Piperidine-triazine compounds for use as stabilizers for organic materials

Abstract: The present invention relates to novel piperidine-triazine compounds of the general formula (I) in which R₁ is e.g. hydrogen or methyl, λ is e.g. 1 and R₂ and R₃ are e.g. N-(2,2,6,6-tetramethyl-4-piperidyl)-tetrahydrofurfurylamino or 1,2,2,6,6-pentamethyl-4-piperidyloxy. These compounds are effective as light stabilizers, heat stabilizers and oxidation stabilizers for organic materials.

Description: The present invention relates to novel piperidine-triazine compounds, to their use as light stabilizers, heat stabilizers and oxidation stabilizers for organic materials, in particular synthetic polymers, and to organic materials thus stabilized. It is known that synthetic polymers are subject to photooxidative degradation when they are exposed to sunlight or other sources of ultraviolet light in the presence of oxygen. For their use in practice, it is therefore necessary to add to them suitable light stabilizers, such as certain benzophenone or benzotriazole derivatives, nickel complexes, substituted benzoic acid esters, alkylidenemalonates, cyanoacrylates, aromatic oxamides or sterically hindered amines. Some triazine derivatives of 2,2,6,6-tetramethyl-4-piperidylamine and their use as stabilizers for synthetic polymers have been reported in US Patents, 3,925,376, 4,108,829, 4,288,593, 4,376,836, 4,433,145 and 4,533,688, in European Patents 176,106, 209,127 and 227,640 and in Belgian Patent 904,401. Furancarboxylic acid derivatives containing 2,2,6,6-tetramethyl-4-piperidyl groups and their use as stabilizers are disclosed in EP-A-149,781 and EP-A-207,396. The present invention relates to triazine derivatives of N-(2,2,6,6-tetramethyl-4-piperidyl)-tetrahydrofurfurylamine, which, apart from being effective as light stabilizers for synthetic polymers, also show, surprisingly, an enhanced antioxidant action, especially in polyolefins. In particular, the present invention relates to novel piperidinetriazine compounds of the general formula (I) in which R₁ is hydrogen, C₁-C₈alkyl, O . , OH, NO, CH₂CN, C₁-C₁₈alkoxy, C₅-C₁₂cycloalkoxy, C₃-C₆alkenyl, C₇-C₉phenylalkyl which is unsubstituted or mono-, di- or tri-substituted on the phenyl by C₁-C₄alkyl, C₁-C₈acyl or C₂-C₄alkyl substituted by OH in the 2-, 3- or 4-position, R₂ is a group -OR₄, -SR₄ or in which R₄ is C₁-C₁₈alkyl, C₅-C₁₂cycloalkyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, C₃-C₁₈alkenyl, phenyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, C₇-C₉phenylalkyl which is unsubstituted or mono-, di- or tri-substituted on the phenyl by C₁-C₄alkyl, or a group of the formula (II) where R₇ has any of the definitions of R₁; R₅ and R₆ which can be identical or different are hydrogen, C₁-₁₈alkyl, C₅-C₁₂cycloalkyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, C₇-C₉phenylalkyl which is unsubstituted or mono-, di- or tri-substituted on the phenyl by C₁-C₄alkyl, C₂-C₄alkyl which is substituted in the 2-, 3- or 4-position by OH, by C₁-C₈alkoxy or by di-(C₁-C₄alkyl)-amino, C₃-C₁₈alkenyl, tetrahydrofurfuryl or a group of the formula (II), or R₅ and R₆, together with the nitrogen atom to which they are linked, form part of a 5-membered to 7-membered heterocyclic ring, λ is an integer from 1 to 6 and , if λ is 1, R₃ has any of the definitions of R₂, with the proviso that R₂ and R₃ are different from if both R₅ and R₆ are a group of the formula (II), and, if λ is 2, R₃ is one of the groups of the formulae (IIIa)-(IIIc) in which R₈ is C₂-C₁₂alkylene, cyclonexylene, cyclohexylenedimethylene, methylenedicyclohexylene, (C₂-C₆alkylidene)-dicyclohexylene, phenylene, (C₁-C₆alkylidene)-diphenylene or xylylene, R₉ and R₁₁ which can be identical or different are hydrogen, C₁-C₁₈alkyl, C₅-C₁₂cycloalkyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, C₇-C₉phenylalkyl which is unsubstituted or mono-, di- or tri-substituted on the phenyl by C₁-C₄alkyl, or a group of the formula (II), R₁₀ is as defined above for R₈ or is C₄-C₁₂alkylene interrupted by 1, 2 or 3 oxygen atoms or by 1 or 2 groups > N-R₁₃, where R₁₃ has any of the definitions of R₉ and R₁₁, or is one of the groups of the formulae (IVa)-(IVd) where R₁₄ is hydrogen, C₁-C₁₈alkyl, C₅-C₁₂cycloalkyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, C₂-C₁₈alkenyl, phenyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl and/or an OH group, C₇-C₉phenylalkyl which is unsubstituted or mono-, di- or tri-substituted on the phenyl by C₁-C₄alkyl and/or an OH group, R₁₅ is C₁-C₁₈alkyl, C₅-C₁₂cycloalkyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, C₃-C₁₈alkenyl or a group of the formula (II) and R₁₆ is C₁-C₁₈alkyl or phenyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, m is zero or 1, R₁₂ is hydrogen or methyl and n is zero, 1, 2, 3 or 4, and, if λ is 3, R₃ is one of the groups of the formulae (Va)-(Vc) in which R₁₇, R₂₀, R₂₁, R₂₂, R₂₃, R₂₄ and R₂₆ which can be identical or different are as defined above for R₉ and R₁₁; R₁₈ and R₁₉ which can be identical or different are C₂-C₁₂alkylene or C₄-C₁₂alkylene interrupted by a group >N-R₂₇ with R₂₇ being as defined above for R₁₃, s and v which can be identical or different are integers from 2 to 6, t is zero or 1 and R₂₅ is C₂-C₁₂alkylene, and, if λ is 4, 5 or 6, R₃ is a group of the formula in which R₂₈ and R₃₁ which can be identical or different are as defined above for R₉ and R₁₁; R₂₉ and R₃₀ which can be identical or different are C₂-C₁₂alkylene and x is 1, 2 or 3, and, if λ is 4, R₃ is also one of the groups of the formulae (VIIa)-(VIIc) in which R₃₂, R₃₅, R₃₆ and R₃₉ which can be identical or different are as defined above for R₉ and R₁₁; R₃₃, R₃₄, R₃₇ and R₃₈ which can be identical or different are C₂-C₁₂alkylene, D₁ is C₂-C₁₂alkylene, 2-hydroxytrimethylene, -CH₂CO-, xylylene or one of the groups of the formulae (VIIIa) and (VIIIb) in which R₄₁ is a direct bond, C₁-C₁₂alkylene, cyclohexylene or phenylene and R₄₂ is as defined above for R₈, and R₄₀ is as defined above for R₂, and, if λ is 6, R₃ is also one of the groups of the formulae (IXa)-(IXc) in which R₄₃, R₄₇, R₄₈ and R₅₁ which can be identical or different are as defined above for R₉ and R₁₁; R₄₄, R₄₅, R₄₆, R₄₉ and R₅₀ which can be identical or different are C₂-C₁₂alkylene and D₂ is as defined above for D₁. Representative examples of C₁-C₈alkyl R₁and R₇ are methyl, ethyl, propyl, butyl, isobutyl, pentyl, hexyl, heptyl and octyl. C₁-C₄alkyl, in particular methyl, is preferred. Examples of C₁-C₁₈alkyl are methyl, ethyl, propyl, isopropyl, butyl, 2-butyl, isobutyl, t-butyl, pentyl, 2-pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, t-octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, hexadecyl and octadecyl. C₁-C₈alkyl is preferred. Examples of OH-substituted C₂-C₄alkyl are 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 2-hydroxybutyl and 4-hydroxybutyl. 2-Hydroxyethyl is preferred. Examples of C₂-C₄alkyl substituted by C₁-C₈alkoxy, preferably C₁-C₄alkoxy, in particular methoxy or ethoxy, are 2-methoxyethyl,2-ethoxyethyl, 3-methoxypropyl, 3-ethoxypropyl, 3-butoxypropyl, 3-octoxypropyl and 4-methoxybutyl. Examples of C₂-C₄alkyl substituted by di-(C₁-C₄alkyl)-amino, preferably dimethylamino or diethylamino, are 2-dimethylaminoethyl, 2-diethylaminoethyl, 3-dimethylaminopropyl, 3-diethylaminopropyl, 3-dibutylaminopropyl and 4-diethylaminobutyl. Representative examples of C₁-C₁₈alkoxy and R₁ and R₇ are methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, pentoxy, isopentoxy, hexoxy, heptoxy, octoxy, decyloxy, dodecyloxy, tetradecyloxy, hexadecyloxy and octadecyloxy. C₆-C₁₂alkoxy, in particular heptoxy or octoxy, is preferred. Examples of unsubstituted or substituted C₅-C₁₂cycloalkyl are cyclopentyl, methylcyclopentyl, dimethylcyclopentyl, cyclohexyl, methylcyclohexyl, dimethylcyclohexyl, trimethylcyclohexyl, t-butylcyclohexyl, cyclooctyl, cyclodecyl and cyclododecyl. Cyclohexyl which is unsubstituted or substituted by C₁-C₄alkyl is preferred. Representative examples of C₅-C₁₂cycloalkoxy R₁ and R₇ are cyclopentoxy, cyclohexoxy, cycloheptoxy, cyclooctoxy, cyclodecyloxy and cyclododecyloxy. Cyclopentoxy and cyclohexoxy are preferred. Examples of alkenyl having up to 18 carbon atoms are vinyl, allyl, 2-methylallyl, hexenyl, decenyl, undecenyl, heptadecenyl and oleyl. Allyl is one of the preferred definitions of R₁ and R₇. In alkenyl R₁, R₄, R₅, R₆, R₇ and R₁₅, the carbon atom in the 1-position is preferably a saturated carbon atom. Examples of substituted phenyl are methylphenyl, dimethylphenyl, trimethylphenyl, t-butylphenyl, di-t-butylphenyl, hydroxyphenyl and 3,5-di-t-butyl-4-hydroxyphenyl. Examples of phenylalkyl which is unsubstituted or substituted on the phenyl, are benzyl, methylbenzyl, dimethylbenzyl, t-butylbenzyl, 2-phenylethyl and 2-(3,5-di-t-butyl-4-hydroxyphenyl)-ethyl. Acyl R₁ and R₇ having up to 8 carbon atoms can be aliphatic or aromatic. Representative examples are formyl, acetyl, propionyl, butyryl, pentanoyl, hexanoyl, octanoyl, benzoyl, acryloyl and crotonyl. C₁-C₈Alkanoyl, C₃-C₈alkenoyl and benzoyl are preferred. Acetyl is particularly preferred. If R₅ and R₆ which, together with the nitrogen atom to which they are linked, form part of a 5-membered to 7-membered heterocyclic ring, this heterocyclic ring preferably contains a further hetero atom, for example nitrogen or oxygen. Representative examples are 1-pyrrolidyl, 1-piperidyl, 4-morpholinyl, 4-methyl-1-piperazinyl, 1-hexahydroazepinyl, 5,5,7-trimethyl-1-homopiperazinyl and 4,5,5,7-tetramethyl-1-homopiperazinyl. 