CA2020558C - Lubricant composition - Google Patents

Abstract

Lubricants can be stabilized against oxidation by the addition of a) a sterically hindered amine and b) a phenol of formula I

(see formula I) wherein A, B and X are as defined in claim 1. It is preferred to use phenols of formula I which contain a thioether group.

Description

- 1 _ A-17655/+
Lubricant composition The present invention relates to lubricant compositions which are stabilized against oxidative degradation. Stabilization is effected by the incorporation of at least two specific additives.
It is known and conventional to incorporate additives into lubricants based on mineral oils or synthetic oils in order to improve their general use properties. Additives for stabilizing lubricants against oxidative degradation, known as antioxidants, are especially important. The oxi-dative degradation of lubricants is particularly significant in the case of engine oils, because high temperatures prevail in the combustion chamber of engines and, as well as oxygen, nitrogen oxides (NO ) are x present and act as oxidation catalysts.
The antioxidants used for lubricants are, in particular, organic sulfur and phosphorus compounds and also aromatic amines and phenols, especially sterically hindered phenols (see e.g. Ullmanns Encyklopadie der techni-schen Chemie (Ullmann's Encyclopaedia of Chemical Technology), 4th edition, Verlag Chemie, volume 20 (1981), page 541-43).
Sterically hindered amines have also already been proposed as stabilizers for lubricating oils, e.g, in US 4 069 199 or JP-A-85128496.
EP-A-356 677 has proposed mixtures of aromatic amines and sterically hindered amines as antioxidants for lubricants, it also being possible for phenolic antioxidants to be added to these mixtures.
It has been found that combinations of phenolic antioxidants with sterically hindered amines are outstandingly suitable for the stabiliza-tion of lubricants, even without the addition of aromatic amines.

~~~~'~~?
The present invention relates to a lubricant composition comprising (A) a mineral or synthetic oil or a mixture of such oils, (B) at least one sterically hindered amine and (C) at least one phenol of formula I
A\
HO-.\._.~._X I
B/.-.
wherein A is hydrogen, C1-Cz4 alkyl, CS-Clz cycloalkyl, C~-C9 phenyl-alkyl, phenyl or a group -CHz-S-Ri or ~H
-CHz-~~~~\ ~-B
.\~/.
X
B is C1-Cz4 alkyl, C5-Clz cycloalkyl, C~-C9 phenylalkyl, phenyl or a group -CHz-S-R1, ?C is hydrogen, C1-C18 alkyl or one of the groups CaH2a Sq-Rz' CbH2b-CO-OR3, -CbH2b-CO-N(RS)(R6), -CHzN(R1°)(Rii) and _Cgz_.\. ~j.-pH
Rl is Cl-Cla alkyl, phenyl or a group -(CHz)c-CO-OR4 or -CHZCHzOR~, Rz is hydrogen, C1-C1° alkyl, phenyl, benzyl or a group -~\._.~.-OH or -(CHz)c-C0-OR'' or -CHzCHzOR9, .-.~
R3 is C1-C5° alkyl or one of the groups -~H-CHz-S-RS
-Q-0-~-CbH2b ~~~ ~/~-OH
and - g _ -CHz-C CHz-0-C-CbH2b_~\'_~~~-OH

wherein Q is Cz-CB alkylene, C4-C6 thiaalkylene.or a group -CHzCHz(OCHzCHz)d-, R'' is Cl-Cz4 alkyl, RS is hydrogen, C1-C18 alkyl or cyclohexyl, R6 is C1-C18 alkyl, cyclohexyl, phenyl, C1-C18 alkyl-substi-tuted phenyl or one of the groups -(CHz)f-NH-~-CbH2b .\°_.~~-OH
-(CHz)i.-0-~-CbH2b ~\~_~~._OH
-C (CHz)_0_~-CbH2~ ~\° ~%~-OH
or RS and Rs together are C4-Ce alkylene which can be interrupted by -0-or -NH-, R~ is hydrogen, C1-C4 alkyl or phenyl, R8 is C1-Cze alkyl, R9 is hydrogen, C1-Cz4 alkyl, phenyl, Cz-C18 alkanoyl or benzoyl, R1° is C1-ClB
alkyl, cyclohexyl, phenyl, C1-C18 alkyl-substituted phenyl or a group -(CHz)f NH -CHz_,\._.~~vOH
R11 is hydrogen, C1-C18 alkyl, cyclohexyl or a group _CHz_,\._~~._OH
._.
~B

or R1° and R11 together are C4-Ca alkylene which can be interrupted by -O- or -Nl3-, a is 0, l, 2 or 3, b is 0, 1, 2 or 3, c is 1 or 2, d ._s 1 to 5, f is 2 to 8 and q is 1, 2, 3 or 4, or, as component (C:), a mixture of polyphenols formed by reacting at least one phf=_nol of the formula qH QH
~_ i'y ~\ i's ~
il i or n i .\,~.
with at least one phenol of the formula /'\
E II i or II I
.\ %. .\ /.
and with formaldeh~rde or paraformaldehyde, wherein C, D and E
independently of the others are C1-Cz4 alkyl, cyclohexyl or phenyl, the composition containing no aromatic amine.
The present invention further relates to a method for stabilising a lubricant against oxidative degeneration, which comprises incorporating .into the lubricant a combination of component s ( B ) and ( C ) .
In this composition, the weight ratio of (B) to (C) is preferably 1:1 to 1:100, especially 1:3 to 1:20. The sum of (B) and (C) is preferably 0.05 to 5% by weight, especially 0.1 to 3% by weight, of: (A).
A and B as C1-C'z4 alkyl can be linear or branched alkyl, e.g. methyl, ethyl, i-propyl, t-butyl, s-butyl, s-pentyl, t-pentyl, n-heayl, i-hexyl, t-hexyl, i-heptyl, n-octyl, t-octyl, :;-decyl, s-dodecyl, n-dodecyl, s-tetradecyl, n-hexadecyl, n-octadecyl,, s-octadecyl or n-eicosyl.

4a A and B as cyc:loalkyl can be e.g. cyclopentyl, cyclohexyl or cyclooctyl, especially cyclohexyl. A and B as phenylalkyl can be e.g. benzyl, phenylethyl, phenylpropyl or a,a-dimethylbenzyl.
RS and R6 as C1-C1z alkyl can be a . g . methyl , ethyl , propyl , butyl , pent:yl , h~~xyl , octyl , decyl or dodecyl . Rl , Rz , R3 and RB as C1-C18 alkyl can also be e.g. tetradecyl, hexadecyl or octadecyl . R4 a.s C1-C'24 alkyl can also be a . g . eicosyl or tetraeicosyl.

~~~~~~~
The subscript a is preferably 0, 1 or 2, especially 0 or 1; b is prefer-ably 0, 1 or 2, especially 1 or 2; q is preferably 1 or 2, especially 1.
Component (A) is a mineral or synthetic base oil of the kind conven-tionally used for the preparation of lubricants. Synthetic oils can be e.g. esters of polycarboxylic acids or of polyols, aliphatic polyesters or poly-a-olefins, silicones, phosphoric acid esters or polyalkylene glycols. The lubricant can also be a grease based on an oil and a thickener. Such lubricants are described e.g. in D. Klamann "Schmier-stoffe and artverwandte Produkte" ("Lubricants and Generically Related Products"), Verlag Chemie, Weinheim 1982.
Component (B) can be any cyclic or non-cyclic, preferably cyclic, sterically hindered amine. (B) is preferably a compound containing at least one group of formula II
RC~ ~CH~
II
RCHz~ \CH3 wherein R is hydrogen or methyl. R is preferably hydrogen. Said compounds are derivatives of polyalkylpiperidines, especially of 2,2,6,6-tetra-methylpiperidine. These compounds preferably carry one or two polar sub-stituents or a polar spiro ring system in the 4-position of the piper-idine ring. They can be low-molecular, oligomeric or polymeric compounds.
