This invention pertains to a novel crystalline modification of 2,2',2"-nitrilo[triethyl-tris- (3,3\5,5'-tetra-tert-butyl-l,r-biphenyl-2,2'-diyl) phosphite], to a process for preparing said modification and the use thereof for stabilizing organic materials against oxidative, thermal or light-induced degradation.

2,2\2"-Nitrilo[triethyl-tris-(3,3'-5,5'-tetra-tert-butyl- l,l'-biphenyl-2,2'-diyl) phosphite] is a compound having the formula I

This compound of formula I is useful as a processing stabilizer for organic polymers as taught in US-A-4318 845 and US-A-4374219. The compound of formula I is disclosed as being a white powder melting at 121-134°C. As such, the powdery product has defects in terms of handling and apparent density, exhibiting poor flowability, meterability, sto¬ rage stability, hydrolytic stability and compatibility in polymeric substrates and lubrica¬ ting oils.

It has now been found that the compound of formula I can be obtained in a different crystalline modification as purified crystalline particles which exhibit acceptable proper¬ ties in respect to handling, apparent density, flowability, meterability, storage stability,

hydrolytic stability and compatibility in polymeric substrates and lubricating oils.

The new modification is characterized by a novel crystalline form, melting in the range of 178-185°C as given by the peak temperature of the endotherm recorded by differential scanning calorimetry (DSC); and by an X-ray diffraction pattern obtained using Cu-Koc which exhibits diffraction angles (2Θ) a seen below:

Peak No. Diffraction Angle

1 5.4

2 6.3

3 8.8

4 9.9

5 10.3

6 10.8

7 11.7

8 13.8

9 14.8

10 15.5

11 16.1

12 17.0

13 17.7

14 18.4

15 20.2

The instant invention also relates to a process for the preparation of this novel gamma cry¬ stalline modification of the compound of formula I.

The process for the preparation of the instant gamma crystalline modification comprises crystallizing or recrystallizing said compound from an alkanol of 4 to 8 carbon atoms.

Examples of alkanols of 4 to 8 carbon atoms useful in the instant process are 1-butanol, 2-butanol, tert-butyl alcohol, isobutanol, amyl alcohol, 1-hexanol, 2-ethylhexanol, 1-octanol and mixtures of such alkanols.

The preferred process for preparing the novel gamma crystalline modification is by cry¬ stallizing or recrystallizing the compound of formula I from n-alkanol of 4 to 8 carbon atoms.

An especially preferred process for preparing the novel gamma crystalline modification is by crystallizing or recrystallizing the compound of formula I from 1-butanol or 1-octanol or a mixture thereof.

The instant invention relates also to the gamma crystalline form of 2,2',2"-nitrilo[triethyl- tris-(3,3',5,5'-tetra-tert-butyl-l, -biphenyl-2,2'-diyl) phosphite], characterized by melting in the range of 178-185°C and by an X-ray diffraction pattern using Cu-Kα which exhibits diffraction angles (2Θ):

Peak No. Diffraction Angle

1 5.4

2 6.3

3 8.8

4 9.9

5 10.3

6 10.8

7 11.7

8 13.8

9 14.8

10 15.5

11 16.1

12 17.0

13 17.7

14 18.4

15 20.2

obtainable by crystallizing or recrystallizing said compound from an alkanol of 4 to 8 carbon atoms.

The gamma crystalline form of formula I according to the invention is highly suitable for

stabilizing organic materials against oxidative, thermal or light-induced degradation.

Examples of such organic materials are:

1. Polymers of monoolefins and diolefins, for example polypropylene, polyisobutylene, polybut-1-ene, poly-4-methylpent-l-ene, polyisoprene or polybutadiene, as well as poly¬ mers of cycloolefins, for instance of cyclopentene or norbornene, polyethylene (which optionally can be crosslinked), for example high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), branched low density polyethylene (BLDPE).

Polyolefins, i.e. the polymers of monoolefins exemplified in the preceding paragraph, preferably polyethylene and polypropylene, can be prepared by different, and especially by the following, methods:

a) radical polymerisation (normally under high pressure and at elevated temperature).

b) catalytic polymerisation using a catalyst that normally contains one or more than one metal of groups IVb, Vb, VIb or Nffl 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(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, Ha and/or Ilia of the Periodic Table. The activators may be modified conveniently with further ester, ether, amine or silyl ether groups. These catalyst systems are usually termed Phillips, Standard Oil Indiana, Ziegler (-Νatta), TΝZ (DuPont), metallocene or single site catalysts (SSC).

2. Mixtures of the polymers mentioned under 1), for example mixtures of polypropylene with polyisobutylene, polypropylene with polyethylene (for example PP/HDPE,

PP/LDPE) and mixtures of different types of polyethylene (for example LDPE/HDPE).

3. Copolymers of monoolefins and diolefins with each other or with other vinyl mono¬ mers, for example ethylene/propylene copolymers, linear low density polyethylene (LLDPE) and mixtures thereof with low density polyethylene (LDPE), propylene/but- 1-ene copolymers, propylene/isobutylene copolymers, ethylene/but-1-ene copolymers, ethylene/hexene copolymers, ethylene/methylpentene copolymers, ethylene/heptene copolymers, ethylene/octene copolymers, propylene/butadiene copolymers, isobutylene/- isoprene copolymers, ethylene/alkyl acrylate copolymers, ethylene/alkyl methacrylate copolymers, ethylene/vinyl acetate copolymers and their copolymers with carbon mon¬ oxide or ethylene/acrylic acid copolymers and their salts (ionomers) as well as terpoly- mers of ethylene with propylene and a diene such as hexadiene, dicyclopentadiene or ethy- lidene-norbornene; and mixtures of such copolymers with one another and with polymers mentioned in 1) above, for example polypropylene/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 mon¬ oxide copolymers and mixtures thereof with other polymers, for example polyamides.

4. Hydrocarbon resins (for example C ₅ -C ₉ ) including hydrogenated modifications thereof (e.g. tackifiers) and mixtures of polyalkylenes and starch.

5. Polystyrene, poly(p-methylstyrene), poly(α-methylstyrene).

6. Copolymers of styrene or α-methylstyrene with dienes or acrylic derivatives, for example styrene/butadiene, styrene/acrylonitrile, styrene/alkyl methacrylate, styrene/buta- diene/alkyl acrylate, styrene/butadiene/alkyl methacrylate, styrene/maleic anhydride, styrene/acrylonitrile/methyl acrylate; mixtures of high impact strength of styrene copoly¬ mers and another polymer, for example a polyacrylate, a diene polymer or an ethylene/- propylene/diene terpolymer; and block copolymers of styrene such as styrene/butadiene/- styrene, styrene/isoprene/styrene, styrene/ethylene/butylene/styrene or styrene/ethylene/- propylene/ styrene.

7. Graft copolymers of styrene or α-methylstyrene, for example styrene on polybutadiene, styrene on polybutadiene-styrene or polybutadiene-acrylonitrile copolymers; styrene and acrylonitrile (or methacrylonitrile) on polybutadiene; styrene, acrylonitrile and methyl methacrylate on polybutadiene; styrene and maleic anhydride on polybutadiene; styrene,

acrylonitrile and maleic anhydride or maleimide on polybutadiene; styrene and maleimide on polybutadiene; styrene and alkyl acrylates or methacrylates on polybutadiene; styrene and acrylonitrile on ethylene/propylene/diene terpolymers; styrene and acrylonitrile on polyalkyl acrylates or polyalkyl methacrylates, styrene and acrylonitrile on acrylate/buta- diene copolymers, as well as mixtures thereof with the copolymers listed under 6), for example the copolymer mixtures known as ABS, MBS, ASA or AES polymers.

8. Halogen-containing polymers such as polychloroprene, chlorinated rubbers, chlorinated or sulfochlorinated polyethylene, copolymers of ethylene and chlorinated ethylene, epi- chlorohydrin homo- and copolymers, especially polymers of halogen-containing vinyl compounds, for example polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, polyvinylidene fluoride, as well as copolymers thereof such as vinyl chloride/vinylidene chloride, vinyl chloride/vinyl acetate or vinylidene chloride/vinyl acetate copolymers.

9. Polymers derived from α,β-unsaturated acids and derivatives thereof such as polyacry- lates and polymethacrylates; polymethyl methacrylates, polyacrylamides and polyacrylo- nitriles, impact-modified with butyl acrylate.

10. Copolymers of the monomers mentioned under 9) with each other or with other unsaturated monomers, for example acrylonitrile/ butadiene copolymers, acrylonitrile/- alkyl acrylate copolymers, acrylonitrile/alkoxyalkyl acrylate or acrylonitrile/vinyl halide copolymers or acrylonitrile/ alkyl methacrylate/butadiene terpolymers.

11. Polymers derived from unsaturated alcohols and amines or the acyl derivatives or acetals thereof, for example polyvinyl alcohol, polyvinyl acetate, polyvinyl stearate, poly¬ vinyl benzoate, polyvinyl maleate, polyvinyl butyral, polyallyl phthalate or polyallyl melamine; as well as their copolymers with olefins mentioned in 1) above.

12. Homopolymers and copolymers of cyclic ethers such as polyalkylene glycols, poly¬ ethylene oxide, polypropylene oxide or copolymers thereof with bisglycidyl ethers.

13. Polyacetals such as polyoxymethylene and those polyoxymethylenes which contain ethylene oxide as a comonomer; polyacetals modified with thermoplastic polyurethanes, acrylates or MBS.

14. Polyphenylene oxides and sulfides, and mixtures of polyphenylene oxides with sty-

rene polymers or polyamides.

15. Polyurethanes derived from hydroxyl-terminated polyethers, polyesters or polybuta- dienes on the one hand and aliphatic or aromatic polyisocyanates on the other, as well as precursors thereof.