4-Morpholinyl is preferred. Examples of alkylene having up to 12 carbon atoms are methylene, ethylene, propylene, trimethylene, tetramethylene, pentamethylene, 2,2-dimethyltrimethylene, hexamethylene, trimethylhexamethylene, decamethylene and dodecamethylene. Examples of C₄-C₁₂alkylene interrupted by 1, 2 or 3 oxygen atoms are 3-oxapentane-1,5-diyl, 3,6-dioxaoctane-1,8-diyl and 3,6,9-trioxaundecane-1,11-diyl. Representative examples of C₄-C₁₂alkylene R₁₀ interrupted by 1 or 2 groups >N-R₁₃ are the groups in which R₁₃ has any of the definitions given. Representative examples of alkylene R₁₈ and R₁₉ interrupted by a group >N-R₂₇ are the groups in which R₂₇ has any of the definitions given. The preferred definitions of R₁ are hydrogen, C₁-C₄alkyl, OH, C₆-C₁₂alkoxy, C₅-C₈cycloalkoxy, allyl, benzyl, acetyl and 2-hydroxyethyl, in particular hydrogen and methyl. Those compounds of the formula (I) are preferred in which R₂ is a group -OR₄, -SR₄ or in which R₄ is C₁-C₁₈alkyl, C₅-C₈cycloalkyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, C₃-C₁₂alkenyl, phenyl, benzyl or a group of the formula (II), and R₅ and R₆ which can be identical or different are hydrogen, C₁-C₁₈alkyl, C₅-C₈cycloalkyl which is unsubstituted or mono-,di- or tri-substituted by C₁-C₄alkyl, benzyl, C₂-C₃alkyl substituted in the 2- or 3-position by OH, by C₁-C₄alkoxy or by di-(C₁-C₄alkyl)-amino, allyl, oleyl, tetrahydrofurfuryl or a group of the formula (II), or the group is 1-pyrrolidyl, 1-piperidyl, 4-morpholinyl or 1-hexahydroazepinyl, and λ is an integer from 1 to 6, and, if λ is 1, R₃ has any of the definitions of R₂ with the proviso that R₂ and R₃ are different from if both R₅ and R₆ are a group of the formula (II), and, if λ is 2, R₃ is one of the groups of the formulae (IIIa)-(IIIc) in which R₈ is C₂-C₁₀alkylene, cyclohexylene, cyclohexylenedimethylene, methylenedicyclohexylene, isopropylidenedicyclohexylene, phenylene or isopropylidenediphenylene, R₉ and R₁₁ which can be identical or different are hydrogen, C₁-C₁₂alkyl, C₅-C₈cycloalkyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, benzyl or a group of the formula (II), R₁₀ is as defined above for R₈ or is C₄-C₁₂alkylene interrupted by 1, 2 or 3 oxygen atoms or by 1 or 2 groups >N-R₁₃ where R₁₃ has any of the definitions given for R₉ and R₁₁, or is one of the groups of the formulae (IVa)-(IVd) in which R₁₄ is hydrogen, C₁-C₁₇alkyl, C₅-C₈cycloalkyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, C₂-C₁₇alkenyl, phenyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl and/or an OH group, C₇-C₈phenylalkyl which is unsubstituted or mono-, di- or tri-substituted on the phenyl by C₁-C₄alkyl and/or an OH group, R₁₅ is C₁-C₁₈alkyl, C₅-C₈cycloalkyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, C₃-C₁₈alkenyl or a group of the formula (II) and R₁₆ is C₁-C₁₂alkyl, phenyl or tolyl, m is zero or 1, R₁₂ is hydrogen or methyl and n is zero, 1, 2, 3 or 4, and, if λ is 3, R₃ is one of the groups of the formulae (Va)-(Vc) in which R₁₇, R₂₀, R₂₁, R₂₂, R₂₃, R₂₄ and R₂₆ which can be identical or different are as defined above for R₉ and R₁₁; R₁₈ and R₁₉ which can be identical or different are C₂-C₁₀alkylene or C₄-C₁₂alkylene interrupted by a group >N-R₂₇ with R₂₇ being as defined above for R₁₃, s and v which can be identical or different are integers from 2 to 6, t is zero or 1 and R₂₅ is C₂-C₁₀alkylene, and, if λ is 4, 5, or 6, R₃ is a group of the formula (VI) in which R₂₈ and R₃₁ which can be identical or different are as defined above for R₉ and R₁₁; R₂₉ and R₃₀ which can be identical or different are C₂-C₁₀alkylene and x is 1, 2 or 3, and, if λ is 4, R₃ is also one of the groups of the formulae (VIIa)-(VIIc) in which R₃₂, R₃₅, R₃₆ and R₃₉ which can be identical or different are as defined above for R₉ and R₁₁; R₃₃, R₃₄, R₃₇ and R₃₈ which can be identical or different are C₂-C₁₀alkylene, D₁ is C₂-C₁₀alkylene, 2-hydroxytrimethylene, -CH₂CO-, xylylene or one of the groups of the formulae (VIIIa) or (VIIIb) in which R₄₁ is a direct bond or C₁-C₁₀alkylene, R₄₂ is as defined above for R₈, and R₄₀ is as defined above for R₂, and, if λ is 6, R₃ is also one of the groups of the formulae (IXa)-(IXc) in which R₄₃, R₄₇, R₄₈ and R₅₁ which can be identical or different are as defined above for R₉ and R₁₁; R₄₄, R₄₅, R₄₆, R₄₉ and R₅₀ which can be identical or different are C₂-C₁₀alkylene and D₂ is as defined above for D₁. Those compounds of the formula (I) are particularly preferred in which R₂ is a group -OR₄ or in which R₄ is C₁-C₁₂alkyl, cyclohexyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, allyl, undecenyl, phenyl, benzyl or a group of the formula (II), R₅ and R₆ which can be identical or different are hydrogen, C₁-C₁₂alkyl, cyclohexyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, benzyl, C₂-C₃alkyl which is substituted in the 2- or 3-position by OH, by methoxy, by ethoxy, by dimethylamino or by diethylamino, allyl, tetrahydrofurfuryl or a group of the formula (II), or the group is 4-morpholinyl, and λ is an integer from 1 to 6, and, if λ is 1, R₃ has any of the definitions given for R₂, with the proviso that R₂ and R₃ are different from if both R₅ and R₆ are a group of the formula (II), and if λ is 2, R₃ is one of the groups of the formulae (IIIb)-(IIIc) in which R₉ and R₁₁ which can be identical or different are hydrogen, C₁-C₈alkyl, cyclohexyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, benzyl or a group of the formula (II), R₁₀ is C₂-C₈alkylene, cyclohexylenedimethylene, methylenedicyclohexylene, C₄-C₁₀alkylene interrupted by 1 or 2 oxygen atoms or C₄-C₁₂alkylene interrupted by 1 or 2 groups >N-R₁₃ where R₁₃ has any of the definitions given for R₉ and R₁₁, or is one of the groups of the formulae (IVa)-(IVc) in which R₁₄ is C₁-C₁₂alkyl, cyclohexyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, C₂-C₁₀alkenyl, phenyl, 3,5-di-t-butyl-4-hydroxyphenyl, benzyl or 2-(3,5-di-t-butyl-4-hydroxyphenyl)-ethyl, R₁₅ is C₁-C₁₂alkyl, cyclohexyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, allyl, undecenyl, oleyl or a group of the formula (II), m is zero or 1, R₁₂ is hydrogen or methyl and n is zero, 1, 2 or 3, and, if λ is 3, R₃ is a group of the formula (Va) in which R₁₇ and R₂₀ which can be identical or different are as defined above for R₉ and R₁₁; R₁₈ and R₁₉ which can be identical or different are C₂-C₈alkylene and R₁₈ is also C₄-C₁₂alkylene interrupted by a group >N-R₂₇ with R₂₇ being as defined above for R₁₃, and, if λ is 4, 5 or 6, R₃ is a group of the formula (VI) in which R₂₈ and R₃₁ which can be identical or different are as defined above for R₉ and R₁₁; R₂₉ and R₃₀ which can be identical or different are C₂-C₈alkylene and x is 1, 2 or 3, and, if λ is 4, R₃ is also a group of the formula (VIIa) in which R₃₂ and R₃₅ which can be identical or different are as defined above for R₉ and R₁₁; R₃₃ and R₃₄ which can be identical or different are C₂-C₈alkylene and D₁ is C₂-C₈alkylene, 2-hydroxytrimethylene, xylylene or a group of the formula (VIIIa) or (VIIIb) in which R₄₁ is a direct bond or C₁-C₈alkylene and R₄₂ is C₄-C₈alkylene, 3-oxapentane-1,5-diyl, cyclohexylenedimethylene or isopropylidenedicyclohexylene, and, if λ is 6, R₃ is also a group of the formula (IXa) in which R₄₃ and R₄₇ which can be identical or different are as defined above for R₉ and R₁₁; R₄₄, R₄₅ and R₄₆ which can be identical or different are C₂-C₈alkylene and D₂ is as defined above for D₁. Those compounds of the formula (I) are of special interest in which R₂ is a group -OR₄ or in which R₄ is C₁-C₈alkyl, cyclohexyl, allyl, phenyl, benzyl, 2,2,6,6-tetramethyl-4-piperidyl