Stabilized polymers having hetero atoms in the main chain

Hydroxyphenyltriazines of formula I ##STR1## wherein R is hydrogen, C.sub.1 -C.sub.18 alkyl, C.sub.2 -C.sub.6 alkyl substituted by halogen or by C.sub.1 -C.sub.12 alkoxy, or is benzyl and R' is hydrogen or methyl, are especially suitable as stabilisers for thermoplastic polymers that comprise hetero atoms in the main chain.

The invention relates to stabilised polymers having hetero atoms in the 
main chain, comprising as stabiliser a 2-hydroxyphenyl-s-triazine having 
specific substituents. 
It is known to stabilise polymers against damage by light, oxygen and heat 
by the addition of a 2-hydroxyphenyl-s-triazine of the formula 
##STR2## 
wherein R may be hydrogen or an organic radical and Ar are aromatic 
radicals that carry no hydroxy groups, see U.S. Pat. No. 3,244,708 and 
CH-B-480 091. Those compounds are UV absorbers and have also been proposed 
for stabilising photographic materials (U.S. Pat. No. 3,843,371) or paints 
(U.S. Pat. No. 4,619,956). 
In those cases there were used specifically triazine derivatives wherein Ar 
is a 2,4-dimethylphenyl radical, because those compounds are relatively 
readily obtainable. Recently, methods of synthesis have been developed 
which make such triazines having other aryl radicals readily obtainable 
also (EP-A-395 938). 
Surprisingly, it has now been found that, in thermoplastic polymers that 
comprise hetero atoms in the main chain, such triazines wherein Ar is a 
phenyl or a p-tolyl radical exhibit an especially good stabilising action, 
which is clearly superior to that of triazines wherein Ar is a 
2,4-dimethylphenyl radical. 
The invention therefore relates to a polymer composition that is stabilised 
against damage by light, oxygen and heat, comprising 
a) at least one thermoplastic polymer that comprises hetero atoms in the 
main chain, and 
b) as stabiliser, at least one hydroxyphenyltriazine compound of formula I 
##STR3## 
wherein R is hydrogen, C.sub.1 -C.sub.18 alkyl, C.sub.2 -C.sub.6 alkyl 
substituted by halogen or by C.sub.1 -C.sub.12 alkoxy, or is benzyl and R' 
is hydrogen or methyl. 
Polymers that comprise hetero atoms in the main chain are especially 
polymers comprising O, S and N. Examples of such polymers are the 
following classes of thermoplastic polymers: 
1. Polyacetals, such as polyoxymethylene, and polyoxymethylenes that 
comprise comonomers, for example ethylene oxide; polyacetals that have 
been modified by thermoplastic polyurethanes, acrylates or MBS. 
2. Polyphenylene oxides and sulfides and mixtures thereof with styrene 
polymers or polyamides. 
3. Polyamides and copolyamides, for example those 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, 
4/6, polyamide 11, polyamide 12, aromatic polyamides starting from 
m-xylene, diamine and adipic acid; polyamides prepared from 
hexamethylenediamine and iso- and/or tere-phthalic acid and, where 
appropriate, an elastomer as modifier, for example 
poly-2,4,4-trimethylhexamethylene terephthalamide, poly-m-phenylene 
isophthalamide. Block copolymers of the above-mentioned polyamides with 
polyolefins, olefin copolymers, ionomers or chemically bonded or grafted 
elastomers; or with polyethers, for example polyethylene glycol, 
polypropylene glycol or polytetramethylene glycol. Also polyamides or 
copolyamides modified by EPDM or ABS; and polyamides condensed during 
processing ("RIM polyamide systems"). 
4. Polyureas, polyimides, polyamide-imides and polybenzimidazoles. 
5. Polyesters, for example those 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, polyhydroxybenzoates, and 
block polyether esters derived from polyethers having hydroxy end groups; 
also polyesters modified by polycarbonates or by MBS. 
6. Polycarbonates and polyester carbonates, especially aromatic 
polycarbonates, for example those based on 2,2-bis(4-hydroxyphenyl)propane 
or 1,1-bis(4-hydroxyphenyl)cyclohexane. 
7. Polysulfones, polyether sulfones and polyether ketones, especially 
aromatic polymers of that class. 