16. Polyamides and copolyamides derived from diamines and dicarboxylic acids and/or from aminocarboxylic acids or the corresponding lactams, for example polyamide 4, poly¬ amide 6, polyamide 6/6, 6/10, 6/9, 6/12, 4/6, 12/12, polyamide 11, polyamide 12, aromatic polyamides starting from m-xylene diamine and adipic acid; polyamides prepared from hexamethylenediamine and isophthalic or/and terephthalic acid and with or without an elastomer as modifier, for example poly-2,4,4,-trimethylhexamethylene terephthalamide or poly-m-phenylene isophthalamide; and also block copolymers of the aforementioned polyamides with polyolefins, olefin copolymers, ionomers or chemically bonded or graf¬ ted elastomers; or with polyethers, e.g. with polyethylene glycol, polypropylene glycol or polytetramethylene glycol; as well as polyamides or copolyamides modified with EPDM or ABS; and polyamides condensed during processing (RIM polyamide systems).

17. Polyureas, polyimides, polyamide-imides and polybenzimidazoles.

18. Polyesters derived from dicarboxylic acids and diols and/or from hydroxycarboxylic acids or the corresponding lactones, for example polyethylene terephthalate, polybutylene terephthalate, poly-l,4-dimethylolcyclohexane terephthalate and polyhydroxybenzoates, as well as block copolyether esters derived from hydroxyl-terminated polyethers; and also polyesters modified with polycarbonates or MBS.

19. Polycarbonates and polyester carbonates.

20. Polysulfones, polyether sulfones and polyether ketones.

21. Crosslinked polymers derived from aldehydes on the one hand and phenols, ureas and melamines on the other hand, such as phenol/formaldehyde resins, urea/formaldehyde resins and melamine/formaldehyde resins.

22. Drying and non-drying alkyd resins.

23. Unsaturated polyester resins derived from copolyesters of saturated and unsaturated dicarboxylic acids with polyhydric alcohols and vinyl compounds as crosslinking agents, and also halogen-containing modifications thereof of low flammability.

24. Crosslinkable acrylic resins derived from substituted acrylates, for example epoxy acrylates, urethane acrylates or polyester acrylates.

25. Alkyd resins, polyester resins and acrylate resins crosslinked with melamine resins, urea resins, polyisocyanates or epoxy resins.

26. Crosslinked epoxy resins derived from polyepoxides, for example from bisglycidyl ethers or from cycloaliphatic diepoxides.

27. Natural polymers such as cellulose, rubber, gelatin and chemically modified homolo¬ gous derivatives thereof, for example cellulose acetates, cellulose propionates and cellu¬ lose butyrates, or the cellulose ethers such as methyl cellulose; as well as rosins and their derivatives.

28. Blends of the aforementioned polymers (polyblends), for example PP/EPDM, Poly- amide/EPDM or ABS, PNC/EVA, PNC/ABS, PNC/MBS, PC/ABS, PBTP/ABS,

PC/ ASA, PC/PBT, PNC/CPE, PNQacrylates, POM/thermoplastic PUR, PC/thermoplastic PUR, POM/acrylate, POM/MBS, PPO HIPS, PPO/PA 6.6 and copolymers, PA/HDPE, PA/PP, PA/PPO.

29. Naturally occurring and synthetic organic materials which are pure monomeric com¬ pounds or mixtures of such compounds, for example mineral oils, animal and vegetable fats, oil and waxes, or oils, fats and waxes based on synthetic esters (e.g. phthalates, adi- pates, phosphates or trimellitates) and also mixtures of synthetic esters with mineral oils in any weight ratios, typically those used as spinning compositions, as well as aqueous emul¬ sions of such materials.

30. Aqueous emulsions of natural or synthetic rubber, e.g. natural latex or latices of carboxylated styrene/butadiene copolymers.

31. Polysiloxanes such as the soft, hydrophilic polysiloxanes described, for example, in US-A-4 259467; and the hard polyorganosiloxanes described, for example, in

US-A-4 355 147.

32. Polyketimines in combination with unsaturated acrylic polyacetoacetate resins or with unsaturated acrylic resins. The unsaturated acrylic resins include the urethane acrylates, polyether acrylates, vinyl or acryl copolymers with pendant unsaturated groups and the acrylated melamines. The polyketimines are prepared from polyamines and ketones in the presence of an acid catalyst.

33. Radiation curable compositions containing ethylenically unsaturated monomers or oligomers and a polyunsaturated aliphatic oligomer.

34. Epoxymelamine resins such as light-stable epoxy resins crosslinked by an epoxy func¬ tional coetherified high solids melamine resin such as LSE-4103 (Monsanto).

Accordingly, the invention also relates to compositions comprising (a) an organic material subjected to oxidative, thermal or light-induced degradation and (b) the gamma crystalline form of 2,2',2"-nitrilo[triethyl-tris-(3,3',5,5'-tetra-tert-butyl-l, l'-biphenyl-2,2'-diyl) phos¬ phite].

Preferably, the organic materials to be protected are natural, semi-synthetic or, preferably, synthetic organic materials. Particular preference is given to thermoplastic polymers, in particular PVC or polyolefins, especially polyethylene and polypropylene.

A preferred organic material is also a lubricant, a lubricating oil, a natural fat or wax, or a fat or wax based on a synthetic ester.

The action of the compounds according to the invention against thermal and oxidative de¬ gradation, especially under thermal stress, such as occurs during processing of thermoplas¬ tics, may be mentioned in particular. Accordingly, the compounds according to the inven¬ tion are highly suitable for use as processing stabilizers.

Preferably, the gamma crystalline form of 2,2',2"-nitrilo[triethyl-tris-(3,3',5,5'-tetra-tert- butyl-l,l'-biphenyl-2,2'-diyl) phosphite] according to the invention is added to the ma¬ terial to be stabilized in amounts of 0.01 to 10%, for example 0.01 to 5%, preferably 0.05 to 3%, in particular 0.05 to 1%, relative to the weight of the organic material to be sta¬ bilized.

The compositions according to the invention can contain, in addition to the gamma cry¬ stalline form of 2,2',2"-nitrilo[triethyl-tris-(3,3',5,5'-tetra-tert-butyl-l, l'-biphenyl-2,2'-di- yl) phosphite], further co-stabilizers, for example the following:

1. Antioxidants

1.1. Alkylated monophenols, for example 2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl- 4,6-dimethylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-butyl-4-isobutylphenol, 2,6-dicyclopentyl-4-methylphenol, 2-(α-methylcyclo- hexyl)-4,6-dimethylphenol, 2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol, 2,6-di-tert-butyl-4-methoxymethylphenol, 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-di- methyl-6-( -methyltridec- -yl)phenol and mixtures thereof.

1.2. Alkylthiomethylphenols, for example 2,4-dioctylthiomethyl-6-tert-butylphenol, 2,4-dioctylthiomethyl-6-methylphenol, 2,4-dioctylthiomethyl-6-ethylphenol, 2,6-di-do- decylthiomethyl-4-nonylphenol.

1.3. Hydroquinones and alkylated hydroquinones, for example 2,6-di-tert-butyl-4- methoxyphenol, 2,5-di-tert-butylhydroquinone, 2,5-di-tert-amylhydroquinone, 2,6-di- phenyl-4-octadecyloxyphenol, 2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxy- anisole, 3,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyphenyl stearate, bis-(3,5-di-tert-butyl-4-hydroxyphenyl) adipate.

1.4. Hydroxylated thiodiphenyl ethers, for example 2,2'-thiobis(6-tert-butyl-4-methyl- phenol), 2,2'-thiobis(4-octylphenol), 4,4'-thiobis(6-tert-butyl-3-methylphenol), 4,4'-thio- bis(6-tert-butyl-2-methylphenol), 4,4'-thiobis-(3,6-di-sec-amylphenol), 4,4'-bis-(2,6-dim- ethyl-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-methyl- cyclohexyl)phenol], 2,2'-methylenebis(4-methyl-6-cyclohexylphenol), 2,2'-methylene- bis(6-nonyl-4-methylphenol), 2,2'-methylenebis(4,6-di-tert-butylphenol), 2,2'-ethylidene- bis(4,6-di-tert-butylphenol), 2,2'-ethylidenebis(6-tert-butyl-4-isobutylphenol), 2,2'-methy- lenebis[6-(α-methylbenzyl)-4-nonylphenol], 2,2'-methylenebis[6-(α,α-dimethylbenzyl)-

4-nonylphenol], 4,4'-methylenebis(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-dodecylmer- captobutane, ethylene glycol bis[3,3-bis(3'-tert-butyl-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-methylphenyl]terephthalate, l,l-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-dodecylmercaptobutan e, l,l,5,5-tetra-(5-tert- butyl-4-hydroxy2-methylphenyl)pentane.

1.6. O-, N- and S-benzyl compounds, for example 3,5,3',5'-tetra-tert-butyl-4,4'-dihydroxy- dibenzyl ether, octadecyl-4-hydroxy-3,5-dimethylbenzylmercaptoacetate, tris-(3,5-di-tert- butyl-4-hydroxybenzyl)amine, bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithio- terephthalate, bis(3,5-di-tert-butyl-4-hydroxybenzyl)sulfιde, isooctyl-3,5di-tert-butyl-4- hydroxybenzylmercaptoacetate.

1.7. Hydroxybenzylated malonates, for example dioctadecyl-2,2-bis-(3,5-di-tert-butyl-2- hydroxybenzyl)-malonate, di-octadecyl-2-(3-tert-butyl-4-hydroxy-5-methylbenzyl)-malo- nate, di-dodecylmercaptoethyl-2,2-bis-(3,5-di-tert-butyl-4-hydroxy benzyl)malonate, bis- [4-( 1 , 1 ,3,3-tetramethylbutyl)phenyl]-2,2-bis(3,5-di-tert-butyl-4-hy droxybenzyl)malonate.