or 1,2,2,6,6-pentamethyl-4-piperidyl, R₅ and R₆ which can be identical or different are C₁-C₈alkyl, cyclohexyl, benzyl, C₂-C₃alkyl substituted in the 2- or 3-position by methoxy, by ethoxy, by dimethylamino or by diethylamino, allyl, tetrahydrofurfuryl, 2,2,6,6-tetramethyl-4-piperidyl or 1,2,2,6,6-pentamethyl-4-piperidyl, or R₅ is also hydrogen, or the group is 4-morpholinyl, and λ is 1, 2, 3 or 4, and, if λ is 1, R₃ has any of the definitions given for R₂, with the proviso that R₂ and R₃ are different from if both R₅ and R₆ are a group of the formula (II), and, if λ is 2, R₃ is one of the groups of the formulae (IIIb)-(IIIc) in which R₉ and R₁₁ which can be identical or different are hydrogen, C₁-C₄alkyl, cyclohexyl, 2,2,6,6-tetramethyl-4-piperidyl or 1,2,2,6,6-pentamethyl-4-piperidyl, R₁₀ is C₂-C₆alkylene, cyclohexylenedimethylene, methylenedicyclohexylene, C₄-C₁₀alkylene interrupted by 1 or 2 oxygen atoms or C₄-C₁₂alkylene interrupted by 1 or 2 groups >N-R₁₃ in which R₁₃ is hydrogen, methyl or a group of the formula (IVa) or (IVb) in which R₁₄ is C₁-C₈alkyl, cyclohexyl, phenyl or 2-(3,5-di-t-butyl-4-hydroxyphenyl)-ethyl and R₁₅ is C₁-C₈alkyl, cyclohexyl, t-butylcyclohexyl or 1,2,2,6,6-pentamethyl-4-piperidyl, and m and n are zero, and, if λ is 3, R₃ is a group of the formula (Va) in which R₁₇ and R₂₀ which can be identical or different are as defined above for R₉ and R₁₁; R₁₈ and R₁₉ which can be identical or different are C₂-C₆alkylene and R₁₈ is also C₄-C₆alkylene interrupted by a group >N-R₂₇ with R₂₇ being as defined above for R₁₃, and, if λ is 4, R₃ is a group of the formula (VI) in which R₂₈ and R₃₁ which can be identical or different are as defined above for R₉ and R₁₁; R₂₉ and R₃₀ which can be identical or different are C₂-C₆alkylene and x is 1, or R₃ is a group of the formula (VIIa) in which R₃₂ and R₃₅ which can be identical or different are as defined above for R₉ and R₁₁; R₃₃ and R₃₄ which can be identical or different are C₂-C₆alkylene and D₁ is a group of the formula (VIIIa) or (VIIIb) in which R₄₁ is a direct bond or C₁-C₄alkylene and R₄₂ is C₄-C₆alkylene. Those compounds of the formula (I) are of particular interest in which R₁ is a hydrogen or methyl, R₂ is a group -OR₄ or in which R₄ is C₁-C₄alkyl, 2,2,6,6-tetramethyl-4-piperidyl or 1,2,2,6,6-pentamethyl-4-piperidyl, R₅ and R₆ which can be identical or different are C₁-C₈alkyl, allyl, tetrahydrofurfuryl, 2,2,6,6-tetramethyl-4-piperidyl or 1,2,2,6,6-pentamethyl-4-piperidyl, or R₅ is also hydrogen, or the group is 4-morpholinyl, and λ is 1, 2, 3 or 4, and, if λ is 1, R₃ has any of the definitions given for R₂, with the proviso that R₂ and R₃ are different from bis-(2,2,6,6-tetramethyl-4-piperidyl)-amino and bis-(1,2,2,6,6-pentamethyl-4-piperidyl)-amino, and, if λ is 2, R₃ is one of the groups of the formulae (IIIb)-(IIIc) in which R₉ and R₁₁ which can be identical or different are hydrogen, methyl, 2,2,6,6-tetramethyl-4-piperidyl or 1,2,2,6,6-pentamethyl-4-piperidyl, R₁₀ is C₂-C₆alkylene or C₄-C₆alkylene interrupted by a group >N-R₁₃ where R₁₃ is hydrogen, methyl or a group of the formula (IVa) or (IVb) in which R₁₄ and R₁₅ are C₁-C₄alkyl, and m and n are zero, and, if λ is 3, R₃ is a group of the formula (Va) in which R₁₇ and R₂₀ which can be identical or different are as defined above for R₉ and R₁₁; R₁₈ and R₁₉ which can be identical or different are C₂-C₆alkylene, and R₁₈ is also C₄-C₆alkylene interrupted by a group >N-R₂₇ with R₂₇ being as defined above for R₁₃, and if λ is 4, R₃ is a group of the formula (VI) in which R₂₈ and R₃₁ which can be identical or different are hydrogen or methyl, R₂₉ and R₃₀ which can be identical or different are C₂-C₃alkylene and x is 1, or R₃ is a group of the formula (VIIa) in which R₃₂ and R₃₅ which can be identical or different are hydrogen, methyl, 2,2,6,6-tetramethyl-4-piperidyl or 1,2,2,6,6-pentamethyl-4-piperidyl, R₃₃ and R₃₄ which can be identical or different are C₂-C₆alkylene and D₁ is a group of the formula (VIIIa) of (VIIIb) in which R₄₁ is a direct bond of C₁-C₄alkylene and R₄₂ is tetramethylene or hexamethylene. The compounds of the formula (I) can be prepared according to processes known per se, for example as described in US Patents 3,925,376 and 4,108,829, by reacting, in any order, cyanuric chloride with compounds of the formulae (Xa)-(Xc) in the appropriate molar ratios. If R₁₀, R₁₈ and R₁₉ are C₄-C₁₂alkylene interrupted by 1 or 2 groups >N-R₁₃ or by a group >N-R₂₇, the compounds of the formula (I) are preferably prepared by reacting the corresponding compounds with R₁₃ and R₂₇ = H with suitable alkylating or acylating reagents. If R₃ is a group of the formula (VIIa) or (IXa), the compounds of the formula (I) are preferably prepared by reacting a compound of the formula (XIa) or (XIb) in which Z is a group of the formula (XII) with a compound of the formula (XIII) W-D-W (XIII) in which W is preferably chlorine or bromine and D is as defined above for D₁ or D₂, or with epichlorohydrin, if D₁ and R₂ are 2-hydroxytrimethylene. If R₁ is methyl, the compounds of the formula (I) are preferably prepared by reacting the corresponding compounds with R₁ = H with formaldehyde and formic acid or with formaldehyde and hydrogen in the presence of a hydrogenation catalyst, for example palladium or platinum. In these reactions, the amine non-piperidine >NH groups and, under certain conditions, also the melamine >NH groups which may be present can also be methylated. The reactions of cyanuric chloride with the compounds of the formulae (Xa)-(Xc) are preferably carried out in an aromatic hydrocarbon solvent, for example toluene, xylene or trimethylbenzene, operating at temperatures from e.g. -20° to 40°C, preferably from -10° to 20°C, for the substitution of the first Cl, from e.g. 40° to 100°C, preferably from 50° to 90°C, for the substitution of the second Cl, and from e.g. 100° to 200°C, preferably from 120° to 180°C, for the substitution of the third Cl. The hydrohalic acid released in the various reactions is neutralized preferably by an inorganic base, for example sodium or potassium hydroxide or carbonate in quantities at least equivalent to the acid released. The compounds of the formula (Xa) can be prepared according to processes known for the reductive amination of a piperidone of the formula (XIV) with tetrahydrofurfurylamine in the presence of a hydrogenation catalyst, such as e.g. platinum, palladium or nickel. The other intermediates used, of the formulae (Xb) and (Xc), are commercial products or products which can be prepared according to known processes. As mentioned at the outset, the compounds of the formula (I) are highly effective in improving the light stability, heat stability and oxidation stability of organic materials, in particular synthetic polymers and copolymers. Examples of such organic materials which can be stabilized are: 1. Polymers of monoolefins and diolefins, for example polypropylene, polyisobutylene, polybutene-1, polymethylpentene-1, polyisoprene or polybutadiene, as well as polymers of cycloolefins, for instance of cyclopentene or norbornene, polyethylene (which optionally can be cross-linked), for example high-density polyethylene (HDPE), low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE). 2. Mixtures of the polymers mentioned under 1), for example mixtures of polypropylene with polyisobutylene, polypropylene with polyethylene (for example PP/HDPE, PP/LDPE) and mixtures of different types of polyethylene (for example LDPE/HDPE). 3. Copolymers of monoolefins and diolefins with each other or with other vinyl monomers, such as, for example, ethylene/propylene, linear low-density polyethylene (LLDPE) and its mixtures with low-density polyethylene (LDPE), propylene/butene-1, ethylene/hexene, ethylene/ethylpentene, ethylene/heptene, ethylene/octene, propylene/isobutylene, ethylene/butene-1, propylene/butadiene, isobutylene/isoprene, ethylene/alkyl acrylates, ethylene/alkyl methacrylates, ethylene/vinyl acetate or ethylene/acrylic acid copolymers and their salts (ionomers) and terpolymers of ethylene with propylene and a diene, such as hexadiene, dicyclopentadiene or ethylidenenorbornene; as well as mixtures of such copolymers and their mixtures with polymers mentioned in 1) above, for example polypropylene/ethylene-propylene copolymers, LDPE/EVA, LDPE/EAA, LLDPE/EVA and LLDPE/EAA. 3a. Hydrocarbon resins (for example C₅-C₉) and hydrogenated modifications thereof (for example tackyfiers). 4. Polystyrene, poly-(p-methylstyrene), poly-(α-methylstyrene). 