8. Mixtures (polyblends) of such polymers with one another or with other 
polymers, for example with polyolefins, polyacrylates, polydienes or other 
elastomers in the form of impact strength modifiers. 
Among those compounds, preference is given to the polycarbonates, 
polyesters, polyamides, polyacetals, polyphenylene oxides and 
polyphenylene sulfides, but especially to the polycarbonates. Those 
compounds are to be understood as being especially those polymers the 
constitutional repeating unit of which corresponds to the formula 
##STR4## 
wherein A is a divalent phenolic radical. Examples of A are given inter 
alia in U.S. Pat. No. 4,960,863 and DE-A-3 922 496. A can be derived, for 
example, from hydroquinone, resorcinol, dihydroxybiphenylene or bisphenols 
in the broadest sense of the term, such as bis(hydroxyphenyl)alkanes, 
cycloalkanes, sulfides, ethers, ketones, sulfones, sulfoxides, 
.alpha.,.alpha.'-bis(hydroxyphenyl)diisopropylbenzenes, for example the 
compounds 2,2-bis(4-hydroxyphenyl)propane, 
2,2-bis(3,5-dimethyl-4-hydroxyphenyl)-propane, 
2,2-bis(3,5-dichloro-4-hydroxyphenyl)propane, 
2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane, 
1,1-bis(4-hydroxyphenyl)cyclohexane, or from the compounds of the formulae 
##STR5## 
The polymers of component a) may be linear or branched. The shaping of 
those polymers takes place at a relatively high temperature, for example 
polycarbonate is injection-moulded at from 220.degree. to 330.degree. C. 
At those temperatures most of the customary light-stabilisers and 
antioxidants are unstable and begin to decompose. The above-mentioned 
triazine derivatives according to the invention are, however, extremely 
resistant to high temperatures and are therefore especially suitable for 
stabilising the mentioned polymers. 
When R in formula I is C.sub.1 -C.sub.18 alkyl, it may be linear or 
branched alkyl and may be, for example, methyl, ethyl, propyl, isopropyl, 
butyl, isobutyl, pentyl, hexyl, 2-ethylbutyl, heptyl, octyl, 2-ethylhexyl, 
nonyl, decyl, dodecyl, tetradecyl or octadecyl. R is halo-substituted or 
C.sub.1 -C.sub.12 alkoxy-substituted C.sub.2 -C.sub.6 alkyl may be, for 
example, 2-chloroethyl, 2-fluoroethyl, 2-methoxyethyl, 2-ethoxyethyl, 
2-isopropoxyethyl, 2-methoxypropyl, 3-butoxypropyl, 2-butoxyethyl, 
2-hexyloxyethyl, 2-octyloxyethyl or 2-dodecyloxyethyl. 
R is preferably C.sub.1 -C.sub.12 alkyl or benzyl, especially C.sub.3 
-C.sub.6 alkyl, very especially propyl. 
In formula I R' is preferably hydrogen. 
Examples of compounds of formula I are: 
2,4-diphenyl-6-(2-hydroxy-4-methoxyphenyl)-1,3,5-triazine 
2,4-diphenyl-6-(2-hydroxy-4-ethoxyphenyl)-1,3,5-triazine 
2,4-diphenyl-6-(2-hydroxy-4-propoxyphenyl)-1,3,5-triazine 
2,4-diphenyl-6-(2-hydroxy-4-butoxyphenyl)-1,3,5-triazine 
2,4-diphenyl-6-(2-hydroxy-4-hexyloxyphenyl)-1,3,5-triazine 
2,4-diphenyl-6-(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine 
2,4-diphenyl-6-(2-hydroxy-4-dodecyloxyphenyl)-1,3,5-triazine 
2,4-diphenyl-6-(2-hydroxy-4-benzyloxyphenyl)-1,3,5-triazine 
2,4-diphenyl-6-(2-hydroxy-4-(2-butoxyethoxy)phenyl)-1,3,5-triazine 
2,4-di-p-tolyl-6-(2-hydroxy-4-methoxyphenyl)-1,3,5-triazine 
2,4-di-p-tolyl-6-(2-hydroxy-4-propoxyphenyl)-1,3,5-triazine 
2,4-di-p-tolyl-6-(2-hydroxy-4-butoxyphenyl)-1,3,5-triazine 
2,4-di-p-tolyl-6-(2-hydroxy-4-hexyloxyphenyl)-1,3,5-triazine 
2,4-di-p-tolyl-6-(2-hydroxy-4-pentoxyphenyl)-1,3,5-triazine 
2,4-di-p-tolyl-6-(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine 
2,4-di-p-tolyl-6-(2-hydroxy-4-benzyloxyphenyl)-1,3,5-triazine 
2,4-di-p-tolyl-6-(2-hydroxy-4-(2-hexyloxyethoxy)phenyl)-1,3,5-triazine. 
