GRAFTING OF ETHYLENICALLY UNSATURATED MONOMERS ONTO POLYMERS

Abstract: The present invention relates to a process for the preparation of grafted polymers wherein in a first step A) a stable nitroxyl radical is grafted onto a polymer, which step comprises heating a polymer and a stable nitroxyl radical (NO•); and in a second step B) the grafted polymer of step A) is heated in the presence of an ethylenically unsaturated monomer or oligomer to a temperature at which cleavage of the nitroxyl-polymer bond occurs and polymerization of the ethylenically unsaturated monomer or oligomer is initiated at the polymer radical; maintaining said temperature for further polymerization and afterwards cooling down the mixture to a temperature below 60 DEG C. Further subjects are grafted polymers prepared by said process, the use of the polymeric radical initiator and the use of NO radicals for grafting polymers.

Description: Grafting Of Ethylenically Unsaturated Monomers Onto Polymers The present invention relates to a process for the preparation of grafted polymers wherein in a first step A) a stable nitroxyl radical is grafted onto a polymer, which step comprises heating a polymer and a compound containing a stable NO* radical to above the melting point of the polymer, mixing and reacting the components at said temperature; and in a second step B) the grafted polymer of step A) is heated in the presence of an ethylenically unsaturated monomer or oligomer to a temperature at which cleavage of the nitroxyl-polymer bond occurs. Further subjects of the present invention are grafted polymers prepared by said process, the use of the polymeric radical initiator and the use of a stable NO radical for grafting polymers. Increasing activities have been directed towards chemical modifications of existing polymers in order to obtain functional and/or engineered new material. Chemical modifications of existing polymers are important for at least two reasons: 1. They can be an inexpensive and rapid way of obtaining new polymers without having to search for new monomers; 2. they may be the only way to synthesize polymers with the intended new characteristics. An important chemical modification is the free radical grafting of reactive monomers, which involves reaction of a polymer with a vinyl-group containing monomer or mixture of monomers capable of forming grafts onto the polymer backbone. If the grafts are long, the modified polymer becomes a true graft copolymer, of which the properties will be very different from those of the original polymer substrate. When the grafts are short with less than, for example five moieties, most of the physical and or mechanical properties of the modified polymer substrate will be retained. The properties are furthermore influenced by the structure of the grafted monomer. For example grafting of a polar monomer onto a non polar polymer such as polyethylene, results in decisively modified properties such as adhesion to other substrates, compatibility with polar surfaces, even at short chain lengths. The advantages of free radical-grafting are further gained with the use of batch mixers or screw extruders as chemical reactors, which allow the free radical-grafting reaction to occur without solvents. This is for example described by G. H. Hu et al., in "Reactive Modifiers for Polymers", first edition, Blackie Academic & Professional an Imprint of Chapman & Hall, London 1997, chapter 1 , pages 1-97. These free radical-grafting reactions are usually performed in the presence of a free radical source such as a peroxide and a reactive monomer, such as for example acrylic acid. However the use of free radical sources such as peroxides may cause undesired properties and lead to problems during processing (gel formation, crosslinking, molecular weight reduction) or during use Typically the long term stability is reduced and/or the polymer cannot anymore be used in outdoor applications or in applications at elevated temperatures EP-A-621 878 discloses a free radical polymerization process which controls the growth of polymer chains to produce short chain or oligomeric homopolymers and copolymers, including block and graft copolymers. The process employs a stable free radical as for example of formula (in part) R'R"N-O» and a free radical initiator. Surprisingly it has now been found that with such R'R"N-O» compounds it is possible to produce a polymeric radical initiator by grafting the group R'R"N-O to the polymer and to use this macromitiator for further grafting reactions of olefinically unsaturated monomers. The polymerization processes and resin products of the present invention are useful in many applications, including a variety of specialty applications, such as for the preparation of grafted block copolymers which are useful as compatibilizing agents for polymer blends, adhesion promoters or dispersing agents for coating systems. One subject of the present invention is a process for the preparation of a grafted polymer wherein in a first step A) a stable nitroxyl radical is grafted onto a polymer, which step comprises heating a polymer and a stable nitroxyl radical (NO»); and in a second step B) the grafted polymer of step A) is heated in the presence of an ethylenically unsaturated monomer or oligomer to a temperature at which cleavage of the nitroxyl-polymer bond occurs and polymerization of the ethylenically unsaturated monomer or oligomer is initiated at the polymer radical; maintaining said temperature for further polymerization and afterwards cooling down the mixture to a temperature below 60° C. The reaction mixture after step A) may also be cooled down to a temperature below 60° C before further reaction of step B) is performed. Optionally a free radical source is additionally present. Preferably the free radical source is a bis-azo compound, a peroxide or a hydroperoxide Specific preferred radical sources are 2,2'-azobιsιsobutyronιtrιle, 2,2'-azobιs(2-methyl- butyronitπle), 2,2'-azobts(2,4-dιmethylvaleronιtrιle), 2,2'-azobιs(4-methoxy-2,4-dιmethylvalero- nitπle), 1 ,1 '-azobιs(1 -cyclohexanecarbonιtrιle), 2,2'-azobιs(ιsobutyramιde) dihydrate, 2- phenylazo-2,4-dιmethyl-4-methoxyvaleronιtrιle, dιmethyl-2,2'-azobιsιsobutyrate, 2- (carbamoylazo)isobutyronitrile, 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis(2- methylpropane), 2,2'-azobis(N,N'-dimethyleneisobutyramidine), free base or hydrochloride, 2,2'- azobis(2-amidinopropane), free base or hydrochloride, 2,2'-azobis{2-methyl-N-[1 ,1 - bis(hydroxymethyl)ethyl]propionamide} or 2,2'-azobis{2-methyl-N-[1 ,1 -bis(hydroxymethyl)-2- hydroxyethyl]propionamide; acetyl cyclohexane sulphonyl peroxide, diisopropyl peroxy dicarbonate, t-amyl perneodecanoate, t-butyl perneodecanoate, t-butyl perpivalate, t-amylperpivalate, bis(2,4- dichlorobenzoyl)peroxide, diisononanoyl peroxide, didecanoyl peroxide, dioctanoyl peroxide, dilauroyl peroxide, bis (2-methylbenzoyl) peroxide, disuccinic acid peroxide, diacetyl peroxide, dibenzoyl peroxide, t-butyl per 2-ethylhexanoate, bis-(4-chlorobenzoyl)-peroxide, t-butyl perisobutyrate, t-butyl permaleinate, 1 ,1 -bis(t-butylperoxy)3,5,5-trimethylcyclohexane, 1 ,1-bis(t- butylperoxy)cyclohexane, t-butyl peroxy isopropyl carbonate, t-butyl perisononaoate, 2,5- dimethylhexane 2,5-dibenzoate, t-butyl peracetate, t-amyl perbenzoate, t-butyl perbenzoate, 2,2-bis (t-butylperoxy) butane, 2,2 bis (t-butylperoxy) propane, dicumyl peroxide, 2,5- dimethylhexane-2,5-di-t-butylperoxide, 3-t-butylperoxy 3-phenylphthalide, di-t-amyl peroxide, α, α'-bis(t-butylperoxy isopropyl) benzene, 3,5-bis (t-butylperoxy)3,5-dimethyl 1 ,2-dioxolane, di-t- butyl peroxide, 2,5-dimethylhexyne-2,5-di-t-butylperoxide, 3,3,6,6,9, 9-hexamethyl 1 ,2,4,5- tetraoxa cyclononane, p-menthane hydroperoxide, pinane hydroperoxide, diisopropylbenzene mono-α-hydroperoxide, cumene hydroperoxide or t-butyl hydroperoxide. Peroxides are most preferred. Examples of suitable polymers are mentioned below. 1. Polymers of monoolefins and diolefins, for example polypropylene, polyisobutylene, polybut- 1 -ene, poly-4-methylpent-1 -ene, polyisoprene or polybutadiene, as well as polymers of cycloolefins, for instance of cyclopentene or norbornene, polyethylene (which optionally can be crosslinked), for example high density polyethylene (HDPE), high density and high molecular weight polyethylene (HDPE-HMW), high density and ultrahigh molecular weight polyethylene (HDPE-UHMW), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), (VLDPE) and (ULDPE). Polyolefins, i.e. the polymers of monoolefins exemplified in the preceding paragraph, preferably polyethylene and polypropylene, can be prepared by different, and especially by the following, methods: a) radical polymerisation (normally under high pressure and at elevated temperature). b) catalytic polymerisation using a catalyst that normally contains one or more than one metal of groups IVb, Vb, Vlb or VIII of the Periodic Table. These metals usually have one or more than one ligand, typically oxides, halides, alcoholates, esters, ethers, amines, alkyls, alkenyls and/or aryls that may be either p- or s-coordinated. These metal complexes may be in the free form or fixed on substrates, typically on activated magnesium chloride, titanium(lll) chloride, alumina or silicon oxide. These catalysts may be soluble or insoluble in the polymerisation medium. The catalysts can be used by themselves in the polymerisation or further activators may be used, typically metal alkyls, metal hydrides, metal alkyl halides, metal alkyl oxides or metal alkyloxanes, said metals being elements of groups la, Ha and/or Ilia of the Periodic Table. The activators may be modified conveniently with further ester, ether, amine or silyl ether groups. These catalyst systems are usually termed Phillips, Standard Oil Indiana, Ziegler (- Natta), TNZ (DuPont), metallocene or single site catalysts (SSC). 2. Mixtures of the polymers mentioned under 1 ), for example mixtures of polypropylene with polyisobutylene, polypropylene with polyethylene (for example PP/HDPE, PP/LDPE) and mixtures of different types of polyethylene (for example LDPE/HDPE). 