5. Copolymers of styrene or α-methylstyrene with dienes or acrylic derivatives, such as, for example, styrene/acrylonitrile, styrene/alkyl methacrylate, styrene/maleic anhydride, styrene/butadiene/ethyl acrylate, styrene/acrylonitrile/methyl acrylate; mixtures of high impact strength from styrene copolymers and another polymer, such as, for example, from a polyacrylate, a diene polymer or an ethylene/propylene/diene terpolymer; and block copolymers of styrene, such as, for example, styrene/butadiene/styrene, styrene/isoprene/styrene, styrene/ethylene/butylene/styrene or styrene/ethylene/propylene/styrene. 6. Graft copolymers of styrene or α-methylstyrene such as, for example, styrene on polybutadiene, styrene on polybutadiene-styrene or polybutadiene-acrylonitrile; styrene and acrylonitrile (or methacrylonitrile) on polybutadiene; styrene and maleic anhydride or maleimide on polybutadiene; styrene, acrylonitrile and maleic anhydride or maleimide on polybutadiene; styrene, acrylonitrile and methyl methacrylate on polybutadiene, styrene and alkyl acrylates or methacrylates on polybutadiene, styrene and acrylonitrile on ethylene/propylene/diene terpolymers, styrene and acrylonitrile on polyacrylates or polymethacrylates, styrene and acrylonitrile on acrylate/butadiene copolymers, as well as mixtures thereof with the copolymers listed under 5), for instance the copolymer mixtures known as ABS, MBS, ASA or AES polymers. 7. Halogen-containing polymers, such as polychloroprene, chlorinated rubbers, chlorinated or sulfochlorinated polyethylene, epichlorohydrin homo- and copolymers, polymers from halogen-containing vinyl compounds, as for example polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, polyvinylidene fluoride, as well as copolymers thereof, as for example vinyl chloride/vinylidene chloride, vinyl chloride/vinyl acetate or vinylidene chloride/vinyl acetate copolymers. 8. Polymers which are derived from α,β-unsaturated acids and derivatives thereof, such as polyacrylates and polymethacrylates, polyacrylamide and polyacrylonitrile. 9. Copolymers from the monomers mentioned under 8) with each other or with other unsaturated monomers, such as, for instance, acrylonitrile/butadiene, acrylonitrile/alkyl acrylate, acrylonitrile/alkoxyalkyl acrylate or acrylonitrile/vinyl halide copolymers or acrylonitrile/alkyl methacrylate/butadiene terpolymers. 10. Polymers which are derived from unsaturated alcohols and amines, or acyl derivatives thereof or acetals thereof, such as polyvinyl alcohol, polyvinyl acetate, polyvinyl stearate, polyvinyl benzoate, polyvinyl maleate, polyvinyl butyral, polyallyl phthalate or polyallylmelamine; as well as their copolymers with olefins mentioned in 1) above. 11. Homopolymers and copolymers of cyclic ethers, such as polyalkylene glycols, polyethylene oxide, polypropylene oxide or copolymers thereof with bis-glycidyl ethers. 12. Polyacetals, such as polyoxymethylene and those polyoxymethylenes which contain ethylene oxide as a comonomer; polyacetals modified with thermoplastic polyurethanes, acrylates or MBS. 13. Polyphenylene oxides and sulfides, and mixtures of polyphenylene oxides with polystyrene or polyamides. 14. Polyurethanes which are derived from polyethers, polyesters or polybutadienes with terminal hydroxyl groups on the one hand on the other hand aliphatic or aromatic polyisocyanates, as well as precursors thereof (polyisocyanates, polyols or prepolymers). 15. Polyamides and copolyamides which are derived from diamines and dicarboxylic acids and/or from aminocarboxylic acids or the corresponding lactams, such as polyamide 4, polyamide 6, polyamide 6/6, 6/10, 6/9, 6/12 and 4/6, polyamide 11, polyamide 12, aromatic polyamides obtained by condensation of m-xylylenediamine and adipic acid; polyamides prepared from hexamethylenediamine and isophthalic or/and terephthalic acid and optionally an elastomer as modifier, for example poly-2,4,4-trimethylhexamethylene-terephthalamide or poly-m-phenylene-isophthalamide. Further, copolymers of the aforementioned polyamides with polyolefins, olefin copolymers, ionomers or chemically bonded or grafted elastomers; or with polyethers, such as for instance, with polyethylene glycols, polypropylene glycols or polytetramethylene glycols. Polyamides or copolyamides modified with EPDM or ABS. Polyamides condensed during processing (RIM-polyamide systems). 16. Polyureas, polyimides and polyamide-imides. 17. Polyesters which are derived from dicarboxylic acids and diols and/or from hydroxycarboxylic acids or the corresponding lactones, such as polyethylene terephthalate, polybutylene terephthalate, poly-1,4-dimethylolcyclohexane terephthalate, poly-[2,2-(4-hydroxyphenyl)-propane] terephthalate and polyhydroxybenzoates as well as block copolyetheresters derived from polyethers having hydroxyl end groups. 18. Polycarbonates and polyester-carbonates. 19. Polysulfones, polyether-sulfones and polyether-ketones. 20. Crosslinked polymers which are 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. 21. Drying and non-drying alkyd resins. 22. Unsaturated polyester resins which are 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 inflammability. 23. Thermosetting acrylic resins, derived from substituted acrylic esters, such as epoxy-acrylates, urethane-acrylates or polyester-acrylates. 24. Alkyd resins, polyester resins or acrylate resins in admixture with melamine resins, urea resins, polyisocyanates or epoxide resins as crosslinking agents. 25. Crosslinked epoxide resins which are derived from polyepoxides, for example from bis-glycidyl ethers or from cycloaliphatic diepoxides. 26. Natural polymers, such as cellulose, rubber, gelatine and derivatives thereof which are chemically modified in a polymer-homologous manner, such as cellulose acetates, cellulose propionates and cellulose butyrates, or cellulose ethers, such as methylcellulose; rosins and their derivatives. 27. Mixtures of polymers as mentioned above, for example PP/EPDM, polyamide 6/EPDM or ABS, PVC/EVA, PVC/ABS, PVC/MBS, PC/ASA, PC/PBT, PVC/CPE, PVC/acrylates, POM/thermoplastic PUR, PC/thermoplastic PUR, POM/acrylate, POM/MBS, PPE/HIPS, PPE/PA 6.6 and copolymers, PA/HDPE, PA/PP, PA/PPE. 28. Naturally occurring and synthetic organic materials which are pure monomeric compounds 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, adipates, phosphates or trimellitates) and also mixtures of synthetic esters with mineral oils in any weight ratios, which materials may be used as plasticizers for polymers or as textile spinning oils, as well as aqueous emulsions of such materials. 29. Aqueous emulsions of natural or synthetic rubbers, for example natural latex or latexes of carboxylated styrene/butadiene copolymers. The compounds of the formula (I) are particularly suitable for improving the light stability, heat stability and oxidation stability of polyolefins, especially polyethylene and polypropylene. The compounds of the formula (I) can be used in mixtures with organic materials in various proportions depending on the nature of the material to be stabilized, on the end use and on the presence of other additives. In general, it is appropriate to use, for example, 0.01 to 5% by weight of the compounds of the formula (I), relative to the weight of the material to be stabilized, preferably from 0.05 to 1%. The compounds of the formula (I) can be incorporated in the polymeric materials by various processes, such as e.g. dry mixing in the form of powder, or wet mixing in the form of solutions or suspensions or also in the form of a masterbatch; in such operations, the polymer can be used in the form of powder, granules, solutions, suspensions or in the form of latices. The materials stabilized with the products of the formula (I) can be used for the production of mouldings, films, tapes, monofilaments, surface coatings and the like. If desired, other conventional additives for synthetic polymers, such as e.g. antioxidants, UV absorbers, nickel stabilizers, pigments, fillers, plasticisers, antistatic agents, flameproofing agents, lubricants, corrosion inhibitors and metal deactivators, can be added to the mixtures of the compounds of the formula (I) with the organic materials. Particular examples of additives which can be used in a mixture with the compounds of the formula (I) are: 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-methylcyclohexyl)-4,6-dimethylphenol, 2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol, 2,6-di-tert-butyl-4-methoxymethylphenol, 2,6-dinonyl-4-methylphenol. 