Novel polyalkylpiperidyl-ureas and their use as stabilizers

Polyalkylpiperidyl-ureas of the formula I ##STR1## in which m is 1-4, X, R.sup.2 and R.sup.3 are monovalent substituents and R.sup.1 is a m-valent radical, can be prepared from the corresponding 4-aminopiperidines by reaction with carbamoyl chlorides. They are outstanding stabilizers for plastics, and especially for polyolefins, to protect them against degradation by the action of light.

The invention relates to novel substituted ureas which have at least one 
polyalkylpiperidine radical as a substituent and are valuable stabilisers 
for plastics, especially to protect these against damage by light. 
Ureas containing polyalkylpiperidine substituents and their use as 
stabilisers are already known. Thus, German Offenlegungsschrift No. 
2,040,975 described derivatives of 4-amino-2,2,6,6-tetramethyl-piperidine 
of the formula 
##STR2## 
in which R.sub.1 is H or an acyl group, R.sub.2 is H or a monovalent 
radical and R.sub.3 inter alia can be a carbamoyl group or a N-substituted 
carbamoyl group, for example, --CONH.sub.2, --CONH-alkyl, --CONH-cycloakyl 
or --CONH-aryl. 
German Offenlegungsschrift No. 2,349,962 described similar compounds of the 
following formula 
##STR3## 
in which R.sub.1 and R.sub.2 are alkyl radicals, R.sub.3 is alkyl, 
alkenyl, alkynyl or aralkyl, R.sub.5 is H or a monovalent radial and 
R.sub.4 inter alia is a N-substituted or unsubstituted carbamoyl group, 
for example --CONH.sub.2, --CONH-alkyl, --CONH-aryl or --CONH-aralkyl. The 
urea derivatives disclosed in these two patent specifications carry at 
least one hydrogen atom either on the nitrogen in the 1-position or on the 
nitrogen in the 3-position of the urea grouping. Examples are 
1-benzyl-3-(1,2,2,6,6-pentamethyl-4-piperidyl)-urea or 
1,1-dimethyl-3-(1,2,2,6,6-pentamethyl-4-piperidyl)-urea. These compounds 
are good light stabilisers for plastics if these are processed at low 
temperatures. At higher processing temperatures, a more or less 
discernible discoloration and a relatively weak stabiliser action result. 
It has been found that polyalkylpiperidylureas in which the urea group does 
not carry a hydrogen atom either on the nitrogen in the 1-position or on 
the nitrogen in the 3-position possess a considerably superior action as 
light stabilisers. In certain substrates their light stabilising action is 
superior to that of most of the known light stabilisers, i.e. including 
those of a chemically completely different constitution. 
The invention therefore relates to compounds of the formula I 
##STR4## 
in which m is 1, 2, 3 or 4, X is H, O, C.sub.1 -C.sub.18 -alkyl, C.sub.3 
-C.sub.5 -alkenyl, propargyl, C.sub.7 -C.sub.12 -phenylalkyl or a group of 
the formula --CO--C.sub.1 --C.sub.8 -alkyl, --CO--C.sub.2 -C.sub.3 
-alkenyl, --CO--O--C.sub.1 -C.sub.10 -alkyl or --CO--N--(C.sub.1 -C.sub.10 
-alkyl).sub.2, R is hydrogen or methyl and R.sup.1, if m is 1, is C.sub.1 
-C.sub.18 -alkyl, C.sub.3 -C.sub.5 -alkenyl, C.sub.3 -C.sub.4 -alkynyl, 
C.sub.5 -C.sub.6 -cycloalkyl, C.sub.7 -C.sub.18 -aralkyl, C.sub.6 
-C.sub.12 -aryl or a group of the formula II 
##STR5## 
or, if m is 2, is C.sub.2 -C.sub.20 -alkylene, C.sub.4 -C.sub.12 -mono- or 
-di-oxaalkylene, a 
##STR6## 
or --(CH.sub.2).sub.3 --N(R.sup.5)--(CH.sub.2).sub.3 -group, 
cyclohexylene, xylylene, hexahydroxylene, or a 
##STR7## 
group, in which R.sup.4 is hydrogen, C.sub.1 -C.sub.4 -alkyl, allyl, 
benzyl or a 
##STR8## 
group, n is an integer from 1 to 5, R.sup.5 is C.sub.1 -C.sub.12 -alkyl, 
phenyl or cyclohexyl, p is nought or 1, R.sup.6 is hydrogen or methyl and 
R.sup.7 is --CH.sub.2 -- or &gt;C(CH.sub.3).sub.2, or R.sup.1, if m is 3, is 
a 
##STR9## 
radical and if m is 4 is a radical of the formula 
##STR10## 
in which R.sup.8 is C.sub.2 -C.sub.20 -alkylene, cyclohexylene or 
xylylene, and R.sup.2 and R.sup.3 independently of one another are C.sub.1 
-C.sub.12 -alkyl, cyclohexyl, C.sub.3 -C.sub.5 -alkenyl, propargyl, 
C.sub.7 -C.sub.12 -phenylalkyl or C.sub.6 -C.sub.12 -aryl and R.sup.2 can 
also be C.sub.1 -C.sub.4 -alkoxy, or R.sup.2 and R.sup.3 together form 
C.sub.4 -C.sub.9 -alkylene or 3-oxa-1,5-pentylene. 