3. Copolymers of monoolefins and diolefins with each other or with other vinyl monomers, for example ethylene/propylene copolymers, linear low density polyethylene (LLDPE) and mixtures thereof with low density polyethylene (LDPE), propylene/but-1-ene copolymers, propylene/isobutylene copolymers, ethylene/but-1-ene copolymers, ethylene/hexene copolymers, ethylene/methylpentene copolymers, ethylene/heptene copolymers, ethylene/octene copolymers, propylene/butadiene copolymers, isobutylene/isoprene copolymers, ethylene/alkyl acrylate copolymers, ethylene/alkyl methacrylate copolymers, ethylene/vinyl acetate copolymers and their copolymers with carbon monoxide or ethylene/acrylic acid copolymers and their salts (ionomers) as well as terpolymers of ethylene with propylene and a diene such as hexadiene, dicyclopentadiene or ethylidene-norbornene; and mixtures of such copolymers with one another and with polymers mentioned in 1) above, for example polypropylene/ethylene-propylene copolymers, LDPE/ethyiene-vinyl acetate copolymers (EVA), LDPE ethylene-acrylic acid copolymers (EAA), LLDPE/EVA, LLDPE/EAA and alternating or random polyalkylene/carbon monoxide copolymers and mixtures thereof with other polymers, for example polyamides. 4. Hydrocarbon resins (for example C 5 -C 9 ) including hydrogenated modifications thereof (e.g. tackifiers) and mixtures of polyalkylenes and starch. 5. Polystyrene, poly(p-methylstyrene), poly(a-methylstyrene). 6 Copolymers of styrene or a-methylstyrene with dienes or acrylic derivatives, for example styrene/butadiene, styrene/acrylonitπle, styrene/alkyl methacrylate, styrene/butadiene/alkyl acrylate, styrene/butadiene/alkyl methacrylate, styrene/maleic anhydride, styrene/acryloni- tπie/methyl acrylate, mixtures of high impact strength of styrene copolymers and another polymer, for example a polyacrylate, a diene polymer or an ethylene/propylene/diene terpo- ly er; and block copolymers of styrene such as styrene/butadiene/styrene, styrene/iso- prene/styrene, styrene/ethylene/butylene/styrene or styrene/ethylene/propylene/ styrene 7 Graft copolymers of styrene or a-methylstyrene, for example styrene on polybutadiene, styrene on polybutadiene-styrene or polybutadiene-acrylonitnle copolymers; styrene and acrylonitnle (or methacrylonitnle) on polybutadiene; styrene, acrylonitnle and methyl methacrylate on polybutadiene; styrene and maleic anhydride on polybutadiene; styrene, acrylonitnle and maleic anhydride or maleimide on polybutadiene; styrene and maleimide on polybutadiene, styrene and alkyl acrylates or methacrylates on polybutadiene, styrene and acrylonitnle on ethylene/propylene/diene terpolymers; styrene and acrylonitnle on polyalkyl acrylates or polyalkyi methacrylates, styrene and acrylonitnle on acrylate/butadiene copolymers, as well as mixtures thereof with the copolymers listed under 6), for example the copolymer mixtures known as ABS, MBS, ASA or AES polymers. 8 Halogen-containing polymers such as polychloroprene, chlorinated rubbers, chlorinated and brommated copolymer of isobutylene-isoprene (halobutyl rubber), chlorinated or sulfo- chlonnated polyethylene, copolymers of ethylene and chlorinated ethylene, epichlorohydπn homo- and copolymers, especially polymers of halogen-containing vinyl compounds, for example polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, polyvinylidene fluoride, as well as copolymers thereof such as vinyl chloride/vinylidene chloride, vinyl chloride/vinyl acetate or vinylidene chloride/vinyl acetate copolymers 9 Polymers derived from ,β-unsaturated acids and derivatives thereof such as polyacrylates and polymethacrylates; polymethyl methacrylates, polyacrylamides and polyacrylonitnles, impact-modified with butyl acrylate 10 Copolymers of the monomers mentioned under 9) with each other or with other unsaturated monomers, for example acrylonitnle/ butadiene copolymers, acrylonitnle/alkyl acrylate copolymers, acrylonitnle/alkoxyalkyl acrylate or acrylonitπle/vinyl halide copolymers or acrylonitnle/ alkyl methacrylate/butadiene terpolymers 11 Polymers derived from unsaturated alcohols and amines or the acyl derivatives or acetals thereof, for example polyvinyl alcohol, polyvinyl acetate, polyvinyl stearate, polyvinyl benzoate, polyvinyl maleate, polyvinyl butyral, polyallyl phthalate or polyallyl melamine; as well as their copolymers with olefins mentioned in 1 ) above. 12. Homopolymers and copolymers of cyclic ethers such as polyalkylene glycols, polyethylene oxide, polypropylene oxide or copolymers thereof with bisglycidyl ethers. 13. Polyacetals such as polyoxymethylene and those polyoxymethylenes which contain ethylene oxide as a comonomer; polyacetals modified with polyurethanes, acrylates or MBS. 14. Polyphenylene oxides and sulfides, and mixtures of polyphenylene oxides with styrene polymers or polyamides. 15. Polyurethanes derived from hydroxyl-terminated polyethers, polyesters or polybutadienes on the one hand and aliphatic or aromatic polyisocyanates on the other, as well as precursors thereof. 16. Polyamides and copolyamides derived from diamines and dicarboxyiic acids and/or from aminocarboxylic acids or the corresponding lactams, for example polyamide 4, polyamide 6, polyamide 6/6, 6/10, 6/9, 6/12, 4/6, 12/12, polyamide 11 , polyamide 12, aromatic polyamides starting from m-xylene diamine and adipic acid; polyamides prepared from hexamethylenediamine and isophthalic or/and terephthalic acid and with or without an elastomer as modifier, for example poly-2,4,4,-trimethylhexamethylene terephthalamide or poly-m- phenylene isophthalamide; and also block copolymers of the aforementioned polyamides with polyolefins, olefin copolymers, ionomers or chemically bonded or grafted elastomers; or with polyethers, e.g. with polyethylene glycol, polypropylene glycol or polytetramethyiene glycol; as well as polyamides or copolyamides modified with EPDM or ABS; and polyamides condensed during processing (RIM polyamide systems). 17. Polyureas, polyimides, polyamide-imides, polyetherimids, polyestehmids, polyhydantoins and polybenzimidazoles. 18. Polyesters derived from dicarboxyiic acids and diols and/or from hydroxycarboxylic acids or the corresponding lactones, for example polyethylene terephthalate, polybutylene terephthalate, poly-1 ,4-dimethylolcyclohexane terephthalate and poiyhydroxybenzoates, as well as block copolyether esters derived from hydroxyl-terminated polyethers; and also polyesters modified with polycarbonates or MBS. 19. Polycarbonates and polyester carbonates. 20. Polysulfones, polyether sulfones and polyether ketones. 21. Blends of the aforementioned polymers (polyblends), for example PP/EPDM, Poly- amide/EPDM or ABS, PVC/EVA, PVC/ABS, PVC/MBS, PC/ABS, PBTP/ABS, PC/ASA, PC/PBT, PVC/CPE, PVC/acrylates, POM/PUR, PC/PUR, POM/acrylate, POM/MBS, PPO/HIPS, PPO/PA 6.6 and copolymers, PA HDPE, PA/PP, PA/PPO, PBT/PC/ABS or PBT/PET/PC. Preferred polymers are polyethylene, polypropylene, polystyrene, styrene block-copolymers, polybutadiene or polyisoprene, EPDM (ethylene-propylene diene monomer) or EPR (ethylene- propylene rubber). More preferred are polyethylene, polypropylene, polybutadiene, SBS and EPDM (ethylene- propylene diene monomer). One preferred nitroxyl radical is of formula (X) wherein n-i is 0 or 1 R 1 0 1 , R10 2 . R 103 are each independently of one another hydrogen, halogen, NO , cyano, -CONR 105 Rιo6 , -(Rιo 9 )COOR 10 , -C(O)-R 107 , -OR 108 , -SR 108 , -NHR 108 , -N(R 10 8) 2 , carbamoyl, di(C r C 18 alkyl)carbamoyl, unsubstituted C r C 18 alkyl, C 2 -Cι 8 alkenyl, C 2 -C 18 alkynyl, C 7 -C 9 phenylalkyl, C 3 -C 12 cycloalkyl or C 3 - C 12 cycloalkyl containing at least one nitrogen or oxygen atom; or C C 18 alkyl, C 2 -C 18 alkenyl, C 2 -Cι 8 alkynyl, C 7 -C 9 phenylalkyl, C 3 -C 12 cycloalkyl or C 3 -C 12 cycloalkyl containing at least one nitrogen or oxygen atom, which are substituted by NO 2 , halogen, amino, hydroxy, cyano, carboxy, C r C alkylthio, CrCalkylamino or di(C 1 -C 4 alkyl)amino; or phenyl, which is unsubstituted or substituted by C 1 -C 4 alkyl, C C 4 alkylthio, halogen, cyano, hydroxy, carboxy, d-C 4 alkylamino or di(C 1 -C 4 aikyl)amino; or R 102 and Rι 03 , together with the linking carbon atom, form a C 3 -C 2 cycloalkyl radical, a (C 4 - C 12 cycloalkanon)-yl radical or a C 3 -C 12 cycloalkyl radical containing at least one O atom and/or a NR 108 group; or if n^ is 1 R 1 Ri 04 is hydrogen, C C 18 alkyl, phenyl, an alkali metal cation or a tetraalkylammonium cation; R 105 and R 106 are hydrogen, d-C^alky!, C 2 -C 18 alkyl which is substituted by at least one hydroxy group or, taken together, form a C 2 -C 12 alkylene bridge or a C 2 -C 12 -alkylene bridge interrupted by at least one O or/and NR 108 atom; R 107 is hydrogen, CrC^alkyl or phenyl; R 108 is hydrogen, C C 18 alkyl or C -C 18 alkyl which is substituted by at least one hydroxy group; R 109 is CrC^alkylen or a direct bond; Rno is C 4 -C 18 alkyl bound via a tertiary C-atom to the nitrogen atom, Cg-Cnphenylalkyl, C 3 - C 12 cycloalkyl or C 3 -C 12 cycloalkyl containing at least one nitrogen or oxygen atom; or C 4 -C 18 alkyl bound via a tertiary C-atom to the nitrogen atom, Cg-Cnphenylalkyl, C 3 -C 12 cycloalkyl or C 3 -C 12 cycloalkyl containing at least one nitrogen or oxygen atom, which are substituted by NO 2 , halogen, amino, hydroxy, cyano, carboxy, d-dalkoxy, C C 4 alkylthio, CrC 4 alkylamino or d CrC^lky amino; or phenyl, naphthyl, which are unsubstituted or substituted by C C 4 alkyl, C C 4 alkoxy, C C 4 alkylthio, halogen, cyano, hydroxy, carboxy, C C 4 alkylamino or di(C r C 4 alkyl)amino; if n^ is 1 Rm is C C 18 alkyl, C 7 -C 9 phenylalkyl, C 3 -C 12 cycloaikyl or C 3 -C 1 cycloalkyl containing at least one nitrogen or oxygen atom; or C C 18 alkyl, C 7 -C 9 phenylalkyl, C 3 -C 12 cycloalkyl or C 3 -C 12 cycloalkyl containing at least one nitrogen or oxygen atom, which are substituted by NO 2 , halogen, amino, hydroxy, cyano, carboxy, C C 4 alkoxy, C C 4 alkylthio, C C alkylamino or di(C 1 -C 4 alkyl)amino; or phenyl, naphthyl, which are unsubstituted or substituted by C C 4 alkyl, C C alkoxy, C C alkylthio, halogen, cyano, hydroxy, carboxy, CrC 4 alkylamino or di(C C 4 alkyl)amino; or a polycyclic cycloaliphatic