The following classes of polyalkylpiperidines are of particular importance:

~~~~:~~3 a) Compounds of formula III
RCHz~ ~CHa/R
Ri i_~.~~~._0- Ri z III
RCHz~~~CH3 n wherein n is a number from 1 to 4, preferably 1 or 2, R is hydrogen or methyl, R11 is hydrogen, oxyl, hydroxyl, Cl-Clz alkyl, C3-Ce alkenyl, C3-Ce alkynyl, C~-Clz aralkyl, C1-Cla alkoxy, CS-Cs cycloalkoxy, C~-C9 phenylalkoxy, Cz-Ce alkanoyl, Ca-CS alkenoyl, C1-C18 alkanoyloxy, benzyl-oxy, glycidyl or a group -CHzCH(OH)-Z, wherein Z is hydrogen, methyl or phenyl, R11 preferably being H, C1-C4 alkyl, allyl, benzyl, acetyl or acryloyl, and R1z when n is 1 is hydrogen, Ci-C18 alkyl which may be interrupted by one or more oxygen atoms, cyanoethyl, banzyl, glycidyl, a monovalent radical of an aliphatic, cycloaliphatic, araliphatic, un-saturated or aromatic carboxylic acid, carbamic acid or phosphorus-containing acid, or a monovalent si.lyl radical, preferably a radical of an aliphatic carboxylic acid having 2 to 18 C atoms, of a cycloaliphatic carboxylic acid having 7 to 15 C atoms, of an ec,f3-unsaturated carboxylic acid having 3 to 5 C atoms or of an aromatic carboxylic acid having 7 to 15 C atoms, Rlz when n is 2 is C1-Clz alkylene, C4-Clz alkenylene, xylylene, a divalent radical of an aliphatic, cycloaliphatic, araliphatic or aromatic dicarboxylic acid, dicarbamic acid or phosphorus-containing acid, or a divalent silyl radical, preferably a radical of an aliphatic dicarboxylic acid having 2 to 36 C atoms, of a cycloaliphatic ar aromatic dicarboxylic acid having 8 - 14 C atoms or of an aliphatic; cycloali-phatic or aromatic dicarbamic acid having 8 - 14 C atoms, Rlz when n is 3 is a trivalent radical of an aliphatic, cycloaliphatic or aromatic tri-carboxylic acid, of an aromatic tricarbamic acid or of a phosphorus-containing acid, or a trivalent silyl radical, and Rlz when n i.s 4 is a tetravalent radical of an aliphatic, cycloaliphatic or aromatic tetra-carboxylic acid.

,", ". P.
_ Any C1-C1z alkyl substituents are e.g. methyl, ethyl, n-propyl, n-butyl, sec-butyl, tert-butyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl or n-dodecyl.
R11 or R12 as Cl-C18 alkyl can be e.g. the groups listed above and additionally n-tridecyl, n-tetradecyl, n-hexadecyl or n-octadecyl, for example.
Riz as C3-Ce alkenyl can be e.g. prop-1-enyl, allyl, methallyl, but-2-enyl, pent-2-enyl, hex-2-enyl, oct-2-enyl or 4-tent-butylbut-2-enyl.
R11 as C3-C8 alkynyl is preferably propargyl.
Rls as C~-Clz aralkyl is especially phenethyl and in particular benzyl.
R11 as C1-Ca alkanoyl is, for example, formyl, propionyl, butyryl or octanoyl, but preferably acetyl, and R11 as C3-CS alkenoyl is especially acryloyl.
RlZ as a monovalent radical of a carboxylic acid is, for example, an acetic acid, caproic acid, stearic acid, acrylic acid, methacrylic acid, benzoic acid or (3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid radical.
R12 as a divalent radical of a dicarboxylic acid is, for example, a malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, malefic acid, itaconic acid, phthalic acid, dibutylmalonic acid, dibenzylmalonic acid, butyl(3,5-di-tert-butyl-4-hydroxybeinzyl)-malonic acid or bicycloheptenedicarboxylic acid radical.
R1z as a trivalent radical of a tricarboxylic acid is e.g. a t=imellitic acid, citric acid or nitrilotriacetic acid radical.
R12 as a tetravalent radical of a tetracarboxyiic acid is e.g. the tetra-valent radical of butane-1,2,3,4-tetracarboxylic acid or of pyromellitic acid.

_ g _ R12 as a divalent radical of a dicarbamic acid is, for example, a hexa-methylenedicarbamic acid or 2,4-toluylenedicarbamic acid radical.
Preferred compounds of formula III are those in which R is hydrogen, R11 is hydrogen or methyl, n is 1 and R1z is C1-C1a alkyl or n is 2 and R12 is the diacyl radical of an aliphatic dicarboxylic acid having 4-12 C
atoms.
The following compounds are examples of polyalkylpiperidine compounds of this class:
1) 4-hydroxy-2,2,6,6-tetramethylpiperidine 2) 1-allyl-4-hydroxy-2,2,6,6-tetramethylpiperidine 3) 1-benzyl-4-hydroxy-2,2,6,6-tetramethylpiperidine 4) 1-(4-tent-butylbut-2-enyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine 5) 4-stearoyloxy-2,2,6,6-tetramethylpiperidine 6) 1-ethyl-4-salicyloyloxy-2,2,6,6-tetramethylpiperidine 7) 4-methacryloyloxy-1,2,2,6,6-pentamethylpiperidine 8) 1,2,2,6,6-pentamethylpiperidin-4-yl a-(3,5-di-tert-butyl-4-hydroxy-phenyl)propionate 9) di(1-benzyl-2,2,6,6-tetramethylpiperidin-4-yl) maleate 10) di(2,2,6,6-tetramethylpiperidin-4-yl) succinate 11) di(2,2,6,6-tetramethylpiperidin-4-yl) glutarate 12) di(2,2,6,6-tetramethylpiperidin-4-yl) adipate 13) di(2,2,6,6-tetramethylpiperidin-4-yl) sebacate 14) di(1,2,2,6,6-pentamethylpiperidin-4-yl) sebacate 15) di(1,2,3,6-tetramethyl-2,6-diethylpiperidin-4-yl) sebacate 16) di(1-allyl-2,2,6,6-tetramethylpiperidin-4-yl) phthalate 17) 1-hydroxy-4-a-cyanoethoxy-2,2,6,6-tetramethylpiperidine 18) 1-acetyl-2,2,6,6-tetramethylpiperidin-4-yl acetate 19) tri(2,2,6,6,-tetramethylpiperidin-4-yl) trimellitate 20) 1-acryloyl-4-benzyloxy-2,2,6,6-tetramethylpiperidine 21) di(2,2,6,6-tetramethylpiperidin-4-yl) diethylmalonate 22) di(1,2,2,6,6-pentamethylpiper.idin-4-yl) dibutylmalonate 23) di(1,2,2,6,6-pentamethylpiperidin-4-yl) butyl(3,5-di-tert-butyl-4-hydroxybenzyl)malonate 24) di(1-octyloxy-2,2,6,6-tetramethylpiperidin-4-yl) sebacate 25) di(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl) sebacate 26) hexane-1',6'-bis(4-carbamoyloxy-1-n-butyl-2,2,6,6-tetramethyl piperidine) 27) toluene-2',4'-bis(4-carbamoyloxy-1-n-propyl-2,2,6,6-tetramethyl-piperidine) 28) dimethyl-bis(2,2,6,6-tetramethylpiperidin-4-oxy)silane 29) phenyl-tris(2,2,6,6-tetramethylpiperidin-4-oxy)silane 30) tris(1-propyl-2,2,6,6-tetramethylpiperidin-4-yl) phosphite 31) tris(1-propyl-2,2,6,6-tetramethylpiperidin-4-yl) phosphate 32) phenyl(bis(1,2,2,6,6-pentamethylpiperidin-4-yl)) phosphonate 33) 4-hydroxy-1,2,2,6,6-pentamethylpiperidine 34) 4-hydroxy-N-hydroxyethyl-2,2,6,6-tetramethylpiperidine 35) 4-hydroxy-N-(2-hydroxypropyl)-2,2,6,6-tetramethylpiperidine 36) 1-glycidyl-4-hydroxy-2,2,6,6-tetramethylpiperidine b) Compounds of formula IV
RCHz\ /CH3/-R1 1 _~ \.-~ Rl'~ IV
\ /
.--.