In formula I, X and R.sup.1 can e alkyl, for example methyl, ethyl, propyl, 
butyl, pentyl, isopentyl, hexyl, octyl, 2-ethylhexyl, dodecyl or 
octadecyl. Alkenyl R.sup.1, R.sup.2, R.sup.3 or X can be, for example, 
allyl, methallyl or 2-butenyl. Alkynyl R.sup.1 can be, for example, 
propargyl or 2-butynyl. 
Phenylalkyl X, R.sup.2 and R.sup.3 can be, for example, phenylpropyl, 
phenylbutyl or phenylethyl, but preferably benzyl. As aralkyl, R.sup.1 can 
additionally also be naphthylmethyl. 
As an acyl radical --CO--C.sub.1 -C.sub.8 -alkyl, X can be, for example, 
acetyl, propionyl, butyryl, isovaleryl, hexanoyl or octanoyl. As 
alkoxycarbonyl --CO--O--C.sub.1 -C.sub.10 -alkyl, X can be, for example, 
methoxycarbonyl, ethoxycarbonyl or octyloxycarbonyl. As a dislkylcarbamoyl 
radical --CO--N--(C.sub.2 -C.sub.10 -alkyl).sub.2, X can be, for example, 
dimethylcarbamoyl, dibutylcarbamoyl or dioctylcarbamoyl. 
Cycloalkyl R.sup.1 can be cyclopentyl or cyclohexyl. Aryl R.sup.1, R.sup.2 
and R.sup.3 can be, for example, phenyl, naphthyl or diphenylyl. 
Alkylene R.sup.1 can be a branched or unbranched alkylene radical, for 
example, 1,2-ethylene, 1,2-propylene, 1,3-propylene, 
2,2-diethyl-1,3-propylene, tetramethylene, hexamethylene or octa-, deca-, 
dodeca- or octadeca-methylene. Oxaalkylene R.sup.1 can be, for example, 
3-oxa-1,5-pentylene, 4-oxa-1,7-heptylene or 4,7-dioxa-1,10-decylene. If 
R.sup.2 and R.sup.3 together are C.sub.4 -C.sub.9 -alkylene or 
3-oxapentylene, they form, together with the N atom to which they are 
bonded, for example, a pyrrolidine, piperidine, 
2,2,6,6-tetramethylpiperidine or morpholine ring. 
Preferred compounds of the formula I are those in which R is hydrogen. 
Further preferred compounds of the formula I are those in which m is 1 or 
2, R is hydrogen, X is hydrogen, C.sub.1 -C.sub.8 -alkyl, allyl or benzyl 
and R.sup.1, if m is 1, is C.sub.1 -C.sub.12 -alkyl or a group of the 
formula II, and, if m is 2, isC.sub.2 -C.sub.10 -alklyene or C.sub.4 
-C.sub.6 -oxaalkylene, 1,4-cyclohexylene or a 
##STR11## 
group, and R.sup.2 and R.sup.3 independently of one another are C.sub.1 
-C.sub.10 -alkyl, phenyl, cyclohexyl, allyl or benzyl, or R.sup.2 and 
R.sup.3 together are C.sub.4 -C.sub.6 -alkylene or 3-oxa-1,5-pentylene. 
Particularly preferred compounds of the formula I are those in which R is 
hydrogen, X is hydrogen, C.sub.1 -C.sub.4 -alkyl, allyl or benzyl and 
R.sup.1, if m is 1, is C.sub.1 -C.sub.4 -alkyl or a group of the formula 
II, and, if m is 2, is C.sub.2 -C.sub.6 -alkylene or C.sub.4 -C.sub.6 
-oxaalkylene, and R.sup.2 and R.sup.3 are C.sub.1 -C.sub.12 -alkyl, 
phenyl, cyclohexyl or allyl, or R.sup.2 and R.sup.3 together are C.sub.4 
-C.sub.6 -alkylene or 3-oxa-1,5-pentylene. 
Examples of compounds of the formula I in which m is 1 are: 
1,1-dimethyl-3,3-di-(2,2,6,6-tetramethyl-4-piperidyl)-urea, 
1,1-dibutyl-3,3-di-(2,2,6,6-tetramethyl-4-piperidyl)-urea, 
1,1-dibenzyl-3,3-di-(1-benzyl-2,2,6,6-tetramethyl-4-piperidyl)-urea, 
1,1,3-trimethyl-3-(1,2,2,6,6-pentamethyl-4-piperidyl)-urea, 
1,1,3-triethyl-3-(2,2,6,6-tetramethyl-4-piperidyl)-urea, 
1,3-dimethyl-1-octyl-3-(tetramethyl-4-piperidyl)-urea, 
1,3-dimethyl-1-phenyl-3-(tetramethyl-4-piperidyl)-urea, 
1,1-dibutyl-3-cyclohexyl-3-(tetramethyl-4-piperidyl)-urea, 
1,2,2,6,6-pentamethyl-4-[(N-piperidinocarbonyl)-methylamino]-piperidine, 
1,1-dimethyl-3,3-di-(1-allyl-2,2,6,6-tetramethyl-4-piperidyl)-urea and 
1,1,3-trimethyl-3-(1,3,3,6-tetramethyl-2,6-diethyl-4-piperidyl)-urea. 