ring system or a polycyclic cycloaliphatic ring system with at least one di- or trivalent nitrogen atom; or R 110 and Rm together form a C 2 -C 12 alkylene bridge, a C 3 -C 12 alkylen-on bridge or a C 2 - C 12 alkylene bridge which is interrupted by at least one O or N atom, which bridges are unsubstituted or substituted with C r Cι 8 alkyl, hydroxy^ t -C^alkyl, phenyl, C 7 -C 9 phenylalkyl, NO 2 , halogen, amino, hydroxy, cyano, carboxy, C C alkoxy, C 1 -C 4 a!kylthio, C C 4 alkylamino or di(C C 4 alkyl)amino, R 112 is hydrogen, -(R 10 9)COOR 104 , cyano, -OR 108 , -SR 108 , -NHR 108 , -N(R 108 ) 2 , -NH-C(O)-R 108 , unsubstituted C C^alkyl, C 2 -C 18 alkenyl, C 2 -C 18 alkynyl, C 7 -C 9 phenylalkyl, C 3 -C 12 cycloalkyl or C 3 - C 12 cycloalkyl containing at least one nitrogen or oxygen atom; or d-Cι 8 alkyl, C 2 -C 18 alkenyl, C 2 -C 18 alkynyl, C 7 -C 9 phenylalkyl, C 3 -C 2 cycloalkyl or C 3 -C 12 cycloalkyl containing at least one nitrogen or oxygen atom, which are substituted by NO 2 , halogen, amino, hydroxy, cyano, carboxy, d-C 4 alkoxy, CrC 4 alkylthio, C 1 -C 4 alkylamino or di(C C 4 alkyl)amino; or phenyl, naphthyl, which are unsubstituted or substituted by CrC 4 alkyl, C C 4 alkoxy, C C 4 alkylthio, halogen, cyano, hydroxy, carboxy, C C alkylamino, di(C 1 -C 4 alkyl)amino; or R„ι and R 112 together with the linking carbon atom form a C 3 -C 12 cycloalkyl radical. Another preferred nitroxyl radical is of formula XXa, XXb or XXc wherein Q is O or NR 22 0, wherein R 22 o is hydrogen or C C 18 alkyl; R 201 is tertiary C 4 -C 18 alkyl or phenyl, which are unsubstituted or substituted by halogen, OH, COOR 221 or C(O)-R 222 wherein R 21 is hydrogen, a alkali metal atom or C C 18 alkyl and R 222 is C C 18 alkyl; or R 201 is C 5 -C 12 cycloalkyl, C 5 -C 12 cycloalkyl which is interrupted by at least one O or N atom, a polycyclic alkyl radical or a polycyclic alkyl radical which is interrupted by at least one O or N atom; R 202 and R 203 are independently d-C^alky!, benzyl, C 5 -C 12 cycloalkyl or phenyl, which are unsubstituted or substituted by halogen, OH, COOR 221 or C(0)-R 22 or together with the carbon atom form a C 5 -C 12 cycloalkyl ring; if Y, is O, R 204 and R 212 are OH, O(alkali-metal) d-C 18 alkoxy, benzyloxy, NR223R224, wherein R 223 and R 22 4 are independently from each other hydrogen, C C 18 alkyl or phenyl, which are unsubstituted or substituted by halogen, OH, COOR 22 ι or C(0)-R 222 ; R 204 is OH, Cι-C 18 alkoxy, benzyloxy, 0-C(0)-(d-C 18 )alkyl or NR 22 3 224 ; R212 are a group C(0)R 2 25, wherein R 2 5 is OH, C C 18 alkoxy, benzyloxy, NR 22 3R 22 4, wherein R 223 and R 224 are independently from each other hydrogen, d-C 18 alkyl or phenyl, which are unsubstituted or substituted by halogen, OH, COOR 22 ι or C(O)-R 2 2; R 2 05, R 2 06, R 20 7 and R 208 are independently of each other d-C 18 alkyl, C 5 -C 12 cycloalykyl or phenyl; or R 205 and R 2 o 6 and/or R 20 7 and R 208 together with the carbon atom form a C 5 -C 12 cycloalkyl ring; R 209 and R 2 ιo are independently of each other hydrogen, formyl, C 2 -C 18 alkylcarbonyl, benzoyl, d-C 18 alkyl, C 5 -C 12 cycloalkyl, C 5 -Cι 2 cycloalkyl which is interrupted by at least one O or N atom, benzyl or phenyl which are unsubstituted or substituted by halogen, OH, COOR 221 or C(0)-R 222 ; R 211 , is formyl, C 2 -C 18 alkylcarbonyl, benzoyl, C r C 18 alkyl, C 5 -C 12 cycloalkyl, C 5 -C 12 cycloalkyl which is interrupted by at least one O or N atom, benzyl or phenyl which are unsubstituted or substituted by halogen, OH, COOR221 or C(O)-R 222 . Still another preferred nitroxyl radical contains a structural element of formula (XXX) (XXX), wherein Gι, G 2 , G 3 , G 4 are independently d-C 6 alkyl or G and G 2 or G 3 and G , or G 1 and G 2 and G 3 and G 4 together form a C 5 -C 12 cycloalkyl group; G 5 , G 6 independently are H, C C 18 alkyl, phenyl, naphthyl or a group COOC C 18 alkyl. More preferred is a nitroxyl radical, wherein the structural element of formula (XXX) is any of formulae A to S wherein G 1 ( G 2 , G 3 and G 4 are independently alkyl of 1 to 4 carbon atoms, or Gπ and G 2 together and G 3 and G 4 together, or G^ and G 2 together or G 3 and G 4 together are pentamethylene; G 5 and G 6 are independently hydrogen or d-C 4 alkyl; R, if m is 1 , is hydrogen, d-C 18 alkyl which is uninterrupted or interrupted by one or more oxygen atoms, cyanoethyl, benzoyl, glycidyl, a monovalent radical of an aliphatic carboxylic acid having 2 to 18 carbon atoms, of a cycloaliphatic carboxylic acid having 7 to 15 carbon atoms, or an α,β-unsaturated carboxylic acid having 3 to 5 carbon atoms or of an aromatic carboxylic acid having 7 to 15 carbon atoms, where each carboxylic acid can be substituted in the aliphatic, cycloaliphatic or aromatic moiety by 1 to 3 -COOZ 12 groups, in which Z 12 is H, C 1 -C 20 alkyl, C 3 - C 12 alkenyl, C 5 -C 7 cycloalkyl, phenyl or benzyl; or R is a monovalent radical of a carbamic acid or phosphorus-containing acid or a monovalent silyl radical; R, if m is 2, is C 2 -Cι 2 alkylene, C 4 -C 12 alkenylene, xylylene, a divalent radical of an aliphatic dicarboxyiic acid having 2 to 36 carbon atoms, or a cycloaliphatic or aromatic dicarboxyiic acid having 8-14 carbon atoms or of an aliphatic, cycloaliphatic or aromatic dicarbamic acid having 8-14 carbon atoms, where each dicarboxyiic acid may be substituted in the aliphatic, cycloaliphatic or aromatic moiety by one or two -COOZ 1 groups; or R is a divalent radical of a phosphorus-containing acid or a divalent silyl radical; R, if m is 3, is a trivalent radical of an aliphatic, cycloaliphatic or aromatic tricarboxylic acid, which may be substituted in the aliphatic, cycloaliphatic or aromatic moiety by -COOZ 1 , of an aromatic tricarbamic acid or of a phosphorus-containing acid, or is a trivalent silyl radical, R, if m is 4, is a tetravalent radical of an aliphatic, cycloaliphatic or aromatic tetracarboxylic acid; p is 1 , 2 or 3, Ri is d-C 12 alkyl, C 5 -C 7 cycloalkyl, C 7 -C 8 aralkyl, C 2 -C 18 alkanoyl, C 3 -C 5 alkenoyl or benzoyl; when p is 1 , R is d-C 18 alkyl, C 5 -C 7 cycloalkyl, C 2 -C 8 alkenyl unsubstituted or substituted by a cyano, carbonyl or carbamide group, or is glycidyl, a group of the formula -CH 2 CH(OH)-Z or of the formula -CO-Z- or -CONH-Z wherein Z is hydrogen, methyl or phenyl; or when p is 2, R 2 is C 2 -C 12 alkylene, C 6 -C 12 -arylene, xylylene, a -CH 2 CH(OH)CH2-O-B-O-CH 2 CH(OH)CH2- group, wherein B is C -C 10 alkylene, C 6 -C 15 arylene or C 6 -C 12 cycloalkylene; or, provided that Rj is not alkanoyl, alkenoyl or benzoyl, R can also be a divalent acyl radical of an aliphatic, cycloaliphatic or aromatic dicarboxyiic acid or dicarbamic acid, or can be the group -CO-; or Rt and R 2 together when p is 1 can be the cyclic acyl radical of an aliphatic or aromatic 1 ,2- or 1 ,3- dicarboxylic acid; or R 2 is a group where T 7 and T 8 are independently hydrogen, alkyl of 1 to 18 carbon atoms, or T 7 and T 8 together are alkylene of 4 to 6 carbon atoms or 3-oxapentamethylene; when p is 3, R 2 is 2,4,6-triazinyl; when n is 1 , R 3 is C 2 -C 8 alkylene or hydroxyalkylene or C 4 -C 22 acyloxyalkylene; or when n is 2, when n is 1 , R 4 is hydrogen, CrC 12 alkyl, C 3 -C 5 alkenyl, C 7 -C 9 aralkyl, C 5 -C 7 cycloalkyl, C 2 -C 4 hydroxyalkyl, C 2 - C 6 -alkoxyalkyl, C 6 -C 10 -aryl, glycidyl, a group of formula -(CH 2 ) m -COO-Q or of the formula - (CH 2 ) m -O-CO-Q wherein m is 1 or 2 and Q is C C -alkyl or phenyl; or when n is 2, R 4 is C 2 -C 12 alkylene, C 6 -C 12 -arylene, a group -CH 2 CH(OH)CH 2 -O-D-O-CH 2 CH(OH)CH 2 - wherein D is C 2 -C 10 alkylene, C 6 -C 15 arylene or C 6 -C 12 cycloalkylene, or a group - CH 2 CH(OZ 1 )CH 2 -(OCH 2 CH(OZ 1 )CH 2 ) 2 - wherein Z is hydrogen, d-C 18 alkyl, allyl, benzyl, C 2 - C 12 alkanoyl or benzoyl; R 5 is hydrogen, d-C 12 alkyi, allyl, benzyl, glycidyl or C 2 -C 6 alkoxyalkyl; Q, is -N(R 7 )- or -O-; E is C C 3 alkylene, the group -CH 2 CH(R 8 )-O- wherein R 8 is hydrogen, methyl or phenyl, the group -(CH 2 ) 3 -NH- or a direct bond; R 7 is C C 18 alkyl, C 5 -C 7 -ycloalkyl, C 7 -C 12 aralkyl, cyanoethyl, C 6 -C 10 aryl, the group -CH CH(R 8 )- OH; or a group of the formula or a group of the formula wherein G is C -C 6 alkylene or C 6 -C 12 arylene and R is as defined above; or R 7 is a group -E-CO-NH-CH 2 -OR 6 ; R 6 is hydrogen or d-C 18 alkyl; Formula (F) denotes a recurring structural unit of a oligomer where T is ethylene or 1 ,2- propylene, or is a repeating structural unit derived from an α-olefin copolymer with an alkyl acrylate or methacrylate; k is 2 to 100; and R 10 is hydrogen, d-C 12 alkyl or C C 12 alkoxy; T 2 has the same meaning as R 4 ; T 3 and T 4 are independently alkylene of 2 to 12 carbon atoms, or T 4 is a group T 5 is C 2 -C 22 alkylene, C 5 -C 7 cycloalkylene, d-C 4 alkylenedi(C 5 -C 7 cycloalkylene), phenylene or phenylenedi(C r C alkylene); T 6 is I I I -NH(CH 2 ) a -N(CH 2 ) b -N[(CH 2 ) c -N-] d H where a, b and c are independently 2 or 3, and d is 0 or 1 ; e is 3 or 4; Ei and E 2, being different, are each oxo or imino; E 3 is hydrogen, alkyl of 1 to 30 carbon atoms, phenyl, naphthyl, said phenyl or said naphthyl substituted by chlorine or by alkyl of 1 to 4 carbon atoms, or phenylalkyl of 7 to 12 carbon atoms, or said phenylalkyl substituted by alkyl of 1 to 4 carbon atoms; E 4 is hydrogen, alkyl of 1 to 30 carbon atoms, phenyl, naphthyl or phenylalkyl of 7 to 12 carbon atoms; or E 3 and E 4 together are polymethylene of 4 to 17 carbon atoms, or said polymethylene substituted by up to four alkyl groups of 1 to 4 carbon atoms; and E 6 is an aliphatic or aromatic or aromatic tetravalent radical. Further suitable heterocyclic NO* radicals are for example mentioned in WO 98/30601 or in WO 98/44008, which are incorporated by reference. Alkyl with up to 20 carbon atoms is, for example, methyl, ethyl, n-propyl, n-butyl, sec-butyl, tert- butyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-hexadecyl or n-octadecyl. The alkyl groups may be linear or branched. C 3 -C 18 alkyl which is interrupted by one or more oxygen atoms is preferably derived from ethylene oxide or propylene oxide. C 3 -C 18 alkyl