The compounds of formula I are known compounds or can be prepared 
analogously to known compounds. They can be prepared in principle by 
etherifying the corresponding 
2,4-diaryl-6-(2,4-dihydroxyphenyl)-1,3,5-triazines. The etherification 
takes place selectively in the 4-position, because the OH group in the 
2-position is sterically hindered by a hydrogen bridge bond. The 
preparation and etherification of the 2,4-dihydroxyphenyltriazines are 
described, for example, in Helv. Chim. Acta 55 (1972), 1566-95; EP-A-395 
938; U.S. Pat. No. 3,118,887; U.S. Pat. No. 3,242,175 or U.S. Pat. No. 
3,244,708. 
The amount of stabiliser to be used depends on the polymer to be stabilised 
and on the intended use of the stabilised polymer. In general, the polymer 
composition according to the invention comprises from 0.1 to 15, 
especially from 0.1 to 5, parts by weight of stabiliser (component b) to 
100 parts by weight of polymer (component a). 
The stabiliser (component b) may also be a mixture of two or more compounds 
of formula I. Apart from the stabiliser of formula I, the polymer 
composition may also comprise other known stabilisers, for example 
antioxidants, light-stabilisers, metal deactivators or processing 
stabilisers. The following compounds are examples thereof. 
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-di-cyclopentyl-4-methylphenol, 
2-(.alpha.-methylcyclohexyl)-4,6-dimethylphenol, 2,6-dimethylphenol, 
2,6-di-octadecyl-4-methylphenol, 2,4,6-tri-cyclohexylphenol, 
2,6-di-tert-butyl-4-methoxymethylphenol, 2,6-di-nonyl-4-methylphenol, 
2,4-dimethyl-6-(1'-methyl-undec-1'-yl)-phenol, 
2,4-dimethyl-6-(1'-methyl-heptadec-1'-yl)-phenol, 
2,4-dimethyl-6-(1'-methyl-tridec-1'-yl)-phenol and mixtures thereof. 
1.2. Alkylthiomethylphenols, for example 
2,4-di-octylthiomethyl-6-tert-butylphenol, 
2,4-di-octylthiomethyl-6-methylphenol, 
2,4-di-octylthiomethyl-6-ethylphenol, 
2,6-di-dodecylthiomethyl-4-nonylphenol. 
1.3. Hydroquinones and alkylated hydroquinones, for example 
2,6-tert-butyl-4-methoxyphenol, 2,5-di-tert-butyl-hydroquinone, 
2,5-di-tert-amyl-hydroquinone, 2,6-diphenyl-4-octadecyloxyphenol, 
2,6-di-tert-butyl-hydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole, 
3,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyphenyl 
stearate, bis(3,5-di-tert-butyl-4-hydroxyphenyl)adipate. 
1.4. Hydroxylated thiodiphenyl ethers, for example 
2,2'-thio-bis(6-tert-butyl-4-methylphenol), 2,2'-thio-bis(4-octylphenol), 
4,4'-thio-bis(6-tert-butyl-3-methylphenol), 
4,4'-thio-bis(6-tert-butyl-2-methylphenol), 
4,4'-thio-bis(3,6-di-sec-amylphenol), 
4,4'-bis-(2,6-dimethyl-4-hydroxyphenyl)disulfide. 