Examples of compounds of the formula I in which m is 2 are: 
N,N'-bis-(dimethylcarbamoyl)-N,N'-bis-(2,2,6,6-tetramethyl-4-piperidyl)-he 
xamethylenediamine, 
N,N'-bis-(dimethylcarbamoyl)-N,N'-bis-(1-allyl-2,2,6,6-tetramethyl-4-piper 
idyl)-tetramethylenediamine, 
N,N'-bis-(diethylcarbamoyl)-N,N'-bis-(1-benzyl-2,2,6,6-tetramethyl-4-piper 
idyl)-2,2,5-trimethyl-hexamethylenediamine, 
N,N'-bis-(diethylcarbamoyl)-N,N'-bis-(1,2,2,6,6-pentamethyl-4-piperidyl)-d 
odecamethylenediamine, 
N,N'-bis-(methyl-phenylcarbamoyl)-N,N'-bis-(1,2,2,6,6-pentamethyl-4-piperi 
dyl)-p-xylylenediamine, N.sup.1,N.sup.4 
-bis-(diethylcarbamoyl)-N.sup.1,N.sup.4 
-bis-(1,2,2,6,6-pentamethyl-4-piperidyl)-N.sup.2,N.sup.3 
-dimethyl-triethylenetetramine, 
1,9-bis-(dicyclohexylcarbamoyl)-1,9-bis-(2,2,6,6-tetramethyl-4-piperidyl)- 
5-methyl-1,5,9-triazanonane, 
1,4,7-tris-(dimethylcarbamoyl)-1,7-bis-(2,2,6,6-tetramethyl-4-piperidyl)-1 
,4,7-triazaheptane, 
N,N'-bis-(dibutylcarbamoyl)-N,N'-bis-(2,2,6,6-tetramethyl-4-piperidyl)-2,2 
,-di-(4-aminocyclohexyl)-propane, 
N,N'-bis-(diphenylcarbamoyl)-N,N'-bis-(1,2,2,6,6-pentamethyl-4-piperidyl)- 
di-(4-amino-3-methyl-cyclohexyl)-methane and 
N,N'-bis-(diethylcarbamoyl)-N,N'-bis-(1,2,3,6-tetramethyl-2,6-diethyl-4-pi 
peridyl)-1,9-diaza-5-oxanonane. 
The compounds of the formula I can be prepared by various methods. The most 
important method is the reaction of a 4-aminopiperidine of the formula III 
with a carbamic acid chloride: 
##STR12## 
The reaction is carried out in the presence of molar amounts of a HCl 
acceptor. Suitable HCl acceptors are inorganic or organic bases, for 
example alkali metal hydroxides, alkali metal carbonates or tertiary 
amines. 
The reaction is preferably carried out in a solvent. Suitable solvents are, 
for example, chloroform, methylene chloride, benzene, toluene, xylene, 
tetrahydrofuran, dioxan, dimethoxyethane or dimethylformamide. 
A second method is the reaction of III with phosgene, if necessary in the 
presence of a proton acceptor, followed by the reaction of the resulting 
carbamoyl chloride IV with a secondary amine: 
##STR13## 
The reaction in the first stage (phosgenation) is effected in an inert 
solvent, for example benzene, toluene, xylene, chloroform, ethyl acetate 
or the like, at -30.degree. to +50.degree. C. The intermediate IV does not 
need to be isolated but can be reacted with the amine immediately after 
the first stage has ended. The reaction with the amine is effected with 
the addition of at least 2 mmols of HCl-acceptor. An excess of the 
secondary amine can also be used for this purpose. 
A third process comprises the reaction of III with a N,N-disubstituted 
urea: 
##STR14## 
For this reaction, the urea can also be used in excess. The reaction is 
carried out without a solvent or in a high-boiling, polar solvent, for 
example dimethylformamide or dimethylsulphoxide, at temperatures of 
150.degree. to 250.degree. C. The course of the reaction can be followed 
by measuring the NH.sub.3 formed. 
The 4-aminopiperidines of the formula III which are used as a starting 
material in all three processes can be obtained from the corresponding 
4-oxopiperidines by catalytic hydrogenation in the presence of the primary 
amines R.sup.1 (NH.sub.2).sub.n, as is described in German 
Offenlegungsschriften Nos. 2,040,975 and 2,349,962. If the substituent X 
is a hydrocarbon or acyl radical, it can be introduced into the 
corresponding NH compound by the conventional methods for the alkylation 
or acylation of secondary amines. This introduction of X can be effected 
at the stage of the 4-oxopiperidines or, preferably, at the stage of the 
4-ureidopipieridines. Piperidin-1-oxyls (X.dbd.0) can be prepared by 
oxidising 4-ureido-1-hydrogenopiperidines (formula I, X.dbd.H) by means of 
percarboxylic acids or by means of H.sub.2 O.sub.2 in the presence of 
tungsten catalysts. 
