2-pentadiene, The polyolefins are preferably chosen from propylens polymers and ethylene polymers/ in particular ethylsne homopolymer/ propylena horciopclymer, ethylene copolymers, propylene copolymers, copolymers of ethylane and of propylans/ and their mixtures. The propylene polymers are generally chosen from propylene homopolymers and copclyners with a melt flow index (MFI) , measured at 230°C L.under a load of 2.1-5 kg according to ASTM standard D 12:18 (1986), of between. 0.1 and 100 dg/min, The ethylene polymers are generally chosen fron ethylene homopolymers and copolymers exhibiting a standard density of between 915 and 960 fcg/ia3 and a melt flow index (measured at 19O"C under a load of 5 kg) cf between 0.1 and 200 dg/min. Ethylene homopolymers and copolymers are par-ticularly preferred. These advantageously exhibit a standard density of at least 315 kg/m3, in particular of at least 936 kg/m3. The standard density generally doas not exceed 960 kg/m3, preferably does not exceed 953 kg/m3. The ethylene homopolymers and copolymers in addition, usually exhibit a melt flow :lndex (measured at 190°C under a load of 5 kg) of at least 0.1 dg/min, preferably of at least 2 dg/xin. The meln flow index generally does not exceed 200 dg/min, mere particularly • does not exceed 40 dg/min. The functionalization agent is generally a compound comprising a vinyl unsaturation and optionally cna or more aromatic nuclei and/or-one or more carbonyl groups. The functionalization agent can bs chosan, for example, from unsaturated mono- or dicarboxylic acids and their derivatives, ur.saturated'i mono- or dicarboxylic acid anhydrides and their derivatives, unsatureted mono- or dicarboxylic acid esters and their derivatives or unsaturated mono- or dicarboxylic acid metal salts ar.d their derivatives,. Tha functiorLalization agents preferably comprise from 3 to 20 carbon atoms. Mention nay be made as typical examples, of acrylic acid, methacrylic acid maleic acid, furaaric acid, itaconic s.cid, crotonic acid, cirraconic acid/ maleic anhydride, itEconic anhydride, crotonic anhydride, citraconic anhydride and thair mixtures, Maleic anhydride is very particularly preferred. In a particularly preferred way, in the compositions according to tha invention, at least one of the olefin polymers functionalized by at least one functionalization agent chosen from cirboxylic acids, their esters, their anhydrides and their metal salts is an ethylene polymer functionalized by muleic anhydride. In. a very particularly preferred way, 'in the compositions according to the invention, the only functionalized olsfin polymer is an esthylena polymer functionalized by maleic anhydride. The malaic anhydride is usually present in the funstioralized ethylene polymer in an amount of 0.001 to 51 by weight, preferably of 0,01 to ;i% by weight and in particular of 0.05 to 1-5 by weight. The ethylene polymer functionalized with maleic anhydride advantageously exhibits a standard density of at least 915 kg/m3, in particular of at least 936 kg/m3. The standard density generally dogis not exceed 9SO kg,/m3, preferably docs not exceed 96R kg/m In. addition, it usually exhibits a melt flow index [measured at 190C under a load of 5 kg) of at least 0.1 dg/min, preferably of at least 2 dg/min. The melt flow index generally does not exceed 50 dg/min, more particularly does not exceed 22 dg/min. The compositions according to the invention can, in addition, optionally comprise additives usual" for polyolefins in an amount ranging up to 106 by weight, such as additional antioxidisir.g agents, lubri-cating agents, fillers, colorants, nucleating agents, uv stabilizers/ antiacid agents, such as calcium ste.arate, agents for modifying thts crystallinity, such as a copolymer of ethylena and of n-butyl or ethyl acrylate/ agents for deactivating metai.s or antistatic agents. One embodiment of the present invention provides for the dilution of the abovedescribad compositions in one or more nonfur.ctdonaliaad olefin polymers. In the case of nonfunctionsilized olefin polders, they are essentially the compounds mentioned above or their mixtures. The composition can be diluted up co 20 times, that is to say by adding thereto up to 95% by weight of at least one nonfunctJonaiized olefin polymer, preferably up to 10 tizr.as, thsit is to say by adding thereto up to 90% by weight of at least one nonfunotionalised olefin polymer, in ?. more th«an preferred way up to 5 times, that is to way by -adding thereto up to 80% by weight of at least one nonfun.ctiona.lized olefin polymer. The compositions according to the invention can be prepared by -any process, such as, ir, particular, solution processes, the processes being carried out in a mixer, for example a 3rabenderft mixe;:, or tha process as being carried out in an extruder. Good results are usually obtained if the compositions according to the invention ara prepared by means c-f the process