The controlled production of polyolefins of different molecular weights, melt viscosity, density or molecular weight distribution may be carried out by means of the known methods of pre- paration, for example extrusion or injection moulding. Some taitor-made polyolefins, for example LDPE, MDPE, HDPE, LLDPE, iPP, sPP or iPS, can be obtained via special polyme- risation techniques using, for example, metallocene and Ziegler catalysts. However, these catalysts entail extra costs for the polyolefin producers. The adjustment of the desired poly- olefin parameters, such as melt viscosity, molecular weight or processing behaviour of the polyolefin, is usefully effected by addition of suitable additives, such as peroxides, polyunsa- turated olefins, polyethylene waxes, unsaturated polymers, fillers or lubricants. Essential to success is in this case the reactivity and mode of action, of example controlled degradation, crosslinking or lubricating effect, of the additives added.

U. S. 4,384,129 or EP-B-0 440 484, for example, describe propenyl-substituted phenol glyci- dyi ethers which can be converted, both with hardeners for epoxy resins and via radical poly- merisation, into polymers having valuable mechanical properties.

The known processes for modifying the molecular weight of polyolefin do not in every re- spect meet the high requirements an additive should fulfil, especially with regard to storage stability, water absorption, susceptibility to hydrolysis, heat stability, colour behaviour, volati- lity, migration behaviour or compatibility. There is thus still a need for an improved process for modifying the molecular weight of polyolefins which circumvents the above disadvan- tages or reduces them substantially and which leads in simple manner to a controlled adjustment of the polyolefin parameters.

Surprisingly, it has now been found that compounds containing at least one epoxy group and at least one alkenyl group are particularly suitable for modifying the molecular weight of poly- olefins according to the above requirements. The molecular weight modification can at the same time go hand in hand with an improvement of the mechanical properties, for example elongation.

Accordingly, this invention relates to a process for modifying the molecular weight of poly- olefins, which comprises adding thereto at least one compound (A), which contains at least one epoxy group and at least one alkenyl group.

The polyolefins can be used in the form of newly prepared polyolefins (virgin material) or recyclates. Within the scope of this invention, recyclates are understood to mean both production waste which is processed again and also polymer waste (scrap material) which is recycled from collected materials.

The collected material originates, for example, from domestic useful material collections or from so-called obligatory returnables, e. g. from the automotive industry, such as old battery boxes. The materia ! s collected are, for example, foils, such as agricultural sheetings, bags, bottles and other containers. The polyolefin recyclates are in this case damaged in many ways oxidatively, thermally and/or light-induced. Moreover, these recyclates can also contain subordinate amounts of admixtures of plastics of different structure, for example styrene po- lymers (e. g. IPS, EPS, ABS, ASA), polyesters (e. g. PET) or polyamides (e. g. PA 6, PA 6.6) as well as customary impurities, such as paint residues, printing inks, metal traces, fuel resi- dues, ethylene glycol, isopropanol or also traces of water.

Examples of polyolefins are: 1. Polymers of monoolefins and diolefins, for example polypropylene, polyisobutylene, po- lybut-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 mole- cular weight polyethylene (HDPE-HMW), high density and ultrahigh molecular weight poly- ethylene (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, prefe- rably 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 n-or a-coordinated.

These metal complexes may be in the free form or fixed on substrates, typically on activated magnesium chloride, titanium (III) 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, Ila and/or Illa 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 monooiefins 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 copo- lymers, 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 copo- lymers with one another and with polymers mentioned in 1) above, for example polypropy- lene/ethylene-propylene copolymers, LDPE/ethylene-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.

The novel process for modifying the molecular weight of polyolefins is of particular interest, the polyolefin being a polypropylene or polyethylene, preferably a copolymer containing ethylene or propylene as main component.

The preferred novel process for modifying the molecular weight of polyolefins is that, wherein compound (A) contains at least two epoxy groups and at least two alkenyl groups.

Another preferred process of this invention for modifying the molecular weight of polyolefins is that, which comprises adding besides compound (A) a compound from the group of the radical formers and/or perchlorates.

Suitable radical formers are, for example, azo compounds, C-radical formers, peroxides, hydroperoxides or peresters.

Suitable azo compounds are, for example, 2,2'-azo-bis (2-methylbutyronitrile) [AIBN], 2,2'- azo-bis (2,4-dimethylvaleronitrile), 2,2'-azo-bis (4-methoxy-2,4-dimethylvaleronitrile), 1,1'-azo- bis (1-cyclohexanecarbonitrile), 2,2'-azo-bis (isobutyramide) dihydrate, 2-phenylazo-2,4-dime- thyl-4-methoxyvaleronitrile, dimethyl-2,2'-azo-bisisobutyrate, 2- (carbamoylazo) isobutyro- nitrile, 2,2'-azo-bis (2,4,4-trimethylpentane), 2,2'-azo-bis (2-methylpropane), 2,2'-azo-bis (N, N'- dimethylenisobutyramidine) as a free base or as a hydrochloride, 2,2'-azo-bis (2-amidino- propane) as a free base or as a hydrochloride, 2,2'-azo-bis {2-methyl-N- 1,1-bis (hydroxyme- thyl) ethyl propionamide} or 2,2'-azo-bis {2-methyl-N- 1,1-bis (hydroxymethyl)-2-hydroxyethyl- propionamide.

Suitable C-radical formers are, for example, 3,4-dimethyl- 3,4-diphenylhexane or poly-1, 4-diisopropylbenzene.