A further possibility for the preparation of the compounds of the formula I 
comprises the N-alkylation of trisubstituted or disubstituted ureas of the 
formula V, VI or VII with the corresponding alkyl, alkenyl or aralkyl 
halides under the conditions of the phase transfer process: 
##STR15## 
These reactions are carried out in a water-immiscible solvent, for example 
benzene, toluene, xylene, methylene chloride or dioxan, and an alkali 
metal hydroxide is added, in powder form or in the form of a concentrated 
aqueous solution, in a molar amount which corresponds to the amount of 
halide used. Solid K.sub.2 CO.sub.3 can also be used. Furthermore, a 
quaternary ammonium salt, for example benzyl-trimethylammonium chloride, 
is added in catalytic amounts, as a phase transfer catalyst. 
The compounds of the formulae V, VI and VII have been disclosed in German 
Offenlegungsschriften Nos. 2,040,975 or 2,349,962, which have been 
mentioned initially, or can be prepared by the methods described in these 
Offenlegungsschriften. Preferably, the compounds of the formula V, VI or 
VII which are used are those in which X is not hydrogen. If, however, a 
compound of the formula V, VI or VII is used in which X is hydrogen, a 
substituent can be introduced on the piperidine nitrogen at the same time, 
and a compound of the formla I is obtained in which X is R.sup.3 or 
R.sup.1. The reaction of a compound of the formula VII with R.sup.1 Hal 
and R.sup.3 Hal is preferably used when R.sup.1 and R.sup.3 are identical. 
The compounds of the formula I are in most cases crystalline substances 
which can be purified by recrystallisation. However, their melting points 
are lower than those of the corresponding ureas which possess CONH groups. 
Their solubility and compatability in diverse substances is also greater 
than that of the CONH compounds. 
The compounds of the formula I are furthermore distinguished by outstanding 
stability to hydrolysis, which is far superior to the stability to 
hydrolysis of the CONH compounds, which in itself is good. 
The most valuable characteristic of the compounds of the formula I is their 
outstanding stabiliser action, in particular against the degradation of 
organic polymers by the action of light. Examples of polymers which are 
damaged by the action of light and which can be stabilised by the addition 
of compounds of the formula I are the following polymers. 
1. Polymers of mono- and di-olefins, for example polyethylene (which can be 
crosslinked), polypropylene, polyisobutylene, polybut-1-ene, 
polymethylpent-1-ene, polyisoprene or polybutadiene and also polymers of 
cycloolefins, for example of cyclopentane or norbornene. 
2. Mixtures of the polymers mentioned under 1), for example mixtures of 
polypropylene with polyethylene or with polyisobutylene. 
3. Copolymers of mono- and di-olefins with one another or with other vinyl 
monomers, for example ethylene/propylene copolymers, propylene/but-1-ene 
copolymers, propylene/isobutylene copolymers, ethylene/but-1-ene 
copolymers, propylene/butadiene copolymers, isobutylene/isoprene 
copolymers, ethylene/ethyl acrylate copolymers, ethylene/alkyl 
methacrylate copolymers, ethylene/vinyl acetate copolymers or 
ethylene/acrylic acid copolymers and their salts (ionomers), and also 
terpolymers of ethylene with propylene and a diene, such as hexadiene, 
dicyclopentadiene or ethylidenenorbornene. 
4. Polystyrene. 
5. Statistical copolymers of styrene or .alpha.-methylstyrene with dienes 
or acrylic derivatives, for example styrene/butadiene, 
styrene/acrylonitrile, styrene/ethyl methacrylate or 
styrene/acrylonitrile/methacrylate; mixtures of high impact strength 
obtained from styrene copolymers and another polymer, for example a 
polyacrylate, a diene polymer or an ethylene/propylene/diene terpolymer; 
and also block copolymers of styrene, for example 
styrene/butadiene/styrene, styrene/isoprene/styrene, 
styrene/ethylene-butylene-/styrene or styrene/ethylene-proplyene/styrene. 
6. Graft copolymers of styrene, for example styrene on polybutadiene, 
styrene and acrylonitrile on polybutadiene, styrene and alkyl acrylates or 
alkyl methacrylates on polybutadiene, styrene and acrylonitrile on 
ethylene/propylene/diene terpolymers, styrene and acrylonitrile on 
polyalkyl acrylates or polyalkyl methacrylates, or styrene and 
acrylonitrile on acrylate/butadiene copolymers, and also mixtures thereof 
with the copolymers listed under 5), for example those known as ABS, MBS, 
ASA or AES polymers. 