according to the invention. The invention, also relates to the use of one or more stabilizing agents comprising one or more sterically hindered phenol groups ar.d at most one ester functional group in the stabilisation of oiefin polymers functional!zed by at least one functior.slization agent chosen from carboxylic acids, their esters their anhydrides and their metal salts. The stabilizing agants comprising one or more sterically hindered phenol groups and at most one ester functional group used in the stabilization are those identified hereinabove. The olefin polymers which can be stabilized are those identified hereinabove. The invention also relates to a process for the preparation of stabilized compositions comprising one or more functionalized olefir. polymers and one or more stabilising agents, according to which one or more olafin polymers/ ore or more functional!zation agents/ one or wore radical initiators/ one or more stabilizing agents comprising one or more statically hindered phenol groups and at most one ester functional group, and optionally one or more additives, are melt blended in a screw extruder. The stabilizing agent comprising one or more sterically hindered phenol groups and at most one ester functional group which can be introduced into the extruder are those identified hersinabove, A preferred case is that where at least one of the stabilising agents introduced im:o the intruder does not comprise an ester functional group. A particularly preferred case is that where at least one of the stabilizing agents introduced intc the extruder is 1,3,5-triaethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxy-benzyl)benzene. A very particularly preferred case is that where the 1,3, 5-trimethyl-2/4, (5-tria (3, 5-di-t-butyl-4-hydroxybenzyl)benzene is introduced into the extruder as sola stabilizing agent. The stabilizing agents are usually employed in an amount of between 0.001 and 1I by weight, preferably between 0.01 and 0.75% by weight and in a particularly preferred way batween 0,1 and 0.51 by weight. These olefin polymers are those identified hereinabove. A preferred process is that in which at least or.e of the olefin polymers introduced into the extruder is an ethylene polymer exhibiting a standard density of 915 to 960 kg/m3 and a welt flew index measured at 130ec under a load of 5 kg, of 0,1 to 200 dg/min. The functionalisation agents which can be introduced into the extruder are chosen from carboxylic acids, their esters, their anhydrides and their metal salts and are essentially those indicated abova. A preferred alternative form of the process is that where at least one of the furictionaliaation agents introduced into the extruder is maleic anhydride. A very particularly preferred alternative form is that where the only functionalizator. agent introduced into the extruder is maleic anhydride. The fnationalisation agents can be introduced into the extruder either in the, solid state or in the moltan state, In the latter case, it is necessary to have available an introduction system maintained at a temperature greater than the malting temperature of the functionalization agent. The functionalization agants are generally used in an amount of 0,001 to 20% by weight, prefarably-.of 0.05 to 10% by weight and in particular of 0.03 to 5% by weight. The grafting reaction in the process according to the invention takes place under the effect of a radical initiator. Organic peroxides are preferably u,s«d as radical initiator. Mention may be mada, as typical examples, of t-butyl cumyl parcxide, l,3-di(2~ t-bxitylperoxylsopropyl)benzene, 3,5-bis t-butylperoxy)-3,S-diraethyl-l/2-dioxolane, di-t-butyl peroxide, 2r S-dimethyl-2, 5-di (t-butylperoxy) hexane. p-menthane hydroperoxidfi, pinane hydroperoxide, diisopropylbenzene mono-et-hydroperoxide, cumane hydroperoxide, t-butyl hydroperoxide and their mixtures. The preferred radical initiator is 2, 5-dimathyl-2 5-di- (t-butylperoxy) hexane. The radical initiator is generally employed in. the process according to the invention in an amount sufficient to allow the grafting to be carried out. The amount is usually between 0.0001$ end 1I, preferably between C.001 and 0.51, in a particularly preferred way between 0.01 and 0.1% by weight, The temperature by which the process is carried out is generally greater than the melting temperature and lower than the decomposition tenperature of the poayolefin and of the functionalised polyolefin, if possibla optionally at an optimum, temperature for the radical initiator. The process according to the invention generally involves processing temperatures in the range from 120°C to 290°C, preferably in the range from 140 to 250 aC and, in a particularly preferred way, in the range from 160 to 220°C. During the process, it is optionally possible to additionally introduce at any point for example, up co 105 by weight of conventional additives for polyolef ins chosen