interrupted by at least one O atom is for example -CH 2 -CH 2 -O-CH 2 -CH 3 , -CH 2 -CH 2 - O-CH 3 or -CH 2 -CH 2 -O-CH 2 -CH 2 -CH 2 -0-CH 2 -CH 3 . It is preferably derived from polyethlene glycol. A general description is -((CH 2 ) a -0) b -H/CH 3 , wherein a is a number from 1 to 6 and b is a number from 2 to 10. C 3 -C 12 alkenyl is linear or branched and for example propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, dodecenyl including their isomers. C 3 -C 8 alkynyl is preferably propargyl. C 5 -C 12 cycloalkyl is typically, cyclopentyl, methylcyclopentyl, dimethylcyclopentyl, cyclohexyl, methylcyclohexyl. Cycloalkyl which is interrupted by at least one O or N atom is for example 2-tetrahydropyran-yl, tetrahydrofurane-yl, 1 ,4 dioxan-yl, pyrrolidin-yl, tetrahydrothiophen-yl, pyrazolidin-yl, imidazolidin-yl, butyrolactone-yl, caprolactame-yl Examples for alkali metal are lithium, sodium or potassium. Alkyl substituted by-OH is typically 2-hydroxyethyl, 2-hydroxypropyl or 2-hydroxybutyl. d-C 18 alkoxy is, for example, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, pentoxy, isopentoxy, hexoxy, heptoxy, octoxy, decyloxy, dodecyloxy, tetradecyloxy, hexadecyloxy and octadecyloxy. d-C 18 Alkyl substituted by d-C 8 alkoxy, preferably by C C alkoxy, in particular by methoxy or ethoxy, is typically 2-methoxyethyl, 2-ethoxyethyl, 3-methoxypropyl, 3-ethoxypropyl, 3- butoxypropyl, 3-octoxypropyl and 4-methoxybutyl. d-C 18 Alkyl substituted by di(d-C 4 alkyl)amino is preferably e.g. dimethylamino, diethylamino, 2- dimethylaminoethyi, 2-diethylaminoethyl, 3-dimethylaminopropyl, 3-diethylaminopropyl, 3- dibutylaminopropyl and 4-diethylaminobutyl. C CiβAlkyI substituted by d-C alkylamino is preferably e.g. methylamino, ethylamino, 2- methylaminoethyl, 2-ethylaminoethyl, 3-methylaminopropyl, 3-ethylaminopropyl, 3-butylamino- propyl and 4-ethylaminobutyl. d-C 4 Alkylthio is typically thiomethyl, thioethyl, thiopropyl, thioisopropyl, thiobutyl and thioisobutyl. C 2 -C 18 alkylcarbonyl is for example acetyl, propionyl, butyryl, pentylcarbonyl, hexylcarbonyl or dodecylcarbonyl. C 7 -C 9 phenylalkyl or C 7 -C 9 aralkyl is for example benzyl, phenylethyl, phenylpropyl, α,α- dimethylbenzyl or α-methylbenzyl. Examples of C 2 -C 12 alkylene bridges, preferably of C 2 -C 6 alkylene bridges, are ethylene, propylene, butylene, pentylene, hexylene. C 2 -C 12 alkylene bridges interrupted by at least one N or O atom are, for example, -CH 2 -O-CH 2 -CH 2 , -CH 2 -O-CH 2 -CH2-CH , -CH2-O-CH2-CH2-CH2-CH2-, -CH 2 -O-CH 2 -CH 2 -O-CH2-, -CH 2 -NH-CH2-CH2, -CH2-NH-CH2-CH2-CH2, -CH 2 -NH-CH 2 -CH 2 -CH 2 -CH 2 -, -CH 2 -NH-CH 2 -CH 2 -NH-CH2- or -CH2-NH-CH 2 -CH 2 -O-CH2-. Examples for C 4 -C 12 cycloalkanone-yl are cyclopentanone-yl, cyclohexanone-yl or cycloheptanone-yl. Phenyl substituted by 1 , 2 or 3 d-C 4 alkyl or d-C 4 alkoxy is typically methylphenyl, dimethyl- phenyl, trimethylphenyl, t-butylphenyl, di-t-butylphenyl, 3,5-di-t-butyl-4-methylphenyl, methoxyphenyl, ethoxyphenyl and butoxyphenyl. Examples of polycyclic cycloaliphatic ring systems are adamantane, cubane, twistane, norbornane, bycyclo[2.2.2]octane or bycyclo[3.2.1 ]octane. An example of a polycyclic heterocycloaliphatic ring system is hexamethylentetramine (urotropine). Examples of monocarboxylic acids with 1 to 18 carbon atoms are formic acid, acetic acid, propionic acid, phenyl acetic acid, cyclohexane carbonic acid, mono-, di- and trichlor-acetic acid or mono-, di- and trifluor-acetic acid. Other suitable acids are benzoic acid, chlor-benzoic acid, methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, chlorbenzenesulfonic acid, trifluormethanesulfonic acid, methylphosphonic acid or phenylphosphonic acid. Examples of a monovalent radical of a carboxylic acid are an acetyl, caproyl, stearoyl, acryloyl, methacryloyl, cyclohexylcarboxylic acid, benzoyl or β-(3,5-di-tert-butyl-4-hydroxyphenyl)- propionyl radical. Further examples are derived from propionic acid, laurinic acid or methyl ethyl acetic acid or the other isomers of valeric acid. Examples of a cycloaliphatic carboxylic acid is for example cyclohexane carboxylic acid or cyclopentane carboxylic acid. An example of an aromatic carboxylic acid is benzoic acid. Typical unsaturated carboxylic acids are acrylic acid, methacrylic acid or crotonic acid. Examples of a monovalent silyl radical are of the formula -(C J H 2) )-Si(Z') 2 Z", in which j is an integer in the range from 2 to 5, and Z' and Z", independently of one another, are C C 4 alkyl or d-C 4 alkoxy. Examples of di-, tri- and tetra valent acids are for example malonyl, succinyl, glutaryl, adipoyl, suberoyl, sebacoyl, maleoyl, itaconyl, phthaloyl, dibutylmalonyl, dibenzylmalonyl, butyl(3,5-di- tert-butyl-4-hydroxybenzyl)malonyl or bicycloheptenedicarbonyl radical or a group of the formula ,trimellitoyl, citryl or nitrilotriacetyl, butane- 1 ,2,3,4-tetracarboxylic acid or pyromellitic acid. Examples of a dicarbamic acid are the hexamethylenedicarbamoyl or 2,4-toluylenedicarbamoyl radicals. C 2 -C 12 alkanoyl is, for example, propionyl, butyryl, octanoyl, dodecanoyl, but preferably acetyl. Hydroxyl-, cyano-, alkoxycarbonyl- or carbamide-substituted alkyl can be, for example, 2- hydroxyethyl, 2-hydroxypropyl, 2-cyanoethyl, methoxycarbonylmethyl, 2-ethoxycarbonylethyl, 2-aminocarbonylpropyl or 2-(dimethylaminocarbonyl)ethyl. Any C 2 -C 12 alkylene radicals are, for example, ethylene, propylene, 2,2-dimethylpropylene, tetramethylene, hexamethylene, octamethylene, decamethylene or dodecamethylene. C -C 1 alkenylene is for example butenylene, pentenylene, hexenylene, heptenylene or nonenylene including their isomers. C 6 -C 12 arylene is, for example, o-, m- or p-phenylene, 1 ,4-naphthylene or 4,4'-diphenyiene. C 4 -C 22 acyloxyalkylene is, for example, 2-ethyl-2-acetoxymethylpropylene. Any C 2 -C 6 alkoxyalkyl substituents are, for example, methoxymethyl, ethoxymethyl, propoxymethyl, tert-butoxymethyl, ethoxyethyl, ethoxypropyl, n-butoxyethyl, tert-butoxyethyl, isopropoxyethyl or propoxypropyl. d-C 18 alkanoyloxy is, for example, formyloxy, acetyloxy, propionyloxy, butyryloxy, valeryloxy, lauroyloxy, paimitoyloxy and stearoyloxy. The nitroxyl radicals of formula (X) are known and may be prepared according to WO 99/03984, EP-A-0891 986 or WO 98/13392. Some typical examples are given below. The nitroxyl radicals of formula XXa, b and c are also known and may be prepared according to European Patent Application No. 98810741.3. Typical examples are given below. The nitroxyl radicals of formula XXX are also known and can be prepared as described in European Patent Application No. 98810531.8. Furthermore DE 26 21 841 , US 4'131 '599 and DE 26 30 798 for example describe the preparation of 2,6-diethyl-2,3,6-trimethyl-4-oxopiperidine and 2,6-dipropyl-3-ethyl-2,6-dimethyl- 4-oxo-piperidine, which are intermediates for the corresponding 1-oxo compounds. . Another method for the preparation of 2,2-dimethyl-6,6-dialkyl-4-oxopiperidine is described by F. Asinger, M. Thiel, H. Baltz, Monatshefte fur Chemie 88, 464 (1957) or by J. Bobbittt et al. in J. Org. Chem. 58, 4837 (1993). The oxidation of the piperidine compound to 1-oxo-piperidine derivatives is well known in the art and for example described by L.B. Volodarsky, V. A. Reznikov, V.I. Ovcharenko in Synthetic Chemistry of Stable Nitroxides, CRC Press, Boca Raton 1994. The tetramethylpiperidine precursors are partially commercially available or can be prepared according to known methods. For example US 5 096 950 and the documents cited therein describe the preparation of the precursors. The oxidation process can be done as described above. Examples are given below. Preferably G 1 ? G 2 , G 3 and G are methyl or ethyl and G 5 and G 6 are hydrogen or methyl. More Preferably Gj, G 2 , G 3 and G 4 are methyl and G 5 and G 6 are hydrogen. Another preferred group of compounds are those wherein G^ and G 3 are ethyl and G 2 and G 4 are methyl, or G*, and G 4 are ethyl and G 2 and G 3 are methyl, and one of G 5 or G 6 is hydrogen and the other methyl or both are hydrogen. A preferred subgroup are compounds of the structural formulae A, B, O or P, wherein m is 1 , R is hydrogen, C r C 18 alkyl which is uninterrupted or interrupted by one or more oxygen atoms, cyanoethyl, benzoyl, glycidyl, a monovalent radical of an aliphatic carboxylic acid having 2 to 18 carbon atoms, of a cycloaliphatic carboxylic acid having 7 to 15 carbon atoms, or an α,β- unsaturated carboxylic acid having 3 to 5 carbon atoms or of an aromatic carboxylic acid having 7 to 15 carbon atoms; p is l ; R T is d-C 12 alkyl, C 5 -C 7 cycloalkyl, C 7 -C 8 aralkyl, C 2 -C 18 alkanoyl, C 3 -C 5 alkenoyl or benzoyl; R 2 is C C 18 alkyl, C 5 -C 7 cycloalkyl, C 2 -C 8 alkenyl unsubstituted or substituted by a cyano, carbonyl or carbamide group, or is glycidyl, a group of the formula -CH 2 CH(OH)-Z or of the formula -CO-Z or -CONH-Z wherein Z is hydrogen, methyl or phenyl. More preferred are those of structure A or B. Preferably R is hydrogen, C C 18 alkyl, cyanoethyl, benzoyl, glycidyl, a monovalent radical of an aliphatic carboxylic acid, having 2 to 18 carbon atoms; Ri is d-C 12 alkyl, C 7 -C 8 aralkyl, C 2 -C 18 alkanoyl, C 3 -C 5 alkenoyl or benzoyl; R 2 is d-C 18 alkyl, glycidyl, a group of the formula -CH 2 CH(OH)-Z or of the formula -CO-Z, wherein Z is hydrogen, methyl or phenyl. Another preferred subgroup is wherein the stable nitroxyl radical is a compound of formula (X), R 10 ι is cyano; R 102 and R 103 are each independently of one another unsubstituted d -C 12 alkyl or phenyl; or R 102 and R 103 , together with the linking carbon atom, form a C 5 -C 7 cycloalkyl radical; R 110 is C 4 -C 12 alkyl bound via a tertiary C-atom to the nitrogen atom, C 9 -Cnphenylalkyl or phenyl; or R 110 and R,,, together form a C 2 -C 6 alkylene bridge which is unsubstituted or substituted with d-C 4 alkyl; and R112 is Cι-C 4 alkyl. A further preferred subgroup is wherein the stable nitroxyl radical is a compound of formula (XXa), Y is O; R 20 ι is tertiary C 4 -C 8 alkyl; R 202 and R 203 are methyl, ethyl or together with the carbon atom form a C 5 -C 6 cycloalkyl ring; R 20 4 is Cι-C 18 