7. Halogen-containing polymers, for example polychloroprene, chlorinated 
rubber or chlorinated or chlorosulfonated polyethylene, and especially 
polymers of halogen-containing vinyl compounds, for example polyvinyl 
chloride, polyvinylidene chloride, polyvinyl fluoride or polyvinylidene 
fluoride; and also copolymers thereof, such as vinyl chloride/vinylidene 
chloride, vinyl chloride/vinyl acetate or vinylidene chloride/vinyl 
acetate. 
8. Polymers which are derived from .alpha.,.beta.-unsaturated acids and 
their derivatives, such as polyacrylates and polymethacrylates, 
polyacrylamides and polyacrylonitriles. 
9. Copolymers of the monomers listed under 8), with one another or with 
other unsaturated monomers, for example acrylonitrile/butadiene 
copolymers, acrylonitrile/alkyl acrylate copolymers, acrylonitrile/vinyl 
chloride copolymers or acrylonitrile/alkyl methacrylate/butadiene 
terpolymers. 
10. Polymers which are derived from unsaturated alcohols and amines or 
their acyl derivatives or acetals, such as polyvinyl alcohol, polyvinyl 
acetate, polyvinyl stearate, polyvinyl benzoate, polyvinyl maleate, 
polyvinylbutyral, polyallyl phthalate or polyallylmelamine. 
11. Homopolymers and copolymers of cyclic ethers, such as polyalklylene 
glycols, polyethylene oxide or polypropylene oxide or their copolymers 
with bis-glycidyl ethers. 
12. Polyacetals, such as polyoxymethylene, and also those polyoxymethylenes 
which contain comonomers, for example ethylene oxide. 
13. Polyphenylene oxides and polyphenylene sulfides. 
14. Polyurethanes which are derived from polyethers, polyesters and 
polybutadienes with terminal hydroxyl groups on the one hand and from 
aliphatic or aromatic polyisocyanates on the other hand, and also their 
precursors. 
15. Polyamides and copolyamides which are derived from diamines and 
dicarboxylic acdis and/or from aminocarboxylic acids or the corresponding 
lactams, such as polyamide 4, polyamide 6, polyamide 6/6, polyamide 6/10, 
polyamide 11, polyamide 12, 
poly-2,4,4-trimethylhexamethylene-terephthalamide or 
poly-m-phenylene-isophthalamide, and also the copolymers thereof with 
polyethers, for example with polyethylene glycol, polypropylene glycol or 
polytetramethyl glycol. 
16. Polyureas, polyimides and polyamide-imides. 
17. Polyesters which are derived from dicarboxylic acids and dialcohols 
and/or from hydroxycarboxylic acids or the corresponding lactones, such as 
polyethylene terephthalate, polybutylene terephthalate, 
poly-1,4-dimethylolcyclohexane terephthalate or polyhydroxybenzoates, and 
also block polyether-esters which are derived from polyethers with 
hydroxyl end groups. 
18. Polycarbonates. 
19. Polysulfones and polyether-sulfones. 
20. Crosslinked polymers which are derived from aldehydes on the one hand 
and from phenols, urea or melamine 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 their halogen-containing 
modifications of low combustibility. 
23. Crosslinkable acrylic resins which are derived from substituted acrylic 
acid esters, for example from epoxyacrylates, urethane-acrylates or 
polyester-acrylates. 
24. Alkyd resins, polyester resins and acrylate resins which are 
crosslinked with melamine resins, urea resins, polyisocyanates or epoxide 
resins. 
25. Crosslinked epoxide resins which are derived from polyepoxides, for 
example from bis-glycidyl ethers or from cycloaliphatic diepoxides. 
26. Naturally occurring polymers, such as cellulose, natural rubber and 
gelatine, and also their polymer-homologously chemically modified 
derivatives, such as cellulose acetates, cellulose propionates and 
cellulose butyrates and the cellulose ethers, such as methylcellulose. 
The stabilisation of polyolefins and styrene polymers and of polyurethanes 
is of particular importance and the compounds of the formula I are 
outstandingly suitable for this. Examples of such polymers are high 
density and low density polyethylene, polypropylene, ethylene/propylene 
copolymers, polystyrene, styrene/butadiene/acrylonitrile copolymers, 
mixtures of polyolefins or of styrene polymers, and polyurethanes based on 
polyethers or polyesters, in the form of films, fibres, lacquers, 
elastomers or foams. The stabilisation of lacquer resins, for example of 
alkyd resins, polyester resins and acrylic resins and their mixtures with 
melamine resins, is also of particular importance. 
The stabilisers are added to the plastics in a concentration of 0.01 to 5% 
by weight, based on the material to be stabilised. Preferably 0.03 to 1.5 
and particularly preferentially 0.2 to 0.6% by weight of the compounds, 
based on the material to be stabilised, is incorporated into the latter. 
The incorporation can be effected after polymerisation, for example by 
mixing the compounds, and if desired further additives, into the melt by 
the methods customary in industry, before or during shaping, or by 
applying the dissolved or dispersed compounds to the polymer, with 
subsequent evaporation of the solvent if necessary. 