from those mentioned hereinabcve.. The process car. also provide for the dilution of the composition in one or more n^nninctionalised olefin polymers. The nonfunctionalized oiefin polymers are essantially the compounds mentioned above o:r their mixtures. The composition can be diluted up -.to 20 times, that Is to say by adding thereto up to 955 by weight of at least one nonfunctionalized olefin polymer, preferably up to 10 times, the.t is to say by adding thereto up to 90% by waight o.! at least one nonfunctionalize d olafin polymer, in a more: then preferred way up to 5 times, that is to $ay by adding thereto up to 30% by weight of at least one nonfunction&lised olefin polymer. The dilution of the composition can take place continuously in the screw extruder in which the preparation of -the stabilized composition takes place. It can also take place in a device separated from the said extruder, for example in a second extruder, optionally after granulation of the stabilized composition. The order of introduction of the ra&ctants is generally riot critical. The functionalization agent, the stabilizing agent and the radical initiator can ba introduced at the same time or independently ir. any order and optionally portionwise. The stabilizing agent is preferably introduced after the functionulization agent and the radical initiator, in a particularly preferred way after the reaction region. In a very particularly preferred way the process for the preparation of stabilized compositions according to the invention comprises the following stages: a) feeding, undar a nitrogen atmosphere, one or more olefin polymera and from 0.001 to 20 by weight of functionalization agant into a corotating twin-screw extruder equipped with a series of associated blending elements with skewed threads, b) feeding from 0.0001 to 1% by weight of a radical initiator, optionally diluted in ons or more clRfin polyxers or optionally introduced by spraying, c) blending one or more molten olefin polymers, the functionalisation agent and the radical initiator in the extruder prepared for a tine sufficient to graft at least a portion of the functionalization agent onto the molten olefin polymer(s), d) feeding into the extruder from 0.001,to 1% by weight of stabilizing agent and optionally one or mere other additives optionally diluted in one or more olafin polymers/ e) devo1ati 1 i.zing the volotile materials by 3 subsequent stage of devolarilization with not .dry air in a decompression region of the extruder/ f) optionally diluting with nonfuntionalized olefin polymare, g) discharging the final composition. A screw extruder within the meaning of the pressent invention comprises at least the following parts: a feed region, a reaction region and at its outlet, a discharge region preceded by a compression region, the latter forcing the molten mass tc pass through the discharge region. In practic®, all the stagas Can be carried out in a corotating or cou.rvterrotating single- or twin-screw extruder which generally comprises, in addition to the aboveraentioned. regions, optionally one or more staged feed devices for the said introduction of the pclyolsfin or polyolerins, functiona.li;:ation agents, radical initiator and/or stabilizing acent, one or more sc:rew elements allowing the propagation of the material to be extruded, one or more heating regions aillowing the constituents to be melted and one or mora devolatilisation regions. If appropriate, the composition can also be diluted in a region allowing the introduction of ncnfunctionalized po3yolefin via an appropriate feed device. In addition, the discharge region can be followed by e. graiulation device. The process according to the invention is advantageously used for the preparation of the compositions according to the invention. Finally, an additional aspect provides for the use of the compositions in accordance with the present invention for compatibilizing olefin polymers with polymers/ fillers and metal substrates which are incompatible with olefin polycters. Incompatible polymers are/ for example/, epoxy resins/ fluoridated resins and particularly poly- (Vinylidenp. flroride), polyamidco and polyeslerS . The compositions according to the invention are preferably used for compatibilizlng oleifin polymers With epoxy resins. Incompatible fillers are, for example, natural fibres, such as flax, hemp, jute and cellulose, and glass fibres glass, silica, talc, calcium carbonate and carbon black. The metal substrates are, for example, steel or aluminium, Preferred usas of the compositions according to the invention are multilayer adhesion and the multi-layesr coating of steel pipes. The following examples serve to illustrate the present invention without, however, limiting the scope thereof. The meanings of the symbols employed, the units expressing the quantities mentioned and the methods for measuring thase quantities are explair.ed