EP2164892A1

EP2164892A1 - Stabilizer compositions

Info

Publication number: EP2164892A1
Application number: EP08774512A
Authority: EP
Inventors: Karl-Heinz Hornbach; Philipp Walter
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2007-07-10
Filing date: 2008-06-30
Publication date: 2010-03-24
Also published as: TW200914512A; WO2009007265A1

Abstract

The invention describes a mixture for the stabilization of a polypropylene-based thermoplastic polymer comprising a) at least a compound of the formula (I). b) at least a compound of the formula (II). c) at least a tocopherol compound, wherein component (c) is present in an amount of 0.0001 to 20%, based on the total weight of components (a), (b) and (c).

Description

Stabilizer compositions

The present invention relates to novel stabilizers mixtures, to compositions comprising a polypropylene-based thermoplastic polymer, and to the novel stabilizer mixtures, as well as the use thereof for stabilizing polypropylene-based thermoplastic polymers against oxidative, thermal or light-induced degradation.

Polypropylene-based thermoplastic polymers, for example polypropylene (PP), are prone to degradation due to their general structure and the method how these polypropylene-based thermoplastic polymers are being prepared. Tertiary carbon atoms as well as catalyst residuals are making polypropylene-based thermoplastic polymers vulnerable to degradation by autoxidation during long-term exposure or polymer processing at high temperatures, for example higher than 230 ⁰C. Particularly, low melt flow rate (MFR) materials with a melt flow rate lower than 20 are processed at high temperatures and under high shear, resulting in more stringent requirements towards processing stability. In general phenol/phosphite blends (IRGANOX 1010 and IRGAFOS 168) in combination with acid scavengers such as calcium stearate (CaSt) or hydrotalcites (Hycite 713) are used as stabilizer packages. It is well know that carbon-centered radical scavengers such as certain type of lactones and vitamin E improve the processing stability.

However, so far vitamin E resulted in color formation or yellowing respectively. It was surprisingly found, that specific blends of Irganox 1010 (RTM), lrgafos 168 (RTM) and vitamin E lead to superior processing stability in terms of melt flow rate (MFR) and yellow index (Yl) retention after multiple pass extrusion of polypropylene-based thermoplastic polymers already in low concentrations.

The present invention accordingly relates to a mixture for the stabilization of a polypropylene-based thermoplastic polymer comprising a) at least a compound of the formula I

b) at least a compound of the formula

c) at least a tocopherol compound,

wherein component (c) is present in an amount of 0.0001 to 20%, based on the total weight of components (a), (b) and (c).

Component (c) is preferably present in an amount of 0.001 to 15%, for example 0.01 to 15%, typically 0.1 to 15%, based on the total weight of components (a), (b) and (c). In a preferred mixture, component (c) is present in an amount of 1 to 15%, for example 2 to 10%, typically 5 to 10%, based on the total weight of components (a), (b) and (c). In a very specifically preferred mixture, component (c) is present in an amount of 5 to 7%, for example 6%, based on the total weight of components (a), (b) and (c).

Preferably, the weight ratio of component (a) to component (b) is from 2 : 1 to 1 : 4, for example 2 : 1 to 1 : 1.

Component (c) is preferably a compound of the formula

wherein

O I l 3)₂ , -CH₂-CH₂-O-C-R₂ ,

R₂ is C₇-C₃oalkyl, and R₃ is Ci-C₃oalkyl.

Alkyl having from 1 to 30 carbon atoms is a branched or unbranched radical, such as, for example, 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, iso- heptyl, 1 ,1 ,3,3-tetramethylbutyl, 1 -methylheptyl, 3-methylheptyl, n-octyl, isooctyl, 2-ethyl- hexyl, 1 ,1 ,3-trimethylhexyl, 1 ,1 ,3,3-tetramethylpentyl, nonyl, isononyl, decyl, isodecyl, unde- cyl, isoundecyl, dodecyl, isododecyl, 1 ,1 ,3,3,5,5-hexamethylhexyl, tridecyl, tetradecyl, penta- decyl, hexadecyl, heptadecyl, octadecyl (stearyl), icosyl or docosyl.

Of interest are mixtures wherein component (c) is a compound of the formula I, wherein R₁ is — (CH₂)- CH- (CH₂)- CH- (CH₂)- CH-(CH₃)₂ . This compound is vitamin E which is CH₃ CH₃ commercially available as Irganox E 201 (RTM) [Ciba Specialty Chemicals Inc.].

The compound of the formula I is Irganox 1010 (RTM) and the compound of the formula Il is lrgafos 168 (RTM). Both are commercially available from Ciba Specialty Chemicals Incorporation. - A -

Of interest are mixtures comprising in addition, besides components (a), (b) and (c), further additives, typically 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-(α-methylcyclohexyl)-4,6-dimethyl- phenol, 2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol, 2,6-di-tert-butyl-4-meth- oxymethylphenol, 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 thereof.

1.2. Alkylthiomethylphenols, for example 2,4-dioctylthiomethyl-6-tert-butylphenol, 2,4-dioctyl- thiomethyl-6-methylphenol, 2,4-dioctylthiomethyl-6-ethylphenol, 2,6-di-dodecylthiomethyl-4- nonylphenol.

1.3. Hydroquinones and alkylated hvdroquinones, 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-hy- droxyphenyl) adipate.