1.2. Alkylated hydroquinones , for example 2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butylhydroquinone, 2,5-di-tert-amylhydroquinone, 2,6-diphenyl-4-octadecyloxyphenol. 1.3. 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). 1.4. 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-butylphenol), 2,2'-ethylidenebis(6-tert-butyl-4-isobutylphenol), 2,2'-methylenebis[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-methylphenyl)3-n-dodecylmercaptobutane, 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. 1.5. Benzyl compounds , for example 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene, bis(3,5-di-tert-butyl-4-hydroxybenzyl) sulfide, isooctyl 3,5-di-tert-butyl-4-hydroxybenzylmercaptoacetate, bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) dithiolterephthalate, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, di-octadecyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, calcium salt of monoethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, 1,3,5-tris(3,5-dicyclohexyl-4-hydroxybenzyl) isocyanurate. 1.6. Acylaminophenols , for example lauric acid 4-hydroxyanilide, stearic acid 4-hydroxyanilide, 2,4-bis(octylmercapto)-6-(3,5-di-tert-butyl-4-hydroxyanilino)-s-triazine, octyl N-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamate. 1.7. Esters of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid with mono- or polyhydric alcohols, e.g. with methanol, diethylene glycol, octadecanol, triethylene glycol, 1,6-hexanediol, pentaerythritol, neopentyl glycol, tris(hydroxyethyl) isocyanurate, thiodiethylene glycol, N,N′-bis(hydroxyethyl)oxalic acid diamide. 1.8. Esters of β-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acid with mono- or polyhydric alcohols, e.g. with methanol, diethylene glycol, octadecanol, triethylene glycol, 1,6-hexanediol, pentaerythritol, neopentyl glycol, tris(hydroxyethyl)isocyanurate, thiodiethylene glycol, N,N′-bis(hydroxyethyl)oxalic acid diamide. 1.9. Esters of β-(3,5-dicyclohexyl-4-hydroxyphenyl)propionic acid with mono- or polyhydric alcohols, e.g. with methanol, diethylene glycol, octadecanol, triethylene glycol, 1,6-hexanediol, pentaerythritol, neopentyl glycol, tris(hydroxyethyl) isocyanurate, thiodiethylene glycol, N,N′-bis(hydroxyethyl)oxalic acid diamide. 1.10. 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-hydroxyphenylpropionyl)hydrazine. 2. UV absorbers and light stabilizers 2.1. 2-(2′-Hydroxyphenyl)benzotriazoles , for example the 5′-methyl, 3′,5′-di-tert-butyl, 5′-tert-butyl, 5′-(1,1,3,3-tetramethylbutyl), 5-chloro-3′,5′-di-tert-butyl, 5-chloro-3′-tert-butyl-5′-methyl, 3′-sec-butyl-5′-tert-butyl, 4′-octoxy,3′,5′-di-tert-amyl and 3′,5′-bis(α,α-dimethylbenzyl) derivatives. 2.2. 2-Hydroxybenzophenones , for example the 4-hydroxy, 4-methoxy, 4-octoxy, 4-decyloxy, 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-butylphenyl salicylate, phenyl salicylate, octylphenyl salicylate, dibenzoylresorcinol, bis(4-tert-butylbenzoyl)resorcinol, benzoylresorcinol, 2,4-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzoate and hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate. 2.4. Acrylates , for example ethyl α-cyano-β,β-diphenylacrylate, isooctyl α-cyano-β,β-diphenylacrylate, methyl α -carbomethoxycinnamate, methyl α-cyano-β-methyl-p-methoxycinnamate, butyl α-cyano-β-methyl-p-methoxycinnamate, methyl α -carbomethoxy-p-methoxycinnamate and N-(β-carbomethoxy-β-cyanovinyl)-2-methylindoline. 2.5. Nickel compounds , for example nickel complexes of 2,2′-thiobis[4-(1,1,3,3-tetramethylbutyl)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 4-hydroxy-3,5-di-tert-butylbenzylphosphonic acid monoalkyl esters, e.g. of the methyl or ethyl ester, nickel complexes of ketoximes, e.g. of 2-hydroxy-4-methylphenyl undecyl ketoxime, 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-tetramethylpiperidyl) sebacate, bis(1,2,2,6,6-pentamethylpiperidyl) sebacate, bis(1,2,2,6,6-pentamethylpiperidyl) n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate, the condensation product of 1-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinic acid, the condensation product 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). 2.7. Oxalic acid diamides , for example 4,4'-dioctyloxyoxanilide, 2,2'-dioctyloxy-5,5'-di-tert-butyloxanilide, 2,2'-didodecyloxy-5,5'-di-tert-butyloxanilide, 2-ethoxy-2'-ethyloxanilide, N,N'-bis(3-dimethylaminopropyl)oxalamide, 2-ethoxy-5-tert-butyl-2'-ethyloxanilide and its mixtures with 2-ethoxy-2'-ethyl-5,4'-di-tert-butyloxanilide and mixtures of ortho- and paramethoxy-disubstituted oxanilides and mixtures of o-and p-ethoxy-disubstituted oxanilides. 2.8. 2-(2-Hydroxyphenvl)-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-hydroxy4-propyloxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2-hydroxy4-octyloxyphenyl)-4,6-bis(4-methylphenyl)-1,3,5-triazine, 2-(2-hydroxy4-dodecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine. 3. Metal deactivators , for example N,N'-diphenyloxalic acid diamide, N-salicylal-N'-salicyloylhydrasine, N,N'-bis(salicyloyl)hydrazine, N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine, 3-salicyloylamino-1,2,4-triazole, bis(benzylidene)oxalodihydrazide. 4. Phosphites and phosohonites , for example triphenyl phosphite, diphenyl alkyl phosphites, phenyl dialkyl phosphites, tris(nonylphenyl) phosphite, trilauryl phosphite, trioctadecyl phosphite, distearyl pentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl) phosphite, diisodecyl pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, tristearyl sorbitol triphosphite, tetrakis(2,4-di-tert-butylphenyl) 4,4'-biphenylenediphosphonite, 3,9-bis(2,4-di-tert-butylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane. 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, pentaerythritol tetrakis(β-dodecylmercapto)propionate. 6. Polyamide stabilizers , for example copper salts in combination with iodides and/or phosphorus compounds and salts of divalent manganese. 7. Basic co-stabilizers , for example melamine, polyvinylpyrrolidone, dicyandiamide, triallyl cyanurate, urea derivatives, hydrazine derivatives, amines, polyamides, polyurethanes, alkali metal salts and alkaline earth metal salts of higher fatty acids, for example Ca stearate, Zn stearate, Mg stearate, Na ricinoleate and K palmitate, antimony pyrocatecholate or zinc pyrocatecholate. 8. Nucleating agents , for example 4-tert-butyl-benzoic acid, adipic acid, diphenylacetic acid. 9. Fillers and reinforcing agents , for example calcium carbonate, silicates, glass fibres, asbestos, talc, kaolin, mica, barium sulfate, metal oxides and hydroxides, carbon black, graphite. 10. Other additives , for example plasticisers, lubricants, emulsifiers, pigments, optical brighteners, flameproofing agents, antistatic agents and blowing agents. In order to illustrate the present invention more clearly, several examples of the preparation of compounds of the formula (I) are described below; these examples are given by way of illustration only and do not imply any restriction. Particularly preferred compounds of formula (I) are those of Examples 2, 5, 7, 13 and 22. Example 1 : Preparation of the compound 80.43 g (0.15 mol) of 2-chloro-4,6-bis-[N-(2,2,6,6-tetramethyl-4-piperidyl)-butylamino]-1,3,5-triazine, 36.06 g (0.15 mol) of N-(2,2,6,6-tetramethyl-4-piperidyl)-tetrahydrofurfurylamine and 12 g (0.3 mol) of sodium hydroxide in 250 ml of mesitylene are heated under reflux for 20 hours, with azeotropic removal of the water of reaction. The mixture is cooled to about 50°C and filtered, and the filtrate is washed with water. The solution is then dried over sodium sulphate and evaporated in vacuo (2 mbar). The residue is taken up in n-hexane, from which the product of melting point 118-120°C crystallizes Analysis for C₄₃H₈₁N₉O Calculated: C = 69.68%; H = 11.15%; N = 17.01% Found: C = 68.75%; H = 10.95%; N = 17.02% Example 2 : Preparation of the compound 36.0 g (0.15 mol) of N-(2,2,6,6-tetramethyl-4-piperidyl)tetrahydrofurfurylamine are added slowly to a solution of 27.67 g (0.15 mol) of cyanuric chloride in 150 ml of xylene, the temperature being maintained at 10°C. After stirring for one hour at ambient temperature, the mixture is cooled at 10°C, and a solution of 6.00 g (0.15 mol) of sodium hydroxide in 50 ml of water is added. The mixture is stirred for 2 hours at ambient temperature, the aqueous phase is separated off, and 53.10 g (0.31 mol) of 1,2,2,6,6-pentamethyl4-piperidinol dissolved in 100 ml of xylene are added to the organic solution. The mixture is heated for 4 hours under reflux, 12.60 g (0.31 mol) of sodium hydroxide are added, and the mixture is then heated