1.5. Alkylidene bisphenols, for example 
2,2'-methylene-bis(6-tert-butyl-4-methylphenol), 
2,2'-methylene-bis(6-tert-butyl-4-ethylphenol), 
2,2'-methylene-bis[4-methyl-6-(.alpha.-methylcyclohexyl)-phenol], 
2,2'-methylene-bis(4-methyl-6-cyclohexylphenol), 
2,2'-methylene-bis(6-nonyl-4-methylphenol), 
2,2'-methylene-bis(4,6-di-tert-butylphenol), 
2,2'-ethylidene-bis(4,6-di-tert-butylphenol), 
2,2'-ethylidene-bis-(6-tert-butyl-4isobutylphenol), 
2,2'-methylene-bis[6-(.alpha.-methylbenzyl)-4-nonylphenol], 
2,2'-methylene-bis[6-(.alpha.,.alpha.-di-methylbenzyl)-4-nonylphenol], 
4,4'-methylene-bis(2,6-di-tert-butylphenol), 
4,4'-methylene-bis(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-methyl-phenyl)dicyclopentadiene, 
bis[2-(3'-tert-butyl-2'-hydroxy-5'-methyl-benzyl)-6-tert-butyl-4-methylphe 
nyl]terephthalate, 1,1-bis(3,5-dimethyl-2-hydroxyphenyl)butane, 
2,2-bis(3,5-di-tert-butyl-4 -hydroxyphenyl)-propane, 
2,2-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)-4-n-dodecylmercaptobutane, 
1,1,5,5-tetra(5-tert-butyl-4-hydroxy-2-methylphenyl)pentane. 
1.6. O-, N- and S-benzyl compounds, for example 
3,5,3',5'-tetra-tert-butyl-4,4'-dihydroxydibenzyl ether, 
octadecyl-4-hydroxy-3,5-dimethylbenzyl mercaptoacetate, 
tris(3,5-di-tert-butyl-4-hydroxybenzyl)amine, 
bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithioterephthalate, 
bis(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide, 
isooctyl-3,5-di-tert-butyl-4-hydroxybenzyl mercaptoacetate. 
1.7. Hydroxybenzylated malonates, for example 
dioctadecyl-2,2-bis(3,5-di-tert-butyl-2-hydroxybenzyl)malonate, 
di-octadecyl-2-(3-tert-butyl-4-hydroxy-5-methylbenzyl)-malonate, 
di-dodecylmercaptoethyl-2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate 
, di-[4-(1,1,3,3-tetramethylbutyl)-phenyl]-2,2-bis(3,5-di-tert-butyl-4-hydr 
oxybenzyl)malonate, 
1.8. Hydroxybenzyl aromatic compounds, for example 
1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene, 
1,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6-tetramethylbenzene, 
2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)phenol. 
1.9. Triazine compounds, for example 
2,4-bis-octylmercapto-6-(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazin 
e, 
2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine 
, 2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,3,5-triazin 
e, 2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,2,3-triazine, 
1,3,5-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, 
1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, 
2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenylethyl)-1,3,5-triazine, 
1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexahydro-1,3,5-tria 
zine, 1,3,5-tris(3,5-dicyclohexyl-4-hydroxybenzyl)isocyanurate. 
1.10. Benzyl phosphonates, for example 
dimethyl-2,5-di-tert-butyl-4-hydroxybenzyl phosphonate, 
diethyl-3,5-di-tert-butyl-4-hydroxybenzyl phosphonate, 
dioctadecyl-3,5-di-tert-butyl-4-hydroxybenzyl phosphonate, 
dioctadecyl-5-tert-butyl-4-hydroxy-3-methylbenzyl phosphonate, calcium 
salt of 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid monoethyl ester. 
1.11. Acylaminophenols, for example 4-hydroxylauric acid anilide, 
4-hydroxystearic acid anilide, 
N-(3,5-di-tert-butyl-4-hydroxyphenyl)-carbamic acid octyl ester. 
1.12. Esters of .beta.-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid 
with mono- or polyhydric alcohols, for example methanol, ethanol, 
octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 
1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene 
glycol, triethylene glycol, pentaerythritol, 
tris(hydroxyethyl)isocyanurate, N,N', bis-(hydroxyethyl)oxalic acid 
diamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, 
trimethylolpropane, 
4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]-octane. 
1.13. Esters of .beta.-(5-tert-butyl-4-hydroxy-3-methylphenyl)-propionic 
acid with mono- or poly-hydric alcohols, for example methanol, ethanol, 
octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 
1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene 
glycol, triethylene glycol, pentaerythritol, 
tris(hydroxyethyl)isocyanurate, N,N'-bis(hydroxethyl)oxalic acid diamide, 
3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, 
trimethylolopropane, 
4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane. 