1.4. Hydroxylated thiodiphenyl 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-hydroxyphenyl)- disulfide.

1.5. 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-(α-methylcyclohexyl)- phenol], 2,2'-methylenebis(4-methyl-6-cyclohexylphenol), 2,2'-methylenebis(6-nonyl-4- methylphenol), 2,2'-methylenebis(4,6-di-tert-butylphenol), 2,2'-ethylidenebis(4,6-di-tert-butyl- phenol), 2,2'-ethylidenebis(6-tert-butyl-4-isobutylphenol), 2,2'-methylenebis[6-(α-methylben- zyl)-4-nonylphenol], 2,2'-methylenebis[6-(α,α-dimethylbenzyl)-4-nonylphenol], 4,4'-methy- lenebis(2,6-di-tert-butylphenol), 4,4'-methylenebis(6-tert-butyl-2-methylphenol), 1 ,1-bis(5- tert-butyl-4-hydroxy-2-methylphenyl)butane, 2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)- 4-methylphenol, 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- butyl-4'-hydroxyphenyl)butyrate], bis(3-tert-butyl-4-hydroxy-5-methyl-phenyl)dicyclopenta- diene, bis[2-(3'-tert-butyl-2'-hydroxy-5'-methylbenzyl)-6-tert-butyl-4-methylphenyl]terephtha- late, 1 ,1-bis-(3,5-dimethyl-2-hydroxyphenyl)butane, 2,2-bis(3,5-di-tert-butyl-4-hydroxyphe- nyl)propane, 2,2-bis(5-tert-butyl-4-hydroxy2-methylphenyl)-4-n-dodecylmercaptobutane, 1 ,1 ,5,5-tetra-(5-tert-butyl-4-hydroxy-2-methylphenyl)pentane.

1.6. Q-, N- and S-benzyl compounds, for example 3,5,3',5'-tetra-tert-butyl-4,4'-dihydroxydi- benzyl 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-S^-di-tert-butyl^-hydroxybenzylmercaptoacetate.

1.7. 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.

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

1.9. Triazine compounds, for example 2,4-bis(octylmercapto)-6-(3,5-di-tert-butyl-4-hydroxy- anilino)-1 ,3,5-triazine, 2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyanilino)-1 ,3,5-tri- azine, 2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyphenoxy)-1 ,3,5-triazine, 2,4,6-tris- (3,5-di-tert-butyl-4-hydroxyphenoxy)-1 ,2,3-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- (3, 5-di-tert-butyl-4-hydroxyphenylethyl)-1 ,3,5-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)iso- cyanurate.

1.10. Benzylphosphonates, 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-δ-tert-butyM-hydroxy-S-methylbenzylphosphonate, the calcium salt of the monoethyl ester of 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid.

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

1.12. Esters of β-(3,5-di-tert-butyl-4-hvdroxyphenyl)propionic acid with mono- or polyhydric alcohols, 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, tris(hydroxyethyl)isocyanurate, N,N'-bis(hydroxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hydroxy- methyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.13. Esters of β-(5-tert-butyl-4-hvdroxy-3-methylphenyl)propionic acid with mono- or polyhydric alcohols, 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, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,N'-bis- (hydroxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hydroxymethyl-1 -phospha-2,6,7-trioxabicyclo[2.2.2]octane; 3,9-bis[2-{3-(3-tert- butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1 ,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]- undecane.

1.14. Esters of β-(3,5-dicvclohexyl-4-hvdroxyphenyl)propionic acid with mono- or polyhydric alcohols, 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. 1.15. Esters of 3,5-di-tert-butyl-4-hvdroxyphenyl acetic acid with mono- or polyhydric alcohols, 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. Amides of β-(3,5-di-tert-butyl-4-hvdroxyphenyl)propionic 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)hy- drazide, N,N'-bis[2-(3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyloxy)ethyl]oxamide (Nau- gard^®XL-1 , supplied by Uniroyal).

1.17. Ascorbic acid (vitamin C)

1.18. 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- naphthyl)-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1 ,3- dimethylbutyl)-N'-phenyl-p-phenylenediamine, N-(1-methylheptyl)-N'-phenyl-p- phenylenediamine, N-cyclohexyl-N'-phenyl-p-phenylenediamine, 4-(p- toluenesulfamoyl)diphenylamine, N,N'-dimethyl-N,N'-di-sec-butyl-p-phenylenediamine, diphenylamine, N-allyldiphenylamine, 4-isopropoxydiphenylamine, N-phenyl-1- naphthylamine, N-(4-tert-octylphenyl)-1 -naphthylamine, N-phenyl-2-naphthylamine, octylated diphenylamine, for example p,p'-di-tert-octyldiphenylamine, 4-n-butylaminophenol, 4-butyrylaminophenol, 4-nonanoylaminophenol, 4-dodecanoylaminophenol, 4- octadecanoylaminophenol, bis(4-methoxyphenyl)amine, 2,6-di-tert-butyl-4-dimethylamino- methylphenol, 2,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, N,N,N',N'-tetra- methyl-4,4'-diaminodiphenylmethane, 1 ,2-bis[(2-methylphenyl)amino]ethane, 1 ,2-bis(phenyl- amino)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-octyldiphenyl- amines, a mixture of mono- and dialkylated nonyldiphenylamines, a mixture of mono- and dialkylated dodecyldiphenylamines, a mixture of mono- and dialkylated isopropyl/isohexyl- diphenylamines, a mixture of mono- and dialkylated tert-butyldiphenylamines, 2,3-dihydro- 3,3-dimethyl-4H-1 ,4-benzothiazine, phenothiazine, a mixture of mono- and dialkylated tert- butyl/tert-octylphenothiazines, a mixture of mono- and dialkylated tert-octyl-phenothiazines, N-allylphenothiazine, N,N,N',N'-tetraphenyl-1 ,4-diaminobut-2-ene.