1.8. Aromatic hydroxybenzyl compounds, for example l,3,5-tris-(3,5-di-tert-butyl-4-hy- droxybenzyl)-2,4,6-trimethylbenzene, l,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6- tetramethylbenzene, 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- hydroxyanilino)-l,3,5-triazine, 2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxy- anilino)- 1 ,3,5-triazine, 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)-l,2,3-triazin e, 1,3,5-tris- (3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, l,3,5-tris(4-tert-butyl-3-hydroxy-2,6-di- methylbenzyl)isocyanurate, 2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenylethyl)-l,3,5-tri - azine, l,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)-hexah ydro-l,3,5-triazine, l,3,5-tris(3,5-dicyclohexyl-4-hydroxybenzyl)isocyanurate.

1.10. Benzylphosphonates, for example dimethyl-2,5-di-tert-butyl-4-hydroxybenzylphos-

phonate, diethyl-3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl3,5-di-tert- butyl-4-hydroxybenzylphosphonate, dioctadecyl-5-tert-butyl-4-hydroxy3-methylbenzyl- phosphonate, the calcium salt of the monoethyl ester of 3,5-di-tert-butyl-4-hydroxybenzyl- phosphonic acid.

1.11. 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 poly- hydric alcohols, e.g. with methanol, ethanol, 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(hy- droxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, tri- methylolpropane, 4-hydroxymethyl-l-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.13. Esters of β-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acid with mono- or polyhydric alcohols, e.g. with methanol, ethanol, octadecanol, 1,6-hexanediol, 1,9-nonane¬ diol, 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, tri- methylolpropane, 4-hydroxymethyl-l-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.14 Esters of β-(3,5-dicvclohexyl-4-hvdroxyphenyl)propionic acid with mono- or poly¬ hydric alcohols, e.g. with methanol, ethanol, 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(hy- droxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, tri- methylolpropane, 4-hydroxymethyl-l-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.15 Esters of 3,5-di-tert-butyl-4-hydroxyphenyl acetic acid with mono- or polyhydric alcohols, e.g. with methanol, ethanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethy¬ lene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl) isocyanurate, N,N'-bis(hydroxy- ethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpro- pane, 4-hydroxymethyl-l-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.16. Amides of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid e.g. N,N'-bis(3,5-di- tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamine, N,N'-bis(3,5-di-tert-butyl- 4-hydroxyphenylpropionyl)trimethylenediamine, N,N'-bis(3,5-di-tert-butyl-4-hydroxy- phenylpropionyl)hydrazine .

2. UV absorbers and light stabilisers

2.1. 2-(2'-Hvdroxyphenyl)benzotriazoles, for example 2-(2'-hydroxy-5'-methylphenyl)- benzotriazole, 2-(3',5'-di-tert-butyl-2'-hydroxyphenyl)benzotriazole, 2-(5'-tert-butyl-2'- hydroxyphenyl)benzotriazole, 2-(2'-hydroxy-5'-(l,l,3,3-tetramethylbutyl)phenyl)benzo- triazole, 2-(3',5'-di-tert-butyl-2'-hydroxyphenyl)-5-chloro-benzotriaz ole, 2-(3'-tert-butyl- 2' -hydroxy-5 '-methylphenyl)-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, mixture of 2-(3'-tert-butyl-2'-hydroxy-5'-(2-octyloxycar- bonylethyl)phenyl)-5-chloro-benzotriazole, 2-(3'-tert-butyl-5'-[2-(2-ethylhexyloxy)-car- bonylethyl]-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- methoxycarbonylethyl)phenyl)benzotriazole, 2-(3'-tert-butyl-2'-hydroxy-5'-(2-octyl- oxycarbonylethyl)phenyl)benzotriazole, 2-(3'-tert-butyl-5'-[2-(2-ethylhexyloxy)carbonyl- ethyl]-2'-hydroxyphenyl)benzotriazole, 2-(3'-dodecyl-2'-hydroxy-5'-methylphenyl)benzo- triazole, and 2-(3'-tert-butyl-2'-hydroxy-5 ^, -(2-isooctyloxycarbonylethyl)phenylbenzotri- azole, 2,2'-methylene-bis[4-(l , 1 ,3,3-tetramethylbutyl)-6-benzotriazole-2-ylphenol] ; the transesterification product of 2-[3'-tert-butyl-5'-(2-methoxycarbonylethyl)-2'-hydroxy- phenyl]-2H-benzotriazole with polyethylene glycol 300; [R-CH ₂ CH ₂ -COO(CH ₂ ) _3T2 — , where R = 3'-tert-butyl-4'-hydroxy-5'-2H-benzotriazol-2-ylphenyl.

2.2. 2-Hydroxybenzophenones, for example the 4-hydroxy, 4-methoxy, 4-octyloxy, 4-de- cyloxy, 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-butylbenzoyl) resorcinol, benzoyl resorcinol, 2,4-di-tertbutylphenyl 3,5-di-tert-butyl- 4-hydroxybenzoate, hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, octadecyl 3,5-di-tert- butyl-4-hydroxybenzoate, 2-methyl-4,6-di-tert-butylphenyl 3 ,5-di-tert-butyl-4-hydroxy-

benzoate.

2.4. Acrylates, for example ethyl α-cyano-β,β-diphenylacrylate, isooctyl α-cyano-β,β-di- phenylacrylate, methyl α-carbomethoxycinnamate, methyl α-cyano-β-methyl-p-methoxy- cinnamate, butyl α-cyano-β-methyl-p-methoxy-cinnamate, methyl α-carbomethoxy-p- methoxycinnamate and N-(β-carbomethoxy-β-cyanovinyl)-2-methylindoline.

2.5. Nickel compounds, for example nickel complexes of 2,2'-thio-bis-[4-(l,l,3,3-tetra- methylbutyl)phenol], such as the 1:1 or 1:2 complex, with or without additional ligands such as n-butylamine, triethanolamine or N-cyclohexyldiethanolamine, nickel dibutyldi- thiocarbamate, 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-methylphenyl undecylketoxime, nickel complexes of l-phenyl-4-lauroyl-5- hydroxypyrazole, with or without additional ligands.

2.6. Sterically hindered amines, for example bis(2,2,6,6-tetramefhyl-piperidyl)sebacate, bis(2,2,6,6-tetramethyl-piperidyl)succinate, bis(l,2,2,6,6-pentamethylpiperidyl)sebacate, bis(l,2,2,6,6-pentamethylpiperidyl) n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate, the condensate of l-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succi- nic acid, the condensate of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenedi- amine and 4-tert-octylamino-2,6-dichloro-l,3,5-triazine, tris(2,2,6,6-tetramethyl-4-piperi- dyl) nitrilotriacetate, tetrakis(2,2,6,6-tetramethyl-4- piperidyl)-l,2,3,4-butane-tetracar- boxylate, l,l'-(l,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-penta- methylpiperidyl)-2-n-butyl-2-(2-hydroxy-3,5-di-tert-butylben zyl)malonate, 3-n-octyl- 7,7,9,9-tetramethyl- 1 ,3,8-triazasprio[4.5]decan-2,4-dion, bis( l-octyloxy-2,2,6,6-tetra- methylpiperidyl)sebacate, bis( l-octyloxy-2,2,6,6-tetramethylpiperidyl)succinate, the condensate of N,N'-bis-(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediami ne and 4-morpholino-2,6-dichloro-l,3,5-triazine, the condensate of 2-chloro-4,6-bis(4-n-butyl- amino-2,2,6,6-tetramethylpiperidyl )-l,3,5-triazine and l,2-bis(3-aminopropylamino)- ethane, the condensate of 2-chloro-4,6-di-(4-n-butylamino-l,2,2,6,6-pentamethylpiperi- dyl)-l,3,5-triazine and l,2-bis-(3-aminopropylamino)ethane, 8-acetyl-3-dodecyl-7 ,7,9,9- tetramethyl-l,3,8-triazaspiro[4.5]decane-2,4-dione, 3-dodecyl-l-(2,2,6,6-tetramethyl-4- piperidyl)pyrrolidin-2,5-dione, 3-dodecyl-l-(l,2,2,6,6-pentamethyl-4-piperidyl)pyrroli- dine-2,5-dione.

2.7. Oxamides, for example 4,4'-dioctyloxyoxanilide, 2,2'-dioctyloxy-5,5'-di-tert-butox- anilide, 2,2'-didodecyloxy-5,5'-di-tert-butoxanilide, 2-ethoxy-2'-ethoxanihde, N,N'- bis(3-dimethylaminopropyl)oxamide, 2-ethoxy-5-tert-butyl-2'-ethoxanilide and its mix¬ ture with 2-ethoxy-2'-ethyl-5,4'-di-tert-butoxanilide and mixtures of ortho- and para- methoxy-disubstituted oxanilides and mixtures of o- and p-ethoxy-disubstituted oxani- lides.

2.8. 2-(2-Hydroxyphenyl)-l,3,5-triazines, for example 2,4,6-tris(2-hydroxy-4-octyloxy- phenyl)- 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)-l,3,5-tr iazine, 2,4-bis(2-hydroxy-4-propyloxyphenyl)-6-(2,4-dimethylphenyl)- 1 ,3,5-triazine, 2-(2-hy- droxy-4-octyloxyphenyl)-4,6-bis(4-methylphenyl)-l,3,5-triazi ne, 2-(2-hydroxy-4-dodecyl- oxyphenyl)-4,6-bis(2,4-dimethylphenyl)- 1 ,3,5-triazine, 2-[2-hydroxy-4-(2hydroxy- 3-butyloxy-propoxy)phenyl]-4,6-bis(2,4-dimethyl)-l,3,5-triaz ine, 2-[2-hydroxy-4-(2- hydroxy-3-octyloxy-propyloxy)phenyl]-4,6-bis(2,4-dimethyl)-l ,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-hydroxyphenyl- propionyl) hydrazine , 3-salicyloylamino-l,2,4-triazole, bis(benzylidene)oxalyl di- hydrazide, oxanilide, isophthaloyl dihydrazide, sebacoyl bisphenylhydrazide, N,N'-di- acetyladipoyl dihydrazide, N,N'-bis(salicyloyl)oxalyl dihydrazide, N,N'-bis(salicyloyl)- thiopropionyl dihydrazide.