1.14. Esters of .beta.-(3,5-dicyclohexyl-4-hydroxyphenyl)-propionic acid 
with mono- or polyhydric alcohols, for example methanol, ethanol, 
octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 
1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene 
glycol, triethylene glycol, pentaerythritol, 
tris(hydroxyethyl)isocyanurate, N,N'-bis-(hydroxyethyl)oxalic acid 
diamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, 
trimethylolpropane, 
4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane. 
1.15. Esters of 3,5-di-tert-butyl-4-hydroxyphenylacetic acid with mono- or 
poly-hydric alcohols, for example methanol, ethanol, octadecanol, 
1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, 
neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene 
glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, 
N,N'-bis-(hydroxyethyl)oxalic acid diamide, 3-thiaundecanol, 
3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 
4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane. 
1.16. Amides of .beta.-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid, 
for example 
N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamine, 
N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine. 
2. UV absorbers and light-stabilisers 
2.1. 2-(2'-hydroxyphenyl)-benzotriazoles, for example 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-, 
3',5'-bis(.alpha.,.alpha.-dimethylbenzyl)-, mixture of 
5-chloro-3'-tert-butyl-5'-(2-octyloxycarbonylethyl)- and 
5-chloro-3'-tert-butyl-5'-[2-(2-ethylhexyloxy)-carbonylethyl]-, 
5-chloro-3'-tert-butyl-5'-(2-methoxycarbonylethyl)-, 
3'-tert-butyl-5'-(2-methoxycarbonylethyl)-, 
3'-tert-butyl-5'-(2-octyloxycarbonylethyl)-, 
3'-tert-butyl-5'-[2-(2-ethylhexyloxy)-carbonylethyl]-, 
3'-dodecyl-5'-methyl-and 
3'-tert-butyl-5'-(2-isooctyloxycarbonylethyl)-2'-hydroxyphenyl-2H-benzotri 
azole(2), 
2,2'-methylene-bis[4-(1,1,3,3-tetramethylbutyl)-6-benzotriazol-2-yl-phenol 
]; transesterification product of 
2-[3'-tert-butyl-5'-(2-methoxycarbonylethyl)-2'-hydroxy-phenyl]-2H-benzotr 
iazole with polyethylene glycol 300; [R-CH.sub.2 CH.sub.2 
-COO(CH.sub.2).sub.3 ].sub.2, wherein 
R=3'-tert-butyl-4'-hydroxy-5'-2H-benzotriazol-2-yl-phenyl. 
2.2. 2-hydroxybenzophenones, for example the 4-hydroxy, 4-methoxy, 
4-octoxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy, 4,2',4'-trihydroxy or 
2'-hydroxy-4,4'-dimethoxy derivative. 
2.3. Esters of unsubstituted or substituted benzoic acids, for example 
4-tert-butyl-phenyl salicylate, phenyl salicylate, octylphenyl salicylate, 
dibenzoylresorcinol, bis(4-tert-butylbenzoyl)resorcinol, 
benzoylresorcinol, 3,5-di-tert-butyl-4-hydroxybenzoic acid 
2,4-di-tert-butylphenyl ester, 3,5-di-tert-butyl-4-hydroxybenzoic acid 
hexadecyl ester, 3,5-di-tert-butyl-4-hydroxybenzoic acid octadecyl ester, 
3,5-di-tert-butyl-4-hydroxybenzoic acid 2-methyl-4,6-di-tert-butylphenyl 
ester. 
2.4. Acrylates, for example .alpha.-cyano-.beta.,.beta.-diphenylacrylic 
acid ethyl ester or isooctyl ester, .alpha.-carbomethoxy-cinnamic acid 
methyl ester, .alpha.-cyano-.beta.-methyl-p-methoxy-cinnamic acid methyl 
ester or butyl ester, .alpha.-carbomethoxy-p-methoxy-cinnamic acid methyl 
ester, N-(.beta.-carbomethoxy-.beta.-cyanovinyl)-2-methyl-indoline. 