2. UV absorbers and light stabilizers

2.1. 2-(2'-Hvdroxyphenyl)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-(α,α-dimethylbenzyl)-2'- hydroxyphenyl)benzotriazole, 2-(3'-tert-butyl-2'-hydroxy-5'-(2-octyloxycarbonylethyl)phenyl)- 5-chloro-benzotriazole, 2-(3'-tert-butyl-5'-[2-(2-ethylhexyloxy)-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-meth- oxycarbonylethyl)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, 2,2'-methylene-bis[4- (1 ,1 ,3,3-tetramethylbutyl)-6-benzotriazole-2-ylphenol]; the transesterification product of 2-[3'- tert-butyl-5'-(2-methoxycarbonylethyl)-2'-hydroxyphenyl]-2H-benzotriazole with polyethylene glycol 300; [R-CH₂CH₂-COO-CH₂CH₂-^ , where R = 3'-tert-butyl-4'-hydroxy-5'-2H-

benzotriazol-2-ylphenyl, 2-[2'-hydroxy-3'-(α_!α-dimethylbenzyl)-5'-(1 _!1 _!3,3-tetramethylbutyl)- phenyl]benzotriazole; 2-[2'-hydroxy-3'-(1 ,1 ,3,3-tetramethylbutyl)-5'-(α,α-dimethylbenzyl)- phenyl]benzotriazole.

2.2. 2-Hvdroxybenzophenones, 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, for example 4-tert-butyl-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 α-cyano-β,β-diphenylacrylate, isooctyl α-cyano-β,β-diphe- nylacrylate, methyl α-carbomethoxycinnamate, methyl α-cyano-β-methyl-p-methoxycinna- mate, butyl α-cyano-β-methyl-p-methoxy-cinnamate, methyl α-carbomethoxy-p-methoxycin- namate, N-(β-carbomethoxy-β-cyanovinyl)-2-methylindoline, neopentyl tetra(α-cyano-β,β-di- phenylacrylate.

2.5. Nickel compounds, for example nickel complexes of 2,2'-thio-bis[4-(1 ,1 ,3,3-tetramethyl- butyl)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- nylundecylketoxime, nickel complexes of 1-phenyl-4-lauroyl-5-hydroxypyrazole, with or without additional ligands.

2.6. Sterically 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- piperidyl) 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-dichloro-1 ,3,5-triazine, tris(2,2,6,6-tetramethyl-4-piperidyl)nitrilotriacetate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1 ,2,3,4-butanetetracarboxylate, 1 ,1 '-(1 ,2-ethanediyl)- bis(3,3,5,5-tetramethylpiperazinone), 4-benzoyl-2,2,6,6-tetramethylpiperidine, 4-stearyloxy- 2,2,6,6-tetramethylpiperidine, 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]decane-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)hexamethylenediamine 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-tetramethyl-1 ,3,8-triazaspiro[4.5]decane-2,4-dione, 3-dodecyl-1 - (2,2,6,6-tetramethyl-4-piperidyl)pyrrolidine-2,5-dione, 3-dodecyl-1-(1 ,2,2,6,6-pentamethyl-4- piperidyl)pyrrolidine-2,5-dione, a mixture 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-trichloro-1 ,3,5-triazine as well as 4-butylamino-2,2,6,6-tetramethylpiperidine (CAS Reg. No. [136504-96-6]); a condensate of 1 ,6-hexanediamine and 2, 4, 6-trichloro-1 ,3,5-triazine as well as N,N-dibutylamine and 4- butylamino-2,2,6,6-tetramethylpiperidine (CAS Reg. No. [192268-64-7]); N-(2,2,6,6- tetramethyl-4-piperidyl)-n-dodecylsuccinimide, N-(1 , 2,2,6, 6-pentamethyl-4-piperidyl)-n- dodecylsuccinimide, 2-undecyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxo-spiro[4,5]decane, a reaction product of 7,7,9,9-tetramethyl-2-cycloundecyl-1-oxa-3,8-diaza-4-oxospiro- [4,5]decane and epichlorohydrin, 1 ,1-bis(1 , 2,2,6, 6-pentamethyl-4-piperidyloxycarbonyl)-2-(4- methoxyphenyl)ethene, N,N'-bis-formyl-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexa- methylenediamine, a diester of 4-methoxymethylenemalonic acid with 1 ,2,2,6,6- pentamethyl-4-hydroxypiperidine, poly[methylpropyl-3-oxy-4-(2,2,6,6-tetramethyl-4- piperidyl)]siloxane, a reaction product of maleic acid anhydride-α-olefin copolymer with 2,2,6,6-tetramethyl-4-aminopiperidine or 1 ,2,2,6,6-pentamethyl-4-aminopiperidine, 2,4-bis[N- (1-cyclohexyloxy-2,2,6,6-tetramethylpiperidine-4-yl)-N-butylamino]-6-(2-hydroxyethyl)amino- 1 ,3,5-triazine, 1 -(2-hydroxy-2-methylpropoxy)-4-octadecanoyloxy-2, 2,6,6- tetramethylpiperidine, 5-(2-ethylhexanoyl)oxymethyl-3,3,5-trimethyl-2-morpholinone,