RCHz/ \CH3 n wherein n is the number 1 or 2, R and R11 are as defined under a), R13 is hydrogen, C1-Clz alkyl, Cz-C~ hydroxyalkyl, C~-C~ cycloalkyl, C7-Cg aralkyl, Cz-C1$ alkanoyl, C3-CS alkenoyl, benzoyl or a group of the formula RCHz\ /CH3~t Rl 1 _~ \
\ _ /
RCHz/~\CH3 and R1'' when n is 1 is hydrogen, C1-C18 alkyl, C3-Cg alkenyl, CS-C~
cycloalkyl, C1-C4 alkyl substituted by a hydroxyl, cyano, alkoxycarbonyl or carbamide group, glycidyl or a group of the formula -CHz-CH(OH)-Z or ~~~r.~
- l0 -of the formula -CONH-Z, whezein Z is hydrogen, methyl or phenyl, Rl.'' when n is 2 is Cz-Clz alkylene, C6-Clz arylene, xylylene, a group -CHz-CH(OH)-CHz- or a group -CHz-CH(OH)-CHz-0-D-0-, wherein D is Cz-Clo alkylene, C6-C15 arylene or C6-Clz cycloalkylene, or, provided that Rls is not alkanoyl, alkenoyl or benzoyl, Rr'' can also be a divalent radical of an aliphatic, cycloaliphatic or aromatic dicarboxylic acid or di-carbamic acid or the group -CO-, or R13 and Rr'" together, when n is 1, can be the divalent radical of an aliphatic, cycloaliphatic or aromatic 1,2- or 1,3-dicarboxylic acid.
Any C1-Clz or C1-C1g alkyl substituents are as already defined under a).
Any CS-C~ cycloalkyl substituents are especially cyclohexyl.
R13 as C~-CB aralkyl is especially phenylethyl or in particular benzyl.
R1j as Cz-CS hydroxyalkyl is especially 2-hydroxyethyl or 2-hydroxy-propyl.
R13 as Cz-C18 alkanoyl is, for example, propionyl, butyryl, octanoyl, dodecanoyl, hexadecanoyl or octadecanoyl, but preferably acetyl, and R13 as C3-CS alkenoyl is especially acryloyl.
R1'' as Cz-CB alkenyl is e.g. allyl, methallyl, but-2-erryl, pent-2-enyl, hex-2-enyl or oct-2-enyl.
Ri'' as C1-C4 alkyl substituted by a hydroxyl, cyano, alkoxycarbonyl or ~arbamide group can be e.g. 2-hydroxyethyl, 2-hydroxypropyl, 2-cyano-ethyl, methoxycarbonylmethyl, 2-ethoxycarbonylethyl, 2-aminocarbonyl-propyl or 2-(dimethylaminocarbonyl)ethyl.
Any Cz-Clz alkylene substituents are e.g. ethylene, propylene, 2,2-di-methylpropylene, tetramethylene, hexamethylene, octamethylene, deca-methylene or dodecamethylene.
Any C6-C15 arylene substituents are e.g: o-, m- or p-phenylene, 1,4-naph-thylene or 4,4'-diphenylene.

D as C6-Clz cycloalkylene is especially cyclohexylene.
Preferred compounds of formula IV are those in which n ~s 1 or 2, R is hydrogen, R11 is hydrogen or methyl, R13 is hydrogen, C1-Clz alkyl or a group of the formula RCHz\ ~CH3/t?
Rz i -~.-. \
RCFIZ~~\CH 3 and Rl'' in the case where n = 1 is hydrogen or C1-Clz alkyl and in the case where n = 2 is Cz-Ce alkylene.
The following compounds are examples of polyalkylpiperidine compounds of this class:

37) N,N'-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexamethylene-1,6-diamine 38) N,N'-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexamethylene-1,6-diacet-amide 39) bis(2,2,6,6-tetramethylpiperidin-4-yl)amine 40) 4-benzoylamino-2,2,6,6-tetramethylpiperidine 41) N,N'-bis(2,2,6,6-tetramethylpiperidin-4-yl)-N, N'-dibutyladipamide 42) N,N'-bis(2,2,6,6-tetramethylpiperidin-4-yl)-N,N'-dicyclohexyl-2-hydroxypropylene-1,3-diamine 43) N,N'-bis(2,2,6,6-tetraraethylpiperidin-4-y1)-p-xylylenediamine 44) N,N'-bis(2,2,6,6-tetramethylpiperidin-4-yl)succindiamide ' 45) di(2,2,6,6-tetramethylpiperidin-4-yl) N-(2,2,6,6-tetramethyl--piperidin-4-yl)-a-aminodipropionate 46) the compound of the formula CHa\ /CH3 aHe CH3-N\~~~j~-~-CHz-CH(OH)-CHz-CH3/~\CH3 /~\.
II I
CH3-~-CH3 /.\.
II I
CH3\ /CHa ~\~~.
CH3_?~~-~~._ _CHz_CH(OH)-CHz-CH3/~\CH3 ~°H9 47) 4-(bis-2-hydroxyethylamino)-1,2,2,6,6-pentamethylpiperidine 48) 4-(3-methyl-4~-hydroxy-5-tart-butylbenzamido)-2,2,6,6-tetramethyl-piperidine 49) 4-methacrylamido-1,2,2,6,6-pentamethylpiperidine c) Compounds of formula V
RCHz\ /CH3/R 0 Ri i _~.-.\ ~ I R1 s V
\ _ /~~
RCHz/~\CH3 0 n wherein n is the number 1 or 2, R and R11 are as defined under a) and Rls when n is 1 is Cz-Ce alkylene, Cz-Ce hydroxyalkylene or C4-Czz acyloxy-alkylene and when n as 2 is the group (-CHz)zC(CHz-)2~
Rls as Cz-G$ alkylene or Cz-C8 hydroxyalkylene as, for example, ethylene, 1-methylethylene, propylene, 2-ethylpxopylene or 2-ethyl-2-hydroxymethyl-propylene.
Rls as C4-Czz acyloxyalkylene is e.g. 2-ethyl-2-acetoxymethylpropylene.
The following compounds are examples of polyalkylpiperidine compounds of this class:

2~~~,~~~r~

50) 9-aza-8,8,10,10-tetramethyl-1,5-dioxaspiro(5.5]undecane 51) 9-aza-8,8,10,10-tetramethyl-3-ethyl-1,5-dioxaspiro(5.5]undecane 52) 8-aza-2,7,7,8,9,9-hexamethyl-1,4-dioxaspiro(4.5]decane 53) 9-aza-3-hydroxymethyl-3-ethyl-8,8,9,10,10-pentamethyl-1,5-dioxaspiro-[5.5]undecane 54) 9-aza-3-ethyl-3-acetoxymethyl-9-acetyl-8,8,10,10-tetramethyl-1,5-dioxaspiro(5.5]undecane 55) 2,2,6,6-tetramethylpiperidine-4-spiro-2'-(1',3'-dioxane)-5'-spiro-5"-( 1 " , 3"-dioxane)-2 "-spiro-4" ' -( 2 " ' , 2 " ' , 6" ' , 6" ' -tetra-methylpiperidine) d) Compounds of formulae VIA, VIB and VIC
_i s RCHz\ /CHa/R

Ri i _~ VIA
\ _ R1~
RCHz~~\CH3 n RCHz\ /CH3/R i - p.._ -T z Rl_~ VIB
\ , ~- -0 RCHz~~\CH3 RCHz\ /CH3/R i - 0- -Tz Ri 1_~ VIC
\ _, - Rm RCHz~A\CH3 n wherein n is the number 1 or 2, R and Rll are as defined under a), Rls is hydrogen, C1-Czz alkyl, allyl, benzyl, glycidyl or Cz-Cs alkoxyalkyl, R1' when n is 1 is hydrogen, C1-Clz alkyl, C3-CS alkenyl, C~-C9 aralkyl, CS-C~ cycloalkyl, Cz-C', hydroxyalkyl, Cz-Cs alkoxyalkyl, Cs-Clo aryl, glycidyl or a group of the formula -(CHz)p C00-Q or of the formula -(CHz)p-0-C0-Q, wherein p is 1 or 2 and Q is Cl-C4 alkyl or phenyl, and R1~ when n is 2 is Cz-Czz alkylene, C4-Clz alkenylene, Cs-Clz arylene, a group -CHz-CH(OH)-CHz-0-D-0-CHz-CH(OH)-CHz°, wherein D is Cz-Clo alkyl-ene, C6-C15 arylene or C6-Clz cycloalkylene, os a group -CHZCH(OZ')CHz-(OCHz-CH(OZ')CHz)z-, wherein Z' is hydrogen, C1-C~,e alkyl, allyl, benzyl, Cz-Clz alkanoyl or benzoyl, and T1 and Tz independently of the other are hydrogen, C1-C18 alkyl or C6-Clo aryl or C~-C9 aralkyl which is unsubstituted or substituted by halogen or C~-C4 alkyl, or T1 and Tz form a C5-C~z cycloalkane ring together with the C atom to which they are bonded.