under reflux for 18 hours with azeotropic removal of the water of reaction. The mixture is then cooled to about 50°C, filtered, washed twice with 100 ml of water at 60°C and, after drying with sodium sulphate, evaporated in vacuo (2 mbar). The residue is treated with n-hexane, from which the product of melting point 87-90°C crystallizes. Analysis for C₃₇H₆₇N₇O₃ Calculated: C = 67.54%; H = 10.26%; N = 14.90% Found: C = 66.99%; H = 10.21%; N = 14.79% Example 3 : Preparation of the compound 22.20 g (0.1 mol) of 2-butoxy-4,6-dichloro-1,3,5-triazine, 48.08 g (0.2 mol) of N-(2,2,6,6-tetramethyl-4-piperidyl)-tetrahydrofurfurylamine and 500 ml of xylene are heated for 2 hours at 90°C. 12.00 g (0.3 mol) of sodium hydroxide are added, and the mixture is heated under reflux for 18 hours, with azeotropic removal of the water of reaction. The mixture is cooled to about 50°C, filtered and evaporated in vacuo (2 mbar). The product has a melting point of 130-131°C. Analysis for C₃₅H₆₃N₇O₃ Calculated: C = 66.75%; H = 10.07%; N = 15.56% Found: C = 66.55%; H = 10.09%; N = 15.62% Examples 4-6 : Following the procedure described in Example 3 and using the appropriate reagents, the following compounds of the formula are prepared: Example 7 : Preparation of the compound 108.17 g (0.45 mol) of N-(2,2,6,6-tetramethyl-4-piperidyl)-tetrahydrofurfurylamine are slowly added to a solution of 27.67 g (0.15 mol) of cyanuric chloride in 300 ml of mesitylene, the temperature being maintained at 0°C. The mixture is heated for 4 hours at 60°C, 25.20 g (0.63 mol) of sodium hydroxide are added, and the mixture is heated under reflux for 18 hours, with azeotropic removal of the water of reaction. The mixture is then cooled to 60°C, filtered and evaporated in vacuo (2 mbar). The residue is then treated with acetonitrile, and the product thus obtained has a melting point of 101-103°C. Analysis for C₄₅H₈₁N₉O₃ Calculated: C = 67.88%; H = 10.25%; N = 15.83% Found: C = 66.48%; H = 10.06%; N = 15.60% Example 8 : Preparation of the compound 48.08 g (0.2 mol) of N-(2,2,6,6-tetramethyl-4-piperidyl)-tetrahydrofurfurylamine are added slowly to a solution of 18.44 g (0.1 mol) of cyanuric chloride in 200 ml of mesitylene, cooled to 10°C. The mixture is then heated for 1 hour to 50°C. After cooling to ambient temperature, a solution of 8.80 g (0.22 mol) of sodium hydroxide in 50 ml of water is added, and the mixture is heated for 3 hours at 80°C. The aqueous phase is separated off, and 5.81 g (0.05 mol) of 1,6-hexanediamine are added. The mixture is heated for 4 hours under reflux and cooled, 8.80 g (0.22 mol) of powdered sodium hydroxide are added and the mixture is heated under reflux for 14 hours, with azeotropic separation of the water of reaction. After cooling to ambient temperature, the reaction mixture is filtered and evaporated in vacuo (2 mbar). The residue is taken up in octane in the presence of a small quantity of water, from which the product of melting point 114-116°C crystallizes. Analysis for C₆₈H₁₂₂N₂₆O₄ Calculated: C = 66.56%; H = 10.01%; N = 18.26% Found: C = 66.49%; H = 9.9%; N = 17.82% Examples 9-11 : Following the procedure described in Example 8, but using the appropriate reagents, the following compounds of the formula are prepared: Example 12 : Preparation of the compound 24.04 g (0.1 mol) of N-(2,2,6,6-tetramethyl-4-piperidyl)-tetrahydrofurfurylamine dissolved in 50 ml of xylene are added to a solution of 20.50 g (0.1 mol) of 2-allylamino-4,6-dichloro-1,3,5-triazine in 500 ml of xylene. The mixture is heated for 4 hours at 60°C and cooled to ambient temperature, and a solution of 4.10 g (0.11 mol) of sodium hydroxide in 30 ml of water is added. After 5 hours' heating at 60°C, the mixture is cooled, the aqueous phase is separated off and 4.31 g (0.05 mol) of piperazine are added. The mixture is heated under reflux for 4 hours and, after the addition of 8.80 g (0.22 mol) of sodium hydroxide at ambient temperature, heating under reflux is continued for 20 hours, with azeotropic removal of the added water and of the water of reaction. The mixture is then cooled to 60°C, filtered and concentrated. On cooling, a product of melting point 210-211°C crystallizes. Analysis for C₄₄H₇₄N₁₄O₂ Calculated: C = 63.58%; H = 8.97%; N = 23.59% Found: C = 63.37%; H = 8.85%; N = 23.47% Example 13 : Preparation of the compound 64.29 g (0.1 mol) of the compound from Example 4, 250 ml of xylene, 12.02 g (0.4 mol) of paraformaldehyde, 4 g of 5% palladium-on-carbon, containing 50% of water, and 80 ml of water are introduced into a 1 litre autoclave. After flushing with nitrogen, hydrogenation is carried out at 130°C under a pressure of 20 bar. After the absorption of hydrogen has ceased, the reaction mixture is cooled to ambient temperature, the catalyst is filtered off, and the filtrate is evaporated in vacuo. This gives a product of melting point 130-132°C. Analysis for C₃₇H₆₆N₈O₃ Calculated: C = 66.22%; H = 9.90%; N = 16.71% Found: C = 66.29%; H = 9.84%; N = 16.64% Example 14 : Preparation of the compound A mixture composed of 3.59 g (0.078 mol) of formic acid and a solution obtained by dissolving 2.43 g (0.081 mol) of paraformaldehyde in 20 ml of a 2% aqueous sodium hydroxide solution are added slowly in 2 hours to a solution, heated at 115°C, of 20.86 g (0.017 mol) of the product from Example 8 in 55 ml of xylene; the water added and the water of reaction are azeotropically removed simultaneously during the addition. The mixture is cooled to 60°C, a solution of 4.00 g (0.1 mol) of sodium hydroxide in 30 ml of water is added, and heating is carried out for 1 hour at 60°C. After the aqueous phase has been separated off, the mixture is dried by separating the water off azeotropically and then evaporated, which gives a product of melting point 123-125°C. Analysis for C₇₂H₁₃₀N₁₆O₄ Calculated: C = 67.36%; H = 10.21%; N = 17.45% Found: C = 66.69%; H = 10.09%; N = 16.82% Examples 15-21 : Following the procedure described in Example 14, but using the appropriate reagents and molar ratios, the following compounds of the formula: are prepared: Example 22 : Preparation of the compound 39.81 g (0.05 mol) of the product from Example 7 are dissolved in a solution of 23.01 g (0.5 mol) of formic acid in 250 ml of water. 13.51 g (0.45 mol) of paraformaldehyde are added, and the mixture is heated under reflux for 10 hours. After cooling to ambient temperature, a solution of 21.38 g (0.53 mol) of sodium hydroxide in 60 ml of water is added. A precipitate forms, which is extracted with 200 ml of dichloromethane. The organic solution is washed repeatedly with water, dried over sodium sulphate and evaporated. The product has a melting point of 119-121°C. Analysis for C₄₈H₈₇N₉O₃ Calculated: C = 68.78%; H = 10.46%; N = 15.04% Found: C = 68.19%; H = 10.36%; N = 15.17% Example 23 Antioxidant action in polypropylene plaques: 1 g of each of the compounds indicated in Table 1 and 1 g of calcium stearate are mixed in a slow mixer with 1,000 g of polypropylene powder of melt index = 2 g/10 minutes (measured at 230°C and 2.16 kg). The mixtures are extruded twice at 200-220°C to give polymer granules which are then converted into plaques of 1 mm thickness by compression-moulding at 230°C for 6 minutes. The plaques are then punched using a DIN 53451 mould, and the specimens obtained are exposed in a forced-circulation air oven maintained at a temperature of 135°C. The specimens are checked at regular intervals by folding them by 180° in order to determine the time (in hours) required for fracturing them. The results obtained are given in Table 1. Stabilizer Time to fracture (hours) Without stabilizer 250 Compound from Example 2 1,960 Compound from Example 4 1,240 Compound from Example 5 1,740 Compound from Example 7 1,630 Compound from Example 13 1,610 Compound from Example 14 1,220 Compound from Example 22 1,690 Example 24 Light-stabilizing action in polypropylene tapes: 1 g of each of the compounds indicated in Table 2, 0.5 g of tris-(2,4-di-t-butylphenyl) phosphite, 0.5 g of pentaerythritol tetrakis-[3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate] and 1 g of calcium stearate are mixed in a slow mixer with 1,000 g of polypropylene powder of melt index = 2 g /10 minutes (measured at 230°C and 2.16 kg). The mixtures are extruded at 200-220°C to give polymer granules which are then converted into stretched tapes of 50 µm thickness and 2.5 mm width, using a pilot-type apparatus (Leonard-Sumirago (VA) Italy) and operating under the following conditions: Extruder temperature: 210-230°C Head temperature: 240-260°C Stretch ratio: 1:6. The tapes thus prepared are exposed, mounted on a white card, in a Weather-O-Meter 65 WR (ASTM G26-77) at a black panel temperature of 63°C. The residual tenacity is measured on samples, taken after various times of exposure to light, by means of a constant-speed tensometer; the exposure time (in hours) needed to have the initial tenacity (T₅₀) is then calculated. Tapes prepared under the same conditions are indicated above, but without the addition of stabilizer, are exposed for comparison. The results obtained are shown in Table 2: Stabilizer T₅₀ (hours) Without stabilizer 500 Compound from Example 1 2,690 Compound from Example 2 2,440 Compound from Example 7 2,030 Compound from Example 13 2,000 Compound from Example 14 2,050 Compound from Example 15 2,420 Compound from Example 22 2,130