Suitable peroxides, hydroperoxides or peresters are, for example, acetylcyclohexanesulfonyl peroxide, diisopropylperoxydicarbonate, tert-amylperneodecanoate, tert-butylperneodecano- ate, tert-butylperpivalate, tert-amylperpivalate, di (2,4-dichlorobenzoyl) peroxide, diisonona- noyl peroxide, didecanoyl peroxide, dioctanoyl peroxide, dilauroyl peroxide, di (4-methylben- zoyl) peroxide, disuccinic acid peroxide, diacetyl peroxide, dibenzoyl peroxide BPO, tert-bu- tylper-2-ethylhexanoate, di (4-chlorobenzoyl) peroxide, tert-butylperisobutyrate, tert-butylper- maleinate, 1,1-bis (tert-butylperoxy) 3,5,5-trimethylcyclohexane, 1,1-bis (tert-butylperoxy) cyclo- hexane, tert-butylperoxyisopropylcarbonate, tert-butylperisononaoate, 2,5-dimethylhexane- 2,5-dibenzoate, tert-butylperacetate, tert-amylperbenzoate, tert-butylperbenzoate, diisopro- pylperoxydicarbonate, bis (4-tert-butylcyclohexyl) peroxidicarbonate, 2,2-bis (tert-butylperoxy)- butane, 2,2-bis (tert-butylperoxy) propane, dicumyl peroxide [DCP], 2,5-dimethylhexane-2,5- di-tert-butylperoxide, 3-tert-butylperoxy-3-phenylphthalide, di-tert-amyl peroxide, 1,3-bis (tert- butylperoxy-isopropyl) benzene, 3,5-bis (tert-butylperoxy) 3,5-dimethyl-2-dioxolane, di-tert-bu- tyl peroxide, peroxide, n-butyl-4,4-di (tert-butylperoxy)- valerate, ethyl-3,3-di (tert-butylperoxy) butyrate, di (1-hydroxycyclohexyl) peroxide, dibenzyl peroxide, tert-butylcumyl peroxide, 3,3,6,6,9,9-hexamethyl, 1,2,4,5-tetraoxacyclononane, p- menthane hydroperoxide, pinane hydroperoxide, diisopropylbenzene monohydroperoxide, cumene hydroperoxide, metylethylketone peroxide or tert-butyl hydroperoxide.

Suitable perchlorates are, for example, alkali perchlorates and alkaline earth perchlorates.

Particularly interesting radical formers are those having high degradation temperatures, in particular those having degradation temperatures higher than 140°C.

A particularly interesting novel process for modifying the molecular weight of polyolefins is that, which comprises adding besides compound (A) a compound from the group of the per- oxides.

Of particular interest is that novel process for modifying the molecular weight of polyolefins, wherein compound (A) is a compound of formula I wherein R, is hydrogen, C1-C4alkyl or C2-C12alkenyl, R2, R3 and R4 are each independently of one another hydrogen, C1-C4alkyl, C2-Cl2alkenyl, R5, R6, R7, R8, Rg and R : o are each independently of one another hydrogen, C,-C4alkyl or C2-C12alkenyl, X is a direct bond, oxygen, sulfur,-SO-, S02-,-CH=CH-or R-c-R, Rn and Riz are each independently of the other hydrogen, CF3 or C1-C12alkyl, or R11 and R12, together with the linking carbon atom, are a C5-C8cycloalkylidene ring which is unsubsti- tuted or substituted by 1 to 3 C1-C4alkyl; m is an integer from 0 to 10, and n is an integer from 0 to 10; with the proviso that at least one of RI, R2, R3 or R4 contains a Cs-Ciaaikenyt group.

Alkyl containing up to 12 carbon atoms is a branched or unbranched radical, such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, 2-ethylbutyl, n-pentyl, isopentyl, 1-methylpentyl, 1,3-dimethylbutyl, n-hexyl, 1-methylhexyl, n-heptyl, isoheptyl, 1,1,3,3-tetra- methylbutyl, 1-methylheptyl, 3-methylheptyl, n-octyl, 2-ethylhexyl, 1,1,3-trimethylhexyl, 1,1,3,3-tetramethylpentyl, nonyl. One of the preferred meanings of R, to R8 is, for example, Ci-Cisaikyi, preferably C1-C12alkyl, e. g. Ci-Cgatkyi. A preferred meaning of R3 and R7 is, for example, C1-C4alkyl, preferably tert-butyl or methyl. A particularly preferred meaning of Rn and R12 is C,-C8alkyl, preferably C1-C4alkyl, e. g. methyl or ethyl.

Alkenyl containing 2 to 12 carbon atoms is a branched or unbranched radical, such as vinyl, propenyl, 2-butenyl, 3-butenyl, isobutenyl, n-2,4-pentadienyl, 3-methyl-2-butenyl, n-2-octenyl, n-2-dodecenyl, isododecenyl, oleyl, n-2-octadecenyl or n-4-octadecenyl. Alkenyl containing 2 to 8, preferably 2 to 4, carbon atoms is preferred, for example propenyl.

A Cs-Cecycioaikyiidene ring which is unsubstituted or substituted by 1 to 3 C1-C4alkyl, which ring preferably contains 1 to 3, more preferably 1 or 2, branched or unbranched alkyl groups, is typically cyclopentylidene, methylcyclopentylidene, dimethylcyclopentylidene, cyclohexyli- dene, methylcyclohexylidene, dimethylcyclohexylidene, trimethylcyclohexylidene, tert-butyl- cyclohexylidene, cycloheptylidene or cyclooctylidene. Cyclohexylidene and tert-butylcyclo- hexylidene are preferred.

Particularly preferred compounds are those of formula 1, wherein R4 is C2-C4alkenyl. Particularly interesting compounds of formula I are those, wherein R, and R3 are hydrogen.

Other preferred compounds of formula I are those, wherein R, is hydrogen, C,-C4alkyl or C2-C8alkenyl, R2 is hydrogen, C,-C4alkyl, C2-C8alkenyl or R3 and R4 are each independently of the other hydrogen, C,-C4alkyl, C2-C8alkenyl, R5, R6, R7, R8, Rg and R10 are each independently of one another hydrogen, C1-C4alkyl or C2-C8alkenyl, X is oxygen, sulfur or R11-C-R12 , R11 and R12 are each independently of the other hydrogen, CF3 or Ci-Cgatkyt, or Rn and Ris, together with linking carbon atom, are a cyclohexylidene ring which is unsubstituted or sub- stituted by 1 to 3 C1-C4alkyl; m is an integer from 0 to 5, and n is an integer from 0 to 5; with the proviso that at least one of RI, R2, R3 or R4 contains a C2-C8alkenyl group.

Particularly preferred compounds of formula I are those, wherein Ri is hydrogen or C2-C6alkenyl, R3 is hydrogen, R4 is hydrogen or C2-C6alkenyl, <BR> <BR> <BR> <BR> Xisoxygenor R11-C-R12 ,<BR> <BR> <BR> <BR> <BR> | R"and R12 are each independently of the other hydrogen, CF3 or C1-C4alkyl, or R11 and R12, together with the linking carbon atom, are a cyclohexylidene ring which is unsubstituted or substituted by 1 to 3 C1-C4alkyl; with the proviso that at least one of Ri, R2, R3 or R4 contains a C2-C6alkenyl group.

Very particularly preferred compounds of formula I are those, wherein R, is hydrogen, R3 is hydrogen, R4 is C3alkenyl, Xi ans<BR> <BR> <BR> <BR> 12' Rn and Ris are C1-C4alkyl.

The compounds of formula I are known from U. S. 4,384,129 or EP-B-0 440 484 and can be prepared in analogy to the literature references cited there.