Any C1-Clz alkyl substituents are e.g. methyl, ethyl, n-propyl, n-butyl, sec-butyl, tert-butyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl or n-dodecyl.
Any C1-C18 alkyl substituents can be e,g. the groups listed above and additionally n-tridecyl, n-tetradecyl, n-hexadecyl or n-octadecyl, for examgle.
Any Cz-C6 alkoxyalkyl substituents are e.g. methoxymethyl, ethoxymethyl, propoxymethyl, tert-butoxymethyl, ethoxyethyl, ethoxypropyl, n-butoXy-ethyl, tert-butoxyethyl, isopropoxyethyl or propoxypropyl.
R1' as C3-GS alkenyl is e.g. prop-1-enyl, allyl, methallyl, but-2-enyl or pent-2-enyl.
R1', T1 and Tz as C~-C9 aralkyl are especially phenethyl or in particular benzyl. If T1 and Tz form a cycloalkane ring together with the C atom, said ring can be e.g. a cyclopentane, cyclohexane, cyclooctane or cyclo-dodecane ring.
R1~ as Cz-C4 hydroxyalkyl is e.g. 2-hydroxyethyl, 2-hydroxypropyl, 2-hydroxybutyl or 4-hydroxybutyl.
R17, T1 and Tz as C6-C1o aryl are especially phenyl or a- or Q-naphthyl which are unsubstituted or substituted by halogen or C1-C4 alkyl.

- is -R1~ as Cz-Clz alkylene is e.g. ethylene, propylene, 2,2-dimethylpropyl-ene, tetramethylene, hexamethylene, octamethylene, decamethylene or dodecamethylene.
R1~ as C4-Clz alkenylene is especially but-2-enylene, pent-2-enylene or hex-3-enylene.
R17 as C6-Clz arylene is, for example, o-, m- or p-phenylene, 1,4-naph-thylene or 4,4'-diphenylene.
Z' as Cz-Clz alkanoyl is, for example, propionyl, butyryl, octanoyl or dodecanoyl, but preferably acetyl.
D as Cz-Clo alkylene, C6-C15 arylene or C6-Clz cycloalkylene is as defined under b).
The following compounds are examples of polyalkylpiperidine compounds of this class:

56) 3-benzyl-1,3,8-triaza-7,7,9,9-tetramethylspiro(4.5]decane-2,4-dione 57) 3-n-octyl-1,3,8-triaza-7,7,9,9-tetramethylspiro[4.5]decane-2,4-dione 58) 3-allyl-1,3,8-triaza-1,7,7,9,9-pentamethylspiso(4.5]decane-2,4-dione 59) 3-glycidyl-1,3,8-triaza-7,7,8,9,9-pentamethylspiro(4.5]decane-2,4-dione 60) 1,3,7,7,8,9,9-heptamethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione 61) 2-isopropyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxospiro(4:5]decane 62) 2,2-dibutyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxospiro[4.5]decane 63) 2,2,4,4-tetramethyl-7-oxa-3,20-diaza-21-oxodispiro[5.1.11.2]-heneicosane 64) 2-butyl-7,7,9,9-tetramethyl-1-oxa-4,8-diaza-3-oxospiro[4.5]decane 65) 8-acetyl-3-dodecyl-1,3,8-triaza-7,7,9,9-tetramethylspiro[4.'S]decane-2,4-dione or the compounds of the following formulae:

m x m U m x I x W~i x~ ~x U . . U
m m x x x ~ v%'~i \x N U ~ ~ V
x m v x v ° W%
x ~ ,\x x U~ ~U //\
U ~ ~
O i II
N
\\
( N
N
v U-~ x U
x ~ ~ i' ~ o o N .. v ~/ /'~ / \ N N
U, ~ ~ II V v x ~ \\ / x m ~ m m ~ m m a m m s m \ / \ / \ / \ /
/ \m m '/. m m / \m U ~~.,/ m ~ ( U U M U U ~' U x x U
x x V U
n r~ n rw ~D r. op rn W O vD v0 _. 2~~~' -m-e) Compounds of formula VII
~~e ~\
\~I~ Rz ° VI I
Ri s /.~/.
n wherein n is the number I or 2, R~& is a group of the formula I~CH3\ /CHzR
-E-(A)X ~~~~~~1-Rli CHa/~\CHzR
wherein R and R11 are as defined under a), E is -0- or -NRzl-, A is Cz-Cs alkylene or -(CHz)3-0- and x is the number 0 or 1, R19 is the same as R18 or is one of the groups -NRzlRzz; _ORz3, -NHCHzORz3 and -N(CHzORz3)z, Rz°
when n = 1 is the same as R18 or R19 and when n = 2 is a group -E-B-E-, wherein B is Cz-C6 alkylene which may be interrupted by -N(Rzl)-, Rzl is C1-Clz alkyl, cyclohexyl, benzyl, C1-C4 hydroxyalkyl or a group of the formula I~CH3\ /CHZR
~-~ Ri i _.\
CH3/~\CHZR
Rzz is C1-Clz alkyl, cyclohexyl, benzyl or C1-C4 hydroxyalkyl and Rz3 is hydrogen, Ci-Clz alkyl or phenyl, or Rzl and Rzz together are C4-CS
-CHZCHz\
alkylene or Cu-C5 oxaalkylene, for example /0 or a group of -CHZCHz -CHZCHz the formula ~1-R11 or Rzl and R22 are each a group of the -CHZCHz formula CH3\ /CH3 aHs HN .-.\._~_.~~.-gH-A-.
\.-./
CH3/ \CH3 \ /
CpH9-.
CHs\I/ \I/CH3 CH3/~~~\CH3 Any C1-C12 alkyl substituents are, for example, methyl, ethyl, n-propyl, n-butyl, sec-butyl, tert-butyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl or n-dodecyl.
Any C1-C4 hydroxyalkyl substituents are e.g. 2-hydroxyethyl, 2-hydroxy-propyl, 3-hydroxypropyl, 2-hydroxybutyl or 4-hydroxybutyl.
A as CZ-C6 alkylene is, for example, ethylene, propylene, 2,2-dimethyl-propylene, tetramethylene or hexamethylene.
If R21 and Rzz together are C4-Cs alkylene or C4-Cs oxaalkylene, this i.s e.g. tetramethylene, pentamethylene or 3-oxapentamethylene.
The compounds of the following formulae are examples of polyalkylpiper-idine compounds of this class:

H3C~ ~\ /CH3 HaC/I\ /I\CHa 70) ~-CbH9 (CH3CH2 ) z~~~/~~~CHzCH3 ) Z
~~C4H9)2 CHa\ /CHa /~ CHa\ /CHs 71) CgHs ~~ ~/._ ~.\~._ ~.\~
~yC2Hs CH3/~\CH3 ~ZHs ~zHs CH3/~\CH3 ~t H3C~ /CH3 N~~~~ where R = -NH-CHZCHzCHz-0-~~~ ~~1-CH3 R~~\N'~~ H3C~~~CFIa N
m M
x x x v/~%

i I\

.
U

m \
/
r.~
m x U-~

-/
\
M
n7 x x U
U

x x x \_ x x x z vl~% x \

_ N
/
\

M M
m m xxUU U x U
~~/\\
U

\ N M

x N

U \ / U N x /

~ ~
\
_ i o, \
N ~ x /

x x s M
M U
U
U

x x ~~ v\

U-J~
M
M

x W%

z x ii , W
r'-'~
..~.

~ \
~
e .

x .~
i U
%
\

x V
~

/'\ /\
n ro a 'n m a ~

\ / \ /

r~ ~/ \eo \m ~
~/.