Sanduvor (Clariant; CAS Reg. No. 106917-31-1], 5-(2-ethylhexanoyl)oxymethyl-3,3,5- trimethyl-2-morpholinone, the reaction product of 2,4-bis[(1-cyclohexyloxy-2,2,6,6-piperidine- 4-yl)butylamino]-6-chloro-s-triazine with N,N'-bis(3-aminopropyl)ethylenediamine), 1 ,3,5- tris(N-cyclohexyl-N-(2,2,6,6-tetramethylpiperazine-3-one-4-yl)amino)-s-triazine, 1 ,3,5-tris(N- cyclohexyl-N-(1 ,2,2,6,6-pentamethylpiperazine-3-one-4-yl)amino)-s-triazine.

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'-ethyloxani- lide, 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-Hydroxyphenyl)-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(2,4-dimethylphenyl)-1 ,3,5-triazine, 2- (2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1 ,3,5-triazine, 2,4-bis(2-hydroxy-4-propyl- oxyphenyl)-6-(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(2,4-dimethylphenyl)-1 ,3,5-triazine, 2-[2-hydroxy-4-(2-hydroxy-3-butyloxypropoxy)phenyl]-4,6-bis(2,4-dimethyl)-1 ,3,5-triazine, 2- [2-hydroxy-4-(2-hydroxy-3-octyloxypropyloxy)phenyl]-4,6-bis(2,4-dimethyl)-1 ,3,5-triazine, 2- [4-(dodecyloxy/tridecyloxy-2-hydroxypropoxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)- 1 ,3,5-triazine, 2-[2-hydroxy-4-(2-hydroxy-3-dodecyloxypropoxy)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-hydr- oxy-4-methoxyphenyl)-4,6-diphenyl-1 ,3,5-triazine, 2,4,6-tris[2-hydroxy-4-(3-butoxy-2- hydroxypropoxy)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, 2,4-bis(4-[2-ethylhexyloxy]-2-hydroxyphenyl)-6-(4- methoxyphenyl)-1 ,3,5-triazine.

3. Metal deactivators, for example N,N'-diphenyloxamide, N-salicylal-N'-salicyloyl hydrazine, N,N'-bis(salicyloyl)hydrazine, N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine, 3-salicyloylamino-1 ,2,4-triazole, bis(benzylidene)oxalyl 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, diphenylalkyl phosphites, phenyldialkyl phosphites, tris(nonylphenyl) phosphite, trilauryl phosphite, trioctadecyl phosphite, distearylpentaerythritol diphosphite, diisodecyl pentaerythritol diphosphite, bis(2,4-di- tert-butylphenyl)pentaerythritol diphosphite, bis(2,4-di-cumylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, diisodecyloxypentaerythritol diphosphite, bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritol diphosphite, bis(2,4,6-tris(tert-butylphenyl)pentaerythritol diphosphite, tristearyl sorbitol triphosphite, tetrakis(2,4-di-tert-butylphenyl) 4,4'-biphenylene diphosphonite, 6-isooctyloxy- 2,4,8, 10-tetra-tert-butyl-12H-dibenz[d,g]-1 ,3,2-dioxaphosphocin, bis(2,4-di-tert-butyl-6- methylphenyl)methyl phosphite, bis(2,4-di-tert-butyl-6-methylphenyl)ethyl phosphite, 6- fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenz[d,g]-1 ,3,2-dioxaphosphocin, 2,2',2"- nitrilo[triethyltris(3,3',5,5'-tetra-tert-butyl-1 ,1 '-biphenyl-2,2'-diyl)phosphite], 2- ethylhexyl(3,3',5,5'-tetra-tert-butyl-1 ,1 '-biphenyl-2,2'-diyl)phosphite, 5-butyl-5-ethyl-2-(2,4,6- tri-tert-butylphenoxy)-1 ,3,2-dioxaphosphirane.

5. Hydroxylamines, for example N,N-dibenzylhydroxylamine, N,N-diethylhydroxylamine, N, N- dioctylhydroxylamine, N,N-dilaurylhydroxylamine, N,N-ditetradecylhydroxylamine, N, N- dihexadecylhydroxylamine, N,N-dioctadecylhydroxylamine, N-hexadecyl-N-octadecylhydrox- ylamine, N-heptadecyl-N-octadecylhydroxylamine, N,N-dialkylhydroxylamine derived from hydrogenated tallow amine.

6. Nitrones, for example, N-benzyl-alpha-phenylnitrone, N-ethyl-alpha-methylnitrone, N- octyl-alpha-heptylnitrone, N-lauryl-alpha-undecylnitrone, N-tetradecyl-alpha-tridecylnnitrone, N-hexadecyl-alpha-pentadecylnitrone, N-octadecyl-alpha-heptadecylnitrone, N-hexadecyl- alpha-heptadecylnitrone, N-ocatadecyl-alpha-pentadecylnitrone, N-heptadecyl-alpha-hepta- decylnitrone, N-octadecyl-alpha-hexadecylnitrone, nitrone derived from N,N-dialkylhydroxyl- amine derived from hydrogenated tallow amine.

7. Thiosynergists, for example dilauryl thiodipropionate, dimistryl thiodipropionate, distearyl thiodipropionate or distearyl disulfide.