The process can be carried out in any heatable reactor which is equipped with a mixing, stirring or kneading device. These reactors may be, for example, closed apparatus with ex- clusion of atmospheric oxygen, which are operated e. g. in an inert gas atmosphere, such as nitrogen. The process is preferably carried out in a kneader or extruder.

The polyolefin to be heated and compound (A), which contains at least one epoxide and at least one alkenyl group, are normally filled into the apparatus when heating starts; however, it is also possible to add the novel compound (A) later to the melted polyolefin.

For the addition, the compound (A) can be independently of one another in the form of a liquid, powder, granules or in compacted form, or it may also be used applied to a substrate, such as silica gel, or together with a polymer powder or wax, for example a polyethylene wax.

It is preferred to add 0.01 to 10 parts, more preferably 0.05 to 5 parts, e. g. 0.05 to 2 parts, of compound (A) per 100 parts of polyolefin.

It is also possible to add additional stabilisers or additives to the polyolefin besides com- pound (A). These additives are, for example, the following: 1. Antioxidants 1.1. Alkylated monophenols, for example 2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-di- methylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-bu- tyl-4-isobutylphenol, 2,6-dicyclopentyl-4-methylphenol, 2- (a-methylcyclohexyl)-4, 6-dimethyl- phenol, 2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol, 2,6-di-tert-butyl-4-metho- xymethylphenol, nonylphenols which are linear or branched in the side chains, for example, 2,6-di-nonyl-4-methylphenol, 2,4-dimethyl-6- (1'-methylundec-1'-yl) phenol, 2,4-dimethyl-6- (1'- methylheptadec-1'-yl) phenol, 2,4-dimethyl-6- (1'-methyltridec-1'-yl) phenol and mixtures there- of.

1.2. Alkylthiomethylphenols, for example 2,4-dioctylthiomethyi-6-tert-butylphenol, 2,4-dioc- tylthiomethyl-6-methylphenol, 2,4-dioctylthiomethyl-6-ethylphenol, 2,6-di-dodecylthiomethyl- 4-nonylphenol.

1.3. Hydroquinones and alkylated hydroquinones, for example 2,6-di-tert-butyl-4-methoxy- phenol, 2,5-di-tert-butylhydroquinone, 2,5-di-tert-amylhydroquinone, 2,6-diphenyl-4-octade- cyloxyphenol, 2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-bu- tyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyphenyl stearate, bis (3,5-di-tert-butyl-4-hyd- roxyphenyl) adipate.

1.4. Tocopherols, for example a-tocopherol, ß-tocopherol, y-tocopherol, 6-tocopherol and mixtures thereof (Vitamin E).

1.5. Hydroxylated thiodiphenvl ethers, for example 2,2'-thiobis (6-tert-butyl-4-methylphenol), 2,2'-thiobis (4-octylphenol), 4,4'-thiobis (6-tert-butyl-3-methylphenol), 4,4'-thiobis (6-tert-butyl- 2-methylphenol), 4,4'-thiobis (3,6-di-sec-amylphenol), 4,4'-bis (2,6-dimethyl-4-hydroxyphe- nyl) disulfide.

1.6. Alkylidenebisphenols, for example 2,2'-methylenebis (6-tert-butyl-4-methylphenol), 2,2'- methylenebis (6-tert-butyl-4-ethylphenol), 2,2'-methylenebis [4-methyl-6- (a-methylcyclohexyl)- phenol, 2,2'-methylenebis (4-methyl-6-cyclohexylphenol), 2,2'-methylenebis (6-nonyl-4-me- thylphenol), 2,2'-methylenebis (4,6-di-tert-butylphenol), 2,2'-ethylidenebis (4,6-di-tert-butylphe- nol), 2,2'-ethylidenebis (6-tert-butyl-4-isobutylphenol), 2,2'-methylenebis [6-(a-methylbenzyl)- 4-nonylphenol, 2,2'-methylenebis 6- a-dimethylbenzyl)-4-nonylphenol, 4,4'-methylene- bis (2,6-di-tert-butylphenol), 4,4'-methylenebis (6-tert-butyl-2-methylphenol), 1,1-bis (5-tert-bu- tyl-4-hydroxy-2-methylphenyl) butane, 2,6-bis (3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-me- thylphenol, 1,1,3-tris (5-tert-butyl-4-hydroxy-2-methylphenyl) butane, 1,1-bis (5-tert-butyl-4- hydroxy-2-methyl-phenyl)-3-n-dodecylmercaptobutane, ethylene glycol bis [3,3-bis (3'-tert-bu- tyl-4'-hydroxyphenyl) butyrate], bis (3-tert-butyl-4-hydroxy-5-methyl-phenyl) dicyclopentadiene, bis 2- (3'-tert-butyl-2'-hydroxy-5'-methylbenzyl)-6-tert-butyl-4-me thylphenyl terephthalate, 1,1- bis (3,5-dimethyl-2-hydroxyphenyl) butane, 2,2-bis (3,5-di-tert-butyl-4-hydroxyphenyl) propane, 2,2-bis (5-tert-butyl-4-hydroxy2-methylphenyl)-4-n-dodecylmercaptobu tane, 1,1,5,5-tetra- (5- tert-butyl-4-hydroxy-2-methylphenyl) pentane.

1.7. O-, N-and S-benzvl compounds, for example 3,5,3', 5'-tetra-tert-butyl-4,4'-dihydroxydi- benzyi ether, octadecyl-4-hydroxy-3,5-dimethylbenzylmercaptoacetate, tridecyl-4-hydroxy- 3,5-di-tert-butylbenzylmercaptoacetate, tris (3,5-di-tert-butyl-4-hydroxybenzyl) amine, bis (4- tert-butyl-3-hydroxy-2, 6-dimethylbenzyl) dithioterephthalate, bis (3,5-di-tert-butyl-4-hydroxy- benzyl) sulfide, isooctyl-3,5-di-tert-butyl-4-hydroxybenzylmercaptoacetate.

1.8. Hydroxybenzylated malonates, for example dioctadecyl-2,2-bis (3,5-di-tert-butyl-2-hy- droxybenzyl) malonate, di-octadecyl-2- (3-tert-butyl-4-hydroxy-5-methylbenzyl) malonate, di- dodecylmercaptoethyl-2,2-bis (3,5-di-tert-butyl-4-hydroxybenzyl) malonate, bis 4- (1,1,3,3-te- tramethylbutyl) phenyl-2,2-bis (3,5-di-tert-butyl-4-hydroxybenzyl) malonate.