x x v .y r. r~

~~~~ ~ a 75) R-NH-(CHz)s-~-(CHz)z-~-~(CHz)j-NH-R
CHs\ /CHs where R - ~N\ ~''H9 /~ ~~H
\ _ C~3~CH3 CaH9-CHa\~/~\I/GH3 GHs/~\N/~\GHs H
76) R-NH-(CHz)a-~-(GHz)z-~-(CHz)a-NH-R
CHs\ /CHs where R - _ ~N\ ~kH9 /~ ~~-GH
\ _ ~~~ CHs\GHs CaH9-CHs\I/~\I/CHs GH3/~~~\CHs Hs 77) R-~-(CHz)s-~-(CHz)z-~-(CHz)a-~-R
CHs\_ /CHs where R - ~N\ ~4H9 /~ ~~-GHs ~\ _ G~3\CHs CaH9°~
GHs\I/~\I/GH3 CH3/~~~\CHs CfIa\ /CH
CBH1'-~-°\.-.~H
°\~I CI~Ia/~\CH
78) CeHl~-l~~~~~~H(CHz)s CHa\I/~\I/CHa CHa/. H .\CHa HzCHzOH
CHa\ ~\ /CHa CHa/~\ /I\CHa 79) ~-CaH9 CHa\ /CHa \~ CHa\ /CHa HO-CHZCHz-?\° ° j~- ~~ -~\°-°~-CH2CHz-0H
/°~° 4H9 4H9 CHa CHa CH3 CH3 Hz-CH=CHz HaC\ ~\ /CHa HaC/i\ /i\CHa Ha 80) HaC\ /CHa \ ~/CH3 s HzC=HC-HzC-~~_.~°-~~~~ ~-,\°_°~-CHz-CH-CHz /°~° C4H9 4H9 H3C CHa CHa CHa f) Oligomeric or polymeric compounds whose repeat structural unit contains a 2,2,6,6-tetraalkylpiperidine radical of formula (I), especially polyesters, polyethers, polyamides, polyamines, polyurethanes, polyureas, polyaminotriazines, poly(meth)acrylates, poly(meth)acrylarnides and copolymers thereof which contain such radicals.

The compounds of the following formulae are examples of 2,2,6,6-poly-alkylpiperidine light stabilizers of this class, m being a number from 2 to about 200:
81) CH3\ /CH3 -~~-CHz-CHz-C-0-CHz-CHz-~. .\ -\ _ /~ m CH3/~\CH3 82) CH~\ /CHa CHs\ /CH3 --~-CHz-CHz-~. '~~-0-~-(CHz)a-C-O-.\. .yCHz-CHz-0-~-(CHz)o-~~
_ m CH3/~\CH3 CHa/~\CH3 83) CH3\ /CzHs CH3\_ /CzHs -~-NH-(CHz)3-~~-.~._NH_~-II/~\j ~-NH-~\. '~-(CHz)a-NH-~-j/~\II
/ . \CHa .\./. CHa/ . \ .\./.
CH3 CzHs CHa CzHs 84) H3 H3 ~IH-~-CH z-~-CH a -~ ( CH z ) s ~"~ m CHa\!/~\I/CH3 CHa\I/~\I/CH3 CH3/~~~\CHa CH3/o~e\CH3 85) -~--~T CHz-CH(0H)-CHz CH3\i/~\I/CHs CH3/~~~\CH3 86) CHa\ /CHa CH3\ /CH3 /.- -~~ ~\ -~~-~4H
0-~\ ~~I-CHz-CH=CH-CHz \ /~ m 4Hy CHa/~\CHa CH3/~\CH3 87) (CH2)s ~_~__~~
N ~m CH3 ,/~\ CHa CHa ~/~\I/CH3 ,t,_C4H9 \I I/ \~
CH3/~~~\CH3 CH3/ ~/~\CH3 CHa\I/~\I/CH3 CH3/~~/~\CH3 88) CH3\ /CH3 CHa\ /CH3 ~e\._.~-CHz_~\._.~._CHz_~. ~~._~~_(CHz)4-CH3/ \CH3 ~_. CH3/.~CH3 m 89) CHs\ /CH3 _~2Hs _.\
-p-CHz_CHz_~~ /..-zHs ' CH3/e\CH3 90) Ha ~~__~1_ --CHz CH3\ /CH3 ~ /.-.
.\ eCHa CH3/~~CH3 91) Ha _~I---CHz CHa\ /CH3 .-.
C6H13-_ -~\ CH3 s-.
CH3/ \CH3 92) /o\
I I
/.
(CHz)s N~
CH3\I/~\I/CH3 CH3\I/~\I/CH3 CH3/'~~\CH3 CH3/~\~~\CH3 93) -~~ (CHz)s Jj CHz-CHz m CH3\I/'\I/CHs CH3\I/o\I/CH3 CH3/e~'\CH3 CH3/~~~\CH3 94) ( CH z ) s ~~~-CH z-~~
m CHa\I/~\I/CH3 CH3\I/~\I/CHs CH3/~~~\CH3 CHa/~~~\CH3 g) Compounds of formula VIII
RCHz\ /CH3/R
Ri i_~~.-~~.=p VIII
RCHz/s\CH3 wherein R and R11 are as defined under a).
Preferred compounds of formula VIII are those in which R is hydrogen or methyl and Rll is hydrogen or methyl.
Examples of such compounds are:
95) 2,2,6,6-tetramethylpiperidin-4-one (triacetonamine) 96) 1,2,2,6,6-pentamethylpiperidin-4-one 97) 1-oxyl-2,2,6,6-tetramethylpiperidin-4-one 9$) 2,3,6-trimethyl-2,6-diethylpiperidin-4-one Polyalkylpiperidines are known compounds and are used as light stabilizers for organic materials. Some of them are commercially available.
Component (C) is a phenolic antioxidant. (C) is preferably a compound of formula I in which A is hydrogen, C1-C° alkyl, cyclohexyl, phenyl or a group qH
-CHz-~~~~~~-B
X
B is C1-C° alkyl, cyclohexyl or phenyl, X is C1-C8 alkyl or one of the groups -CaH2a-S-Rz, -CbH2b-COORS, -CHZN(R1°)(Rii) and _CHz_.\. "%._OH
Rz is C1-Clz alkyl, phenyl or a group -(CHz)c-COOR'', R3 is Ci-C1g alkyl or a group -Q-OOC-CbH2b ~~~ ~j~-OH
.-~,\ B
in which Q is Cz-C6 alkylene, -CHZCHzSCHZCHz- or -CHZCHz(OCHZCHz)d , R'' is C1-C18 alkyl, R1° and Ril independently of the other are Cl-Clz alkyl or R1° and R11 together are pentamethylene or 3-oxapentamethylene, a is i or 2, b is 1 or 2, c is 1 or 2 and d is 1 to 3, or (C) is a reaction mixture of a phenol of the formula Fd ~.., ~' , ! .' a~ ~~
_ 27 _ QH QH
_ /~\ C\ /~\
C II I or II I
.\~/. .\./.
with a phenol of the Formula QH QH
_ /.~ /
E II i or II I
. . .\
and (para)formaldehyde, in which formulae C, D and E independently of the others are C1-CB alkyl.
One class which is particularly suitable as component (C) consists of the compounds of formula I in which A and B independently of the other are C1-C4 alkyl, X is a group -CaH2a-S -Rz, a is 0 or 1, g is 1 or 2, Rz is Ca-C18 alkyl, phenyl or -CHz-CO-OR4 and R'' is C1-Cle alkyl, especially the compounds of formula I in which A and B independently of the other are C1-C4 alkyl, X is -CHz-S-Rz, Rz is C8-Clz-alkyl or -CHz-CO-OR'' and R'' is Ce-Cl$ alkyl. In this class, especially preferred compounds of formula I are those in which A and B are tert-butyl and X is -CHzSCH2C00(CB-C13 alkyl).
Another class which is particularly suitable as component (C) consists of the compounds of formula I in which A and B independently of the other are C1-C4 alkyl, X is a group -CbH2b-CO-~R3, b is 1 or 2 and R3 is one of the groups -(CHz)z-S-(CHz)z-0-G-CbH2b-~\. ~~._OH

_ 28 --(CHz)s-0-~-CbH2b ~\'_~~._OH
and -CHz-C CHzO-~-CbH2b ~\°_~~._OH
especially the compounds of formula I in which X is a group -(CHz)z-CO-OR3 and R3 is a group -(CHz)z-S-(CHz)z-0-~°(CHz)_,\._.~~-OH
Another class which is particularly suitable as component (C) consists of the methylenebisphenols of the formula ~H 1H
_ /.\ /
B II j-CHz II I-B and '~~/° '~~/°
HO-'~e_,~.~CHz-~~. ~~~-OH , B/~_ -wherein A, B and X independently of the others are C1-C4 alkyl.
Another class which is particularly suitable as component (C) consists of mixtures of polyphenols obtained by reacting at least one dialkylated phenol o~ the formula .,, QH QH
_ /~\ C\ /~~
C II I or II I
.\./. .\ /.
with at least one monoalkylated phenol of the formula QH qH
_ /~\ /
E II I or II I
. \ / . o \ , / a and formaldehyde or paraformaldehyde, G, D and E independently of the others being C1-C~, alkyl.