alkoxy, benzyloxy or R 22 3R22 4 , wherein R 2 3 and R 224 are independently of each other hydrogen or C C 8 alkyl; or of formula (XXb), wherein Q^ is O; R205. R 2 06. R207 and R 2 o8 are independently of each other methyl or ethyl; or R205 and R 2 o6 and/or R 207 and R 208 together with the carbon atom form a C 5 -C 6 cycloalkyl ring; R 209 and R210 are independently of each other formyl, C 2 -C 8 alkylcarbonyl, benzoyl, C r C 8 alkyl, benzyl or phenyl; or of formula (XXc), wherein Y^ is O; R 2 05, R 2 06, R207 and R 208 are independently of each other methyl or ethyl; or R205 and R206 and/or R 207 and R 208 together with the carbon atom form a C 5 -C 6 cycloalkyl ring; R 211 is formyl, C 2 -C 18 alkylcarbonyl, benzoyl, d-C 18 alkyl, benzyl or phenyl and R212 is OH, C C 18 alkoxy, benzyloxy, NR 22 3R22 4 , wherein R223 and R 224 are independently of each other hydrogen or d-C 18 alkyl. Preferably the polymer to be grafted on contains unsaturated moieties selected from the group consisting of polydienes, co-, block-, random- and tapered polymers of styrene, terpolymers with diolefins and copolymers with diolefins. Preferred unsaturated polymers are polybutadiene, polyisoprene, styrene-isoprene-block- copolymers (SI, SIS), styrene-butadiene-block-copoiymers (SB, SBS, SEBS), ABS, EPDM, butyl rubber, chloroprene rubber and nitrile rubber having a content of unsaturated repeating units from 0.1 to 85%. Mostly preferred are SB, SBS, EPDM having a content of unsaturated repeating units from 1 to 70%. Preferably the ethylenically unsaturated monomer or oligomer is selected from the group consisting of styrene, substituted styrene, conjugated dienes, maleic acid anhydride, acroiein, vinyl acetate, (alkyl)acrylic acidanhydrides, (alkyl)acrylic acid salts, (alkyl)acrylic esters or (alkyl)acrylamides. More preferably the ethylenically unsaturated monomer is styrene, α-methyl styrene, p-methyl styrene or a compound of formula CH 2 =-C(R a )-(C=Z)-R b , wherein R a is hydrogen or C 1 -C 4 alkyl, R b is NH 2 , OCH 3 , glycidyl, unsubstituted d-C 18 alkoxy or hydroxy-substituted C C 18 alkoxy, unsubstituted d-C 18 alkylamino, di(C 1 -C 18 alkyl)amino, hydroxy-substituted C C 18 alkylamino or hydroxy-substituted di(CrC 18 alkyl)amino; Me is a monovalent metal atom Z is oxygen or sulfur. Most preferably R a is hydrogen or methyl, R b is NH 2 , gycidyl, unsubstituted or with hydroxy substituted d-C 4 alkoxy, unsubstituted d-C 4 alkylamino, di(C 1 -C alkyl)amino, hydroxy- substituted d-C 4 alkylamino or hydroxy-substituted di(C C 4 alkyl)amino;and Z is oxygen. Specifically preferred ethylenically unsaturated monomers are methylacrylate, ethylacrylate, butylacrylate, isobutylacrylate, tert. butylacrylate, hydroxyethylacryiate, hydroxypropylacrylate, dimethylaminoethylacrylate, glycidylacrylates, methyl(meth)acrylate, ethyl(meth)acrylate, butyl(meth)acrylate, hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, dimethylaminoethyl(meth)acrylate, glycidyl(meth)acrylates, acrylonitnle, acrylamide or methacrylamide. The temperature applied in the first reaction step depends on the polymer and is for example 50° to 150° C above the glass transition temperature (Tg) for amorphous polymers and 20° to 180° C above the melting temperature (Tm) for semi-crystalline polymers. Typical are following temperatures: low density polyethylene LDPE 170-260° C high density polyethylene HDPE 180-270° C polypropylene PP 180-280° C polystyrene PS 190-280° C styrene-block copolymers SB(S) 180-260° C ethylene-propylene-diene modified EPDM 180-260° C ethylene propylene rubber EPR 180-260° C In a preferred process the temperature in the first step A) is from 150° C to 300° C, more preferred from 170° C to 280° C. Preferably the temperature in the second step B) is from 70° to 280° C, more preferably from 70° to 210° C. Preferably the stable nitroxyl radical is present in an amount from 0.1 % to 30%, more preferably in an amount from 0.1 % to 20% and most preferably in an amount from 0.5% to 10% based on the weight of the polymer. Preferably the weight ratio of the reaction product of step A) to the ethylenically unsaturated monomer or oligomer added in step B) is from 1 :1000 to 10:1 , more preferably from 1 :100 to 1 :1 and most preferably from 1 :50 to 1 :1. Step A) of the process may be performed in any reactor suitable for mixing a polymer melt. Preferably the reactor is an extruder or kneading apparatus as for example described in "Handbuch der Kunststoffextrusion" Vol. I, editor F. Hensen, W. Knappe and H. Potente, 1989, pages 3-7. If an extruder is used the process may be described as reactive extrusion process. Examples of reactiv extrusion equipment and processes are given by G. H. Hu et al., in "Reactive Modifiers for Polymers", first edition, Blackie Academic & Professional an Imprint of Chapman & Hall, London 1997, chapter 1 , pages 1-97. Preferably, if an extruder is used, a reduced pressure of less than 200 mbar is applied during extrusion. Volatile by products may be removed thereby. The reaction time for step A) depends on the desired amount of grafted ONR'R" initiator moieties. Typical reaction times are from a few minutes to an hour. Preferably the reaction time is from 1 min to 1 h, most preferably from 2 min to 20 min. The reaction step B) may be performed immediately after step A), however it is also possible to store the intermediate polymeric radical initiator at room temperature for some time. The intermediate polymeric radical initiator is stable at room temperature and no loss of activity occurs up to several months. The reaction step B) may be performed in any reactor suitable for mixing a polymer melt with a monomer. It is also possible to dissolve or disperse the polymer and to add the monomer to the solution. The process B) may thus optionally be performed in solution. The degree of grafting depends on the reaction time, on the temperature used and the activity of the polymeric initiator. Preferably the reaction time for step B) is from 1 min to 20 hours, more preferably from 30 min to 5 hours. If the reaction step B) is performed in an extruder, a reaction time of 2 to 20 minutes is preferred. The grafted polymers are useful in many applications such as compatibilizers in polymer blends or alloys, adhesion promoters between two different substrates, surface modification agents, nucleating agents, coupling agents between filler and polymer matrix or dispersing agents. The process is particularly useful for the preparation of grafted block copolymers. Grafted block copolymers are, for example, grafted block copolymers of polystyrene and polyacrylate (e.g., poly(styrene-co-acrylate) or poly(styrene-co-acrylate-co-styrene). They are usefull as adhesives or as compatibilizers for polymer blends or as polymer toughening agents. Poly(methylmethacrylate-co- acrylate) diblock graft copolymers or poly(methylacrylate-co- acrylate-co-methacrylate) thblock graft copolymers are useful as dispersing agents for coating systems, as coating additives (e.g. rheological agents, compatibilizers, reactive diluents) or as resin component in coatings(e.g. high solid paints). Graft block copolymers of styrene, (meth)acrylates and/or acrylonitrile are useful for plastics, elastomers and adhesives. Furthermore, graft block copolymers of this invention, wherein the grafted blocks have polar monomers on a non polar polymer are useful in many applications as amphiphilic surfactants or dispersants for preparing highly uniform polymer blends. Thus, the present invention also encompasses in the synthesis novel graft block, multi-block, star, gradient, random, hyperbranched and dendritic copolymers. The polymers prepared by the present invention are particularly useful for following applications: adhesives, detergents, dispersants, emulsifiers, surfactants, defoamers, adhesion promoters, corrosion inhibitors, viscosity improvers, lubricants, rheology modifiers, thickeners, crosslinkers, paper treatment, water treatment, electronic materials, paints, coatings, photography, ink materials, imaging materials, superabsorbants, cosmetics, hair products, preservatives, biocide materials or modifiers for asphalt, leather, textiles, ceramics and wood. Because the present graft polymerizaton is a "living" polymerization, it can be started and stopped practically at will. Furthermore, the polymer product retains the functional alkoxyamine group allowing a continuation of the polymerization in a living matter. Thus, in one embodiment of this invention, once the first monomer is consumed in the initial polymerizing step a second monomer can then be added to form a second block on the growing graft polymer chain in a second polymerization step. Therefore it is possible to carry out additional graft polymerizations with the same or different monomer(s) to prepare multi-block graft copolymers. Furthermore, since this is a living radical polymerization, graft blocks can be prepared in essentially any order Consequently further subjects of the present invention are a polymeric radical initiator prepared according to step A) of the process without an additional free radical source and a polymeric radical initiator prepared according to step A) of the process with an additional free radical source. The polymeric radical initiator obtainable by step A) of the above process is schematically represented in formula (P1) (P1 ), wherein R 498 is hydrogen, substituted or unsubstituted d-C 18 alkyl, C 2 -C 18 alkenyl, C 2 -d 8 alkιnyl; C 3 - docycloalkyl or C 3 -C 12 cycloalkyl containing at least one nitrogen or oxygen atom or C 3 - C 12 cycloalkyl containing at least one nitrogen or oxygen atom, which are substituted by NO 2 , halogen, ammo, hydroxy, cyano, carboxy; d-C 4 alkoxy, d-C 4 alkylthιo, Cι-C alkylamιno or dι(d- C 4 alkyl)amιno, 0(C C 18 alkyl), O(C 2 -C 18 alkeny), C 7 -Cnphenylalkyl, O-phenyl, OC 7 -C 9 phenylalkyl or halogen or phenyl and naphthyl which are unsubstituted or substituted by C C 4 alkyl, d- dalkoxy, d-C 4 alkylthιo, halogen, cyano, hydroxy, carboxy, d-C 4 alkylamιno or dι(d- C 4 alkyl)amιno, R 499 is the stable nitroxyl radical, bound at the oxygen atom; R 500 is substituted or unsubstituted