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

9. Basic co-stabilizers, for example melamine, polyvinylpyrrolidone, dicyandiamide, triallyl cyanurate, urea derivatives, hydrazine derivatives, amines, 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). Especially preferred are 1 ,3:2,4-bis(3',4'-dimethylbenzylidene)sorbitol, 1 ,3:2,4- di(paramethyldibenzylidene)sorbitol, and 1 ,3:2,4-di(benzylidene)sorbitol.

1 1. Fillers and reinforcing agents, for example calcium carbonate, silicates, glass fibres, glass beads, asbestos, talc, kaolin, mica, barium sulfate, metal oxides and hydroxides, carbon black, graphite, wood flour and flours or fibers of other natural products, synthetic fibers.

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-431661 1 ; DE-A-4316622; DE-A-4316876; EP-A-0589839, EP-A-0591 102; EP-A-1291384 or 3-[4-(2- acetoxyethoxy)phenyl]-5,7-di-tert-butylbenzofuran-2-one, 5,7-di-tert-butyl-3-[4-(2- stearoyloxyethoxy)phenyl]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-dimethylphenyl)-5,7-di-tert-butylbenzofuran-2-one, 3-(3,5-dimethyl-4- pivaloyloxyphenyl)-5,7-di-tert-butylbenzofuran-2-one, 3-(3,4-dimethylphenyl)-5,7-di-tert- butylbenzofuran-2-one, 3-(2,3-dimethylphenyl)-5,7-di-tert-butylbenzofuran-2-one, 3-(2- acetyl-δ-isooctylphenyO-δ-isooctylbenzofuran^-one.

Preferred further additives are for example light-stabilizers, acid scavengers and/or antistatic agents.

The mixture of components (a), (b) and (c) and optionally further additives is suitable for stabilizing polypropylene-based thermoplastic polymers against oxidative, thermal or light-indu- ced degradation. Special attention is drawn to their excellent action as antioxidant in the stabilization of polypropylene-based thermoplastic polymers with a melt flow rate lower than 20 after multiple pass extrusion.

Polypropylene-based thermoplastic polymers an 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, VIb 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 π- or σ-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 Ia, Na 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).

Illustrative examples of such polypropylene-based thermoplastic polymers are:

Mixtures of polypropylene with polyisobutylene and polypropylene with polyethylene (for example PP/HDPE, PP/LDPE).

Copolymers of monoolefins and diolefins with each other or with other vinyl monomers, for example ethylene/propylene copolymers, propylene/but-1-ene copolymers, propylene/isobu- tylene copolymers; propylene/butadiene copolymers, 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 above, for example polypropylene/ethylene-propylene copolymers.

A further object of the invention is therefore a composition comprising i) a polypropylene- based thermoplastic polymer which is susceptible to oxidative, thermal or light-induced degradation, and ii) at least a mixture of components (a), (b) and (c).

To be singled out for special mention is the efficacy of the novel mixtures against oxidative or thermal degradation, especially under the action of heat which occurs during the processing of thermoplasts. The mixtures of this invention are therefore admirably suited for use as processing stabilizers.

The mixture of components (a), (b) and (c) and optionally further additives, for example typically those as outlined above, will preferably be added to the polypropylene-based thermoplastic polymer to be stabilized in concentrations of 0.001 to 5 %, preferably 0.01 to 5 %, typically 0.01 to 1 %, based on the weight of said material. Most preferably, the mixture of components (a), (b) and (c) and optionally further additives, for example typically those as outlined above, will preferably be added to the polypropylene-based thermoplastic polymer to be stabilized in concentrations of 0.05 to 0.5%, for example 0.1 %, based on the weight of said material.

The co-stabilizers are added, for example, in concentrations of from 0.01 to 10 %, based on the total weight of the polypropylene-based thermoplastic polymer to be stabilized.

Further preferred compositions also comprise, besides components (i) and (ii), further additives selected from the group consisting of light-stabilizers and/or acid scavengers. Especially preferred acid scavengers are for example salts of carboxyl acids like for example calcium stearate, zinc stearate or zinc octoate; or metal oxides.

Also of interest as yet further additives in the compositions according to the invention are alkaline earth metal salts of higher fatty acids or lactic acid, such as, for example, calcium stearate, calcium lactate or calcium stearoyl-2-lactylate. The terms calcium lactate and calcium stearoyl-2-lactylate are to be understood as meaning those compounds as disclosed in U.S. 4,366,280. A further description of calcium lactate may be found, for example, in The Merck Index, Eleventh Edition, 1683, page 254 (1989). A useful description of calcium stearoyl-2-lactylate may be found, for example, in The Merck Index, Eleventh Edition, 1711 , page 257 (1989). These known commercially available compounds are, for example, used also as additives in foodstuffs. They are available from the American Ingredients Company, PATCO Polymer Additives Division, Kansas City, USA, under the following tradenames: Pationic 1230 (RTM) (calcium lactate); Pationic 1240 (RTM) (mixture of calcium lactate and calcium hydroxide); Pationic 930 (RTM) (calcium stearoyl-2- lactylate); Pationic 940 (RTM) (mixture of calcium stearoyl-2-lactylate and calcium hydroxide); Pationic 1250 (RTM) (mixture of calcium lactate, calcium stearoyl-2-lactylate and calcium hydroxide).