The mixtures formed by this reaction contain predominantly diphenols and triphenols.
Examples of compounds of formula I are: tridecyl 4-(4-hydroxy-3,5-di-tert-butylphenyl)-3-thiabutyrate, 3-thiapenta-1,5-diol di(3-(4-hydroxy-3,5-di-tart-butylphenyl)]propionate, di(3-thiapentadecyl) di(4-hydroxy-3,5-di-tart-butylphenyl)malonate, octadecyl 4-(4-hydroxy-3,5-di-tert-butylphenyl)-3-thiabutyrate, 4-(2-thiapropyl)-2,6-di-tart-butylphenol, octadecyl 3-(4-hydroxy-3,S-di-tart-butylphenyl)propionate, 3-thiapenta-decyl 3-(4-hydroxy-3,5-di-tart-butylphenyl)propionate, di(4-hydroxy-3,5-di-tart-butylphenyl) sulfide, di(4-hydroxy-3,5-di-tart-butylphenyl) disulfide, 2,4-di(octylthiomethyl)-6-methylphenol, N-octadecyl-3-(4-hydroxy-3,5-di-tart-butylphenyl)propionamide, N,N'-(3-(4-hydroxy-3,5-di-tert-butylphenyl)propionyl]hexamethylenediamine, 4,4'-methylene-bis(2,6-di-tart-butylphenol), 2,2'-methylene-bis(2-tart-butyl-4-methylphenol), 2,4-di(4-hydroxy-3,5-di-tart-butylbenzyl)-6-tart-butylphenol, 4,4'-methylene-bis(2-tart-butyl-4-(4-hydroxy-3,5-di-tart-butylbenzyl)phenol], 4-dimethylaminomethy2-2,6-di-tart-butylphenol, 4-dibutylaminomethyl-2-methyl-6-tart-butylphenol and N-di(4-hydroxy-3,5-di-tart-butylbenzyl)-octylamine.

~~~"~Cs~~

Especially preferred lubricant compositions are those in which (B) is a compound of formula IX or X
C~13/CH 3 C~13/CH 3 _. _~
Ri i_~~ \ Y R~ i_~~ \.-p \ _ /~ \ _ /
C~3\CH a Cti s\CH 3 n IX X
in which n is 1 or 2, R11 is hydrogen or methyl and Y when n is 1 is -0(C°-Cis alkyl) and when n is 2 is a group -NH-(CHz)s-NH- or -0-CO-(CHz) -CO-0- in which m is 2-8, and (C) is a compound of formula I
m in which A is hydrogen, Cr-C4 alkyl or a group A
-CHz-~~/~\ ~-B
.\~/.
?~
B is C1-C4 alkyl, X is C1-C4 alkyl or one of the groups -CHz-S-Rz, -CHzCH2C00R3, -CHzN(R1°)(Rii) and ~,A
_CHz_~\._.~._OH
._.~
Rz is Ci-C1° alkyl or -(CHz)z-COOR'", R3 is Cl-Crg alkyl or -CHzCHz-S-CHzCHz-0-~-CHzCHz-~~~ ~j~-OH
._.
R'' is C1-Cls alkyl and R1° and R11 are C1-Cg alkyl, or (C) is a reaction mixture of 2-tent-butylphenol, 2,6-di-tert-butylphenol and (para)formal-dehyde.

~5 ~' ,~ j ',~ t °tJ~~ tys:9Cl Components (B) and (C) can be added direct to the base oil or (B) and (C) are first dissolved in a small amount of base oil, with heating if necessary, and the solution is mixed with the remainder of the oil. As a further possibility, a concentrated solution of (B) and (C) in a solvent is mixed with the oil.
The addition of (B) and (C) to the base oil stabilizes the oil against oxidative degradation and reduces the formation of sludge in engine oils.
The lubricant composition can additionally contain other additives, e.g.
phosphorus(III) esters, metal passivators, rust inhibitors, agents for improving the viscosity index, pour point depressors, daspersants, surfactants and/or wearing protection additives.
Examples of phosphorus(III) esters are: traphenyl phosphate, decyl-diphenyl phosphate, phenyldidecyl phosphate, tris(nonylphenyl) phosphate, tralauryl phosphate, trioctadecyl phosphate, distearylpentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl) phosphate, diasodecylpenta-erythratol diphosphite, bas(2,4-da-tert-butylphenyl)pentaerythritol di-phosphite, tristearylsorbitol triphosphite, tetrakas(2,4-di-tert-butyl-phenyl)-4,4'-biphenylene daphosphonite and bis(2,6-da-tert-butyl-4-methylphenyl)pentaerythratol diphosphite.
Examples of metal passavators, e.g. for copper, are: triazoles, benzo-triazoles and derivatives thereof, tolutriazoles and derivatives thereof, 2-mercaptobenzothiazole, 2-mercaptobenzotraazole, 2,5-dimercaptobenzo-triazole, 2,5-dimercaptobenzothiadiazole, 5,5'-methylene-bas-benzo-triazole, 4,5,6,7-tetrahydrobenzotriazole, salicylidenepropylenediamane, salacylaminoguanidane and salts thereof.
Examples of rust inhibitors are:
a) Organic acids and their esters, metal salts and anhydrides, e.g..:
N-oleoylsarcosane, sorbitan monooleate, lead naphthenate, an alkenyl-succinic anhydride, e.g. dodecenylsuccinic anhydride, alkenylsuccanic acid partial esters and partial amides, 4-nonylphenoxyacetic acid.

b) Nitrogen-containing compounds, e.g.:
I. Primary, secondary or tertiary aliphatic or cycloaliphatic amines and amine salts of organic and inorganic acids, e.g. oil-soluble alkylammonium carboxylates.
II. Heterocyclic compounds, e.g.:
substituted imidazolines and oxazolines.
c) Phosphorus-containing compounds, e.g.:
amine salts of phosphoric acid partial asters or phosphonic acid partial esters, zinc dialkyldithiophosphates.
d) Sulfur-containing compounds, e.g.:
barium dinonylnaphthalenesulfonates, calcium petroleumsulfonates.
Examples of agents for improving the viscosity index are: polyacrylates, polymethacrylates, vinylpyrrolidone/methacrylate copolymers, polyvinyl-pyrrolidones, polybutenes, olefin copolymers, styrene/acrylate copoly-mers, polyethers.
Examples of pour paint depressors are: polymethacrylate, alkylated naph-thalene derivatives.
Examples of dispersants/surfactants are: polybutenylsuccinamides or poly-butenylsuccinimides, polybutenylphosphonic acid derivatives, basic mag-nesium, calcium and barium sulfonates and phenates.
Examples of wearing protection additives are: compounds containing sulfur and/or phosphorus and/or halogen, such as sulfurized vegetable oils, zznc dialkyldithiophosphates, tritolyl phosphate, chlorinated paraffins, alkyl and aryl disulfides and trisvlfides, triphenyl.phosphorothionates, di-ethanolaminomethyltolyltriazole, di(2-ethylhexyl)aminomethyltolyl-triazole.

an The lubricant can also contain solid lubricants such as graphite or molybdenum sulfide.
The following Examples illustrate the invention in greater detail.
Percentages are by weight.
Example 1: The oxidation behaviour of lubricating oils stabilized according to the invention is tested by the TOST (turbine oxidation stability test) method according to ASTM D-943.
This is performed by adding 60 rnl of water to 300 ml of a mineral oil (Mobil STOCK 305) containing 0.05% of a corrosion inhibitor (Reocor~ 12) and heating the mixture at 95°C for 1000 hours, in the presence of iron and copper wire, while oxygen is passed through. The formation of acids is measured by determining the neutralization number TAN (mg KOH/g oil) and the amount of sludge formed (= SLUDGE) is also measured.
The Following stabilizers are used;
(CH3)aC\
P-1 HO-°\ /~ CHz S,-CHz-COOCI3Hz~
(CH3)3C~~=v C~ /CH 3 H-1 HN~\~/a~~ -OCi zHz s CH3' \CH3 The total amount of stabilizers is 0.25%, based on the oil. The.composi-tion of the stabilizer mixture is varied. The results are listed in Table 1.