4. Phosphites and phosphonites, for example triphenyl phosphite, diphenyl alkyl phos¬ phites, phenyl dialkyl phosphites, tris(nonylphenyl) phosphite, trilauryl phosphite, triocta- decyl phosphite, distearyl pentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl) phos¬ phite, diisodecyl pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)-pentaeryt hritol diphosphite, diisode- cyloxypentaerythritol diphosphite, bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritol di¬ phosphite, bis(2,4,6-tris(tert-butylphenyl)pentaerythritol diphsophite, tristearyl sorbitol tri- phosphite, tetrakis(2,4-di-tert-butylphenyl) 4,4'-biphenylene diphosphonite, 6-isooctyl- oxy-2,4,8,10-tetra-tert-butyl-12H-dibenz[d,g]-l,3,2-dioxapho sphocin, 6-fluoro-2,4,8,10- tetra-tert- butyl- 12-methyl-dibenz[d,g] - 1 ,3 ,2-dioxaphosphocin, bis(2,4-di-tert-butyl-6- methylphenyl)methylphosphite, bis(2,4-di-tert-butyl-6-methylphenyl)ethylphosphite.

5. 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-mercaptobenzimidazole, zinc dibutyldithiocarbamate, dioctadecyl disulfide, penta¬ erythritol tetrakis(β-dodecylmercapto)propionate.

6. Hydroxylamines, for example, N,N-dibenzylhydroxylamine, N,N-diethylhydroxyl- amine, N,N-dioctylhydroxylamine, N,N-dilaurylhydroxylamine, N,N-ditetradecylhydro- xylamine, N,N-dihexadecylhydroxylamine, N,N-dioctadecylhydroxylamine, N-hexade- cyl-N-octadecylhydroxylamine, N-heptadecyl-N-octadecylhydroxylamine, N,N-dialkylhy- droxylamine derived from hydrogenated tallow amine.

7. Nitrones, for example, N-benzyl-alpha-phenyl nitrone, N-ethyl-alpha-methyl nitrone, N-octyl-alpha-heptyl nitrone, N-lauryl-alpha-undecyl nitrone, N-tetradecyl-alpha-tridecyl nitrone, N-hexadecyl-alpha-pentadecyl nitrone, N-octadecyl-alpha-heptadecylnitrone, N-hexadecyl-alpha-heptadecyl nitrone, N-octadecyl-alpha-pentadecyl nitrone, N-hepta- decyl-alpha-heptadecyl nitrone, N-octadecyl-alpha-hexadecyl nitrone, nitrone derived from N,N-dialkylhydroxylamine derived from hydrogenated tallow amine.

8. Polyamide stabilisers, for example, copper salts in combination with iodides and/or phosphorus compounds and salts of divalent manganese.

9. Basic co-stabilisers, for example, melamine, polyvinylpyrrolidone, dicyandiamide, tri- allyl cyanurate, urea derivatives, hydrazine derivatives, amines, polyamides, polyure- thanes, alkali metal salts and alkaline earth metal salts of higher fatty acids for example calcium stearate, zinc stearate, magnesium behenate, magnesium stearate, sodium rici- noleate and potassium palmitate, antimony pyrocatecholate or tin pyrocatecholate.

10. Nucleating agents, for example, 4-tert-butylbenzoic acid, adipic acid, diphenylacetic acid.

11. Fillers and reinforcing agents, for example, calcium carbonate, silicates, glass fibres, asbestos, talc, kaolin, mica, barium sulfate, metal oxides and hydroxides, carbon black, graphite.

12. Other additives, for example, plasticisers, lubricants, emulsifiers, pigments, optical brighteners, flameproofing agents, antistatic agents and blowing agents.

13. Benzofuranones and indolinones, for example those disclosed in US-A-4325 863, US-A-4 338 244 or US-A-5 175 312, or 3-[4-(2-acetoxyethoxy)phenyl]-5,7-di-tert-butyl- benzofuran-2-one, 5,7-di-tert-butyl-3-[4-(2-stearoyloxyethoxy)phenyl]benzofura n-2-one, 3,3'-bis[5,7-di-tert-butyl-3-(4-[2-hydroxyethoxy]phenyl)benz ofuran-2-one], 5,7-di-tert-bu- tyl-3-(4-ethoxyphenyl)benzofuran-2-one, 3-(4-acetoxy-3,5-dimethylphenyl)-5,7-di-tert- butyl-benzofuran-2-one, 3-(3,5-dimethyl-4-pivaloyloxyphenyl)-5,7-di-tert-butyl-benzo fu- ran-2-one.

The co-stabilizers, with the exception of the benzofuranones listed under 13, are added for example in concentrations of 0.01 to 10%, relative to the total weight of the material to be stabilized.

Further preferred compositions comprise, in addition to components (a) and (b) further additives, in particular phenolic antioxidants, light stabilizers or processing stabilizers.

Particularly preferred additives are phenolic antioxidants (item 1 of the list), statically hin¬ dered amines (item 2.6 of the list), phosphites and phosphonites (item 4 of the list) and peroxide-destroying compounds (item 5.) of the list.

Additional additives (stabilizers) which are also particularly preferred are benzofuran-2- ones, such as described, for example, in US-A-4325 863, US-A-4338 244 or US-A-5 175 312.

Examples of such benzofuran-2-ones are compounds of the formula

in which

R _π is phenyl or phenyl which is substituted by 1 to 3 alkyl radicals together having at most 18 carbon atoms, alkoxy having 1 to 12 carbon atoms, alkoxycarbonyl having 2 to 18 carbon atoms or chlorine;

R ₁₂ is hydrogen;

R ₁₄ is hydrogen, alkyl having 1 to 12 carbon atoms, cyclopentyl, cyclohexyl or chlorine;

R ₁₃ has the meaning of R ₁₂ or R ₁₄ or is a radical of the formula ,

O O O O

II II II II

— (CH ₂ ) _n -C-NR ₁₈ -A-NR ₁₈ -C-(CH ₂ ) _n -E • — (CH ₂ ) _n -C-NR ₁₈ -A-O-C-(CH ₂ ) _n -E -

-D-E, in which

R ₁₆ is hydrogen, alkyl having 1 to 18 carbon atoms, alkyl having 2 to 18 carbon atoms which is interrupted by oxygen or sulfur, dialkylaminoalkyl having a total of 3 to 16 carbon atoms, cyclopentyl, cyclohexyl, phenyl or phenyl which is substituted by 1 to 3 alkyl radicals together having at most 18 carbon atoms; n is 0, 1 or 2; the substituents R ₁₇ , independently of one another, are hydrogen, alkyl having 1 to 18 carbon atoms, cyclopentyl, cyclohexyl, phenyl, phenyl which is substituted by 1 or 2 alkyl radicals together having at most 16 carbon atoms, a radical of the formula -C ₂ H ₄ OH,

O -C ₂ H ₄ -O-C _m H _2m+1 or -C ₂ H ₄ -O-C-R ₂₀ or together with the nitrogen atom to which they are attached form a piperidine or morpholine radical; m is 1 to 18;

R ₂ o is hydrogen, alkyl having 1 to 22 carbon atoms or cycloalkyl having 5 to 12 carbon atoms;

A is alkylene having 2 to 22 carbon atoms which may be interrupted by nitrogen, oxygen or sulfur;

R ₁₈ is hydrogen, alkyl having 1 to 18 carbon atoms, cyclopentyl, cyclohexyl, phenyl, phenyl which is substituted by 1 or 2 alkyl radicals together having at most 16 carbon atoms, or is benzyl;

Rj ₉ is alkyl having 1 to 18 carbon atoms;

D is -O-, -S-, -SO-, -SO ₂ - or -C(R ₂₁ ) ₂ - ; the substituents R ₂ ι, independently of one another, are hydrogen, C _r C ₁₆ alkyl, the two R ₂₁ together containing 1 to 16 carbon atoms, R ₂₁ is furthermore phenyl or a radical of the

formula , in which n, R ₁₆ and R ₁₇ are as defined above;

E is a radical of the formula

in which R _π , R ₁₂ and R ₁₄ are as defined above; and

R ₁₅ is hydrogen, alkyl having 1 to 20 carbon atoms, cyclopentyl, cyclohexyl, chlorine or a

O Q radical of the formula -CH ₂ -C-OR ₁₆ or -CH ₂ -C-N(R ₁₇ ) ₂ , in which R ₁₆ and R ₁₇ defined above, or R ₁₅ together with R ₁₄ forms a tetramethylene radical.

Preference is given to those benzofuran-2-ones in which R ₁₃ is hydrogen, alkyl having 1 to 12 carbon atoms, cyclopentyl, cyclohexyl, chlorine or a radical of the formula

as defined above, R ₁₆ is in particular hydrogen, alkyl having 1 to 18 carbon atoms, cyclopentyl or cyclohexyl.

Preference is given furthermore to those benzofuran-2-ones in which R _π is phenyl or phenyl which is substituted by 1 or 2 alkyl radicals together having at most 12 carbon atoms; R ₁₂ is hydrogen; R ₁₄ is hydrogen or alkyl having 1 to 12 carbon atoms; R ₁₃ is

hydrogen, alkyl having 1 to 12 carbon atoms, ,

^or -D-E; R ₁₅ is hydrogen, alkyl having 1 to 20 carbon atoms,

-CH ₂ -C P-OR ₁₆ or -CH ₂ -C ?-N(R ₁₇ ) ₂ , or R ₁₅ together with R ₁₄ forms a tetramethylene radical, n, R ₁₆ , R ₁₇ , D and E being as defined at the beginning.

Of particular interest are also those benzofuran-2-ones in which R _π is phenyl; R ₁₃ is hydrogen, alkyl having 1 to 12 carbon atoms or -D-E; R ₁₂ and R ₁₄ , independently of one another, are hydrogen or alkyl having 1 to 4 carbon atoms; and R ₁₅ is alkyl having 1 to 20 carbon atoms, D and E being as defined at the beginning.