hereinbelow. Standard density (3D) of the polyolefin expressed in kg/m3, measured according to ISO standard 1183 (1567). The melt: flow index of the polyolefin (Ml) is determined at !SOaC under a load, of 5 kg, 8/2 mm die/ according to ISO standard 1133 (1:391) . The grafted content of MA is evaluated by IR spectrosccpy. Two films are preparec. per sample and analysed directly after pressir.g and then after degassing for 1 h at 120°c undar vacuum in order to remove/ if necessary, the residual frtie anhydride. The MA level/ measured by IR, is expresses', by the ratio of the absorbance of the carbonyl (1785 en"1) to the absor-bance at 3610 eafl characteristic of PI. The acid level is expressed by the ratio of the s.bsorbance at 1715 cm"1 to thfc absorbance at 3510 cm"1. The values obtained are converted to I by waight of grafted mai.eic anhydride by ma.'cing use of a relationship based on a titrimetric calibration. The frea maleic anhydride.- s detected, by the characteristic bands at 895, 840 and/or 700 cm"1. The thermal stability is determined by measuring the induction period under oxygen at 210 °C according to ASTM standard D 3895 11992, . The peel strength was evaluated on 5 x 15 cm three-layer plates. 5 x 15 x 3 nun, metal plates are sandblasted for at most 24 h befo:re coating. An approximately 100 μm layer of epoxy primer is applied at 200°C by electrostatic powdering. The plate is placed in a mould base preheated to 230"c. A £ilm of the adhaslve composition of the examples hereinbelow with a thicknese of approximately 250 ,μm is applied and then an Eltex GTB 201 PE plate with a thickness of approximately 3 mm. The peel strength i.s then measured according to DIN standard 30670 (1991). In the examples which follow ths base resin is the Eltex A 4090 P HDPE polyethylene resin with an MI6 of 29 dg/min and, a standard density sf 952 kg/m3 The maieic anhydride (MA.) is milled. Th.a peroxide is 2, 5-dimathyl-2,5~di(t-butylperoxy)hexane (D3PE-peroxyd Chemie). After grafting, the products are driad in an oven at 8C°C under vacuum for 16 h in order to remove the free MA. Example 1 A sample of Eltex* A 4090 P polyethylene func-tionalied with maleic anhydride in ths absence of any stabilizing agent which comprises 1 of grafted maleic anhydride and which exhibits a melt flow index of 6.6 dg/min before and after hydrolysis, is mixed on a Brabenders mixer an 180°C, 50 rotations per minute, for 6 ruin in the presence of 3 g/kg of the stabilizing agent 1,3,5-triwethyl-2,4,e-tris (3,5-di-t-butyl-4-hydroxybanzyl)benzene (stabilising agent A) . Half of tha sample is hydrolysecl in the presence of steam for 7 days at 100°C and then dried under vacuum overnight at 35°C. Measurements of the melt flow index and of the tharmal stability were carried out on the samples as such or on the samples after hydrolysis . The results of these measurements ara summarized in Table I. Example 2 (comparative) The procedure is the same as in Example 1 except that the stabilizing agent employed is the stabilizing agent pentaerythrityl hetrakis(3,5-di-t-butyl-4-hydroxyphenylpropionate) (stabilizing agent B) . The results of the measurements of melt flow index and of thermal stability are summarir.ed in Table I. Table I (Table Removed) It is apparent from the analysis of the- results that the compositions according to the invention sxhibic a constant long-term melt flow index and thermal stability. Example 3 A mixture of linear high density polyethylene (HOPE) sold under the tradenaine Eltstx® A 4090 P, and of maleic anhydride in the solid state, at a content of 0.4% by weight, is fad to a Krupp Werner & Pfleidarer ZSK58 corotating twin-screw extruder, The extruder is arranged so that it successively comprises the following regions: (1) Main feed region (2) Heating region provided with a feed orifice'. (3) Reaction region provided with a feisd orifice (4) Degassing region for discharging the volatile materials (5) Compression region (6) Discharge region. The HEPS, blended with the maleic anhydride, is fed 1:0 the ir.ain feed region under «i strsan of nitrogen. The peroxide is fad to the main hopper in the feed region at a content of 0.045% by weight in the form of a masterbatch with the HDPS. The stabilising agent 1, 3,, 5-trimethyl~2,4, 6-tris{3, S-t~butyl-4-hydroxy-phenyl)benzene (stabilizing agent A) is added in the reg;.on 3 at a content of 0.3S by weight in an concentrated masterbatch KDPE/stabilizing agent 10 fold. The other operating conditions are as follows: Temperature profile: 210°C Throughput of 180 kg/h Screw spead: 300 revolutions per minute. Tha functionalized polyethylene comprises 0.53 by weight of maleic anhydride and exhibits a melt flow index MI5 of 20 dg/min and a tharmal, stability of 20 min. The peel strength was evaluated as described hareinabove on the sample as such or on the sample aged for 15 days at: 80 C in water. The results of the peal strengths, measured at 23°C and 508C, are presented in Table II herainbelow. Example 4 fcomparative) The procedure is carried out ir. the way described in Example 3, except that the stabilizing agent employed is the stabilizing " agant pentaerythrityl tetrakis (3, 5-di.