n~
- ~ ~ r.~ 'ti Table 1 Proportion TOST

100 % - 0,19 64 mg 95 % 5 % 0 17 mg 90 % 10 % 0 8 mg 75 % 25 % 0 26 mg Example 2: Testing is carried out as in Example 1, using the following stabilizers:
~CH3)3G~ /C(CHa)s a . .
P-2 HO-~~~ ~j~-CH2CHzC00CHzGHzSCHzCHz00CCHzCHz-~~ j~-OH
- . s = .
~CH3)3C/~ \CtCHs)a C~ /CH 3 C~ /CH 3 H-2 CHs-N~\~/-~~ -00G-(CHz)e-C00-~~~ / -CH3 CH3~ \CH3 oCH3A \CH3 The total concentration is 0.25%, based on the oil.
Table 2 Proportion TOST

100 % >2 >1000 mg 95 % 5 % 0,26 219 mg 90 % 10 % 0,24 190 mg Example 3: Testing is carried out as in Example 1, using the following stabilizers:
(CH3)3C~ ~C(CH3)3 P-2 HO-~~~ ~j~-CHzCH2C00CHzCHzSCiizCHz00CCHzCHz-'~~-~~°-OH
(CH3)3C~~= ~~C(CH3)3 C~ /CH 3 C~ /CH 3 \ /- \ /.
H-3 HN/ ~ ~ -NH-(CHz)s-NH-~~~~ H
C~.~CH 3 . C~.~CH 3 The total concentration is 0.25%. The results are listed in Table 3.
Table 3 Proportion TOST

100 % - >2 >1000 mg 95 % 5 % 0,24 180 m~
Example 4: Testing is carried out as in Example 1, using the following stabilizers:
(CH3)3C~ /C(CH3)3 P-2 HO-~~~_'j~_CHzCHZC00CHzCHzSCHzCHz00CCHzCHz_;\~_.~~-off .-. .
(CH3)3~ -e\C(CH3)3 C~ /CH 3 H-1 HN~~/~~~ -OC1 zHz s CH3~ \CH3 The total concentration is 0.25%. The results are listed in Table 4.
Table 4 Proportion TOST

100 % - >2 1000 mg 95 % 5 % 0 86 mg 85 % 15 % 0,10 44 mg 75 % 25 % 0,03 75 mg Example 5: Testing is carried out as in Example 1, using the following stabilizers:
~CH3~3C~ ~C~CH3~3 P-2 HO-~~~-~j~-CHzCHzC00CHzCHzSCHzCHz00CCHaCHz-~~~ ~j~-OH
~CH3)3C~~=~ .-~~C~GH3)3 C~ /CH 3 H-4 HN~\~/ ~~ =o CH3~ \CH3 The total concentration is 0,25%. The results are listed in Table 5.
Table 5 Proportion TOST

100 % - >2 >1000 mg 95 % 5 % 0,18 91 mg 90 % 10 % 0.16 161 mQ

E:cample 6: The oxidation resistance of the oils stabilized according to the invention is measured in a differential scanning calorimeter. To do this, a base oil is mixed in a small A1 dish with 0.025% of iron(III) acetylacetonate (as oxidation catalyst) and 0.55% o.f a stabilizer and the mixture is heated isothermally at 160°C in a calorimeter under 10 bar of oxygen. The time at which the exothermic reaction begins, TB (induction time), and the time at which the exothermic reaction ends, T~, are measured: the longer the induction time, the higher the oxidation resistance. The stabilizers used are the phenolic antioxidants P-1 and P-2 and also:
P-3: the reaction pzoduct of 160 g of 2,6-di-tert-butylphenol, 40 g of 2-tert-butylphenol, 5.8 g of KOH, 50 ml of ethanol and 24 g of paraform-aldehyde at 80°C, containing the following main components:
(CH3)3C\ /C(CH3)3 HO-.\._.~.-CHz-.\> ,j._OH
(CH3)3L./.=. .c~\C(CH3)3 (CH3)3C\ /C(CH3)3 HO-~~. .~~ CHz /~~~ CHz ~~. ~~._pH
\ / II I \ /
/.
(CH3)3C/~-. ~\ / \0H ~-~\C(CHa)a 4(CH3)3 (CHs)aC\ /C(CHa)a HO-.\._.~.~CHz~~I/~~ i-.CHz-il/~~ i-CHz.~,\~_.~~-OH
(CFi3)3C/~-. ~\ /~\OH ~\ ~~\0H ~=~\C(CH3)3 4(CH3)3 ~(CH3)3 QH QH
P-4: (CHa)aC-~/~\~I CHz ~I/~\~-C(CH3)a /. .\~~.
I I
C('CHa)s C(CHs)a ~~.~~~~3 3~

P-5: a 1:1 mixture of QH QH
(CHa)aCy/e\~yC(CHa)a and ~/~~~~-C(Ctla)a .
4(CH3)3 ~(CH3)3 The following sterically hindered amine is used:
CF~I3/CH a C~I a/CH a H-5 H~~_o~._pOC-(CHz)a-C00-~~~_~~IH
C~3~CH3 C~3~CHa The results are listed in Table 6.
Table 6 Stabilizer TB(min) TE (min) 0,55 % P-1 1,47 9,12 0,55 % H-5 17,16 22,97 0,45 % P-i + 0,10 % H-5 14,02 27,71 0,55 % P-2 16,08 26,07 0,55 % H-5 17,16 22,97 0, 45 % P-2 +0,10 % H-5 32,27 47,90 0,55 % P-3 7,21 14,20 0,55 % H-5 17,16 22,97 0,45 % P-3 +0,10 % H-5 50,55 67.97 >. ,r~
~~Gsi~ ~>,.3(:~

0,55 % P-4 3,00 9,67 0,55 % H-5 17,16 22,97 0,45 % P-4 +0,10 % H-5 12,02 20,37 0,55 % P-5 4,46 16,44 0,55 % H-5 17,16 22,97 0,45 % P-5 +0,10 % H-5 14,10 23,23 It can be seen from this Table that when using stabilizer mixtures of 0.10% of component A and 0.45% of component B, the oxidation resistance of the oil is higher than would be expected from the data for the individual components.
Example 7: The oxidation resistance is tested in a differential scanning calorimeter as in Example 6, except that the measurements are made under 8 bar o~ air with which 380 ppm of (NO) have been mixed, rather than x under oxygen, and the isothermal temperature is 170°C. Only the beginning of the exotherms is measured.
Stabilizer TB(min) 0,55 % P-2 11,2 0,55 % H-5 <2 0,45 % P-2 + 0,10 % H-5 20,7 0,55 % P-6 3,8 0,55 % H-S <2 0,45 % P-6 + 0,10 % H-5 10,8 P-6 HO-~~~ ~j~-CHZN(C4H9)z

Claims (23)

1. A lubricant composition comprising (A) a mineral or synthetic oil or a mixture of such oils, (B) at least one sterically hindered amine and (C) at least one phenol of formula I

wherein A is hydrogen, C1-C24 alkyl, C5-C12 cycloalkyl, C7-C9 phenyl-alkyl, phenyl or a group -CH2-S-R1 or B is C1-C24 alkyl, C5-C12 cycloalkyl, C7-C9 phenylalkyl, phenyl or a group -CH2-S-R1, X is hydrogen, C1-C18 alkyl or one of the groups C a H2a-S q-R2, C b H2b-CO-OR3, -C b H2b-CO-N(R5)(R6), -CH2N(R10)(R11) and R1 is C1-C18 alkyl, phenyl or a group -(CH2)c-CO-OR4 or -CH2CH2OR9, R2 is hydrogen, C1-C18 alkyl, phenyl, benzyl or a group or -(CH2)c-CO-OR4 or -CH2CH2OR9 R3 is C1-C50 alkyl or one of the groups wherein Q is C2-C8 alkylene, C4-C6 thiaalkylene or a group -CH2CH2(OCH2CH2)d-, R4 is C1-C24 alkyl, R5 is hydrogen, C1-C18 alkyl or cyclohexyl, R6 is C1-C18 alkyl, cyclohexyl, phenyl, C1-C18 alkyl-substi-tuted phenyl or one of the groups or R5 and R6 together are C4-C8 alkylene which can be interrupted by -O-or -NH-, R7 is hydrogen, C1-C4 alkyl or phenyl, R8 is C1-C18 alkyl, R9 is hydrogen, C1-C24 alkyl, phenyl, C2-C18 alkanoyl or benzoyl, R10 is C1-C18 alkyl, cyclohexyl, phenyl, C1-C18 alkyl-substituted phenyl or a group R11 is hydrogen, C1-C18 alkyl, cyclohexyl or a group ar R10 and R11 together are C4-C8 alkylene which can be interrupted by -O- or -NH-, a is 0, 1, 2 or 3, b is 0, 1, 2 or 3, c is 1 or 2, d is 1 to 5, f is 2 to 8 and q is 1, 2, 3 or 4, or, as component (C), a mixture of polyphenols formed by reacting at least one phenol of the formula with at least one phenol of the formula and with formaldehyde or paraformaldehyde, wherein C, D and E indepen-dently of the others are C1-C24 alkyl, cyclohexyl or phenyl, the composition containing no aromatic amine.