Of special interest are finally also those benzofuran-2-ones in which R _n is phenyl; R ₁₃ is alkyl having 1 to 4 carbon atoms or -D-E; R ₁₂ and R ₁₄ are hydrogen; and R ₁₅ is alkyl having 1 to 4 carbon atoms, cyclopentyl or cyclohexyl, D being a group -C(R ₂₁ ) ₂ - and E being a radical of the formula

the substituents R ₂₁ being identical to or different from one another and each being alkyl having 1 to 4 carbon atoms, and R _π , R ₁₂ , R ₁₄ and R ₁₅ being as defined.

The amount of additional additives, in particular stabilizers, for example of the benzofu- ran-2-ones mentioned, can vary within wide limits. For example, 0.0005 to 10, preferably 0.001 to 5, in particular 0.01 to 2, % by weight thereof can be present in the compositions according to the invention.

Incorporation of the gamma crystalline form of 2,2',2"-nitrilo[triethyl-tris-(3,3',5,5'tetra- tert-butyl-l,l'-biphenyl-2,2'-diyl) phosphite] and, if desired, further additives in the poly¬ mer organic material is carried out by known methods, for example before or during moul¬ ding or by applying the dissolved or dispersed compounds to the polymer organic mate-

rial, if appropriate with subsequent slow evaporation of the solvent. The gamma crystal¬ line form according to the invention can also be added to the materials to be stabilized in the form of a masterbatch containing them, for example, in a concentration of 2.5 to 25% by weight.

The gamma crystalline modification according to the invention can also be added before or during polymerization or before crosslinking.

The gamma crystalline modification according to the invention can be incorporated in the material to be stabilized in pure form or encapsulated in waxes, oils or polymers.

The gamma crystalline modification according to the invention can also be sprayed onto the polymer to be stabilized. They are capable of diluting other additives (for example the abovementioned customary additives) or their melts, thus enabling them to be sprayed onto the polymer to be stabilized also together with these additives. Addition by spraying during deactivation of the polymerization catalysts is particularly advantageous, it being possible, for example, for the steam used for deactivation to be used for spraying.

In the case of bead polymerized polyolefins, it may be advantageous, for example, to apply the gamma crystalline modification according to the invention, if desired together with other additives, by spraying.

The materials thus stabilized can be used in a wide range of forms, for example as films, fibres, tapes, moulding compositions, profiles or as binders for paints, adhesives or ce¬ ments.

As already mentioned, the organic materials to be protected are preferably organic, iii par¬ ticular synthetic, polymers. Of these, the materials being protected are particularly advan¬ tageously thermoplastic materials, in particular polyolefins. The excellent efficiency of the gamma crystalline form of 2,2',2"-nitrilo[triethyl-tris-(3,3',5,5'-tetra-tert-butyl-l, -biphe- nyl-2,2'-diyl) phosphite] as processing stabilizer (thermal stabilizer) should be mentioned in particular. To this end, it is advantageously added to the polymer before or during its processing. It is however also possible to stabilize other polymers (for example elasto¬ mers) or lubricants or hydraulic fluids against degradation, for example light-induced or thermal-oxidative degradation. For elastomers, see the above list of possible organic mate¬ rials.

Suitable lubricants and hydraulic fluids are based, for example, on mineral or synthetic oils or mixtures thereof. Lubricants are known to one skilled in the art and described in the relevant technical literature, for example in Dieter Klamann, "Schmierstoffe und ver- wandte Produkte" (Verlag Chemie, Weinheim 1982), in Schewe-Kobek, "Das Schmier- mittel-Taschenbuch" (Dr. Alfred Hϋthig- Verlag, Heidelberg, 1974) and in "Ullmanns Enzyklopadie der technischen Chemie" vol. 13, pages 85-94 (Verlag Chemie, Weinheim, 1977).

Accordingly, a preferred embodiment of the present invention is the use of the gamma crystalline form of 2,2',2"-nitrilo[triethyl-tris-(3,3',5,5'-tetra-tert-butyl-l, l '-biphenyl- 2,2'-diyl) phosphite] for stabilizing organic materials against oxidative, thermal or light- induced degradation.

The gamma crystalline modification according to the invention is preferably used as pro¬ cessing stabilizer (thermal stabilizer) of thermoplastic polymers.

The present invention also provides a process for stabilizing an organic material against oxidative, thermal or light-induced degradation, which comprises incorporating therein or applying thereto the gamma crystalline form of 2,2',2"-nitrilo[triethyl-tris-(3,3',5,5'tetra- tert-butyl-l,l'-biphenyl-2,2'-diyl) phosphite]. •

The phenolic antioxidant of particular interest is selected from the group consisting of n-octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, neopentanetetrayl tetrakis(3,5- di-tert-butyl-4-hydroxyhydrocinammate), di-n-octadecyl 3,5-di-tert-butyl-4-hydroxyben- zylphosphonate, 1 ,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, thiodiethylene bis(3,5-di-tert-butyl-4-hydroxyhydrocinnamate), l,3,5-trimethyl-2,4,6-tris(3,5-di-tert- butyl-4-hydroxybenzyl)benzene, 3,6-dioxaoctamethylene bis(3-methyl-5-tert-butyl-4- hydroxyhydrocinnamate), 2,6-di-tert-butyl-p-cresol, 2,2'-ethylidene-bis(4,6-di-tert-butyl- phenol), 1 ,3,5-tris(2,6-dimethyl-4-tert-butyl-3-hydroxybenzyl)isocynur ate, 1 , 1 ,3,-tris(2- methyl-4-hydroxy-5-tert-butylphenyl)butane, l,3,5-tris[2-(3,5-di-tert-butyl-4-hydroxy- hydrocinnamoyloxy)ethyl]isocyanur ate, 3,5-di-(3,5-di-tert-butyl-4-hydroxybenzyl)mesi- tol, hexamethylene bis(3,5-di-tert-butyl-4-hydroxyhydrocinnamate), l-(3,5-di-tert-butyl- 4-hydroxyanilino)-3,5-di(octylthio)-s-triazine, N,N'-hexamethylene-bis(3,5-di-tert-butyl- 4-hydroxyhydrocinnamamide), calcium bis(ethyl 3,5-di-tert-butyl-4-hydroxybenzylphos- phonate), ethylene bis[3,3-di(3-tert-butyl-4-hydroxyphenyl)butyrate], octyl 3,5-di-tert-

butyl-4-hydroxybenzylmercaptoacetate, bis(3,5-di-tert-butyl-4-hydroxyhydrocinnamoyl)- hydrazide, and N,N'-bis[2-(3,5-di-tert-butyl-4-hydroxyhydrocinnamoyloxy)-et h yl]- oxamide.

A most preferred phenolic antioxidant is neopentanetetrayl tetrakis(3,5-di-tert-butyl-4- hydroxyhydrocinnamate), n-octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, 1,3,5- trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benze ne, l,3,5-tris(3,5-di-tert- butyl-4-hydroxybenzyl)isocyanurate, 2,6-di-tert-butyl-p-cresol or 2,2'-ethylidene-bis(4,6- di-tert-butylphenol).

The hindered amine compound of particular interest is selected from the group consisting of bis(2,2,6,6-tetramethylpiperidin-4-yl) sebacate, bis(l,2,2,6,6-pentamethylpiperidin- 4-yl) sebacate, di(l,2,2,6,6-pentamethylpiperidin-4-yl) (3,5-di-tert-butyl-4-hydroxy- benzyl)butylmalonate, 4-benzoyl-2,2,6,6-tetramethylpiperidine, 4-stearyloxy-2,2,6,6-tetra- methylpiperidine, 3-n-octyl-7,7,9,9-tetramethyl-l,3,8-triaza-spiro[4.5]decane- 2 ,4-dϊone, tris(2,2,6,6-tetramethylpiperidin-4-yl) nitrilotriacetate, 1 ,2-bis(2,2,6,6-tetramethyl-3-oxo- piperazin-4-yl)ethane, 2,2,4,4-tetramethyl-7-oxa-3,20-diaza-21-oxodispiro[5.1.11.2] heneicosane, polycondensation product of 2,4-dichloro-6-tert-octylamino-s-triazine and 4,4'-hexamethylenebis(amino-2,2,6,6-tetramethylpiperidine), polycondensation product of l-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinic acid, polycon¬ densation product of 4,4'-hexamethylenebis-(amino-2,2,6,6-tetramethylpiperidine) and 1 ,2-dibromoethane, tetrakis(2,2,6,6-tetramethylpiperidin-4-yl) 1 ,2,3,4-butanetetracarboxy- late, tetrakis(l,2,2,6,6-pentamethylpiperidin-4-yl) 1,2,3,4-butanetetracarboxylate, polycon¬ densation product of 2,4-dichloro-6-morpholino-s-triazine and 4,4'-hexamethylenebis- (amino-2,2,6,6-tetramethylρiperidine), N,N',N",N'"-tetrakis[(4,6-bis(butyl-2,2,6,6-tetra- methyl-piperidin-4-yl)-amino-s-triazin-2-yl]-l,10-diamino-4, 7-diaza decane, mixed [2,2,6,6-tetramethylpiperidin-4-yl/β,β,β',β'-tetramethyl -3,9-(2,4,8,10-tetraoxaspiro[5.5]- undecane) diethyl] 1,2,3,4-butanetetracarboxylate, mixed [1,2,2,6,6-pentamethylpiperi- din-4-yl/β,β,β' ,β'-tetramethyl-3,9-(2,4,8,10-tetraoxaspiro[5.5] undecane) diethyl] 1,2,3,4- butanetetracarboxylate, octamethylene bis(2,2,6,6-tetramethylpiperidin-4-carboxylate), 4,4'-ethylenebis(2,2,6,6-tetramethylpiperazin-3-one), and bis(l-octyloxy-2,2,6,6-tetra- methylpiperidin-4-yl) sebacate.