1.9. Aromatic hydroxvbenzyl compounds, for example 1,3,5-tris- (3, 5-di-tert-butyl-4-hydroxy- benzyl)-2,4,6-trimethylbenzene, 1,4-bis 5,6-tetrame- thylbenzene, 2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) phenol.

1.10. Triazine compounds, for example 2,4-bis (octylmercapto)-6- (3, 5-di-tert-butyl-4-hydro- xyanilino)-1,3,5-triazine, 2-octylmercapto-4,6-bis 5-tri- azine, 2-octylmercapto-4,6-bis 5-triazine, 2,4,6-tris- 3-triazine, 1,3,5-tris- (3, 5-di-tert-butyl-4-hydroxyben- zyl) isocyanurate, 1,3,5-tris (4-tert-butyl-3-hydroxy-2, 6-dimethylbenzyl) isocyanurate, 2,4,6-tris- 5-triazine, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxy- phenylpropionyl) hexahydro-1,3,5-triazine, 1,3,5-tris (3,5-dicyclohexyl-4-hydroxybenzyl) isocya- nurate.

1.11. Benzvlphosphonates, for example dimethyl-2, 5-di-tert-butyl-4-hydroxybenzylphospho- nate, diethyl-3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl3, 5-di-tert-butyl-4-hy- droxybenzylphosphonate, dioctadecyl-5-tert-butyl-4-hydroxy-3-methylbenzylphosphonate , the calcium salt of the monoethyl ester of 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid.

1.12. Acylaminophenols, for example 4-hydroxylauranilide, 4-hydroxystearanilide, octyl N- (3,5-di-tert-butyl-4-hydroxyphenyl) carbamate.

1.13. Esters of D- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid with mono-or polyhydric alcools, e. g. with methanol, ethanol, n-octanol, i-octanol, octadecanol, 1,6-hexanediol, 1,9- nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethy- lene glycol, triethylene glycol, pentaerythritol, tris (hydroxyethyl) isocyanurate, N, N'-bis (hy- droxyethyl) oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylol- propane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo [2.2.2] octane.

1.14. Esters of (3- (5-tert-butyl-4-hvdroxv-3-methylphenyl) propionic acid with mono-or poly- hydric alcools, e. g. with methanol, ethanol, n-octanol, i-octanol, octadecanol, 1,6-hexane- diol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris (hydroxyethyl) isocyanurate, N, N'- bis (hydroxyethyl) oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trime- thylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo [2.2.2] octane.

1.15. Esters of i- (3. 5-dicyclohexvydroxypheny propionic acid with mono-or polyhydric alcools, e. g. with methanol, ethanol, octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris (hydroxyethyl) isocyanurate, N, N'-bis (hydroxyethyl) ox- amide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hy- droxymethyl-1-phospha-2,6,7-trioxabicyclo [2.2.2] octane.

1.16. Esters of 3,5-di-tert-butvl-4-hydroxyphenvl acetic acid with mono-or polyhydric alco- hols, e. g. with methanol, ethanol, octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris (hydroxyethyl) isocyanurate, N, N'-bis (hydroxyethyl) ox- amide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hy- droxymethyl-1-phospha-2,6,7-trioxabicyclo [2.2.2] octane.

1.17. Amides of 6- (3. 5-di-tert-butvt-4-hvdroxyphenvt) DroDionic acid e. g. N, N'-bis (3,5-di-tert- butyl-4-hydroxyphenylpropionyl) hexamethylenediamide, N, N'-bis (3,5-di-tert-butyl-4-hydroxy- phenylpropionyl) trimethylenediamide, N, N'-bis (3,5-di-tert-butyl-4-hydroxyphenylpropionyl)- hydrazide, N, N'-bis 2- (3- 3, 5-di-tert-butyl-4-hydroxyphenyl propionyloxy) ethyl oxamide (Naugard@XL-1 supplie by Uniroyal).

1.18. Ascorbic acid (vitamin C) 1.19. Aminic antioxidants, for example N, N'-di-isopropyl-p-phenylenediamine, N, N'-di-sec- butyl-p-phenylenediamine, N, N'-bis (1,4-dimethylpentyl)-p-phenylenediamine, N, N'-bis (1- ethyl-3-methylpentyl)-p-phenylenediamine, N, N'-bis (1-methylheptyl)-p-phenylenediamine, N, N'-dicyclohexyl-p-phenylenediamine, N, N'-diphenyl-p-phenylenediamine, N, N'-bis (2-naph- thyl)-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, N- (1, 3-dimethylbutyl)- N'-phenyl-p-phenylenediamine, N- (1-methylheptyl)-N'-phenyl-p-phenylenediamine, N-cyclo- hexyl-N'-phenyl-p-phenylenediamine, 4-(p-toluenesulfamoyl) diphenylamine, N, N'-dimethyl- N, N'-di-sec-butyl-p-phenylenediamine, diphenylamine, N-allyldiphenylamine, 4-isopropoxy- diphenylamine, N-phenyl-1-naphthylamine, N- (4-tert-octylphenyl)-1-naphthylamine, N-phe- nyl-2-naphthylamine, octylated diphenylamine, for example p, p'-di-tert-octyidiphenylamine, 4- n-butylaminophenol, 4-butyrylaminophenol, 4-nonanoylaminophenol, 4-dodecanoylamino- phenol, 4-octadecanoylaminophenol, bis (4-methoxyphenyl) amine, 2,6-di-tert-butyl-4-dime- thylaminomethylphenol, 2,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, N, N, N', N'-tetramethyl-4, 4'-diaminodiphenylmethane, 1,2-bis (2-methylphenyl) amino ethane, 1,2-bis (phenylamino) propane, (o-tolyl) biguanide, bis 4-(1', 3'-dimethylbutyl) phenyl amine, tert- octylated N-phenyl-1-naphthylamine, a mixture of mono-and dialkylated tert-butyl/tert-octyl- diphenylamines, a mixture of mono-and dialkylated nonyldiphenylamines, a mixture of mono-and dialkylated dodecyidiphenylamines, a mixture of mono-and dialkylated isopro- pyl/isohexyldiphenylamines, a mixture of mono-and dialkylated tert-butyldiphenylamines, phenothiazine, a mixture of mono-and dial- kylated tert-butyl/tert-octylphenothiazines, a mixture of mono-and dialkylated tert-octyl-phe- nothiazines, N-allylphenothiazine, N, N, N', N'-tetraphenyl-1,4-diaminobut-2-ene, N, N-bis- (2,2,6,6-tetramethyl-piperid-4-yl-hexamethylenediamine, bis (2,2,6,6-tetramethylpiperid-4-yl)- sebacate, 2,2,6,6-tetramethylpiperidin-4-one, 2,2,6,6-tetramethylpiperidin-4-ol.