Especially preferred co-additives are phenolic antioxidants (point 1.1 to 1.16 of the list), UV absorbers and light-stabilizers (point 2 of the list), for example sterically hindered amines (HALS, point 2.6 of the list).

As a conventional stabilizer combination for the processing of polymeric organic materials, such as, for example, polyolefins, into corresponding moulded articles, the combination of a phenolic antioxidant with a secondary antioxidant based on an organic phosphite or phos- phonite is recommended. Depending on the substrate and process, however, many poly- olefin processors are obliged to operate processes in the high-temperature range above approx. 280⁰C. The inclusion of a processing stabilizer of component (c) [tocopherol compound] is particularly suitable for high-temperature applications, especially in the temperature range above 300⁰C. Technical materials and moulded articles for instance based on polypropylene-based thermoplastic polymers, such as, for example, pipes and their technical variants (fittings), can be manufactured with a higher output and fewer rejects. A further advantage of the stabilizer mixture of components (a), (b) and (c) is also that they can be used in a very small amount, which results in a reduction in the overall antioxidant concentration compared with conventional stabilizer mixtures. For instance the use of a low concentration of component (c) [most preferably 6%, based on the total weight of components (a), (b) and (c)] allows the overall stabilizer concentration to be reduced by approximately a third in, for example, polypropylene-based thermoplastic polymers, which at the same time represents an economic advantage. Components (a), (b) and (c), and also where applicable further additives, are incorporated into the polypropylene-based thermoplastic polymer according to known methods, for example before or during the shaping, or alternatively by applying a solution or dispersion of the stabilizer mixture to the polypropylene-based thermoplastic polymer, if necessary with subsequent evaporation of the solvent. The stabilizer mixture of components (a), (b) and (c), and where applicable further additives, may also be added to the polypropylene-based thermoplastic polymer to be stabilized in the form of a masterbatch.

The present invention relates therefore also to a masterbatch composition comprising a stabilizer mixture comprising components (a), (b) and (c) and optionally further additives as outlined above and a thermoplastic material which is identical or compatible with the polypropylene-based thermoplastic polymer to be stabilized. Preferably, the masterbatch composition comprises 10 to 80% by weight of said thermoplastic material.

The stabilizer mixture of components (a), (b) and (c), and where applicable further additives, may also be added before or during polymerization or before crosslinking.

The stabilizer mixture of components (a), (b) and (c), and where applicable further additives, may be incorporated into the polypropylene-based thermoplastic polymers to be stabilized in pure form or encapsulated in waxes, oils or polymers.

The stabilizer mixture of components (a), (b) and (c), and where applicable further additives, may also be sprayed onto the polypropylene-based thermoplastic polymers to be stabilized. The mixture can be used to dilute other additives (e.g. the above-mentioned conventional additives) or melts thereof, so that it is also possible for the mixture to be sprayed together with those additives onto polypropylene-based thermoplastic polymers to be stabilized. Addition by spraying during the deactivation of the polymerisation catalysts is especially advantageous, it being possible, for example, for the vapour used for the deactivation to be utilised for the spraying.

For example, where the polypropylene-based thermoplastic polymers are polymerized in the form of beads, it may be advantageous for the stabilizer mixture of components (a), (b) and (c), and where applicable other additives, to be applied by spraying. The polypropylene-based thermoplastic polymers stabilized in that manner may be used in an extremely wide variety of forms, e.g. in the form of films, fibres, tapes, moulding compounds or profiles, or as binders for surface-coatings, especially powder coatings, adhesives or cements.

The polypropylene-based thermoplastic polymers stabilized in that manner may likewise be used in an extremely wide variety of forms, especially in the form of thick-layer polypropylene moulded articles that are in lasting contact with extracting media, such as, for example, pipes for liquids or gases, films, fibres, geomembranes, tapes, profiles or tanks.

The polypropylene-based thermoplastic polymer compositions according to the present invention can be advantageously used for the preparation of various shaped articles. Examples are:

1-1 ) Floating devices, marine applications, pontoons, buoys, plastic lumber for decks, piers, boats, kayaks, oars, and beach reinforcements.

I-2) Automotive applications, in particular bumpers, dashboards, battery, rear and front linings, moldings parts under the hood, hat shelf, trunk linings, interior linings, air bag covers, electronic moldings for fittings (lights), panes for dashboards, headlamp glass, instrument panel, exterior linings, upholstery, automotive lights, head lights, parking lights, rear lights, stop lights, interior and exterior trims; door panels; gas tank; glazing front side; rear windows; seat backing, exterior panels, wire insulation, profile extrusion for sealing, cladding, pillar covers, chassis parts, exhaust systems, fuel filter / filler, fuel pumps, fuel tank, body side mouldings, convertible tops, exterior mirrors, exterior trim, fasteners / fixings, front end module, glass, hinges, lock systems, luggage / roof racks, pressed/stamped parts, seals, side impact protection, sound deadener / insulator and sunroof.

I-3) Road traffic devices, in particular sign postings, posts for road marking, car accessories, warning triangles, medical cases, helmets, tires.

I-4) Devices for plane, railway, motor car (car, motorbike) including furnishings. I-5) Devices for space applications, in particular rockets and satellites, e.g. reentry shields.

I-6) Devices for architecture and design, mining applications, acoustic quietized systems, street refuges, and shelters.

11-1 ) Appliances, cases and coverings in general and electric/electronic devices (personal computer, telephone, portable phone, printer, television-sets, audio and video devices), flower pots, satellite TV bowl, and panel devices.