A most preferred hindered amine compound is bis(2,2,6,6-tetramethylpiperidin-4-yl) seba¬ cate, the polycondensation product of l-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxy- piperidine and succinic acid, the polycondensation product of 2,4-dichloro-6-tert-octyl-

amino-s-triazine and 4,4' -hexamethylenebis(amino-2,2,6,6-tetramethylpiperidine) , N,N',N",N'"-tetrakis[(4,6-bis(butyl-(2,2,6,6-tetramethyl-pip eridin-4-yl)amino)-s-triazine- 2-yl]- 1 , 10-diamino-4,7-diazadecane or bis( 1 -octyloxy-2,2,6,6-tetramethylpiperidin-4-yl) sebacate.

The lubricating oil may be a mineral oil, a synthetic oil or any mixture of such oils. Mine¬ ral oils are preferred and examples of these include paraffinic hydrocarbon oils e.g. a mineral oil having a viscosity of 46 mm ² /s at 40°C; "150 Solvent Neutral" a solvent refined neutral mineral oil having a viscosity of 32 mm ² /s at 40°C; and "solvent bright- stocks", a high boiling residue from the process of refining mineral oil, and having a vis¬ cosity of 46 mm ² /s at 40°C.

Synthetic lubricating oils which may be present may be synthetic hydrocarbons such as polybutenes, alkyl benzenes and poly-alpha olefins as well as simple di-, tri- and tetra- esters, complex esters and polyesters derived from carboxylic acid esters of formula: G ₁ -OCC-alkylene-COOG ₂ wherein "alkylene" denotes an alkylene residue having from 2 to 14 carbon atoms and Gj and G ₂ are the same or different and each is an alkyl group having from 6 to 18 carbon atoms. Tri-esters which are of use as lubricating oil base stocks are those derived from trimethylolpropane and C ₆ -C ₁₈ mono-carboxylic acids or mixtures thereof, whereas suitable tetra-esters include those derived from pentaerythritol and a C ₆ -C ₁₈ mono-carboxylic acid or mixtures thereof.

Complex esters suitable for use as components of the composition of the present invention are those derived from monobasic acids, dibasic acids and polyhydric alcohols, for instance the complex ester derived from trimethylol propane, caprylic acid and sebacic acid.

Suitable polyesters are those derived from any aliphatic dicarboxylic acid having from 4 to 14 carbon atoms and at least one aliphatic dihydric alcohol having from 3 to 12 carbon atoms, e.g. those derived from azelaic acid or sebacic acid and 2,2,4- trimethylhexane- 1,6- diol.

Other lubricating oils are those known to the art-skilled and described e.g. in Schewe-Kobek, "Schmiermittel-Taschenbuch", (Huethig Verlag, Heidelberg 1974), and in D. Klamann, "Schmierstoff und verwandte Produkte", (Verlag Chemie, Weinheim 1982).

The lubricating oils applicational media can also contain other additives which may be added to improve the basic properties of lubricants e.g. metal passivators, viscosity-index improvers, pour-point depressants, dispersing agents, detergents, additional rust inhibitors, extreme pressure additives, an ti- wear additives and antioxidants.

Examples of phenolic antioxidants

1. Alkylated monophenols, for example 2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl- 4,6-dimethylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-butyl-4-isobutylphenol, 2,6-dicyclopentyl-4-methylphenol, 2-(α-methylcyclo- hexyl)-4,6-dimethylphenol, 2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol, 2,6-di-tert-butyl-4-methoxymethylphenol, 2,6-dinonyl-4-methylphenol, 2,4-dimethyl-6- ( 1 '-methylundec- 1 '-yl)phenol, 2,4-dimethyl-6-( 1 '-methylheptadec- 1 '-yl)phenol, 2,4-di- methyl-6-(l'-methyltridec- -yl)phenol and mixtures thereof.

2. Alkylthiomethylphenols, for example 2,4-dioctylthiomethyl-6-tert-butylphenol, 2,4-di- octylthiomethyl-6-methylphenol, 2,4-dioctylthiomethyl-6-ethylphenol and 2,6-didodecyl- thiomethyl-4-nonylphenol.

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-octa- decyloxyphenol, 2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole, 3,5- di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyphenyl stearate and bis-(3,5- di-tert-butyl-4-hydroxyphenyl) adipate.

4. Tocopherols, for example α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol and mixtures thereof (Vitamin E).

5. Hydroxylated thiodiphenyl ethers, for example 2,2'-thiobis(6-tert-butyl-4-methylphe- nol), 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) and 4,4'-bis-(2,6-di- methyl-4-hydroxyphenyl) disulfide.

6. Alkylidene bisphenols, 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-methyl- cyclohexyl)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-butylphenol), 2,2'-ethylidenebis(6-tert- butyl-4-isobutylphenol), 2,2'-methy- lenebis[6-(α-methylbenzyl)-4-nonylphenol], 2,2'-methylenebis[6-(α,α-dimethylbenzyl)- 4-nonylphenol], 4,4'-methylenebis(2,6-di-tert-butylphenol), 4,4'-methylenebis(6-tert-bu- tyl-2-methylphenol), l,l-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, l,l-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)-3-n-dodecylme r- captobutane, ethylene glycol bis[3,3-bis-(3'-tert-butyl-4'-hydroxyphenyl)butyrate], bis(3- tert-butyl-4-hydroxy-5-methylphenyl)dicyclopentadiene, bis[2-(3 ' -tert-butyl-2' hydroxy- 5 ' -methylbenzyl)-6-tert-butyl-4-methylphenyl] terephthalate, 1 , 1 -bis(3 ,5-dimethyl-2-hy- droxyphenyl)butane, 2,2-bis(3,5-di-tert-butyl-4hydroxyphenyl)propane, 2,2-bis(5-tert- butyl-4-hydroxy-2-methylphenyl)-4-n-dodecylmercaptobutane and 1 , 1 ,5,5-tetra(5-tert- butyl-4-hydroxy-2-methylphenyl)pentane.

7. O-, N- and S-Benzyl compounds, for example 3,5,3',5'-tetra-tert-butyl-4,4'-dihydroxydi- benzyl ether, octadecyl 4-hydroxy-3,5-dimethylbenzyl-mercaptoacetate, tris(3,5-di-tert- butyl-4-hydroxybenzyl)amine, bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-dithio- terephthalate, bis(3,5-di-tert-butyl-4-hydroxybenzyl) sulfide and isooctyl 3,5-di-tert- butyl-4-hydroxybenzylmercaptoacetate.

8. Hydroxybenzylated malonates, for example dioctadecyl 2,2-bis(3,5-di-tert-butyl-2- hydroxybenzyl)malonate, dioctadecyl 2(3-tert-butyl-4-hydroxy-5-methylbenzyl)malonate, didodecylmercaptoethyl 2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate and bis[4- (l,l,3,3-tetramethylbutyl)phenyl] 2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate.

9. Aromatic hydroxybenzyl compounds, for example l,3,5-tris(3,5-di-tert-butyl-4- hydroxybenzyl)-2,4,6-trimethylbenzene, l,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)- 2,3,5,6-tetramethylbenzene and 2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)phenol.

10. Triazine compounds, for example 2,4-bis(octylmercapto)-6-(3,5-di-tert-butyl-4-hy- droxyanilino)-l,3,5-triazine, 2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyanilino)-

1 ,3,5-triazine, 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)-l,2,3-triazin e, l,3,5-tris(3,5-di-tert-butyl- 4-hydroxybenzyl) isocyanurate, l,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) iso¬ cyanurate, 2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenylethyl)-l,3,5-tri azine, l,3,5-tris(3,5- di-tert-butyl-4-hydroxyphenylpropionyl)hexahydro-l,3,5-triaz ine and l,3,5-tris(3,5-di-

cyclohexyl-4-hydroxybenzyl) isocyanurate.

11. Benzylphosphonates, for example dimethyl 2,5-di-tert-butyl-4-hydroxybenzylphospho- nate, diethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl 3,5-di-tert-butyl- 4-hydroxybenzylphosphonate, dioctadecyl 5-tert-butyl-4-hydroxy-3-methylbenzylphos- phonate and the calcium salt of monoethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate.

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

13. Esters of β-(3,5-di-tert-butyl-4-hvdroxyphenyl)propionic acid with mono- or polyhy¬ dric alcohols, for example 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)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanedi¬ ol, trimethylolpropane and 4-hydroxymethyl-l-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

14. Esters of β-(5-tert-butyl-4-hvdroxy-3-methylphenyl)propionic acid with mono- or polyhydric alcohols, for example with methanol, ethanol, octanol, octadecanol, 1,6- hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodi¬ ethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl) isocyanurate, N,N'-bis-(hydroxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, tri¬ methylhexanediol, trimethylolpropane and 4-hydroxymethyl-l-phospha-2,6,7-trioxabi- cyclo[2.2.2]octane.

15. Esters of β-(3,5-dicvclohexyl-4-hydroxyphenyl)propionic acid with mono- or polyhy¬ dric alcohols, for example 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)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexane¬ diol, trimethylolpropane and 4-hydroxymethyl-l-phospha-2,6,7-trioxabicyclo-[2.2.2]- octane.

16. Esters of 3,5-di-tert-butyl-4-hvdroxyphenylacetic acid with mono- or polyhydric alco¬ hols, for example with methanol, ethanol, octanol, octadecanol, 1,6-hexanediol, 1,9- nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, di-

ethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl) isocyanurate, N,N'- bis-(hydroxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, tri¬ methylolpropane and 4-hydroxymethyl-l-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

17. Amides of β-(3,5-di-tert-butyl-4-hvdroxyphenyl)propionic acid, for example N,N'-bis- (3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenedia mine, N,N'-bis(3,5-di- tert-butyl-4-hydroxyphenylpropionyl)trimethylenediamine and N,N'-bis(3,5-di-tert-butyl- 4-hydroxyphenylpropionyl)hydrazine.