The compounds can also be added to the plastics to be stabilised in the 
form of a master batch which contains these compounds, for example in a 
concentration of 2.5 to 25% by weight. 
In addition to the compounds of the formula I, yet further known 
stabilisers can also be added to the plastics. These can be, for example, 
antioxidants, light stabilisers or metal deactivators or also 
costabilisers, for example those of the organic phosphite type. 
Furthermore, other additives customary in plastics technology can be 
added, for example flame-proofing agents, antistatic agents, plasticisers, 
lubricants, blowing agents, pigments, reinforcing materials or fillers. 
Specific examples of such known and conventional additives are listed on 
pages 25-32 of German Offenlegungsschrift No. 2,349,962. 
The invention therefore also relates to the plastics which are stabilised 
by the addition of 0.01 to 5% by weight of a compound of the formula I and 
which, if desired, can contain yet further known and conventional 
additives. The plastics stabilised in this way can be used in very diverse 
forms, for example as films, fibres, tapes or profiles or as binders for 
lacquers, adhesives or putties, or as a coating for photograhic films and 
papers.

The preparation and use of the compounds according to the invention are 
described in more detail in the following examples. Parts and percentages 
are by weight. The temperatures are in degrees Centigrade. 
EXAMPLE 1 
33.9 g (0.315 mol) of dimethylcarbamoyl chloride are added dropwise, with 
stirring, at 105.degree.-110.degree. C. to a solution of 55 g (0.15 mol) 
of N,N'-bis-(2,2,6,6-tetramethyl-4-piperidyl)-hexamethylenediamine in 130 
ml of xylene and 44.6 g (0.345 mol) of ethyldiisopropylamine and the 
mixture is stirred for a total of 12 hours at 110.degree.. For working up, 
the reaction mixture is washed repeatedly with water, dried over sodium 
sulfate and completely freed from the solvent in vacuo. The crude compound 
is recrystallised from ligroin (boiling point 110.degree.-140.degree.) and 
by this means 
N,N'-bis-dimethylcarbamoyl-N,N'-bis-(2,2,6,6-tetramethylpiperid-4-yl)-hexa 
methylenediamine with a melting point of 142.degree.-144.degree. is 
obtained. 
##STR16## 
The following compounds are prepared analogously: 
__________________________________________________________________________ 
Nbis-(2,2,6,6-tetramethylpiperid-4-yl)-N'diethylurea 
##STR17## melting point 154-155.degree. 
(compound No. 2) 
Nbis-(2,2,6,6-tetramethylpiperid-4-yl)-N'dimethylurea 
##STR18## melting point 137-138.degree. 
(compound No. 3) 
N,N'bis-(1,2,2,6,6-pentamethylpiperid-4-yl)-N,N'bis- 
(di-sec.-butyl-carbamoyl)-ethylenediamine 
##STR19## melting point 194-196.degree. 
(compound No. 4) 
N,N'bis-(2,2,6,6-tetramethylpiperid-4-yl)-N,N'bis- 
(diphenylcarbamoyl)-hexamethylenediamine 
##STR20## melting point 250-252.degree. 
(compound No. 5) 
N,N'bis-(2,2,6,6-tetramethylpiperid-4-yl)-N,N'bis- 
(dimethylcarbamoyl)-1,8-diamino-3,6-dioxa-octane 
##STR21## melting point 70-71.degree. 
(compound No. 6) 
N,N'bis-(1,2,2,6,6-pentamethylpiperid-4-yl)-N,N'bis- 
(dimethylcarbamoyl)-hexamethylenediamine 
##STR22## melting point 136-137.degree. 
(compound No. 7) 
N,N'bis-(1,2,2,6,6-pentamethylpiperid-4-yl)-N,N'bis- 
(diethylcarbamoyl)-trimethylenediamine 
##STR23## (compound No. 8) 
viscous oil, analysis: 
calculated 
C 68.5% 
H 11.5% 
N 14.5% 
found C 68.5% 
H 11.7% 
N 14.5% 
Nbis (1,2,2,6,6-pentamethylpiperid-4-yl)-N'dimethylurea 
##STR24## melting point 156-157.degree. 
(compound No. 9) 
N,N'bis-(2,2,6,6-tetramethylpiperid-4-yl)-N,N'bis- 
(hexamethyleneiminocarbonyl)-hexamethylenediamine 
##STR25## melting point 98-100.degree. 
(compound No. 10) 
N,N'bis-(2,2,6,6-tetramethylpiperid-4-yl)-N,N'bis- 
(morpholinocarbonyl)-hexamethylenediamine 
##STR26## melting point 123-124.degree. 
(compound No. 11) 
N,N'bis-(2,2,6,6-tetramethylpiperid-4-yl)-N,N'bis- 
(diallylcarbamoyl)-hexamethylenediamine 
##STR27## melting point 74-74.degree. 
(compound No. 12) 
N,N'bis-(2,2,6,6-tetramethylpiperid-4-yl)-N,N'bis- 
(dicyclohexylcarbamoyl)-hexamethylenediamine 
##STR28## melting point 216-217.degree. 