-t-butyl-4-hydroxyphanylpropionate) (stabilizing agent B), all the other conditions being identical, Ths results of the peel strengths, measured at 23"C and 8Q°C, are presented in Table II hereinbelow. Table II (Table Removed) It may be observed from the analysis of these results that the compositions according to the invention give better long-term adhesion. CLAIMS 1. Compositions comprising one or more olefin polymers functionalized by at least one functionaliza— tion agent chosen from carboxylic acic.s, their esters, their anhydrides and their metal salts and one or more stabilizing agents comprising one or more sterically hindered phenol groups and at most one ester functional group from which at least one of the stabilizing agents is 1, 3, 5-trimethyl-2, 4, 6-tris (3, 5-di-t--butyl-4-hydroxy- banzyl)benzena. 2. Compositions according to Claim 1, characterized in chat the amount of stabili2ing agent is between 0.001 and 1% by weight, 3. Compositions according to any one of Claims 1 to 2, characterized in that at least one of the olefin polymers functionalized by at least one functionaliza- tion agent chosen from carboxylic acids, their esters, their anhydrides and their metal salts is an ethylene polymer functionalized by maleic anhydride. 4. Compositions according to Claim 3, charac terized in that the maleic anhydride is present in the functionalized ethylane polymer ir. an amount of 0.001 to 5* by weight. 5. Compositions according- to Claim 3 or 4, charac terized in chat the ethylene polymer functionalized 'by maleic anhydride exhibits a standard density of 915 to 960 kg/m3 and a melt flow index, measured at 190aC under a load of 5 kg, of 0.1 to 50 dg/min. 6. Compositions according to any one of Claims 1 to 5, characterized in that the composition is diluted in one or more nonfunctionalized olefin polymers. 7. Use of one or more stabilizing agents compris ing one or more sterically hindered phenol groups and at most one ester functional group from which at least one of the stabilizing agents is 1,3,5-t.rimethyl--2,4, 6- tris; (3, 5-di-t-butyl-4-hydroxybenzyl) benzune in the stabilization of. olefin polymers functionalized by at least one functionalization agent chosen from carboxylic acids, their asters,- their anhydrides and their metal salts. 8. Process for the preparation of stabilized compositions comprising one or. more funstionalized olefin polymers and one cr more stabilizing agents, characterized in that one or more olefin polymers, one cr more functionalisation agents;, one or moro radical initiators, one or more stabilising agents comprising one cr more sterically hindered phenol groups and at most one ester functional group from which at least one of the stabilizing agents is 1, 3, .5-trimethyl-2, 4, 6-tris-(3,5-di-t-butyl-4-hydroxybenzyl)benzaene, and optionally one or more additives are malt blended in a screw extruder. 9,. Process according to Claim 8, characterized in that at least, one of the olefin polymers introduced into the extruder is an ethylene polymer axhibiting a standard density of 915 to 960 lcg/m3 and a melt flow index, measured at 190°C undar a load of 5 kg,, of 0.1 tc 200 dg/min, 10. Process according to any one of Claims 9 to 9, characterized in that at least one of the func- tionalisation agents introduced into the extruder is maleic anhydride, 11. Process according to any one oi: Claims 9 to ,10, characterized in that the processing temperature lies between 120 °C and 290°C. 12. Process according to any ona of Claims to to 11, characterized in that the stabilized composition is diluted in one or more nonf unctionalized olefin polymers. 13. Use of compositions according to any one of Cla.ims 1 to 6 cr obtained by a process according to any one of Claims.s 8 to 12 for compatibilizing olefin polymers with polymers, fillers .and natal substrates which are incompatible with olefin polymers. 14- Use according to Claim 13, characterized in that the incompatible polymers are epoxy resins. 15. Use according to Claim :13 or 14 in multilayer adhesion. 16. Use according to any one of Claims 13 to 15 in the multilayer coating of steel pipes.

Documents:

in-pct-2001-00988-del-abstract.pdf

in-pct-2001-00988-del-claims.pdf

in-pct-2001-00988-del-correspondence-others.pdf

in-pct-2001-00988-del-correspondence-po.pdf

in-pct-2001-00988-del-description (complete).pdf

in-pct-2001-00988-del-form-1.pdf

in-pct-2001-00988-del-form-13.pdf

in-pct-2001-00988-del-form-19.pdf

in-pct-2001-00988-del-form-2.pdf

in-pct-2001-00988-del-form-3.pdf

in-pct-2001-00988-del-form-5.pdf

in-pct-2001-00988-del-form-6.pdf

in-pct-2001-00988-del-gpa.pdf

in-pct-2001-00988-del-petition-137.pdf

in-pct-2001-00988-del-petition-138.pdf