2. A composition according to claim 1, wherein the weight ratio of (B) to (C) is 1:1 to 1:100.

3. A composition according to claim 1, wherein the weight ratio of (B) to (C) is 1:3 to 1:20.

4. A composition according to claim 1, wherein the sum of (B) and (C) is 0.05 to 5% by weight of (A).

5. A composition according to claim 1, wherein (B) is a compound containing at least one group of formula II

wherein R is hydrogen or methyl.

6. A composition according to claim 5, wherein (B) is a compound containing at least one group of formula II in which R is hydrogen.

7. A composition according to claim 5, wherein (B) is a compound of formula III

wherein R is hydrogen, R11 is hydrogen or methyl, n is 1 and R12 is C1-C18 alkyl or n is 2 and R12 is the diacyl radical of an aliphatic dicarboxylic acid having 4-12 C atoms,

8. A composition according to claim 5, wherein (B) is a compound of formula IV

wherein n is 1 or 2, R is hydrogen, R11 is hydrogen or methyl, R13 is hydrogen, C1-C12 alkyl or a group of the formula and R14 in the case where n = 1 is hydrogen or C1-C12 alkyl and in the case where n = 2 is C2-C8 alkylene.

9. A composition according to claim 5, wherein (B) is a compound of formula VIII

wherein R is hydrogen or methyl and R11 is hydrogen or methyl.

10. A composition according to claim 1, wherein (C) is a compound of formula I in which A is hydrogen, C1-C8 alkyl, cyclohexyl, phenyl or a group B is C1-C8 alkyl, cyclohexyl or phenyl, X is C1-C8 alkyl or one of the groups -C a H2a-S-R2, -C b H2b-COOR3, -CH2N(R10)(R11) and R2 is C1-C12 alkyl, phenyl or a group -(CH2)-COOR4, R3 is C1-C18 alkyl or a group in which Q is C2-C6 alkylene, -CH2CH2SCH2CH2- or -CH2CH2(OCH2CH2)d-, R4 is C1-C18 alkyl, R10 and R11 independently of the other are C1-C12 alkyl or R10 and R11 together are pentamethylene or 3-oxapentamethylene, a is 1 or 2, b is 1 or 2, c is 1 or 2 and d is 1 to 3, or wherein (C) is a reaction mixture of a phenol of the formula with a phenol of the formula and (para)formaldehyde, in which formulae C, D and E independently of the others are C1-C8 alkyl.

11. A composition according to claim 1, wherein (C) is a compound of formula I in which A and B independently of the ether axe C1-C4 alkyl, X
is a group -C a H2a-S q-R2, a is 0 or 1, q is 1 or 2, R2 is C4-C18 alkyl, phenyl or -CH2-CO-OR4 and R4 is C1-C18 alkyl.

12. A composition according to claim 1, wherein (C) is a compound of formula I in which A and B independently of the other are C1-C4 alkyl, X
is -CH2-S-R2, R2 is C8-C12 alkyl or -CH2-CO-OR4 and R4 is C8-C18 alkyl.

13. A composition according to claim 1, wherein (C) is a compound of formula I in which A and B independently of the other are C1-C4 alkyl, X
is a group -C b H2b-CO-OR3, b is 1 or 2 and R3 is one of the groups

14. A composition according to claim 1, wherein (C) is a compound of formula I in which A and B independently of the other are C1-C4 alkyl, X
is a group -(CH2)2-CO-OR3 and R3 is a group

15. A composition according to claim 1, wherein (C) is a compound of the formula wherein A, B and X independently of the others are C1-C4 alkyl.

16. A composition according to claim 15, wherein A, B and X are tert-butyl.

17. A composition according to claim 1, wherein (C) is a mixture of polyphenols obtained by reacting at least one dialkylated phenol of the formula with at least one monoalkylated phenol of the formula and formaldehyde or paraformaldehyde, C, D and E independently of the others being C1-C4 alkyl.

18. A composition according to claim 17, wherein C, D and E are tert-butyl.

19. A composition according to claim 1, wherein (B) is a compound of formula IX or X

in which n is 1 or 2, R11 is hydrogen or methyl and Y when n is 1 is -O(C8-C15 alkyl) and when n is 2 is a group -NH-(CH2)6-NH- or -O-CO-(CH2)-CO-O- in which m is 2-8, and (C) is a compound of formula I
in which A is hydrogen, C1-C4 alkyl or a group B is C1-C4 alkyl, X is C1-C4 alkyl or one of the groups -CH2-S--R2, -CH2CH2COOR3, -CH2N(R10)(R11) and R2 is C1-C18 alkyl or -(CH2)2-COOR4, R3 is C1-C18 alkyl or R4 is C1-C18 alkyl and R10 and R11 are C1-C8 alkyl, or (C) is a reaction mixture of 2-tert-butylphenol, 2,6-di-tert-butylphenol and (para)formal-dehyde.

20. A composition according to claim 19, wherein (B) is a compound of formula IX in which n is 2 and Y is.a group -NH-(CH2-)6-NH- or -O-CO-(CH2)8-CO-O, and (C) is the compound of the formula

21. A composition according to claim 1 which is an engine oil.

22. A method for stabilising a lubricant composition against oxidative degradation, which comprises incorporating into the lubricant composition:
(B) at least one sterically hindered amine; and, (C) at least one phenol of formula I

wherein A is hydrogen, C1-C24 alkyl, C5-C12 cycloalkyl, C7-C9 phenylalkyl, phenyl or a group -CH2-S-R1 or B is C1-C24 alkyl, C5-C12 cycloalkyl, C7-C9 phenylalkyl, phenyl or a group -CH2-S-R1, X is hydrogen, C1-C18 alkyl or one of the groups -C a H2a-S q-R2, -C b H2b-CO-OR3, -C b H2b-CO-N(R5)(R6), -CH2N(R10)(R11) and R1 is C1-C18 alkyl, phenyl or a group - (CH2)c-CO-OR4 or -CH2CH2OR9, R2 is hydrogen, C1-C18 alkyl, phenyl, benzyl or a group or -(CH2)c-CO-OR4 or -CH2CH2OR9 R3 is C1-C50 alkyl or one of the groups wherein Q is C2-C8 alkylene, C4-C6 thiaalkylene or a group -CH2CH2(OCH2CH2)d-, R4 is C1-C24 alkyl, R5 is hydrogen, C1-C18 alkyl or cyclohexyl , R6 is C1-C18 alkyl, cyclohexyl, phenyl, C1-C18 alkyl-substituted phenyl or one of the groups or R5 and R6 together are C4-C8 alkylene which can be interrupted by -O- or -NH-, R7 is hydrogen, C1-C4 alkyl or phenyl, R8 is C1-C18 alkyl, R9 is hydrogen, C1-C24 alkyl, phenyl, C2-C18 alkanoyl or benzoyl, R10 is C1-C18 alkyl, cyclohexyl, phenyl, C1-C18 alkyl-substituted phenyl or a group R11 is hydrogen, C1-C18 alkyl, cyclohexyl or a group or R10 and R11 together are C4-C8 alkylene which can be interrupted by -O- or -NH-, a is 0, 1, 2 or 3, b is 0, 1, 2 or 3, c is 1 or 2, d is 1 to 5, f is 2 to 8 and q is 1, 2, 3 or 4, or, as component (C), a mixture of polyphenols formed by reacting at least one phenol of the formula with at least one phenol of the formula and with formaldehyde or paraformaldehyde, wherein C, D
and E independently of the others are C1-C24 alkyl, cyclohexyl or phenyl, the composition containing no aromatic amine.

23. A method according to claim 22 for reducing the formation of sludge in an engine oil.