(compound No. 13) 
Nbis-(1,2,2,6,6-pentamethylpiperid-4-yl)-N'di-sec.- 
butyl-urea 
##STR29## melting point 100-102.degree. 
(compound No. 14) 
Ndodecyl-N(2,2,6,6-tetramethylpiperid-4-yl)-N'dimethyl- 
urea 
##STR30## boiling point 190.degree./0.03 mm 
Hg (bulb tube) (compound No. 15) 
Nbutyl-N(1,2,2,6,6-pentamethylpiperid-4-yl)-N'dioctyl- 
urea 
##STR31## boiling point 205.degree./0.01 mm 
Hg (bulb tube) (compound No. 16) 
N,N'bis-(1,2,2,6,6-tetramethylpiperid-4-yl)-N,N'bis- 
(methylmethoxycarbamoyl)-trimethylenediamine 
##STR32## (compound No. 17) 
Elementary analysis 
calculated: 
C 62.78 
H 10.54 
N 15.15% 
C.sub.29 H.sub.58 N.sub.6 O.sub.4 
found: 
C 62.5 
H 10.8 
N 14.9% 
__________________________________________________________________________ 
EXAMPLE 2 
26.9 g (0.05 mol) of 
N,N'-bis-(dimethylcarbamoyl)-N,N'-bis-(2,2,6,6-tetramethyl-4-piperidyl)-he 
xamethylenediamine (prepared according to Example 1), 18.2 g (0.15 mol) of 
allyl bromide, 16.6 g of powdered potassium carbonate, 0.5 g of powdered 
potassium iodide and 70 ml of ethyl methyl ketone are stirred for 24 hours 
at about 72.degree.-74.degree. (reflux temperature) in a nitrogen 
atmosphere. The reaction mixture is then filtered to remove the inorganic 
salts, the solvent is removed from the filtrate in vacuo and the crude 
compound is crystallised from pentane, by which means 
N,N'-bis-(dimethylcarbamoyl)-N,N'-bis-(1-allyl-2,2,6,6-tetramethylpiperid- 
4-yl)-hexamethylenediamine with a melting point of 96.degree.-98.degree. C. 
is obtained. Elementary analysis: C.sub.36 H.sub.68 N.sub.6 O.sub.2 
calculated: C, 70.08; H, 11.11; N, 13.62; O, 5.19%; found: C, 69.9; H, 
11.3; N, 13.5; O, 5.1%. 
##STR33## 
The following compounds are prepared analogously: 
__________________________________________________________________________ 
Nbis-(1-allyl-2,2,6,6-tetramethylpiperid-4-yl)-N' 
dimethylurea 
##STR34## melting point 88.5-90.degree. 
(compound No. 19) 
N,N'bis-(1-allyl-2,2,6,6-tetramethylpiperid-4-yl)-N,N' 
bis-(diethylcarbamoyl)-hexamethylenediamine 
##STR35## melting point 68-69.degree. (compound 
No. 20) 
N,N'bis-(1-allyl-2,2,6,6-tetramethylpiperid-4-yl)-N,N' 
bis-(dicyclohexylcarbamoyl)-hexamethylenediamine 
##STR36## melting point 172-173.degree. 
(compound No. 21) 
__________________________________________________________________________ 
EXAMPLE 3 
17.6 g (0.13 mol) of diethylcarbamoyl chloride are added dropwise at 
110.degree.-120.degree., with stirring, to a solution of 34.6 g (0.06 mol) 
of 
N,N'-bis-(1-benzyl-2,2,6,6-tetramethylpiperid-4-yl)-hexamethylenediamine ( 
melting point: 101.degree.-103.degree., prepared by reductive amination of 
1-benzyl-2,2,6,6-tetramethyl-piperid-4-one with hexamethylenediamine) in 
150 ml of xylene and 15 g of triethylamine. After a reaction time of 9 
hours at about 115.degree., the reaction mixture is cooled to room 
temperature, diluted with toluene, washed repeatedly with water, dried 
over sodium sulfate and completely freed from the solvents in vacuo. The 
crude compound is further purified by chromatography on silica gel 
(eluant: diethyl ether) and is recrystallized from n-hexane, by which 
means pure 
N,N'-bis-diethylcarbamoyl-N,N'-bis-(1-benzyl-2,2,6,6-tetramethylpiperid-4- 
yl)-hexamethylenediamine is obtained. Melting point 
123.degree.-124.degree., elementary analysis: C.sub.48 H.sub.80 N.sub.6 
O.sub.2 calculated: C, 75.56; H, 10.43; N, 10.87%; found: C, 75.7; H, 
10.4; N, 10.9%. 