d-C 18 alkyl, C 2 -d 8 alkenyl, C 3 -C 20 cycloalkyl, phenyl, C 7 - Cnphenylalkyl; R50 1 is hydrogen, substituted or unsubstituted d-C 18 alkyl, C 2 -C 18 alkenyl, C 2 -C 18 alkιnyl, C 3 - C 20 cycloalkyl, phenyl, O(d-C 18 alkyl), O(C 2 -C 18 alkeny), C 7 -Cnphenylalkyl, O-phenyl, O- C 7 - C 9 phenylalkyl or halogen, CN, COOR 500 , CONR 50 oR 5 oo, Q5 IS CR502R5031 (CR502R503)n, C≡CR 508 R509, (C≡CR 508 R 5 o9)n, O, C=O, N R510, NR 51 1 -C=0, 0-C(O)-0, S0 2 , S, S1R512R513, O- R502, R503, R504, R505, Rsoe, R507, Rsos, R509, R510. R511. R512 and R513 independently of each other are hydrogen, substituted or unsubstituted d-C 18 alkyl, C 2 -C 18 alkenyl, C 2 -C 18 alkιnyl, C 3 - C 7 cycloalkyl, phenyl, 0(d-C 18 alkyl), 0(C 2 -C 18 alkeny), C 7 -dιPhenylalkyl, O-phenyl, O- C 7 - C 9 phenylalkyl or halogen, n is a number from 1 to 10, y is a number from 1 to 25000 and; z is a number from 0 to 25000. Preferably R 501 is H or methyl; Q 5 is CR502R503, CH=CH 2 , CRso^CRsosCRsoeRsc^, wherein R 502 and R 503 is H, methyl or C 2 -C 9 alkenyl and R 50 , R505, 506 and R 507 are independently H or methyl. Examples for the different substituents have been already given. Within this selection polyethylene, polypropylene and polybutadiene, SBS and EPDM are especially preferred. A further subject of the invention is a polymer of formula (P2) obtainable by step B) of the above process. Definitions and examples of the substituents are as given above; Q 6 is a homo-, co- or tapered polymer resulting from the monomers as described above, t is a number from 0 to 25000. R 49 g may be removed thermally or chemically. Preferably the polymer (P2) is grafted with a monomer selected from the groups described above and more preferably with styrenes, (meth)acrylates, butadiene, isoprene. Most preferred are SB-gr-styrenes, SB-c-(meth)acrylates, Sl-g-styrenes, Sl- 7-(meth)acrylates, SBS-g-styrenes, SBS-o/-(meth)acrylates, EPDM-g-styrenes, EPDM- ;-(meth)acrylates. Still a further subject is a polymer obtainable by step A) and B) of the process as defined above. Yet another subject of the present invention is a composition comprising a) a polymeric radical initiator prepared according to step A) as defined above optionally the preparation being done in the presence of a free radical source and b) an ethylenically unsaturated monomer or oligomer. Examples for the different substituents and their preferences are already given, they apply also for the other subjects of the invention. Further subjects are the use of a stable nitroxyl radical for the preparation of a grafted polymer as defined above and the use of a grafted polymer according to step A) as defined above, as macroinitiator for radical polymerization. Also subject of the present invention is the use of the polymer prepared according to the process as defined above, as adhesive or compatibilizer for polymer blends or as polymer toughening agents. Poly(methylmethacrylate-co- acrylate) diblock graft copolymers or poly(methylacrylate-co- acrylate-co-methacrylate) triblock graft copolymers are useful as dispersing agents for coating systems, as coating additives (e.g. rheological agents, compatibilizers, reactive diluents) or as resin component in coatings(e.g. high solid paints). Graft block copolymers of styrene, (meth)acryiates and/or acrylonitrile are useful for plastics, elastomers and adhesives. Furthermore, graft block copolymers of this invention, wherein the grafted blocks have polar monomers on a non polar polymer are useful in many applications as amphiphilic surfactants or dispersants for preparing highly uniform polymer blends. The following examples illustrate the invention. A) Grafting of R'R"N-O* to the polymer (preparation of a polymeric initiator) In a Brabender mixer chamber W50 (40 rpm) heated to 180 - 220° C, 36.6 g of a commercially available polypropylene (MFR230/2J 6 = 1 - 43 according to ISO 1133) are kneaded under N2 for 10 min. The additives (Table 1 ) are introduced into the mixer chamber right at the beginning, together with the polypropylene. After 10 min the mixing is stopped. The polymer material is removed from the mixer chamber, compression molded at 30° C at about 50 kN for 1 min and comminuted into granules. The granulated polymer is dissolved, reprecipitated and high temperature NMR spectra are taken to determine whether polymer bound NO-moieties are present. Table 1 Grafting of R'R"N-O * to polypropylene compound 1 : benzoic acid 2,2,6, 6-tetramethyl-piperidin-1-oxyl-4-yl ester compound 2: 4-hydroy-2,2,6,6-tetramethyl-piperidin-1-oxyl peroxide 1 : dicumylperoxide B) Grafting of R'R"N-O * to the polymer and subseguent polvmernalogous reaction Commercially available polymers (SBS = styrene/butadiene/styrene copolymer, Kraton D 1102 CU, supplier: Shell; SEBS = styrene/ethylene/butadiene/styrene copolymer Kraton G 1652, supplier: Shell; EPDM = ethylene/propylene/ethylidenenorbomene terpolymer, Buna EP G 3850, supplier: Bayer) are extruded together with the compounds given in Table 2 in a twin screw extruder (TW 100 of Haake, Germany) at 180 - 210° C (heating zones 1 -5) and 40 rpm. In an evacuated Schlenk reactor, purged with argon, 5 g of the granulated polymer is dissolved in 50 - 100 mL monomer under argon atmosphere. Dissolved oxygen is removed in freeze- thaw-cycles (liquid nitrogen). The reaction mixture is stirred and heated under argon atmosphere. Remaining monomer is removed under vacuum and the residue is dried under vacuum until constant weight is achieved. Molecular weights and molecular weight distributions are determined by gel permeation chromatograpgy (GPC). The results are shown in Table 3. Table 2 Grafting of R'R"N-O * to the polymer compound 4: decanedioic acid bis(2,2,6,6-tetramethyl-pipehdin-1 -oxyl-4-yl) ester compound 5: dodecanoic acid 2,6-diethyl-2,3,6-trimethyl-piperidin-1-oxyl-4-yl ester *bimodal distribution; peak molecular weight (Mp) from high MW peak Table 3 Polvmeranalogous reactions

Claims: Claims 1. A process for the preparation of a grafted polymer wherein in a first step A) a stable nitroxyl radical is grafted onto a polymer, which step comprises heating a polymer and a stable nitroxyl radical (NO»); and in a second step B) the grafted polymer of step A) is heated in the presence of an ethylenically unsaturated monomer or oligomer to a temperature at which cleavage of the nitroxyl-polymer bond occurs and polymerization of the ethylenically unsaturated monomer or oligomer is initiated at the polymer radical; maintaining said temperature for further polymerization and afterwards cooling down the mixture to a temperature below 60° C. 2. A process according to claim 1 , wherein a free radical source is additionally present. 3. A process according to claim 2, wherein the free radical source is a bis-azo compound, a peroxide or a hydroperoxide. 4. A process according to claim 3 wherein the free radical source is 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methyl-butyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(4-methoxy- 2,4-dimethylvaleronitrile), 1 ,1 '-azobis(1-cyclohexanecarbonitrile), 2,2'-azobis(isobutyramide) dihydrate, 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile, dimethyl-2,2'-azobisisobutyrate, 2- (carbamoylazo)isobutyronitrile, 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis(2- methylpropane), 2,2'-azobis(N,N'-dimethyleneisobutyramidine), free base or hydrochloride, 2,2'- azobis(2-amidinopropane), free base or hydrochloride, 2,2'-azobis{2-methyl-N-[1 ,1 - bis(hydroxymethyl)ethyl]propionamide} or 2,2'-azobis{2-methyl-N-[1 ,1-bis(hydroxymethyl)-2- hydroxyethyljpropionamide; acetyl cyclohexane sulphonyl peroxide, diisopropyl peroxy dicarbonate, t-amyl perneodecanoate, t-butyl perneodecanoate, t-butyl perpivalate, t-amylperpivalate, bis(2,4- dichlorobenzoyl)peroxide, diisononanoyl peroxide, didecanoyl peroxide, dioctanoyl peroxide, dilauroyl peroxide, bis (2-methylbenzoyl) peroxide, disuccinic acid peroxide, diacetyl peroxide, dibenzoyl peroxide, t-butyl per 2-ethylhexanoate, bis-(4-chlorobenzoyl)-peroxide, t-butyl perisobutyrate, t-butyl permaleinate, 1 ,1 -bis(t-butylperoxy)3,5,5-thmethylcyclohexane, 1 ,1 -bis(t- butylperoxy)cyclohexane, t-butyl peroxy isopropyl carbonate, t-butyl perisononaoate, 2,5- dimethylhexane 2,5-dibenzoate, t-butyl peracetate, t-amyl perbenzoate, t-butyl perbenzoate, 2,2-bis (t-butylperoxy) butane, 2,2 bis (t-butylperoxy) propane, dicumyl peroxide, 2,5- dimethylhexane-2,5-di-t-butylperoxide, 3-t-butylperoxy 3-phenylphthalide, di-t-amyl peroxide, α, α'-bis(t-butylperoxy isopropyl) benzene, 3,5-bis (t-butylperoxy)3,5-dimethyl 1 ,2-dioxolane, di-t- butyl peroxide, 2,5-dimethylhexyne-2,5-di-t-butylperoxide, 3,3,6,6,9,9-hexamethyl 1 ,2,4,5- tetraoxa cyclononane, p-menthane hydroperoxide, pinane hydroperoxide, diisopropylbenzene mono-α-hydroperoxide, cumene hydroperoxide or t-butyl hydroperoxide. 5. A process according to claim 1 wherein the polymer is polyethylene, polypropylene, polystyrene, a styrene block-copolymer, polybutadiene, polyisoprene, EPDM (ethylene- propylene diene monomer) or EPR (ethylene-propylene rubber). 