2. UV absorbers and light stabilisers 2.1.2- (2'-HvdroxvPhenvl) benzotriazoles, for example 2- (2'-hydroxy-5'-methylphenyl) benzo- triazole, 2- (3', 5'-di-tert-butyl-2'-hydroxyphenyl) benzotriazole, 2- (5'-tert-butyl-2'-hydroxyphe- nyl) benzotriazole, 2- (2'-hydroxy-5'- (1,1,3,3-tetramethylbutyl) phenyl) benzotriazole, 2- (3', 5'-di- tert-butyl-2'-hydroxyphenyl)-5-chloro-benzotriazole, 2- (3'-tert-butyl- 2'-hydroxy-5'-methylphe- nyl)-5-chloro-benzotriazole, 2- (3'-sec-butyl-5'-tert-butyl-2'-hydroxyphenyl) benzotriazole, 2- (2'- hydroxy-4'-octyloxyphenyl) benzotriazole, 2- (3', 5'-di-tert-amyl-2'-hydroxyphenyl) benzotriazole, 2- (3', 5'-bis (a, a-dimethylbenzyl)-2'-hydroxyphenyl) benzotriazole, 2- (3'-tert-butyl-2'-hydroxy-5'- (2-octyloxycarbonylethyl) phenyl)-5-chloro-benzotriazole, 2- (3'-tert-butyl-5'- 2- (2-ethylhexyl- oxy) carbonylethyl-2'-hydroxyphenyl)-5-chloro-benzotriazole, 2- (3'-tert-butyl-2'-hydroxy-5'- (2- methoxycarbonylethyl) phenyl)-5-chloro-benzotriazole, 2- (3'-tert-butyl-2'-hydroxy-5'- (2-me- thoxycarbonylethyl) phenyl) benzotriazole, 2- (3'-tert-butyl-2'-hydroxy-5'- (2-octyloxycarbonyl- ethyl) phenyl) benzotriazole, 2- (3'-tert-butyl-5'- 2- (2-ethylhexyloxy) carbonylethyl-2'-hydroxy- phenyl) benzotriazole, 2- (3'-dodecyl-2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (3'-tert-butyl- 2'-hydroxy-5'-(2-isooctyloxycarbonylethyl) phenylbenzotriazole,(2-isooctyloxycarbonylethyl) phenylbenzotriazole, 3,3- tetramethylbutyl)-6-benzotriazole-2-ylphenol; the transesterification product of 2- 3'-tert- butyl-5'- (2-methoxycarbonylethyl)-2'-hydroxyphenyl-2H-benzotriazole with polyethylene gly- col 300; R-CH2CH2-COO-CH2CH2--where R = 3'-tert-butyl-4'-hydroxy-5'-2H- 2 benzotriazol-2-ylphenyl, 2- 2'-hydroxy-3'- (a, a-dimethylbenzyl)-5'- (1,1,3,3-tetramethylbutyl)- phenyl benzotriazole; 2- 2'-hydroxy-3'- (1,1,3,3-tetramethylbutyl)-5'- (a, a-dimethylbenzyl) phe- nyl benzotriazole.

2.2.2-Hydroxybenzophenones, for example the 4-hydroxy, 4-methoxy, 4-octyloxy, 4-decyl- oxy, 4-dodecyloxy, 4-benzyloxy, 4,2', 4'-trihydroxy and 2'-hydroxy-4,4'-dimethoxy derivatives.

2.3. Esters of substituted and unsubstituted benzoic acids, as for example 4-tertbutyl-phenyl salicylate, phenyl salicylate, octylphenyl salicylate, dibenzoyl resorcinol, bis (4-tert-butylben- zoyl) resorcinol, benzoyl resorcinol, 2,4-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzo- ate, hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, octadecyl 3,5-di-tert-butyl-4-hydroxyben- zoate, 2-methyl-4,6-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzoate.

2.4. Acrylates, for example ethyl a-cyano-ß, ß-diphenylacrylate, isooctyl a-cyano-ß, ß-diphe- nylacrylate, methyl a-carbomethoxycinnamate, methyl a-cyano-p-methyl-p-methoxy-cinna- mate, butyl a-cyano-p-methyl-p-methoxy-cinnamate, methyl a-carbomethoxy-p-methoxycin- namate and N- (p-carbomethoxy-i-cyanovinyl)-2-methylindoline.

2.5. Nickel compounds, for example nickel complexes of 2,2'-thio-bis 4- (1,1,3,3-tetrame- thylbutyl) phenol, such as the 1: 1 or 1: 2 complex, with or without additional ligands such as n-butylamine, triethanolamine or N-cyclohexyldiethanolamine, nickel dibutyldithiocarbamate, nickel salts of the monoalkyl esters, e. g. the methyl or ethyl ester, of 4-hydroxy-3,5-di-tert- butylbenzylphosphonic acid, nickel complexes of ketoximes, e. g. of 2-hydroxy-4-methylphe- nyl undecylketoxime, nickel complexes of 1-phenyl-4-lauroyl-5-hydroxypyrazole, with or with- out additional ligands.