II-2) Jacketing for other materials such as steel or textiles.

11— 3) Devices for the electronic industry, in particular insulation for plugs, especially computer plugs, cases for electric and electronic parts, printed boards, and materials for electronic data storage such as chips, check cards or credit cards.

II-4) Electric appliances, in particular washing machines, tumblers, ovens (microwave oven), dish-washers, mixers, and irons.

11— S) Covers for lights (e.g. street-lights, lamp-shades).

II-6) Applications in wire and cable (semi-conductor, insulation and cable-jacketing).

II-7) Foils for condensers, refrigerators, heating devices, air conditioners, encapsulating of electronics, semi-conductors, coffee machines, and vacuum cleaners.

111-1 ) Technical articles such as cogwheel (gear), slide fittings, spacers, screws, bolts, handles, and knobs.

III-2) Rotor blades, ventilators and windmill vanes, solar devices, swimming pools, swimming pool covers, pool liners, pond liners, closets, wardrobes, dividing walls, slat walls, folding walls, roofs, shutters (e.g. roller shutters), fittings, connections between pipes, sleeves, and conveyor belts.

III-3) Sanitary articles, in particular shower cubicles, lavatory seats, covers, and sinks. 111-4) Hygienic articles, in particular diapers (babies, adult incontinence), feminine hygiene articles, shower curtains, brushes, mats, tubs, mobile toilets, tooth brushes, and bed pans.

111-5) Pipes (cross-linked or not) for water, waste water and chemicals, pipes for wire and cable protection, pipes for gas, oil and sewage, guttering, down pipes, and drainage systems.

111-6) Profiles of any geometry (window panes) and siding.

111-7) Glass substitutes, in particular extruded plates, glazing for buildings (monolithic, twin or multiwall), aircraft, schools, extruded sheets, window film for architectural glazing, train, transportation, sanitary articles, and greenhouse.

111-8) Plates (walls, cutting board), extrusion-coating (photographic paper, tetrapack and pipe coating), silos, wood substitute, plastic lumber, wood composites, walls, surfaces, furniture, decorative foil, floor coverings (interior and exterior applications), flooring, duck boards, and tiles.

111-9) Intake and outlet manifolds.

111-10) Cement-, concrete-, composite-applications and covers, siding and cladding, hand rails, banisters, kitchen work tops, roofing, roofing sheets, tiles, and tarpaulins.

IV-1 ) Plates (walls and cutting board), trays, artificial grass, astroturf, artificial covering for stadium rings (athletics), artificial floor for stadium rings (athletics), and tapes.

IV-2) Woven fabrics continuous and staple, fibers (carpets / hygienic articles / geotextiles / monofilaments; filters; wipes / curtains (shades) / medical applications), bulk fibers (applications such as gown / protection clothes), nets, ropes, cables, strings, cords, threads, safety seat-belts, clothes, underwear, gloves; boots; rubber boots, intimate apparel, garments, swimwear, sportswear, umbrellas (parasol, sunshade), parachutes, paraglides, sails, "balloon-silk", camping articles, tents, airbeds, sun beds, bulk bags, and bags. IV-3) Membranes, insulation, covers and seals for roofs, tunnels, dumps, ponds, dumps, walls roofing membranes, geomembranes, swimming pools, curtains (shades) / sun-shields, awnings, canopies, wallpaper, food packing and wrapping (flexible and solid), medical packaging (flexible & solid), airbags/safety belts, arm- and head rests, carpets, centre console, dashboard, cockpits, door, overhead console module, door trim, headliners, interior lighting, interior mirrors, parcel shelf, rear luggage cover, seats, steering column, steering wheel, textiles, and trunk trim.

V) Films (packaging, dump, laminating, agriculture and horticulture, greenhouse, mulch, tunnel, silage), bale wrap, swimming pools, waste bags, wallpaper, stretch film, raffia, desalination film, batteries, and connectors.

VI-1 ) Food packing and wrapping (flexible and solid), bottles.

VI-2) Storage systems such as boxes (crates), luggage, chest, household boxes, pallets, shelves, tracks, screw boxes, packs, and cans.

VI-3) Cartridges, syringes, medical applications, containers for any transportation, waste baskets and waste bins, waste bags, bins, dust bins, bin liners, wheely bins, container in general, tanks for water / used water / chemistry / gas / oil / gasoline / diesel; tank liners, boxes, crates, battery cases, troughs, medical devices such as piston, ophthalmic applications, diagnostic devices, and packing for pharmaceuticals blister.

Vl 1-1 ) Extrusion coating (photo paper, tetrapack, pipe coating), household articles of any kind (e.g. appliances, thermos bottle / clothes hanger), fastening systems such as plugs, wire and cable clamps, zippers, closures, locks, and snap-closures.

VII-2) Support devices, articles for the leisure time such as sports and fitness devices, gymnastics mats, ski-boots, inline-skates, skis, big foot, athletic surfaces (e.g. tennis grounds); screw tops, tops and stoppers for bottles, and cans.

VII-3) Furniture in general, foamed articles (cushions, impact absorbers), foams, sponges, dish clothes, mats, garden chairs, stadium seats, tables, couches, toys, building kits (boards / figures / balls), playhouses, slides, and play vehicles. Vl 1-4) Materials for optical and magnetic data storage.

VII-5) Kitchen ware (eating, drinking, cooking, storing).