6. A process according to claim 1 , wherein the stable free nitroxyl radical is a compound of formula (X) wherein nj is 0 or 1 Rιoι > R 1 0 2 , R 103 are each independently of one another hydrogen, halogen, NO 2 , cyano, -CONR 105 R 106 , -(Rιo 9 )COOR 10 , -C(O)-R 107 , -OR 108 , -SR 108 , -NHR 108 , -N(R 108 ) 2 , carbamoyl, di(C C 18 alkyl)carbamoyl, -C(=NR 10 5)(NHR 10 6); unsubstituted d-C 18 alkyl, C 2 -C 18 alkenyl, C 2 -C 18 alkynyl, C -C 9 phenylalkyl, C 3 -C 12 cycloalkyl or C 3 - Cι 2 cycloalkyl containing at least one nitrogen or oxygen atom; or d-C 18 alkyl, C 2 -C 18 alkenyl, C 2 -C 18 alkynyl, C 7 -C 9 phenylalkyl, C 3 -C 1 cycloalkyl or C 3 -C 12 cycloalkyl containing at least one nitrogen or oxygen atom, which are substituted by NO 2 , halogen, amino, hydroxy, cyano, carboxy, C C alkoxy, C r C 4 alkylthio, C C 4 alkylamino or di(d-C 4 alkyl)amino; or phenyl, which is unsubstituted or substituted by C C 4 alkyl, C C alkoxy, C C 4 alkylthio, halogen, cyano, hydroxy, carboxy, C C alkylamino or di(C C 4 alkyl)amino; or R 102 and R 103 , together with the linking carbon atom, form a C 3 -C 12 cycloalkyl radical, a (C 4 - C 12 cycloalkanon)-yl radical or a C 3 -C 12 cycloalkyl radical containing at least one O atom and/or a NR 108 group; or if n^ is 1 R 1 R 104 is hydrogen, C C 18 alkyl, phenyl, an alkali metal cation or a tetraalkylammonium cation; R 105 and Rιoβ are hydrogen, d-C 18 alkyl, C 2 -C 18 alkyl which is substituted by at least one hydroxy group or, taken together, form a C 2 -C 12 alkylene bridge or a C 2 -C l2 -alkylene bridge interrupted by at least one O or/and NRι 08 atom; Ri 07 is hydrogen, d-C 18 aikyl or phenyl; R 108 is hydrogen, C C 18 alkyl or C 2 -C 18 alkyl which is substituted by at least one hydroxy group; R 109 is d-C 12 alkylen or a direct bond; Rno is C 4 -C 18 alkyl bound via a tertiary C-atom to the nitrogen atom, Cg-Cnphenylalkyl, C 3 - C 12 cycloalkyl or C 3 -C 2 cycloalkyl containing at least one nitrogen or oxygen atom; or C -C 18 alkyl bound via a tertiary C-atom to the nitrogen atom, Cg-Cnphenylalkyl, C 3 -C 12 cycloalkyl or C 3 -C 12 cycloalkyl containing at least one nitrogen or oxygen atom, which are substituted by NO 2 , halogen, amino, hydroxy, cyano, carboxy, d-C 4 alkoxy, C r C 4 alkylthio, d-C alkylamino or di(d-C 4 alkyl)amino; or phenyl, naphthyl, which are unsubstituted or substituted by d-C 4 alkyl, d-C 4 alkoxy, C dalkylthio, halogen, cyano, hydroxy, carboxy, C C alkylamino or di(C 1 -C 4 alkyl)amino; if n, is 1 Rm is Cι-C 18 alkyl, C 7 -C 9 phenylalkyl, C 3 -C 12 cycloalkyl or C 3 -C 12 cycloalkyl containing at least one nitrogen or oxygen atom; or CrCι 8 alkyl, C 7 -C 9 phenylalkyl, C 3 -C 12 cycloalkyl or C 3 -C 12 cycloalkyl containing at least one nitrogen or oxygen atom, which are substituted by NO 2 , halogen, amino, hydroxy, cyano, carboxy, C 1 -C 4 alkoxy, d-C 4 alkylthio, C r C 4 alkylamino or di(C C 4 alkyl)amino; or phenyl, naphthyl, which are unsubstituted or substituted by d-C 4 alkyl, d-C alkoxy, d- C 4 alkylthio, halogen, cyano, hydroxy, carboxy, d-C alkylamino or di(C C 4 alkyl)amino; or a polycyclic cycloaliphatic ring system or a polycyclic cycloaliphatic ring system with at least one di- or trivalent nitrogen atom; or R 110 and Rm together form a C 2 -C 12 alkylene bridge, a C 3 -C 12 alkylen-on bridge or a C 2 - C 12 alkylene bridge which is interrupted by at least one O or N atom, which bridges are unsubstituted or substituted with C C 18 alkyl, hydroxy(d-C 4 )alkyl, phenyl, C 7 -C 9 phenylalkyl, N0 2 , halogen, amino, hydroxy, cyano, carboxy, d-C alkoxy, d-C alkylthio, d-C alkylamino or di(d-C alkyl)amino, Rn 2 is hydrogen, -(R 109 )COOR 10 , cyano, -OR 108 , -SR 108 , -NHR 108 , -N(R 108 ) 2 , -NH-C(O)-R 108 , unsubstituted C C 18 alkyl, C 2 -C 18 alkenyl, C 2 -C 18 alkynyl, C 7 -C 9 phenylalkyl, C 3 -C 12 cycloalkyl or C 3 - Cι 2 cycloalkyl containing at least one nitrogen or oxygen atom; or d-C 18 alkyl, C 2 -C 18 alkenyl, C 2 -C 18 alkynyl, C 7 -C 9 phenylalkyl, C 3 -C 12 cycloalkyl or C 3 -C 12 cycloalkyl containing at least one nitrogen or oxygen atom, which are substituted by NO , halogen, amino, hydroxy, cyano, carboxy, d-C 4 alkoxy, d-C 4 alkylthio, d-C 4 alkylamino or di(C C 4 alkyl)amino; or phenyl, naphthyl, which are unsubstituted or substituted by C r C alkyl, C C 4 alkoxy, C C 4 alkylthio, halogen, cyano, hydroxy, carboxy, C C 4 alkylamino, di(C C alkyl)amino; or Rm and R 112 together with the linking carbon atom form a C 3 -C 12 cycloalkyl radical. 7. A process according to claim 1 wherein the stable nitroxyl radical is a compound of formula XXa, XXb or XXc wherein Q is O or NR 22 o, wherein R 2 o is hydrogen or C r C 18 alkyl; R 201 is tertiary C 4 -C 18 alkyi or phenyl, which are unsubstituted or substituted by halogen, OH, COOR 221 or C(O)-R 222 wherein R 22 ι is hydrogen, a alkali metal atom or d-C 18 alkyl and R 222 is C r C 18 alkyl; or R 201 is C 5 -C 12 cycloalkyl, C 5 -C 12 cycloalkyl which is interrupted by at least one O or N atom, a polycyclic alkyl radical or a polycyclic alkyl radical which is interrupted by at least one O or N atom; R 202 and R 203 are independently d-C 18 alkyl, benzyl, C 5 -C 12 cycloalkyl or phenyl, which are unsubstituted or substituted by halogen, OH, COOR 221 or C(O)-R 222 or together with the carbon atom form a C 5 -C 12 cycloalkyl ring; R 20 and R 2 ι 2 are OH, O(alkali-metal) C C 18 alkoxy, benzyloxy, NR 22 3R 22 , wherein R 223 and R 224 are independently from each other hydrogen, d-C 18 alkyl or phenyl, which are unsubstituted or substituted by halogen, OH, COOR 22 ι or C(O)-R 222 ; if Y, is CH 2) R 204 is OH, C C 18 alkoxy, benzyloxy, O-C(O)-(C r C 18 )alkyl or NR 223 R 224 ; R 212 are a group C(O)R 225 , wherein R 2 5 is OH, C r C 18 alkoxy, benzyloxy, NR 223 R 22 4, wherein R 223 and R 224 are independently from each other hydrogen, d-C 18 alkyl or phenyl, which are unsubstituted or substituted by halogen, OH, COOR 22 ι or C(O)-R 222 ; R 2 05, R 2 06, 2 o 7 and R 2 oβ are independently of each other d-C 18 alkyl, C 5 -C 12 cycloalykyl or phenyl; or R 205 and R 206 and/or R 207 and R 208 together with the carbon atom form a C 5 -C 12 cycloalkyl ring; R 20 g and R 2 ιo are independently of each other hydrogen, formyl, C 2 -C 18 alkylcarbonyl, benzoyl, d-C 18 alkyl, C 5 -C 12 cycloalkyl, C 5 -C 12 cycloalkyl which is interrupted by at least one O or N atom, benzyl or phenyl which are unsubstituted or substituted by halogen, OH, COOR 22 ι or C(O)-R 222 ; R 21 , is formyl, C 2 -C 18 alkylcarbonyl, benzoyl, d-C 18 alkyl, C 5 -C 12 cycloalkyl, C 5 -C 12 cycloalkyl which is interrupted by at least one O or N atom, benzyl or phenyl which are unsubstituted or substituted by halogen, OH, COOR 221 or C(O)-R 2 2 2 . 8. A process according to claim 1 wherein the stable nitroxyl radical contains a structural element of formula (XXX) (XXX), wherein G u G 2 , G 3 , G 4 are independently d-C 6 alkyl or Gi and G or G 3 and G 4 , or G^ and G 2 and G 3 and G 4 together form a C 5 -C 2 cycloalkyl group; G 5 , G 6 independently are H, d-C 18 alkyl, phenyl, naphthyl or a group COOC C 18 alkyl. 9. A process according to claim 8, wherein the compound containing the structural element of formula (XXX) is any of formulae A to S wherein Gi, G 2 , G 3 and G 4 are independently alkyl of 1 to 4 carbon atoms, or Gj and G 2 together and G 3 and G together, or -, and G 2 together or G 3 and G 4 together are pentamethylene; G 5 and G 6 are independently hydrogen or C C 4 alkyl; R, if m is 1 , is hydrogen, CrC 18 alkyl which is uninterrupted or interrupted by one or more oxygen atoms, cyanoethyl, benzoyl, glycidyl, a monovalent radical of an aliphatic carboxylic acid having 2 to 18 carbon atoms, of a cycloaliphatic carboxylic acid having 7 to 15 carbon atoms, or an α,β-unsaturated carboxylic acid having 3 to 5 carbon atoms or of an aromatic carboxylic acid having 7 to 15 carbon atoms, where each carboxylic acid can be substituted in the aliphatic, cycloaliphatic or aromatic moiety by 1 to 3 -COOZ 12 groups, in which Z 12 is H, Cι-C 20 alkyl, C 3 - C 12 alkenyl, C 5 -C 7 cycloalkyl, phenyl or benzyl; or R is a monovalent radical of a carbamic acid or phosphorus-containing acid or a monovalent silyl radical; R, if m is 2, is C 2 -C 1 alkylene, C -C 12 alkenylene, xylylene, a divalent radical of an aliphatic dicarboxyiic acid having 2 to 36 carbon atoms, or a cycloaliphatic or aromatic dicarboxyiic acid having 8-14 carbon atoms or of an aliphatic, cycloaliphatic or aromatic dicarbamic acid having 8-14 carbon atoms, where each dicarboxyiic acid may be substituted in the aliphatic, cycloaliphatic or aromatic moiety by one or two -COOZ 12 groups; or R is a divalent radical of a phosphorus-containing acid or a divalent silyl radical; R, if m is 3, is a trivalent radical of an aliphatic, cycloaliphatic or aromatic tricarboxylic acid, which may be substituted in the aliphatic, cycloaliphatic or aromatic moiety by -COOZ 12 , of an aromatic tricarbamic acid or of a phosphorus-containing acid, or is a trivalent silyl radical, R, if m is 4, is a tetravalent radical of an aliphatic, cycloaliphatic or aromatic tetracarboxylic acid; p is 1 , 2 or 3, Ri is d-C 12 alkyl, C 5 -C 7 cycloalkyl, C 7 -C 8 aralkyl, C 2 -C 18 alkanoyl, C 3 -C 5 alkenoyl or benzoyl; when p is 1 , R 2 is d-C 18 alkyl, C 5 -C 7 cycloalkyl, C 2 -C 8 alkenyl unsubstituted or substituted by a cyano, carbonyl or carbamide group, or is glycidyl, a group of the formula -CH CH(OH)-Z or of the formula -CO-Z- or -CONH-Z wherein Z is hydrogen, methyl or phenyl; or when p is 2, R 2 is C 2 -C 12 alkylene, C 6 -C 12 -arylene, xylylene, a -CH 2 CH(OH)CH 2 -O-B-O-CH 2 CH(OH)CH 2 - group, wherein B is C 2 -C 10 alkylene, C 6 -C 15 arylene or C 6 -C 12 cycloalkylene; or, provided that R, is not alkanoyl, alkenoyl or benzoyl, R 2 can also be a divalent acyl radical of an aliphatic, cycloaliphatic or aromatic dicarboxyiic acid or dicarbamic acid, or can be the group -CO-; or R^ and R 2 together when p is 1 can be the cyclic acyl radical of an aliphatic or aromatic 1 ,2- or 1 ,3- dicarboxylic acid; or R 2 is a group where T 7 and T 8 are independently hydrogen, alkyl of 1 to 18 carbon atoms, or T 7 and T 8 together are alkylene of 4 to 6 carbon atoms or 3-oxapentamethylene; when p is 3, R 2 is 2,4,6-thazinyl; when n is 1 , R 3 is C 2 -C 8 alkylene or hydroxyalkylene or C -C 2 acyloxyalkylene; or when n is 2, when n is 1 , R 4 is hydrogen, d-C 12 alkyl, C 3 -C 5 alkenyl, C 7 -C 9 aralkyl, C 5 -C 7 cycloalkyl, C 2 -C 4 hydroxyalkyl, C 2 - C 6 -alkoxyalkyI, C 6 -C 10 -aryl, glycidyl, a group of formula -(CH 2 ) m -COO-Q or of the formula - (CH 2 ) m -O-CO-Q wherein m is 1 or 2 and Q is d-C 4 -alkyl or phenyl; or when n is 2, R 4 is C 2 -C 12 alkylene, C 6 -C 12 -arylene, a group -CH 2 CH(OH)CH2-O-D-O-CH 2 CH(OH)CH 2 - wherein D is C 2 -C 10 alkylene, C 6 -Cι 5 arylene or C 6 -d 2 cycloalkylene, or a group - CH 2 CH(OZ 1 )CH 2 -(OCH 2 CH(OZ 1 )CH2)2- wherein Z is hydrogen, d-C 18 alkyl, allyl, benzyl, C 2 - C 12 alkanoyl or benzoyl; R 5 is hydrogen, d-C 12 alkyl, allyl, benzyl, glycidyl or C 2 -C 6 alkoxyalkyl; Q T is -N(R 7 )- or -O-; E is C r C 3 alkylene, the group -CH 2 CH(R 8 )-O- wherein R 8 is hydrogen, methyl or phenyl, the group -(CH 2 ) 3 -NH- or