2.6. Stericallv hindered amines, for example bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (2,2,6,6-tetramethyl-4-piperidyl) succinate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis (1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperi- dyl), n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate, the condensate of 1- (2-hydroxyethyl)- 2,2,6,6-tetramethyl-4-hydroxypiperidine and succinic acid, linear or cyclic condensates of N, N'-bis (2,2,6,6-tetramethyl-4-piperidyl) hexamethylenediamine and 4-tert-octylamino-2,6-di- chloro-1,3,5-triazine, tris (2,2,6,6-tetramethyl-4-piperidyl) nitrilotriacetate, tetrakis (2,2,6,6-tetra- methyl-4-piperidyl)-1,2,3,4-butane-tetracarboxylate, 1,1'- (1, 2-ethanediyl)-bis (3,3,5,5-tetrame- thylpiperazinone), 4-benzoyl-2,2,6,6-tetramethylpiperidine, 4-stearyloxy-2,2,6,6-tetramethyl- piperidine, bis (1,2,2,6,6-pentamethylpiperidyl)-2-n-butyl-2-(2-hydroxy-3, 5-di-tert-butylbenzyl)- malonate, 3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro [4.5] decan-2,4-dione, bis (1-octyloxy- 2,2,6,6-tetramethylpiperidyl) sebacate, bis (1-octyloxy-2,2,6,6-tetramethylpiperidyl) succinate, linear or cyclic condensates of N, N'-bis (2,2,6,6-tetramethyl-4-piperidyl) hexamethylenedi- amine and 4-morpholino-2, 6-dichloro-1,3,5-triazine, the condensate of 2-chloro-4,6-bis (4-n- butylamino-2,2,6,6-tetramethylpiperidyl)-1,3,5-triazine and 1,2-bis (3-aminopropylamino)- ethane, the condensate of 2-chloro-4, 6-di- (4-n-butylamino-1,2,2,6,6-pentamethylpiperidyl)- 1,3,5-triazine and 1,2-bis (3-aminopropylamino) ethane, 8-acetyl-3-dodecyl-7,7,9,9-tetrame- thyl-1,3,8-triazaspiro [4.5] decane-2,4-dione, 3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidyl) pyr- rolidin-2, 5-dione, 3-dodecyl-1- (1,2,2,6,6-pentamethyl-4-piperidyl) pyrrolidine-2, 5-dione, a mix- ture of 4-hexadecyloxy-and 4-stearyloxy-2,2,6,6-tetramethylpiperidine, a condensate of N, N'-bis (2,2,6,6-tetramethyl-4-piperidyl) hexamethylenediamine and 4-cyclohexylamino-2,6- dichloro-1,3,5-triazine, a condensate of 1,2-bis (3-aminopropylamino) ethane and 2,4,6-tri- chloro-1,3,5-triazine as well as 4-butylamino-2,2,6,6-tetramethylpiperidine (CAS Reg. No.

[136504-96-6]); N- (2,2,6,6-tetramethyl-4-piperidyl)-n-dodecylsuccinimide, N- (1, 2, 2, 6, 6-penta- methyl-4-piperidyl)-n-dodecylsuccinimide, 2-undecyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4- oxospiro [4,5] decane, a reaction product of 7,7,9,9-tetramethyl-2-cycloundecyl-1-oxa-3,8-di- aza-4-oxospiro [4,5] decane and epichlorohydrin, 1,1-bis (1,2,2,6,6-pentamethyl-4-piperidyl- oxycarbonyl)-2- (4-methoxyphenyl) ethene, N, N'-bis-formyl-N, N'-bis (2,2,6,6-tetramethyl-4-pi- peridyl) hexamethylenediamine, diester of 4-methoxy-methylene-malonic acid with 1,2,2,6,6- pentamethyl-4-hydroxypiperidine, poly methylpropyl-3-oxy-4-(2,2,6,6-tetramethyl-4-piperi- dyl) siloxane, reaction product of maleic acid anhydride-a-olefin-copolymer with 2,2,6,6- tetramethyl-4-aminopiperidine or 1,2,2,6,6-pentamethyl-4-aminopiperidine.

2.7. Oxamides, for example 4,4'-dioctyloxyoxanilide, 2,2'-diethoxyoxanilide, 2,2'-dioctyloxy- 5,5'-di-tert-butoxanilide, 2,2'-didodecyloxy-5, 5'-di-tert-butoxanilide, 2-ethoxy-2'-ethyloxanilide, N, N'-bis (3-dimethylaminopropyl) oxamide, 2-ethoxy-5-tert-butyl-2'-ethoxanilide and its mixture with 2-ethoxy-2'-ethyl-5,4'-di-tert-butoxanilide, mixtures of o-and p-methoxy-disubstituted oxanilides and mixtures of o-and p-ethoxy-disubstituted oxanilides.

2.8.2-2-Hvdroxyphenyl)-1, 3, 5-triazines, for example 2,4,6-tris (2-hydroxy-4-octyloxyphenyl)- 1,3,5-triazine, 2- (2-hydroxy-4-octyloxyphenyl)-4,6-bis 5-triazine, 2- 5-triazine, 2,4-bis (2-hydroxy-4-propyl- oxyphenyl)-6-(2, 4-dimethylphenyl)-1,(2, 4-dimethylphenyl)-1, 3,5-triazine, 2- (2-hydroxy-4-octyloxyphenyl)-4, 6-bis (4- methylphenyl)-1,3,5-triazine, 2- (2-hydroxy-4-dodecyloxyphenyl)-4, 6-bis (2,4-dimethylphenyl)- 1,3,5-triazine, 2- (2-hydroxy-4-tridecyloxyphenyl)-4,6-bis 5-triazine, 2- 2-hydroxy-4- (2-hydroxy-3-butyloxy-propoxy) phenyl-4,6-bis 5-triazine, 2- 2- hydroxy-4- (2-hydroxy-3-octyloxy-propyloxy) phenyl-4, 6-bis 5-triazine, 2- 4- (dodecyloxy/tridecyloxy-2-hydroxypropoxy)-2-hydroxy-phenyl-4 ,6-bis (2,4-dimethylphenyl)- 1,3,5-triazine, 2- 2-hydroxy-4- (2-hydroxy-3-dodecyloxy-propoxy) phenyl-4,6-bis (2,4-dimethyl- phenyl)-1,3,5-triazine, 2- (2-hydroxy-4-hexyloxy) phenyl-4, 6-diphenyl-1,3,5-triazine, 2- (2- hydroxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine, 2,4,6-tris 2-hydroxy-4- (3-butoxy-2- hydroxy-propoxy) phenyl-1,3,5-triazine, 2- (2-hydroxyphenyl)-4- (4-methoxyphenyl)-6-phenyl- 1,3,5-triazine, 2- {2-hydroxy-4- 3- (2-ethylhexyl-1-oxy)-2-hydroxypropyloxy phenyl}-4, 6-bis (2,4- dimethylphenyl)-1,3,5-triazine.

3. Metal deactivators, for example N, N'-diphenyloxamide, N-salicylai-N'-salicyloyl hydrazine, N, N'-bis (salicyloyl) hydrazine, N, N'-bis (3,5-di-tert-butyl-4-hydroxyphenylpropionyl) hydrazine, 3-salicyioylamino-1,2,4-triazole, bis (benzylident30xalyl dihydrazide, oxanilide, isophthaloyl dihydrazide, sebacoyl bisphenylhydrazide, N, N'-diacetyladipoyl dihydrazide, N, N'-bis (salicyl- oyl) oxalyl dihydrazide, N, N'-bis (salicyloyl) thiopropionyl dihydrazide.