2.5. Nickel compounds, for example nickel complexes of 
2,2'-thio-bis[4-(1,1,3,3-tetramethylbutyl)phenol], such as the 1:1 or the 
1:2 complex, where appropriate with additional ligands, such as 
n-butylamine, triethanolamine or N-cyclohexyl-diethanolamine, nickel 
dibutyl dithiocarbamate, nickel salts of 4-hydroxy-3,5-di-tert-butyl 
benzyl phosphonic acid monoalkyl esters, such as the methyl ester or the 
ethyl ester, nickel complexes of ketoximes, such as 
2-hydroxy-4-methyl-phenyl-undecyl ketoxime, nickel complexes of 
1-phenyl-4-lauroyl-5-hydroxy-pyrazole, where appropriate with additional 
ligands. 
2.6. Sterically hindered amines, for example 
bis(2,2,6,6-tetramethyl-piperidyl)sebacate, 
bis(2,2,6,6-tetramethyl-piperidyl)succinate, 
bis(1,2,2,6,6-pentamethylpiperidyl)sebacate, 
n-butyl-3,5-di-tert-butyl-4-hydroxybenzyl-malonic acid 
bis(1,2,2,6,6-pentamethylpiperidyl) ester, condensation product of 
1-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinic acid, 
condensation product of 
N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 
4-tert-octylamino-2,6-dichloro-1,3,5-s-triazine, 
tris(2,2,6,6-tetramethyl-4-piperidyl)nitrilotriacetate, 
tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetraoate, 
1,1'-(1,2-ethanediyl)-bis(3,3,5,5-tetramethylpiperazinone), 
4-benzoyl-2,2,6,6-tetramethylpiperidine, 
4-stearyloxy-2,2,6,6-tetramethylpiperidine, 
bis(1,2,2,6,6-pentamethylpiperidyl)-2-n-butyl-2-(2-hydroxy-3,5-di-tert-but 
yl benzyl)-malonate, 
3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione, 
bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)sebacate, 
bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)succinate, condensation 
product of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine 
and 4-morpholino-2,6-dichloro-1,3,5-triazine, condensation product of 
2-chloro-4,6-di-(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)-1,3,5-triazi 
ne and 1,2-bis(3-aminopropylamino)ethane, condensation product of 
2-chloro-4,6-di-(4-n-butylamino-1,2,2,6,6-pentamethylpiperidyl)-1,3,5-tria 
zine and 1,2-bis(3-aminopropylamino)ethane, 
8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-di 
one, 3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidyl)pyrrolidine-2,5-dione, 
3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperidyl)-pyrrolidine-2,5-dione. 
2.7. Oxalic acid diamides, for example 4,4'-di-octyloxy-oxanilide, 
2,2'-di-octyloxy-5,5'-tert-butyl oxanilide, 
2,2'-di-dodecyloxy-5,5'-di-tert-butyl oxanilide, 2-ethoxy-2'-ethyl 
oxanilide, N,N'-bis(3-dimethylaminopropyl)oxalamide, 
2-ethoxy-5-tert-butyl-2'-ethyl oxanilide and a mixture thereof with 
2-ethoxy-2'-ethyl-5,4'-di-tert-butyl oxanilide, mixtures of o- and 
p-methoxy-disubstituted and of o- and p-ethoxy-disubstituted oxanilides. 
2.8. Further 2-(2-hydroxyphenyl)-1,3,5-triazines, for example 
2,4,6-tris(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine, 
2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 
2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 
2,4-bis(2-hydroxy-4-propoxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazine, 
2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(4-methylphenyl)-1,3,5-triazine, 
2-(2-hydroxy-4-dodecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin 
e, 
2-[2-hydroxy-4-(2-hydroxy-3-butoxy-propoxy)phenyl]-4,6-bis(2,4-dimethylphe 
nyl)-1,3,5-triazine, 
2-[2-hydroxy-4-(2-hydroxy-3-octyloxy-propoxy)phenyl]-4,6-bis-(2,4-dimethyl 
phenyl)-1,3,5-triazine. 
3. Metal deactivators, for example N,N'-diphenyloxalic acid diamide, 
N-salicylal-N'-salicyloylhydrazine, N,N'-bis(salicyloyl)hydrazine, 
N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine, 
3-salicyloylamino-1,2,4-triazole, bis(benzylidene)oxalic acid dihydrazide, 
oxanilide, isophthalic acid dihydrazide, sebacic acid bisphenylhydrazide, 
N,N'-diacetal-adipic acid dihydrazide, N,N'-bis-salicyloyl-oxalic acid 
dihydrazide, N,N'-bis-salicyloyl-thiopropionic acid dihydrazide. 