Claims: A compound of the formula (I) in which R₁ is hydrogen, C₁-C₈alkyl, 0 . , OH, NO, CH₂CN, C₁-C₁₈alkoxy, C₅-C₁₂cycloalkoxy, C₃-C₆alkenyl, C₇-C₉phenylalkyl which is unsubstituted or mono-, di- or tri-substituted on the phenyl by C₁-C₄alkyl, C₁-C₈acyl or C₂-C₄alkyl substituted by OH in the 2-, 3- or 4-position, R₂ is a group -OR₄, -SR₄ or in which R₄ is C₁-C₁₈alkyl, C₅-C₁₂cycloalkyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, C₃-C₁₈alkenyl, phenyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, C₇-C₉phenylalkyl which is unsubstituted or mono-, di- or tri-substituted on the phenyl by C₁-C₄alkyl, or a group of the formula (II) where R₇ has any of the definitions of R₁; R₅ and R₆ which can be identical or different are hydrogen, C₁-C₁₈alkyl, C₅-C₁₂cycloalkyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, C₇-C₉phenylalkyl which is unsubstituted or mono-, di- or tri-substituted on the phenyl by C₁-C₄alkyl, C₂-C₄alkyl which is substituted in the 2-, 3-or 4-position by OH, by C₁-C₈alkoxy or by di-(C₁-C₄alkyl)-amino, C₃-C₁₈alkenyl, tetrahydrofurfuryl or a group of the formula (II), or R₅ and R₆, together with the nitrogen atom to which they are linked, form part of a 5-membered to 7-membered heterocyclic ring, λ is an integer from 1 to 6, and, if λ is 1, R₃ has any of the definitions of R₂, with the proviso that R₂ and R₃ are different from if both R₅ and R₆ are a group of the formula (II), and, if λ is 2, R₃ is one of the groups of the formulae (IIIa)-(IIIc) in which R₈ is C₂-C₁₂alkylene, cyclohexylene, cyclohexylenedimethylene, methylenedicyclohexylene, (C₂-C₆alkylidene)-dicyclohexylene, phenylene, (C₁-C₆alkylidene)-diphenylene or xylylene, R₉ and R₁₁ which can be identical or different are hydrogen, C₁-C₁₈alkyl, C₅-C₁₂cycloalkyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, C₇-C₉phenylalkyl which is unsubstituted or mono-, di- or tri-substituted on the phenyl by C₁-C₄alkyl, or a group of the formula (II), R₁₀ is as defined above for R₈ or is C₄-C₁₂alkylene interrupted by 1, 2 or 3 oxygen atoms or by 1 or 2 groups >N-R₁₃, where R₁₃ has any of the definitions of R₉ and R₁₁, or is one of the groups of the formulae (IVa)-(IVd) where R₁₄ is hydrogen, C₁-C₁₈alkyl, C₅-C₁₂cycloalkyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, C₂-C₁₈alkenyl, phenyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl and/or an OH group, C₇-C₉phenylalkyl which is unsubstituted or mono-, di- or tri-substituted on the phenyl by C₁-C₄alkyl and/or an OH group, R₁₅ is C₁-C₁₈alkyl, C₅-C₁₂cycloalkyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, C₃-C₁₈alkenyl or a group of the formula (II) and R₁₆ is C₁-C₁₈alkyl or phenyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, m is zero or 1, R₁₂ is hydrogen or methyl and n is zero, 1, 2, 3 or 4, and, if λ is 3, R₃ is one of the groups of the formulae (Va)-(Vc) in which R₁₇, R₂₀, R₂₁, R₂₂, R₂₃, R₂₄ and R₂₆ which can be identical or different are as defined above for R₉ and R₁₁; R₁₈ and R₁₉ which can be identical or different are C₂-C₁₂alkylene or C₄-C₁₂alkylene interrupted by a group >N-R₂₇ with R₂₇ being as defined above for R₁₃, s and v which can be identical or different are integers from 2 to 6, t is zero or 1 and R₂₅ is C₂-C₁₂alkylene, and, if λ is 4, 5 or 6, R₃ is a group of the formula in which R₂₈ and R₃₁ which can be identical or different are as defined above for R₉ and R₁₁; R₂₉ and R₃₀ which can be identical or different are C₂-C₁₂alkylene and x is 1, 2 or 3, and, if λ is 4, R₃ is also one of the groups of the formulae (VIIa)-(VIIc) in which R₃₂, R₃₅, R₃₆ and R₃₉ which can be identical or different are as defined above for R₉ and R₁₁; R₃₃, R₃₄, R₃₇ and R₃₈ which can be identical or different are C₂-C₁₂alkylene, D₁ is C₂-C₁₂alkylene, 2-hydroxytrimethylene, -CH₂CO-, xylylene or one of the groups of the formulae (VIIIa) and (VIIIb) in which R₄₁ is a direct bond, C₁-C₁₂alkylene, cyclohexylene or phenylene and R₄₂ is as defined above for R₈, and R₄₀ is as defined above for R₂, and, if λ is 6, R₃ is also one of the groups of the formulae (IXa)-(IXc) in which R₄₃, R₄₇, R₄₀ and R₅₁ which can be identical or different are as defined above for R₉ and R₁₁; R₄₄, R₄₅, R₄₆, R₄₉ and R₅₀ which can be identical or different are C₂-C₁₂alkylene and D₂ is as defined above for D₁. A compound of the formula (I) according to claim 1, wherein R₁ is hydrogen, C₁-C₄alkyl, OH, C₆-C₁₂alkoxy, C₅-C₈cycloalkoxy, allyl, benzyl, acetyl or 2-hydroxyethyl. A compound of the formula (I) according to claim 1, wherein R₂ is a group -OR₄, -SR₄ or in which R₄ is C₁-C₁₈alkyl, C₅-C₈cycloalkyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, C₃-C₁₂alkenyl, phenyl, benzyl or a group of the formula (II), R₅ and R₆ which can be identical or different are hydrogen, C₁-C₁₈alkyl, C₅-C₈cycloalkyl which is unsubstituted or mono-,di- or tri-substituted by C₁-C₄alkyl, benzyl, C₂-C₃alkyl substituted in the 2- or 3-position by OH, by C₁-C₄alkoxy or by di-(C₁-C₄alkyl)-amino, allyl, oleyl, tetrahydrofurfuryl or a group of the formula (II), or the group is 1-pyrrolidyl, 1-piperidyl, 4-morpholinyl or 1-hexahydroazepinyl, and λ is an integer from 1 to 6, and, if λ is 1, R₃ has any of the definitions of R₂ with the proviso that R₂ and R₃ are different from if both R₅ and R₆ are a group of the formula (II), and, if λ is 2, R₃ is one of the groups of the formula (IIIa)-(IIIc) in which R₈ is C₂-C₁₀alkylene, cyclohexylene, cyclohexylenedimethylene, methylenedicyclohexylene, isopropylidenedicyclohexylene, phenylene or isopropylidenediphenylene, R₉ and R₁₁ which can be identical or different are hydrogen, C₁-C₁₂alkyl, C₅-C₈cycloalkyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, benzyl or a group of the formula (II), R₁₀ is as defined above for R₈ or is C₄-C₁₂alkylene interrupted by 1, 2 or 3 oxygen atoms or by 1 or 2 groups >N-R₁₃ where R₁₃ has any of the definitions given for R₉ and R₁₁, or is one of the groups of the formulae (IVa)-(IVd) in which R₁₄ is hydrogen, C₁-C₁₇alkyl, C₅-C₈cycloalkyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, C₂-C₁₇alkenyl, phenyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl and/or an OH group, C₇-C₈phenylalkyl which is unsubstituted or mono-, di- or tri-substituted on the phenyl by C₁-C₄alkyl and/or an OH group, R₁₅ is C₁-C₁₈alkyl, C₅-C₈cycloalkyl which is unsubstituted or mono-, di-or tri-substituted by C₁-C₄alkyl, C₃-C₁₈alkenyl or a group of the formula (II) and R₁₆ is C₁-C₁₂alkyl, phenyl or tolyl, m is zero or 1, R₁₂ is hydrogen or methyl and n is zero, 1, 2, 3 or 4, and, if λ is 3, R₃ is one of the groups of the formulae (Va)-(Vc) in which R₁₇, R₂₀, R₂₁, R₂₂, R₂₃, R₂₄ and R₂₆ which can be identical or different are as defined above for R₉ and R₁₁; R₁₈ and R₁₉ which can be identical or different are C₂-C₁₀alkylene or C₄-C₁₂alkylene interrupted by a group >N-R₂₇ with R₂₇ being as defined above for R₁₃, s and v which can be identical or different are integers from 2 to 6, t is zero or 1 and R₂₅ is C₂ - C₁₀ - alkylene, and, if λ is 4, 5 or 6, R₃ is a group of the formula (VI) in which R₂₈ and R₃₁ which can be identical or different are as defined above for R₉ and R₁₁; R₂₉ and R₃₀ which can be identical or different are C₂-C₁₀alkylene and x is 1, 2 or 3, and, if λ is 4, R₃ is also one of the groups of the formulae (VIIa)-(VIIc) in which R₃₂, R₃₅, R₃₆ and R₃₉ which can be identical or different are as defined above for R₉ and R₁₁; R₃₃, R₃₄, R₃₇ and R₃₈ which can be identical or different are C₂-C₁₀alkylene, D₁ is C₂-C₁₀alkylene, 2-hydroxytrimethylene, -CH₂CO-, xylylene or one of the groups of the formulae (VIIIa) or (VIIIb) in which R₄₁ is a direct bond or C₁-C₁₀alkylene, R₄₂ is as defined above for R₈, and R₄₀ is as defined above for R₂, and, if λ is 6, R₃ is also one of the groups of the