Vl 1-6) Boxes for CD's, cassettes and video tapes; DVD electronic articles, office supplies of any kind (ball-point pens, stamps and ink-pads, mouse, shelves, tracks), bottles of any volume and content (drinks, detergents, cosmetics including perfumes), and adhesive tapes.

Vl 1-7) Footwear (shoes / shoe-soles), insoles, spats, adhesives, structural adhesives, food boxes (fruit, vegetables, meat, fish), synthetic paper, labels for bottles, couches, artificial joints (human), printing plates (flexographic), printed circuit boards, and display technologies.

Vl 1-8) Devices of filled polymers (talc, chalk, china clay (kaolin), wollastonite, pigments, carbon black, TiO₂, mica, nanocomposites, dolomite, silicates, glass, asbestos).

Thus, a further embodiment of the present invention relates to a shaped article, in particular a film, pipe, profile, bottle, tank or container, fiber containing a composition as described above.

A film is preferred. The film can be prepared as a blown film cast film or via extrusion coating. Especially preferred is a multilayer film.

A further embodiment of the present invention relates to a molded article containing a composition as described above. The molding is in particular effected by injection, blow, compression, roto-molding or slush-molding or extrusion.

The present invention relates also to a process for stabilizing a polypropylene-based thermoplastic polymer against oxidative, thermal or light-induced degradation, which comprises incorporating therein or applying thereto at least a mixture of components (a), (b) and (c). A preferred embodiment of the present invention is likewise the use of a mixture of components (a), (b) and (c) as stabilizers, especially processing stabilizers (thermostabilizers), for polypropylene-based thermoplastic polymers against oxidative, thermal or light-induced degradation.

The preferred mixture of components (a), (b) and (c) for use as stabilizer and the process for stabilizing are the same as those described for the compositions comprising a polypropylene-based thermoplastic polymer.

The following Examples illustrate the invention further. Parts or percentages relate to weight.

Example 1 : Stabilization of multiple-extruded polypropylene (PP).

3.0 kg of unstabilized polypropylene homopolymer (PP) powder are dry-blended with 0.02% of calcium stearate, 0.02% of DHT 4A (RTM) (Kyowa Chemical Industry Co., Ltd., [Mg₄₅AI₂(OH)₁₃CO₃ - S-S H₂O]) and the tested additives. This blend is then extruded in a twin- screw extruder of Berstorff (RTM) (ZSK 25, L/D=46) at temperatures of at most 230⁰C. The extrudate is cooled by drawing it through a water bath and is then granulated. This granulate is repeatedly extruded in a single-screw extruder from Gottfert L/D 25 at 26O⁰C. After the 1^st, 3^rd and 5^th extrusion pass, the melt flow index (MFI) [determined according to ISO 1 133] and Yellowness Index (Yl) [determined according to ASTM D 1925] is measured. The results are summarized in Tables 1 - 4.

Table 1 : Stabilizer composition (formulation) in weigh t-%

Formulation Irganox 1010 (RTM) lrgafos 168 (RTM) Irganox E 201 (RTM)

_Aa) 50 50 — βa) 33.3 66.7 — ca)

20 80 —

_Db) 31.3 62.7 6

_Eb) 47 47 6 Table 2:

Table 3:

Table 4:

a) Comparative Example/Formulation. b) Example/Formulation according to the invention.

Claims

What is claimed is:

1. A mixture for the stabilization of a polypropylene-based thermoplastic polymer comprising a) at least a compound of the formula I

b) at least a compound of the formula

c) at least a tocopherol compound,

2. A mixture according to claim 1 , wherein the weight ratio of component (a) to component (b) is from 2 : 1 to 1 : 4.

3. A mixture according to claim 1 , wherein component (c) is a compound of the formula

wherein

O I l 3)₂ , -CH₂-CH₂-O-C-R₂ ,

R₂ is C₇-C₃oalkyl, and R₃ is Ci-C₃oalkyl.

4. A mixture according to claim 3, wherein R₁ is -(CH₂)₃-CH-(CH₂)₃-CH-(CH₂)-CH-(CH₃)₂ CH₃ CH₃

5. A mixture according to claim 1 , comprising besides components (a), (b) and (c) further additives.

6. A mixture according to claim 5, comprising as further additives light stabilizers, acid scavengers and/or antistatic agents.

7. A composition comprising i) a polypropylene-based thermoplastic polymer which is susceptible to oxidative, thermal or light-induced degradation, and ii) a mixture of components (a), (b) and (c) according to claim 1 .

8. A composition according to claim 7, wherein component (ii) is present in an amount of from 0.001 to 5 %, based on the weight of component (i).

9. A composition according to claim 7, comprising besides components (i) and (ii) further additives.

10. A masterbatch composition comprising a stabilizer mixture according to claim 1 and a thermoplastic material which is identical or compatible with the polypropylene-based thermoplastic polymer to be stabilized.

11. A masterbatch composition according to claim 10 comprising 10 to 80% by weight of said thermoplastic material.

12. A shaped article containing a mixture according to claim 1.

13. A process for stabilizing a polypropylene-based thermoplastic polymer against oxidative, thermal or light-induced degradation, which comprises incorporating therein or applying thereto at least a mixture according to claim 1.

14. The use of a mixture according to claim 1 as stabilizer for a polypropylene-based thermoplastic polymer against oxidative, thermal or light-induced degradation.