4. Phosphites and phosphonites, for example triphenyl phosphite, diphenyl alkyl phosphites, phenyl dialkyl phosphites, tris (nonylphenyl) phosphite, trilauryl phosphite, trioctadecyl phos- phite, distearyl pentaerythritol diphosphite, tris (2,4-di-tert-butylphenyl) phosphite, diisodecyl pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis (2,6-di- tert-butyl-4-methylphenyl) pentaerythritol diphosphite, diisodecyloxypentaerythritol diphos- phite, bis (2,4-di-tert-butyl-6-methylphenyl) pentaerythritol diphosphite, bis (2,4,6-tris (tert-butyl- phenyl) pentaerythritol diphosphite, tristearyl sorbitol triphosphite, tetrakis (2,4-di-tert-butyl- phenyl) 4,4'-biphenylene diphosphonite, 6-isooctyloxy-2,4,8,10-tetra-tert-butyl-12H-dibenz- [d, g]-1,3,2-dioxaphosphocin, 6-fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenz [d, g]-1,3,2-di- oxaphosphocin, bis (2,4-di-tert-butyl-6-methylphenyl) methyl phosphite, bis (2,4-di-tert-butyl-6- methylphenyl) ethyl phosphite, 2,2', 2"-nitrilo triethyltris (3,3', 2,2'-diyl) phosphite], 2-ethylhexyl (3,3', 5,5'-tetra-tert-butyl-1, 1'-biphenyl-2, 2'-dyl) phosphite, 5-butyl-5-ethyl-2- (2,4,6-tri-tert-butylphenoxy)-1,3,2-dioxaphosphinane.

5. Hydroxylamines, for example N, N-dibenzylhydroxylamine, N, N-diethylhydroxylamine, N, N- dioctylhydroxylamine, N, N-dilaurylhydroxylamine, N, N-ditetradecylhydroxylamine, N, N-di- hexadecylhydroxylamine, N, N-dioctadecylhydroxylamine, N-hexadecyl-N-octadecylhydroxyl- amine, N-heptadecyl-N-octadecylhydroxylamine, N, N-dialkylhydroxylamine derived from hydrogenated tallow amine.

6. Nitrones, for example N-benzyl-alpha-phenyl-nitrone, N-ethyl-alpha-methyl-nitrone, N-oc- tyl-alpha-heptyl-nitrone, N-lauryl-alpha-undecyl-nitrone, N-tetradecyl-alpha-tridcyl-nitrone, N- hexadecyl-alpha-pentadecyl-nitrone, N-octadecyl-alpha-heptadecyl-nitrone, N-hexadecyl-al- pha-heptadecyl-nitrone, N-ocatadecyl-alpha-pentadecyl-nitrone, N-heptadecyl-alpha-hepta- decyl-nitrone, N-octadecyl-alpha-hexadecyl-nitrone, nitrone derived from N, N-dialkylhydro- xylamine derived from hydrogenated tallow amine.

7. Thiosvnerqists, for example dilauryl thiodipropionate or distearyl thiodipropionate.

8. Peroxide scavengers, for example esters of-thiodipropionic acid, for example the lauryl, stearyl, myristyl or tridecyl esters, mercaptobenzimidazole or the zinc salt of 2-mercapto- benzimidazole, zinc dibutyidithiocarbamate, dioctadecyl disulfide, pentaerythritol tetrakis (p- dodecylmercapto) propionate.

9. Basic co-stabilisers, for example melamine, polyvinylpyrrolidone, dicyandiamide, triallyl cyanurate, urea derivatives, hydrazine derivatives, amines, polyamides, polyurethanes, alkali metal salts and alkaline earth metal salts of higher fatty acids, for example, calcium stearate, zinc stearate, magnesium behenate, magnesium stearate, sodium ricinoleate and potassium palmitate, antimony pyrocatecholate or zinc pyrocatecholate.

10. Nucleating agents, for example inorganic substances such as talcum, metal oxides such as titanium dioxide or magnesium oxide, phosphates, carbonates or sulfates of, preferably, alkaline earth metals; organic compounds such as mono-or polycarboxylic acids and the salts thereof, e. g. 4-tert-butylbenzoic acid, adipic acid, diphenylacetic acid, sodium succinate or sodium benzoate; polymeric compounds such as ionic copolymers (ionomers).

11. Fillers and reinforcing agents, for example calcium carbonate, silicates, glass fibres, glass bulbs, asbestos, talc, kaolin, mica, barium sulfate, metal oxides and hydroxides, car- bon black, graphite, wood flour and flours or fibres of other natural products, synthetic fibres.

12. Other additives, for example plasticisers, lubricants, emulsifiers, pigments, rheology additives, catalysts, flow-control agents, optical brighteners, flameproofing agents, antistatic agents and blowing agents.

13. Benzofuranones and indolinones, for example those disclosed in U. S. 4,325,863; U. S. 4,338,244; U. S. 5,175,312; U. S. 5,216,052; U. S. 5,252,643; DE-A-4316611; DE-A-4316622; DE-A-4316876; EP-A-0589839 or EP-A-0591102 or 3- 4- (2-acetoxyethoxy)- phenyl-5,7-di-tert-butyl-benzofuran-2-one, 5,7-di-tert-butyl-3- [4- (2-stearoyloxyethoxy) phe- nyl benzofuran-2-one, 3,3'-bis [5,7-di-tert-butyl-3-(4-[2-hydroxyethOxy] phenyl) benzofuran-2- one], 5,7-di-tert-butyl-3- (4-ethoxyphenyl) benzofuran-2-one, 3- (4-acetoxy-3, 5-dimethylphe- nyl)-5,7-di-tert-butyl-benzofuran-2-one, 3- (3, 5-dimethyl-4-pivaloyloxyphenyl)-5, 7-di-tert-butyl- benzofuran-2-one, 3- (3, 4-dimethylphenyl)-5, 7-di-tert-butyl-benzofuran-2-one, 3- (2,3-dime- thylphenyl)-5, 7-di-tert-butyl-benzofuran-2-one.

With the exception of the fillers, reinforcing agents (item 11 in the list) and glass fibres, the additional additives are added to the polyolefin typically in concentrations from 0.01 to 10 %, based on the total weight of the polyolefin designated for a molecular weight modification.

The fillers and reinforcing agents (item 11 in the list), such as talcum, calcium carbonate, mica or kaolin, are added to the polyolefin e. g. in concentrations from 0.01 to 40 %, based on the total weight of the polyolefin.

The fillers and reinforcing agents (item 11 in the list), such as metal hydroxide, in particular aluminium hydroxide or magnesium hydroxide, are added to the polyolefin e. g. in concentra- tions from 0.01 to 60 %, based on the total weight of the polyolefin.