Examples of aminic antioxidants:

N,N'-diisopropyl-p-phenylenediamine, N,N'-di-sec-butyl-p-phenylenediamine, N,N'-bis- (l,4-dimethylpentyl)-p-phenylenediamine, N,N'-bis(l-ethyl-3-methylpentyl)-p-pheny- lenediamine , N,N' -bis( 1 -methylheptyl)-p-phenylenediamine, N,N' -dicyclohexyl-p-pheny- lenediamine, N,N'-diphenyl-p-phenylenediamine, N,N'-bis(2-naphthyl)-p-phenylenedi- amine, N-isopropyl-N' -phenyl-p-phenylenediamine, N-( 1 ,3-dimethyl-butyl)-N' -phenyl-p- phenylenediamine, N-(l-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-isopro- poxydiphenylamine, N-phenyl-1-naphthylamine, N-phenyl-2-naphthylamine, octylated di¬ phenylamine, for example p,p'-di-tert-octyldiphenylamine, 4-n-butylaminophenol, 4-buty- rylaminophenol, 4-nonanoylaminophenol, 4-dodecanoylaminophenol, 4-octadecanoyl- aminophenol, bis(4-methoxyphenyl)amine, 2,6-di-tert-butyl-4-dimethylaminomethyl- phenol, 2,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, N,N,N',N'-tetra- methyl-4,4' -diaminodiphenylmethane, 1 ,2-bis[(2-methyl-phenyl)amino]ethane, 1 ,2-bis- (phenylamino)propane, (o-tolyl)biguanide, bis[4-( ,3'-dimethylbutyl)phenyl]amine, tert- octylated N-phenyl-1-naphthylamine, a mixture of mono- and dialkylated tert-butyl/tert- octyldiphenylamines, a mixture of mono- and dialkylated isopropyl/isohexyldiphenyl- amines, mixtures of mono- and dialkylated tert-butyldiphenylamines, 2,3-dihydro-3,3-di- methyl-4H-l,4-benzothiazine, phenothiazine, N-allylphenothiazine, N,N,N',N'-tetra- phenyl- 1 ,4-diaminobut-2-ene, N,N-bis(2,2,6,6-tetramethylpiperid-4-yl-hexamethylenedi- amine, bis(2,2,6,6-tetramethylpiperid-4-yl) sebacate, 2,2,6,6-tetramethylpiperidin-4-one and 2,2,6,6-tetramethylpiperidin-4-ol.

Examples of other antioxidants:

Aliphatic or aromatic phosphites, esters of thiodipropionic acid or of thiodiacetic acid, or salts of dithiocarbamic or dithiophosphoric acid, 2,2,12,12-tetramethyl-5,9-dihydroxy-

3,7,1 l-trithiatridecane and 2,2,15,15-tetramethyl-5,12-dihydroxy-3,7,10,14-tetrathiahexa - decane.

Examples of metal deactivators, for example for copper, are: a) Benzotriazoles and derivatives thereof, for example 4- or 5-alkylbenzotriazoles (e.g. tolutriazole) and derivatives thereof, 4,5,6,7-tetrahydrobenzotriazole and 5,5'- methylenebisbenzotriazole; Mannich bases of benzotriazole or tolutriazole, e.g. l-[bis(2-ethylhexyl)aminomethyl)tolutriazole and l-[bis(2-ethylhexyl)amino- methyl) benzotriazole; and alkoxyalkylbenzotriazoles such as l-(nonyloxymethyl)- benzotriazole, l-(l-butoxyethyl) benzotriazole and l-(l-cyclohexyloxybutyl)- tolutriazole.

b) 1 ,2,4-Triazoles and derivatives thereof, for example 3-alkyl(or aryl)- 1 ,2,4-triazoles, and Mannich bases of 1,2,4-triazoles, such as l-[bis(2-ethylhexyl)aminomethyl- 1,2,4-triazole; alkoxyalkyl- 1,2,4-triazoles such as l-(l-butoxyethyl)-l,2,4-triazole; and acylated 3-amino- 1,2,4-triazoles.

c) Imidazole derivatives, for example 4,4'-methylenebis(2-undecyl-5-methylimid- azole) and bis[(N-methyl)imidazol-2-yl]carbinol octyl ether.

d) Sulfur-containing heterocyclic compounds, for example 2-mercaptobenzothiazole, 2,5-dimercapto-l,3,4-thiadiazole and derivatives thereof; and 3,5-bis[di(2-ethyl- hexyl)aminomethyl]- 1 ,3,4-thiadiazolin- 2-one.

e) Amino compounds, for example salicylidenepropylenediamine, salicylaminoguani- dine and salts thereof.

Examples of rust inhibitors are: a) Organic acids, their esters, metal salts, amine salts and anhydrides, for example alkyl- and alkenylsuccinic acids and their partial esters with alcohols, diols or hydroxycarboxylic acids, partial amides of alkyl- and alkenylsuccinic acids, 4-nonylphenoxyacetic acid, alkoxy- and alkoxyethoxycarboxylic acids such as dode- cyloxyacetic acid, dodecyloxy(ethoxy)acetic acid and the amine salts thereof, and also N-oleoylsarcosine, sorbitan monooleate, lead naphthenate, alkenylsuccinic anhydrides, for example dodecenylsuccinic anhydride, 2-carboxymethyl-l-dodecyl- 3-methylglycerol and the amine salts thereof.

b) Nitrogen-containing compounds, for example:

I. Primary, secondary or tertiary aliphatic or cycloaliphatic amines and amine salts of organic and inorganic acids, for example oil-soluble alkylammonium carboxylates, and also l-[N,N-bis(2-hydroxyethyl)amino]-3-(4-nonyl- phenoxy)propan-2-ol.

II. Heterocyclic compounds, for example: substituted imidazolines and oxazo- lines, and 2-heptadecenyl-l-(2-hydroxyethyl)imidazoline.

c) Phosphorus-containing compounds, for example: Amine salts of phosphoric acid partial esters or phosphonic acid partial esters, and zinc dialkyldithiophosphates.

d) Sulfur-containing compounds, for example: barium dinonylnaphthalenesulfonates, calcium petroleum sulfonates, alkylthio-substituted aliphatic carboxylic acids, esters of aliphatic 2-sulfocarboxylic acids and salts thereof.

e) Glycerol derivatives, for example: glycerol monooleate, l-(alkylphenoxy)-3-(2- hydroxyethyl)glycerols, l-(alkylphenoxy)-3-(2,3-dihydroxypropyl)glycerols and 2- carboxyalkyl- 1 ,3-dialkylglycerols.

Examples of viscosity index improvers are:

Poly acrylates, polymethacrylates, vinylpyrrolidone/methacrylate copolymers, polyvinyl- pyrrolidones, polybutenes, olefin copolymers, styrene/acrylate copolymers and polyethers.

Examples of pour-point depressants are: Polymethacrylate and alkylated naphthalene derivatives.

Examples of dispersants/surfactants are:

Polybutenylsuccinic amides or -imides, polybutenylphosphonic acid derivatives and basic magnesium, calcium and barium sulfonates and phenolates.

Examples of an ti wear additives are:

Sulfur- and/or phosphorus- and/or halogen-containing compounds, e.g. sulfurised olefins and vegetable oils, zinc dialkyldithiophosphates, alkylated triphenyl phosphates, tritolyl phosphate, tricresyl phosphate, chlorinated paraffins, alkyl and aryl di- and trisulfides,

amine salts of mono- and dialkyl phosphates, amine salts of methylphosphonic acid, di- ethanolaminomethyltolyltriazole, bis(2-ethylhexyl)aminomethyltolyltriazole, derivatives of 2,5-dimercapto-l,3,4-thiadiazole, ethyl 3-[(diisopropoxyphosphinothioyl)thio]propio- nate, triphenyl thiophosphate (triphenylphosphorothioate), tris(alkylphenyl) phosphoro- thioate and mixtures thereof (for example tris(isononylphenyl) phosphorothioate), di- phenyl monononylphenyl phosphorothioate, isobutylphenyl diphenyl phosphorothioate, the dodecylamine salt of 3-hydroxy-l,3-thiaphosphetane 3-oxide, trithiophosphoric acid 5,5,5-tris[isooctyl 2-acetate], derivatives of 2-mercaptobenzothiazole such as l-[N,N-bis- (2-ethylhexyl)aminomethyl] -2-mercapto- 1 H- 1 ,3-benzothiazole, and ethoxycarbonyl-5- octyldithiocarbamate.

Differential scanning calorimetry (DSC) measurements are obtained on a TA Instrument Inc., 910 differential scanning calorimeter, with a 100 ml/min nitrogen purge, aligned alu¬ minum pan, temperature scan at 5°C/min to 230°C.

X-ray diffraction patterns are recorded on a Philips Norelco X-ray Diffractometer unit, using Cu-Kα radiation with a nickel filter. All samples have a uniform particle size of 40 to 75 microns. This is the same particle size distribution obtained with the prior art com¬ pound of Example 3.

The examples which follow further illustrate the invention. The parts or percentages given are by weight.

Example 1: Synthesis of the gamma crystalline modification of 2,2',2"-nitrilo[triethyl- tris-(3,3 ' ,5,5 ' -tetra-tert-butyl- 1 , 1 ' -biphenyl-2,2' -diyl) phosphite] .