a direct bond; R 7 is d-C 18 alkyl, C 5 -C 7 -ycloalkyl, C 7 -C 12 aralkyl, cyanoethyl, C 6 -C 10 aryl, the group -CH 2 CH(R 8 )- OH; or a group of the formula or a group of the formula wherein G is C 2 -C 6 alkylene or C 6 -C 12 arylene and R is as defined above; or R 7 is a group -E-CO-NH-CH 2 -OR 6 ; R 6 is hydrogen or d-C 18 alkyl; Formula (F) denotes a recurring structural unit of a oligomer where T is ethylene or 1 ,2- propylene, or is a repeating structural unit derived from an α-olefin copolymer with an alkyl acrylate or methacrylate; k is 2 to 100; and R 10 is hydrogen, d-C 1 alkyl or C C 12 alkoxy; T 2 has the same meaning as R ; T 3 and T 4 are independently alkylene of 2 to 12 carbon atoms, or T 4 is a group T 5 is C 2 -C 22 alkylene, C 5 -C 7 cycloalkylene, CrC alkylenedi(C 5 -C 7 cycloalkylene), phenylene or phenylenedi(d-C 4 alkylene); T 6 is I I I -NH(CH 2 ) a -N(CH 2 ) b -N[(CH 2 ) c -N-] d H where a, b and c are independently 2 or 3, and d is 0 or 1 ; e is 3 or 4; Ei and E 2, being different, are each oxo or imino; E 3 is hydrogen, alkyl of 1 to 30 carbon atoms, phenyl, naphthyl, said phenyl or said naphthyl substituted by chlorine or by alkyl of 1 to 4 carbon atoms, or phenylalkyl of 7 to 12 carbon atoms, or said phenylalkyl substituted by alkyl of 1 to 4 carbon atoms; E is hydrogen, alkyl of 1 to 30 carbon atoms, phenyl, naphthyl or phenylalkyl of 7 to 12 carbon atoms; or E 3 and E 4 together are polymethylene of 4 to 17 carbon atoms, or said polymethylene substituted by up to four alkyl groups of 1 to 4 carbon atoms; and E 6 is an aliphatic or aromatic or aromatic tetravalent radical. 10. A process according to claim 9, wherein G,, G 2 , G 3 and G 4 are methyl and G 5 and G 6 are hydrogen. 11. A process according to claim 9 wherein the compound is of the structural formula A, B, O or P, wherein m is 1 , R is hydrogen, d-Cι 8 alkyl which is uninterrupted or interrupted by one or more oxygen atoms, cyanoethyl, benzoyl, glycidyl, a monovalent radical of an aliphatic carboxylic acid having 2 to 18 carbon atoms, of a cycloaliphatic carboxylic acid having 7 to 15 carbon atoms, or an α,β- unsaturated carboxylic acid having 3 to 5 carbon atoms or of an aromatic carboxylic acid having 7 to 15 carbon atoms; P is 1 ; R, is d-C 12 alkyl, C 5 -C 7 cycloalkyl, C 7 -C 8 aralkyl, C 2 -C 18 alkanoyl, C 3 -C 5 alkenoyl or benzoyl; R 2 is C r C 18 alkyl, C 5 -C 7 cycloalkyl, C 2 -C 8 alkenyl unsubstituted or substituted by a cyano, carbonyl or carbamide group, or is glycidyl, a group of the formula -CH CH(OH)-Z or of the formula -CO-Z or -CONH-Z wherein Z is hydrogen, methyl or phenyl. 12. A process according to claim 11 , wherein R is hydrogen, d-C 18 alkyl, cyanoethyl, benzoyl, glycidyl, a monovalent radical of an aliphatic, carboxylic acid; Ri is C C 12 alkyI, C 7 -C 8 aralkyl, C 2 -d 8 alkanoyl, C 3 -C 5 alkenoyl or benzoyl; R 2 is d-C 18 alkyl, glycidyl, a group of the formula -CH CH(OH)-Z or of the formula -CO-Z, wherein Z is hydrogen, methyl or phenyl. 13. A process according to claim 6 wherein the stable nitroxyl radical is a compound of formula (X), Π T is 1 R101 is cyano; R10 2 and R 103 are each independently of one another unsubstituted d -C 12 alkyl or phenyl; or R 102 and R 103 , together with the linking carbon atom, form a C 5 -C 7 cycloalkyl radical; R 110 is C 4 -C 12 alkyl bound via a tertiary C-atom to the nitrogen atom, Cg-Cnphenylalkyl or phenyl; or R 110 and Rm together form a C 2 -C 6 alkylene bridge which is unsubstituted or substituted with d-C 4 alkyl; and R 112 is C C alkyl; 14. A process according to claim 7 wherein the stable nitroxyl radical is a compound of formula (XXa), Y is O; R 201 is tertiary C 4 -C 8 alkyl; R 202 and R 203 are methyl, ethyl or together with the carbon atom form a C 5 -C 6 cycloalkyl ring; R 20 4 is d-C 18 alkoxy, benzyloxy or NR 22 3R 22 4, wherein R 2 3 and R 2 2 4 are independently of each other hydrogen or d-C 8 alkyl; or of formula (XXb), wherein Q T is O; R 2 05 > R 2 06 > R207 and R 208 are independently of each other methyl or ethyl; or R 205 and R 206 and/or R 207 and R 208 together with the carbon atom form a C 5 -C 6 cycloalkyl ring; R 209 and R 210 are independently of each other formyl, C 2 -C 8 alkylcarbonyl, benzoyl, d-C 8 alkyl, benzyl or phenyl; or of formula (XXc), wherein Y^ is O; R205 > R 2 o6 > R207 and R 208 are independently of each other methyl or ethyl; or R 205 and R 206 and/or R 207 and R 208 together with the carbon atom form a C 5 -C 6 cycloalkyl ring; R 211 is formyl, C 2 -Cι 8 alkylcarbonyl, benzoyl, C C 18 alkyl, benzyl or phenyl and R 212 is OH, C r C 18 alkoxy, benzyloxy, NR 223 R 224 , wherein R 223 and R 224 are independently of each other hydrogen or d-C 18 alkyl. 15. A process according to claim 1 , wherein the polymer to be grafted on contains unsaturated moieties selected from the group consisting of polydienes, co-, block-, random- and tapered polymers of styrene, terpolymers with diolefins and copolymers with diolefins. 16. A process according to claim 1 , wherein the ethylenically unsaturated monomer or oligomer is selected from the group consisting of styrene, substituted styrene, conjugated dienes, maleic acid anhydride, acrolein, vinyl acetate, (alkyl)acrylic acidanhydrides, (alkyl)acrylic acid salts, (alkyl)acrylic esters or (alkyl)acrylamides. 17. A process according to claim 1 wherein the ethylenically unsaturated monomer is styrene, α-methyl styrene, p-methyl styrene or a compound of formula CH 2 =C(R a )-(C=Z)-R b , wherein R a is hydrogen or d-C alkyl, R b is NH 2 , OCH 3 , glycidyl, unsubstituted d-C 18 alkoxy or hydroxy- substituted d-dsalkoxy, unsubstituted d-C 18 alkylamino, di(C 1 -C 18 alkyl)amino, hydroxy- substituted d-C 18 alkylamino or hydroxy-substituted di(d-C 18 alkyl)amino; Me is a monovalent metal atom Z is oxygen or sulfur. 18. A process according to claim 17, wherein R a is hydrogen or methyl, R b is NH 2 , gycidyl, unsubstituted or with hydroxy substituted d-C 4 alkoxy, unsubstituted d-C 4 alkylamino, di(d- C 4 alkyl)amino, hydroxy-substituted C r C alkylamino or hydroxy-substituted di(d- C 4 alkyl)amino;and Z is oxygen. 19. A process according to claim 18, wherein the ethylenically unsaturated monomer is methylacrylate, ethylacrylate, butylacrylate, isobutylacrylate, tert. butylacrylate, hydroxyethyl- acrylate, hydroxypropylacrylate, dimethylaminoethylacrylate, glycidylacrylates, methyl(meth)acrylate, ethyl(meth)acrylate, butyl(meth)acrylate, hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, dimethylaminoethyl(meth)acrylate, glycidyl(meth)acrylates, acrylonitnle, acrylamide or methacrylamide. 20. A process according to claim 1 , wherein the temperature in the first step A) is from 150° C to 300° C. 21. A process according to claim 1 , wherein the temperature in the second step B) is from 70° C to 280° C. 22. A process according to claim 1 , wherein the stable nitroxyl radical is present in an amount of from 0.1 % to 30% based on the weight of the polymer. 23. A process according to claim 1 , wherein the ratio of the reaction product of step A) to the ethylenically unsaturated monomer or oligomer added in step B) is from 1 :1000 to 10:1. 24. A polymeric radical initiator obtainable according to step A) of claim 1 or claim 2. 25. A polymeric radical initiator of formula (P1 ) (P1), wherein R 498 is hydrogen, substituted or unsubstituted d-C 18 alkyl, C 2 -C 18 alkenyl, C 2 -Cι 8 alkinyl; C 3 - C 20 cycloalkyl or C 3 -C 1 cycloalkyl containing at least one nitrogen or oxygen atom or C 3 - Cι 2 cycloalkyl containing at least one nitrogen or oxygen atom, which are substituted by N0 2 , halogen, amino, hydroxy, cyano, carboxy; d-C 4 alkoxy, d-C 4 alkylthio, C C alkylamino or di(d- C 4 alkyl)amino, O(C Cι 8 alkyl), O(C 2 -C 18 alkeny), d-Cnphenylalkyl, O-phenyl, OC 7 -C 9 phenylalkyl or halogen or phenyl and naphthyl which are unsubstituted or substituted by d-C 4 alkyl, d- dalkoxy, Cι-C 4 alkylthio, halogen, cyano, hydroxy, carboxy, C r C 4 alkylamino or di(C C 4 alkyl)amino; R 4 g 9 is the stable nitroxyl radical, bound at the oxygen atom; R 50 o is substituted or unsubstituted d-C 18 alkyl, C 2 -d 8 alkenyl, C 3 -C 20 cycloalkyl, phenyl, C 7 - Cuphenylalkyl; R 501 is hydrogen, substituted or unsubstituted d-C 18 alkyl, C 2 -C 18 alkenyl, C 2 -C 18 alkinyl, C 3 - C 20 cycloalkyl, phenyl, O(C C 18 alkyl), O(C 2 -C 18 alkeny), C 7 -Cnphenylalkyl, O-phenyl, O- C 7 - Cgphenylalkyl or halogen, CN, COOR 50 o, CONR 50 oR 5 oo; Q5 iS CR502R503. (CR 5 02R503)n> (C≡CR 508 R 5 09)n, O, C=O, NR 510 , NR 5 n-C=O, O-C(O)-O, SO 2 , S, SiR 5 ι 2 R5i3, O- R502, R503> R504, R505, R506, R507, Rsoβ, R509, R510. R511, R512 and R 513 independently of each other are hydrogen, substituted or unsubstituted d-C 18 alkyl, C -C 18 alkenyl, C 2 -C 18 alkinyl, C 3 - C 7 cycloalkyl, phenyl, O(d-C 18 alkyl), O(C 2 -C 18 alkeny), d-Cnphenylalkyl, O-phenyl, O- C 7 - Cgphenylalkyl or halogen; n is a number from 1 to 10; y is a number from 1 to 25000 and; z is a number from 0 to 25000. 26. A polymer obtainable according to step A) and B) of the process of claim 1 or claim 2. 27. A polymer of formula (P2), wherein the definitions are as given in claim 25, Q 6 is a homo-, co- or tapered polymer prepared from the monomers as given in claims 15 to 18; and t is a number from 0 to 25000. 28. A composition comprising a) a polymeric radical initiator prepared according to step A) of claim 1 or claim 2 and b) an ethylenically unsaturated monomer or oligomer. 29. Use of a stable nitroxyl radical for the preparation of a grafted polymer according to claim 1 or claim 2. 30. Use of a grafted polymer according to step A) of claim 1 or claim 2 as macroinitiator for radical polymerization. 31. Use of the polymer obtained according to the process of claiml or claim 2 as adhesive or as compatibilizer for polymer blends or as polymer toughening agent.

Inventors: PFAENDNER RUDOLF, ROTH MICHAEL, PFAENDNER, RUDOLF, ROTH, MICHAEL
Applicants: CIBA SC HOLDING AG, PFAENDNER RUDOLF, ROTH MICHAEL, CIBA SPECIALTY CHEMICALS HOLDING INC., PFAENDNER, RUDOLF, ROTH, MICHAEL
Application year: 1999
Main classification: C08F291
IPC codes: C08F2, C08F4, C08F255, C08F291, C08F293