Carbon black used as filler is usefully added to the polyolefin in concentrations from 0.01 to 5 %, based on the total weight of the polyolefin.

Glass fibres used as reinforcing agents are usefully added to the polyolefin in concentrations from 1 to 30 %, based on the total weight of the polyolefin.

Other conventional polyolefin additives may also be polymers which improve the material properties of the predamaged polyolefin, for example elastomers (impact strength improvers) or compatibilisers (compatibility improvers).

Impact strength improvers are homo-or copolymers which can modify brittle polyolefins such that their impact strength is maintained also in the cold. Polymers suitable therefor are, for example, EPM polymers, EPDM polymers, ABR, BR or SBR graft polymers.

Compatibility improvers may be, for example, copolymers, in particular block copolymers, of styrene with butadiene and, where appropriate, acrylonitrile. Other compatibility improvers may contain copolymers of ethylene and propylene and, where appropriate, a third monomer component, such as butadiene. Chlorinated polyethylene or ethylene/vinyl acetate copoly- mers are also suitable as compatibility improvers, depending of course on the respective composition of the plastics mixture or of the recyclate. Other suitable compatibility improvers preferably contain polar groups, such as maleic anhydride/styrene copolymers or graft polymers containing acrylic acid groups.

The compatibility improvers are preferably used in amounts from 1 to 20 %, based on the total weight of the polyolefin.

Another interesting novel process for modifying the molecular weight of polyolefins is that, which comprises adding besides compound (A) other additives, in particular UV absorbers and light stabilisers (item 2 in the list); nucleating agents (item 10 in the list); fillers and re- inforcing agents (item 11 in the list); and/or compatibility improvers.

The incorporation of compound (A), which contains at least one epoxy group and at least one alkenyl group, and optional further additives into the polyolefin is carried out by known methods, for example before or during moulding or also by applying the liquid, dissolve or dispersed additive mixture to the polyolefin, if required with subsequent evaporation of the solvent. The additive mixture can also be added to the polyolefin designated for a molecular weight modification in the form of a masterbatch containing it, for example, in a concentra- tion from 2.5 to 25 % by weight, based on the weight of the polyolefin.

The novel compound (A) and optional further additives can be incorporated into the polyole- fin designated for molecular weight modification in pure form or encapsulated in waxes, oils or polymers.

The novel compound (A) and optional further additives can also be sprayed onto the polyole- fin designated for molecular weight modification. They are able to dilute other additives (e. g. the conventional additives cited above) or their melts so that they can also be sprayed to- gether with these additives onto the polyolefin designated for molecular weight modification.

The polyolefins so obtained can be used for a very wide range of purposes, for example for tubes, profiles, sheets, for example insulating sheets, pallets, cable insulations, sports equip- ments, garden furniture, foils, construction parts, vehicle and machine parts, containers of all kinds, for example bottles, or packaging material. In another of its aspects, this invention also relates to the use of compound (A), which con- tains at least one epoxy group and at least one alkenyl group, for modifying the molecular weight of polyolefins. The preferences of use correspond to those of the process.

This invention also relates to a composition, which comprises a) a polyolefin, and b) at least one compound (A), which contains at least one epoxy group and at least one alkenyl group.

The preference of the composition correspond to those of the process.

Preferred compositions are those which comprise, besides the components a) and b), addi- tionally c) at least one compound from the group of the radical formers and/or perchlorates.

Particularly preferred compositions are those which, besides the components a) and b), addition comprise c) at least one peroxide.

It is preferred to add 0.001 to 10 parts, particularly preferably 0.01 to 5 parts, e. g. 0.01 to 2 parts, of component (c) per 100 parts of polyolefin.

This invention also relates to polyolefins having a modified molecular weight, which poly- olefins are obtainable by the process of this invention.

The following non-limitative Examples illustrate the invention in more detail. As in the re- mainder of the description, parts and percentages are by weight, unless otherwise stated.

Example 1: Modification of the molecular weight of polyethylene.

In a Plasticorder, of Brabender, fitted with a mixing chamber W 50,36 g of polyethylene (HostalenO GM 6255, of Hostalen Polyethylen GmbH) are kneaded at 220°C and at 40 rpm for 10 minutes together with the additives indicated in Table 1. Blending is then stopped and the poiymer composition is taken out of the mixing chamber and is prepressed at 220°C with about 50 KN for one minute. After comminuting the sample, the melt index (MFR) is measured (at 260°C with 21.6 kg in accordance with ISO 1133). Marked increase of the melt index signifies high chain degradation of the polymer, i. e. bad stability. The results are compile in Table 1.

Table 1: Example Additives Melt index (MFR) 1aa) 18.1 1 ba) 0.05 % dicumyl peroxidec) 39.3 0.50 % compound (101 d) 2.27 1.00 % compound (10t) d) 0.51 1 b) 0.50 % compound (101). q 0.05 % dicumyl peroxide" Footnotes a) to d) see end of Table 2 (Example 2).

Under processing conditions without additive (Example 1a), the polyethylene used under- goes a loss in molecular weight which is even increased by a radical former (cumyl peroxide, Example 1 b). In Examples 1c to 1e of this invention, a molecular weight modification of the polyethylene is found which shows in a desired lowering of the melt index.

Example 2: Molecular weight modification of polyethylene.

In a twin-screw extruder ZSK 25, of Werner & Pfleiderer, a commercially available poly- ethylene (HostalenO GM 6255, of Hostalen Polyethylen GmbH) is extruded at 250°C and at 100 rpm together with the additives indicated in Table 2 and is then subjected to strand pelletisation in a water bath. Test samples are then injection moulded from the polymer granules at a temperature of at most 240°C, and their tensile strength in N/mm2 and ultimate elongation in % is determined in a tensile test (Universal Test Machine UPM 1464, of Zwick) in accordance with DIN 53448. The higher the values, the more stable the polymer. The results are compiled in Table 2.

Table 2: Tensile strength Ultimate elon- Example Additives in N/m M2 gation in % 2a a) 34. 4 79 2bb) 0. 50 % compound (101 d) 32.7 267 a) Comparison Examples. b) Examples of this invention. c) Dicumyl peroxide signifies bis (a, (x-dimethylbenzyl) peroxide, of Fluka, Switzerland (cata- logue number 36590). d) Compound (101) signifies 2,2'-dipropenyl-bisphenol A-diglycidyl ether of formula A1.

In contrast to the Comparison Example 2a, Example 2b of this invention provides a markedly improved ultimate elongation at retained tensile strength.