##STR37## 
The following compound is prepared analogously: 
##STR38## 
EXAMPLE 4 
A solution of 16.5 g of n-butyl bromide in 10 ml of benzene is added 
dropwise in the course of 90 minutes, at 78.degree., to a vigorously 
stirred mixture (under a nitrogen atmosphere) of 9.65 g of 
N-(1,2,2,6,6-pentamethylpiperidin-4-yl)-N'-dimethylurea (prepared from 
4-amino-1,2,2,6,6-pentamethylpiperidine and dimethylcarbamoyl chloride: 
melting point 111.degree.-112.degree.), 40 ml of benzene, 5.6 g of sodium 
hydroxide, 11.06 g of potassium carbonate and 1.4 g of tetrabutylammonium 
hydrogen sulfate. The mixture is then stirred for a further 30 hours at 
78.degree.-80.degree.. For working up, the white suspension is cooled to 
room temperature, 200 ml of diethyl ether are added, the resulting mixture 
is filtered, the filtrate is freed from the solvents in vacuo and the 
residue is purified by column chromatography on silica gel (60 Merck) 
(eluant: diethyl ether/methanol/triethylamine, 90:7:3), by which means 
pure N-butyl-N-(1,2,2,6,6-pentamethylpiperid-4-yl)-N'-dimethylurea with a 
melting point of 83.degree.-85.degree. is obtained (crystallised from 
acetonitrile). C.sub.17 H.sub.35 N.sub.3 O(281.47): calculated: C, 68.64; 
H, 11.86; N, 14.13%; found: C, 68.5; H, 11.6; N, 14.1%. 
##STR39## 
EXAMPLE 5 
A solution of 29.7 g (0.21 mol) of redistilled 
2,2,6,6-tetramethylpiperidine in 50 ml of xylene is added dropwise in the 
course of 1.5 hours, at -40.degree., to 40.2 g of a 25.7% solution of 
phosgene in xylene (0.105 mol), with stirring and under an inert gas 
atmosphere. After adding the amine, the mixture is stirred for a further 4 
hours at -10.degree. and for 18 hours at -5.degree. to 0.degree.. The 
2,2,6,6-tetramethylpiperidinocarboxylic acid chloride which is thus 
obtained is not isolated but is now treated with a solution of 19.73 g 
(0.05 mol) of 
N,N'-bis-(2,2,6,6-tetramethyl-piperid-4-yl)-hexamethylenediamine and 20.4 
ml (0.12 mol) of diisopropyl-ethylamine in 50 ml of xylene, this solution 
being added in the course of 2 hours, at -10.degree.. After stirring for a 
further 18 hours at room temperature and for 6 hours at 50.degree. C., 
the reaction mixture is cooled to room temperature, diluted with 300 ml of 
hexane and extracted four times with 150 ml of water, the organic phase is 
dried over sodium sulfate and the solvents are distilled off completely 
under a waterpump vacuum. The residue, which solidifies as crystals after 
a short time, is recrystallised from acetonitrile, and by this means pure 
N,N'-bis(2,2,6,6-tetramethylpiperid-4-yl)-N,N'-bis-(2,2,6,6-tetramethylpip 
eridinocarbonyl)-hexamethylenediamine is obtained as a colourless compound 
with a melting point of 137.degree.-139.degree.. 
##STR40## 
Elementary analysis: C.sub.44 H.sub.84 N.sub.6 O.sub.2 calculated: N, 
11.54%; found: N, 11.5%. 
EXAMPLE 6 
Stabilisation of polypropylene against light 
100 parts of polypropylene powder (Moplen, fibre grade, from Montedison) 
are homogenised with 0.2 part of octadecyl 
.beta.-(3,5-di-tert.-butyl-4-hydroxyphenyl)-propionate, 0.1 part of 
calcium stearate and 0.25 part of a stabiliser from Table 1 which follows, 
for 10 minutes in a Brabender plastograph at 200.degree. C. The 
composition thus obtained is removed from the kneader as rapidly as 
possible and pressed in a toggle press to give a 2-3 mm thick sheet. Part 
of the resulting pressed blank is cut out and pressed between two 
high-gloss hard aluminum foils for 6 minutes at 260.degree., using a hand 
hydraulic laboratory press, to give a 0.1 mm thick film, which is 
immediately quenched in cold water. Cut pieces are now punched from this 
film and exposed in a Xenotest 1,200. These test pieces are removed from 
the exposure apparatus at regular intervals and their carbonyl content is 
tested in a IR spectrophotometer. The increase in the carbonyl extinction 
at 5.85 .mu.m during exposure is a measure of the photo-oxidative 
degradation of the polymer (see Balaban et al., J. Polymer Sci., Part C; 
22, 1,059-1,071 (1969)) and, according to experience, is associated with a 
deterioration of the mechanical properties of the polymer. The time taken 
to reach a carbonyl extinction of about 0.3, at which the comparison film 
is brittle, is taken as a measure of the protective effect. 
The ratio of this exposure time to the exposure time of a blank sample 
without light stabiliser is the protection factor PF. 
##EQU1## 
The following table gives the protection factors for the light stabilisers 
testedd. 
______________________________________ 
Light protection 
Light stabiliser used 
factor PF 
______________________________________ 
without 1 
Compound No. 1 12 
2 13.8 
3 15.7 
18 8.4 
19 13.0 
20 8.7 
22 6.9 
______________________________________