formulae (IXa)-(IXc) in which R₄₃, R₄₇, R₄₈ and R₅₁ which can be identical or different are as defined above for R₉ and R₁₁; R₄₄, R₄₅, R₄₆, R₄₉ and R₅₀ which can be identical or different are C₂-C₁₀alkylene and D₂ is as defined above for D₁. A compound of the formula (I) according to claim 1, wherein R₂ is a group -OR₄ or in which R₄ is C₁-C₁₂alkyl, cyclohexyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, allyl, undecenyl, phenyl, benzyl or a group of the formula (II), R₅ and R₆ which can be identical or different are hydrogen, C₁-C₁₂alkyl, cyclohexyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, benzyl, C₂-C₃alkyl which is substituted in the 2- or 3-position by OH, by methoxy, by ethoxy, by dimethylamino or by diethylamino, allyl, tetrahydrofurfuryl or a group of the formula (II), or the group is 4-morpholinyl, and λ is an integer from 1 to 6, and, if λ is 1, R₃ has any of the definitions given for R₂, with the proviso that R₂ and R₃ are different from if both R₅ and R₆ are a group of the formula (II), and if λ is 2, R₃ is one of the groups of the formulae (IIIb)-(IIIc) in which R₉ and R₁₁ which can be identical or different are hydrogen, C₁-C₈alkyl, cyclohexyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, benzyl or a group of the formula (II), R₁₀ is C₂-C₈alkylene, cyclohexylenedimethylene, methylenedicyclohexylene, C₄-C₁₀alkylene interrupted by 1 or 2 oxygen atoms or C₄-C₁₂alkylene interrupted by 1 or 2 groups >N-R₁₃ where R₁₃ has any of the definitions given for R₉ and R₁₁, or is one of the groups of the formulae (IVa)-(IVc) in which R₁₄ is C₁-C₁₂alkyl, cyclohexyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, C₂-C₁₀alkenyl, phenyl, 3,5-di-t-butyl-4-hydroxyphenyl, benzyl or 2-(3,5-di-t-butyl-4-hydroxyphenyl)-ethyl, R₁₅ is C₁-C₁₂alkyl, cyclohexyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄alkyl, allyl, undecenyl, oleyl or a group of the formula (II), m is zero or 1, R₁₂ is hydrogen or methyl and n is zero, 1, 2 or 3, and, if λ is 3, R₃ is a group of the formula (Va) in which R₁₇ and R₂₀ which can be identical or different are as defined above for R₉ and R₁₁; R₁₈ and R₁₉ which can be identical or different are C₂-C₈alkylene and R₁₈ is also C₄-C₁₂alkylene interrupted by a group >N-R₂₇ with R₂₇ being as defined above for R₁₃, and, if λ is 4, 5 or 6, R₃ is a group of the formula (VI) in which R₂₈ and R₃₁ which can be identical or different are as defined above for R₉ and R₁₁; R₂₉ and R₃₀ which can be identical or different are C₂-C₈alkylene and x is 1, 2 or 3, and, if λ is 4, R₃ is also a group of the formula (VIIa) in which R₃₂ and R₃₅ which can be identical or different are as defined above for R₉ and R₁₁; R₃₃ and R₃₄ which can be identical or different are C₂-C₈alkylene and D₁ is C₂-C₈alkylene, 2-hydroxytrimethylene, xylylene or a group of the formula (VIIIa) or (VIIIb) in which R₄₁ is a direct bond or C₁-C₈alkylene and R₄₂ is C₄-C₈alkylene, 3-oxapentane-1,5-diyl, cyclohexylenedimethylene or isopropylidenedicyclohexylene, and, if λ is 6, R₃ is also a group of the formula (IXa) in which R₄₃ and R₄₇ which can be identical or different are as defined above for R₉ and R₁₁; R₄₄, R₄₅ and R₄₆ which can be identical of different are C₂-C₈alkylene and D₂ is as defined above for D₁. A compound of the formula (I) according to claim 1, wherein R₂ is a group -OR₄ or in which R₄ is C₁-C₈alkyl, cyclohexyl, allyl, phenyl, benzyl, 2,2,6,6-tetramethyl-4-piperidyl or 1,2,2,6,6-pentamethyl-4-piperidyl, R₅ and R₆, which can be identical or different are C₁-C₈alkyl, cyclohexyl, benzyl, C₂-C₃alkyl substituted in the 2- or 3-position by methoxy, by ethoxy, by dimethylamino or by diethylamino, allyl, tetrahydrofurfuryl, 2,2,6,6-tetramethyl-4-piperidyl or 1,2,2,6,6-pentamethyl-4-piperidyl, or R₅ is also hydrogen, or the group is 4-morpholinyl, and λ is 1, 2, 3 or 4, and, if λ is 1, R₃ has any of the definitions given for R₂, with the proviso that R₂ and R₃ are different from if both R₅ and R₆ are a group of the formula (II), and, if λ is 2, R₃ is one of the groups of the formulae (IIIb)-(IIIc) in which R₉ and R₁₁ which can be identical or different are hydrogen, C₁-C₄alkyl, cyclohexyl, 2,2,6,6-tetramethyl-4-piperidyl or 1,2,2,6,6-pentamethyl-4-piperidyl, R₁₀ is C₂-C₆alkylene, cyclohexylenedimethylene, methylenedicyclohexylene, C₄-C₁₀alkylene interrupted by 1 or 2 oxygen atoms or C₄-C₁₂alkylene interrupted by 1 or 2 groups >N-R₁₃ in which R₁₃ is hydrogen, methyl or a group of the formula (IVa) or (IVb) in which R₁₄ is C₁-C₈alkyl, cyclohexyl, phenyl or 2-(3,5-di-t-butyl-4-hydroxyphenyl)-ethyl and R₁₅ is C₁-C₈alkyl, cyclohexyl, t-butylcyclohexyl or 1,2,2,6,6-pentamethyl-4-piperidyl, and m and n are zero, and, if λ is 3, R₃ is a group of the formula (Va) in which R₁₇ and R₂₀ which can be identical or different are as defined above for R₉ and R₁₁; R₁₈ and R₁₉ which can be identical or different are C₂-C₆alkylene and R₁₈ is also C₄-C₆alkylene interrupted by a group >N-R₂₇ with R₂₇ being as defined above for R₁₃, and, if λ is 4, R₃ is a group of the formula (VI) in which R₂₈ and R₃₁ which can be identical or different are as defined above for R₉ and R₁₁; R₂₉ and R₃₀ which can be identical or different are C₂-C₆alkylene and x is 1, or R₃ is a group of the formula (VIIa) in which R₃₂ and R₃₅ which can be identical or different are as defined above for R₉ and R₁₁; R₃₃ and R₃₄ which can be identical or different are C₂-C₆alkylene and D₁ is a group of the formula (VIIIa) or (VIIIb) in which R₄₁ is a direct bond or C₁-C₄alkylene and R₄₂ is C₄-C₆alkylene. A compound of the formula (I) according to claim 1, wherein R₁ is hydrogen or methyl, R₂ is a group -OR₄ or in which R₄ is C₁-C₄alkyl, 2,2,6,6-tetramethyl-4-piperidyl or 1,2,2,6,6-pentamethyl-4-piperidyl, R₅ and R₆ which can be identical or different are C₁-C₈alkyl, allyl, tetrahydrofurfuryl, 2,2,6,6-tetramethyl-4-piperidyl or 1,2,2,6,6-pentamethyl-4-piperidyl, or R₅ is also hydrogen, or the group is 4-morpholinyl, and λ is 1, 2, 3 or 4, and, if λ is 1, R₃ has any of the definitions given for R₂, with the proviso that R₂ and R₃ are different from bis-(2,2,6,6-tetramethyl-4-piperidyl)-amino and bis-(1,2,2,6,6-pentamethyl-4-piperidyl)-amino, and, if λ is 2, R₃ is one of the groups of the formulae (IIIb)-(IIIc) in which R₉ and R₁₁ which can be identical or different are hydrogen, methyl, 2,2,6,6-tetramethyl-4-piperidyl or 1,2,2,6,6-pentamethyl-4-piperidyl, R₁₀ is C₂-C₆alkylene or C₄-C₆alkylene interrupted by a group >N-R₁₃ where R₁₃ is hydrogen, methyl or a group of the formula (IVa) or (IVb) in which R₁₄ and R₁₅ are C₁-C₄alkyl, and m and n are zero, and, if λ is 3, R₃ is a group of the formula (Va) in which R₁₇ and R₂₀ which can be identical or different are as defined above for R₉ and R₁₁; R₁₈ and R₁₉ which can be identical or different are C₂-C₆alkylene, and R₁₈ is also C₄-C₆alkylene interrupted by a group >N-R₂₇ with R₂₇ being as defined above for R₁₃, and if λ is 4, R₃ is a group of the formula (VI) in which R₂₈ and R₃₁ which can be identical or different are hydrogen or methyl, R₂₉ and R₃₀ which can be identical or different are C₂-C₃alkylene and x is 1, or R₃ is a group of the formula (VIIa) in which R₃₂ and R₃₅ which can be identical or different are hydrogen, methyl, 2,2,6,6-tetramethyl-4-piperidyl or 1,2,2,6,6-pentamethyl-4-piperidyl, R₃₃ and R₃₄ which can be identical or different are C₂-C₆alkylene and D₁ is a group of the formula (VIIIa) or (VIIIb) in which R₄₁ is a direct bond or C₁-C₄alkylene and R₄₂ is tetramethylene or hexamethylene. The compounds according to claim 1. A composition containing an organic material susceptible to degradation induced by light, heat or oxidation and at least one compound of the formula (I) according to claim 1. A composition according to claim 8, wherein the organic material is a synthetic polymer. A composition according to claim 9 which, in addition to the compound of the formula (I) also contains other conventional additives for synthetic polymers. A composition according to claim 8, wherein the organic material is a polyolefine. A composition according to claim 8, wherein the organic material is polyethylene or polypropylene. The use of a compound of the formula (I) for stabilizing an organic material against degradation induced by light, heat or oxidation.

Inventors: BORZATTA VALERIO DR, CANTATORE GUISEPPE DR, MASINA FRANCA, BORZATTA, VALERIO, DR., CANTATORE, GUISEPPE, DR., MASINA, FRANCA
Applicants: CIBA GEIGY AG, CIBA GEIGY SPA, CIBA-GEIGY AG, CIBA-GEIGY S.P.A.
Application year: 1989
Main classification: C07D405
IPC codes: C08K5, C07D405, C09K15