The compound of formula 1, 2,2',2"-nitrilo[triethyl-tris-(3,3',5,5'-tetra-tert-butyl-l, r-bi- phenyl-2,2'-diyl) phosphite], is prepared according to procedure of Example 4 of US-A-4 318 845. A 10 g sample of the compound of formula (I) is recrystallized from 100 ml of 1-butanol to obtain 4.8 g of the novel crystal modification of the compound of for¬ mula (I) having a mp = 182°C (the melting point is determined by differential scanning ca¬ lorimetry and the peak temperature in the endotherm is recorded as the melting point) and exhibiting an X-ray diffraction pattern obtained using Cu-Kα which exhibits diffraction angles (2θ):

Peak No. Diffraction Angle Relative

Intensity(%)

1 5.4 100

2 6.3 38.0

3 8.8 19.0

4 9.9 43.7

5 10.3 39.4

6 10.8 74.6

7 11.7 9.2

8 13.8 27.5

9 14.8 17.6

10 15.5 39.4

11 16.1 33.1

12 17.0 47.9

13 17.7 50.0

14 18.4 34.7

15 20.2 33.8

Example 2: Synthesis of the gamma crystalline modification of 2,2' ,2"-nitr tris-(3,3',5,5'-tetra-tert-butyl-l,l'-biphenyl-2,2'-diyl) phosphite].

The compound of formula I, 2,2',2"-m ^' trilo[triethyl-tris-(3,3'-5,5'-tetra-tert-butyl-l,r-bi - phenyl-2,2'-diyl) phosphite], is prepared according to procedure of Example 4 of US-A-4318 845. A 5.0 g sample of the compound of formula I is recrystallized from 45 ml of 1 -octanol to obtain 2.4 g of the novel crystal modification of the compound of for¬ mula (I) having a mp = 178.6°C (the melting point is determined by differential scanning calorimetry and the peak temperature in the endotherm is recorded as the melting point) and exhibiting an X-ray diffraction pattern obtained using Cu-Kα which exhibits diffrac¬ tion angles (2θ) (± 0.2°) which are the same as that found for the gamma crystalline form prepared in Example 1.

Such data show that the gamma crystals prepared in Example 1 and Example 2 are essen¬ tially the same.

Example 3: Comparative Example.

A compound of formula I is prepared according to the procedure of Example 4 of US-A-4 318 845. This compound exhibits an X-ray diffraction pattern obtain using Cu-Kα which exhibits diffraction angles (2Θ):

Peak No. Diffraction Angle Relative Intensity(%)

1 5.0 100

2 5.7 47.2

3 7.0 8.0

4 7.9 30.4

5 8.8 40.0

6 10.6 57.6

7 11.5 21.6

8 13.5 22.4

9 14.3 21.6

10 15.6 37.6

11 16.1 44.0

12 16.5 65.6

13 16.9 43.2

14 17.3 74.4

15 18.3 48.8

16 18.6 21.6

17 19.5 23.2

18 20.3 16.8

19 20.8 20.0

A comparison of the X-ray diffraction patterns of the instant gamma modification as seen in Examples 1 and 2 with the X-ray diffraction pattern of the prior art compound of Example 4 of US-A-4 318 845 clearly indicates that the two materials are not the same.

Example 4: Process Stabilization of Polypropylene at 274°C.

When unstabilized polypropylene containing 0.075% by weight of calcium stearate is

admixed with an effective amount of the gamma crystalline modification of the compound of formula I as prepared in Example 1 and then extruded from an extruder at 274°C, the melt flow rate (in grams/10 minutes) is determined by ASTM method D1238.

The instant gamma modification of the compound of formula I is particularly effective in stabilizing polypropylene against thermal and oxidative degradation as shown by a mini¬ mum change in the melt flow rate.

Example 5: Hydrolytic Stability of Gamma Modification.

To demonstrate the superior storage stability of the new gamma form, an accelerated test is performed on the instant compound of Example 2 and on the amorphous form of the compound of formula I prepared by heating the compound of Example 4 of US-A-4318 845 to 210°C until a clear melt is obtained. The melt is cooled rapidly to ambient temperature to yield a glassy solid with a T _g (DSC) of 105-110°C which is amor¬ phous.

The two test compounds are exposed to 80% humidity at 50°C and the rate of hydrolysis is monitored by liquid chromatography. As a function of time, a greater amount of the gamma form is found remaining compared to the amorphous form after any given time of humidity exposure indicating that the gamma form would have superior storage stability compared to the amorphous form of the compound of formula I.

Example 6: Stabilization of Unsaturated Elastomer.

The instant compound of Example 1 is evaluated in an emulsion of SBR (cold poly¬ merized, 23.5 % styrene with a 52 Mooney Viscosity). The unstabilized SBR (60 g) is added to the mixing chamber of a Brabender Plasticorder set at 150°C and 60 rpm. After 30 seconds, 0.5 % by weight of the compound of instant Example 1 is added to the cham¬ ber. Stability of the SBR is determined by the time until onset of crosslinking of the rubber as indicated by an increase in the torque curve. The sample stabilized by the instant com¬ pound has a longer induction time till crosslinking occurs than does the unstabilized SBR.

Example 7: Stabilization of Polyol.

A premix of 10 g of water, 0.25 g of triethylenetetramine, 2 g of L-5740 (silicone surfac-

tant, Union Carbide) and 20 g of ANTIBLAZE® AB-100 (chlorinated aromatic flame retardant, Albright & Wilson) is added to 200 g of 3000 molecular weight polyether polyol containing the stabilizer package listed below*. The mixture is stirred for five minutes with a high speed Lightning Mixer. Then 0.4 g of stannous octoate is added and the mix¬ ture is stirred for 5 seconds. Finally, 125 g of toluene diisocyanate (80 % 2,6-isomer; 20 % 2,4-isomer) is added. The mixture is stirred for 7 seconds at high speed mixing and is then poured into a 25.4 cm x 25.4 cm x 12.7 cm cardboard box. The foam is allowed to rise completely. After standing 5 minutes, the box is removed and the sample cured in a micro¬ wave over for five minutes at 50% power. The foam is then immediately air over cured at 125°C for three minutes. The foams are then cut in half for visual assessment of discolora¬ tion or scorch.

^♦ Stabilizer package: Control is 2,6-di-tert-butyl-4-methylphenol (BHT) 2000 ppm; and NAUGARD® 445 (diphenylamine antioxidant, Uniroyal) 2000 ppm.

Instant package is the above plus 1000 ppm of the compound of Example 1.

Visual inspection of the two foams shows that the foam containing the instant stabilizer package with the compound of Example 1 present is less discolored than the foam stabi¬ lized with the control stabilizer package. The instant compound demonstrates better scorch protection.

Example 8: Stabilization of Polycarbonate.

Additive free bisphenol A polycarbonate (LEXAN® 141-11 IN, General Electric) is dried and blended with 0.3 weight percent of a benzotriazole UV absorber (TINUVIN® 329, Ciba-Geigy) and 0.08 weight percent of instant compound of Example 1. The mixture is extruded and pelletized at 288°C on a 2.54 cm single screw extruder. Injection molded plaques 5.08 cm x 5.08 cm x 3.175 mm are prepared in a BOY 30M injection molder at 293°C with a mold temperature of 150°C. The resulting plaques are measured for yellow¬ ness index (YI) using ASTM D 1925-70. The plaques containing the instant compound of Example 1 have a lower YI values than those containing the UV absorber alone demon¬ strating the better performance achieve by the concomitant presence of the instant phos¬ phite.

Example 9: Stabilization of Poly(ethylene terephthalate).

Polyethylene terephthalate), PET (KODAPAR® 7352, Eastman Chemical) is tumble blended with 0.5 % by weight of the compound of instant Example 1. The polymer is then extruded and pelletized at 260°C in a 2.54 cm single screw extruder. The pellets are collected, redried and reextruded 5 times. Pellets are collected from each extrusion pass and the polymer intrinsic viscosity measured. PET containing the instant compound of Example 1 shows a higher retention of original intrinsic viscosity through the five extru¬ sion passes than does PET containing no stabilizer.

Example 10: Stabilization of Poly(butylene terephthalate).

Poly(butylene terephthalate), PBT (RYNITE® 9160, DuPont) is tumble blended with 0.3 % by weight of the compound of instant Example 1. The polymer is then extruded and pelletized at 260°C. A portion of the collected pellets are reextruded under the same con¬ ditions for a second pass. The remainder from the first extrusion is injection molded into 5.08 cm x 5.08 cm x 3.175 mm plaques at 282°C with a 100°C mold temperature in a BOY 30M molder. Intrinsic viscosities of the second pass extradate and the injection mol¬ ded plaques are determined. The PBT containing the instant compound of Example 1 shows a better retention of intrinsic viscosity value than does PBT containing no stabili¬ zer.

The plaques are measured for yellowness index (color) using ASTM D 1925-70. The plaques containing the instant compound of Example 1 have a lower YI values (less disco¬ loration) than do the plaques prepared from the control unstabilized PBT.

Example 11: Stabilization of 6,6-Nylon.

6,6-Nylon (ZYTEL® 101, DuPont) is thoroughly dried in a vacuum oven and tumble blended with 0.5 % by weight of the compound of instant Example 1. The polyamide is extruded on a 2.54 cm MPM extruder at 302°C. The collected pellets are injection molder at 302°C with the mold at 150°C in a BOY 30M injection molder. The plaques obtained are measured for yellowness index (YI) values using ASTM D1925-70. The plaques con¬ taining the instant compound of Example 1 exhibit lower YI values (less discoloration) than do the unstabilized control plaques.

Example 12: Stabilization of ABS.

A solution of 0.25 g of the instant compound of Example 1 in 40 ml of hexane/methanol is added to a rapidly stirred suspension of 100 g of ABS (acrylonitrile/butadiene/styrene ter- polymer) in 600 g of water. The suspension is filtered and dried under vacuum at 40°C for 40 hours. To the dried powder is added 2 % by weight of titanium dioxide and 1 % by weight of N,N'-ethylenebisstearamide on a two roll mill at 180°C over four minutes. Compression molded plaques (0.8 mm) are prepared at 175°C and placed in an air oven at 180°C for 45 minutes. The color of said plaques are determined as yellowness index values using ASTM D 1925-70. The plaques containing the instant compound of Example 1 exhibit lower yellowness index values (less discoloration) than do the control plaques from unstabilized ABS resin.