4. Phosphites and phosphonites, for example triphenyl phosphite, 
diphenylalkyl phosphites, phenyldialkyl phosphites, 
tris(nonylphenyl)phosphite, trilauryl phosphite, trioctadecyl phosphite, 
distearylpentaerythritol diphosphite, 
tris(2,4-di-tert-butylphenyl)phosphite, diisodecylpentaerythritol 
diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, 
bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 
bisisodecyloxypentaerythritol diphosphite, 
bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritol diphosphite, 
bis(2,4,6-tert-butylphenyl)pentaerythritol diphosphite, tristearylsorbitol 
triphosphite, tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene 
diphosphonite, 
6-isooctyloxy-2,4,8,10-tetra-tert-butyl-12H-dibenz[d,g]-1,3,2-dioxaphospho 
cine, 
6-fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenz[d,g]-1,3,2-dioxaphosph 
ocine. 
5. Peroxide-destroying compounds, for example esters of 
.beta.-thio-dipropionic acid, for example the lauryl, stearyl, myristyl or 
tridecyl ester, mercaptobenzimidazole, the zinc salt of 
2-mercaptobenzimidazole, zinc dibutyl dithiocarbamate, dioctadecyl 
disulfide, pentaerythritol tetrakis(.beta.-dodecylmercapto)propionate. 
6. Polyamide stabilisers, for example copper salts in combination with 
iodides and/or phosphorus compounds and salts of divalent manganese. 
7. Basic co-stabilisers, for example melamine, polyvinylprrrolidone, 
dicyandiamide, triallyl cyanurate, urea derivatives, hydrazine 
derivatives, amines, polyamides, polyurethanes, alkali metal and alkaline 
earth metal salts of higher fatty acids, for example calcium stearate, 
zinc stearate, magnesium behenate, magnesium stearate, sodium ricinoleate, 
potassium palmitate, antimony pyrocatecholate or stannic pyrocatecholate. 
8. Nucleation agents, for example 4-tert-butylbenzoic acid, adipic acid, 
diphenylacetic acid. 
9. Fillers and thickeners, for example calcium carbonate, silicates, glass 
fibres, asbestos, talcum, kaolin, mica, barium sulfate, metal oxides and 
hydroxides, carbon black, graphite. 
10. Other additives, for example plasticisers, lubricants, emulsifiers, 
pigments, optical brighteners, flame-retardants, antistatic agents, 
blowing agents. 
The addition of the stabiliser and, where appropriate, further additives to 
the polymer is advantageously effected before the shaping, for example by 
mixing the pulverulent components or by adding the stabiliser to the melt 
or solution of the polymer. 
The invention therefore relates also to a method for stabilising 
thermoplastic polymers that comprise hetero atoms in the main chain 
against damage by light, oxygen and heat, which method comprises adding to 
the polymers as stabiliser at least one compound of formula I, and to the 
use of compounds of formula I for stabilising thermoplastic polymers that 
comprise hetero atoms in the main chain against damage by light, oxygen 
and heat. 
The resulting stabilised polymer compositions can be converted in 
accordance with customary methods, for example hot compression moulding, 
spinning, extruding or injection moulding, into shaped articles, for 
example fibres, films, small strips, sheets, profiled sheets, vessels, 
pipes and other profiles. 
The invention therefore relates also to the use of the polymer composition 
according to the invention for the preparation of a shaped article. 
Also of interest is the use of the polymer composition according to the 
invention is multilayer systems. In that case a polymer composition 
according to the invention having a relatively high content of stabiliser 
of formula I, for example 5-15% by weight, is applied in a thin layer 
(10-100 .mu.m) to a shaped article made from a polymer that comprises 
little or no stabiliser of formula I. The layer can be applied 
simultaneously with the shaping of the basic article, for example by means 
of so-called co-extrusion. The layer can, however, also be applied to the 
ready-shaped basic article, for example by means of lamination with a film 
or coating with a solution. The outer layer or layers of the finished 
article act as a UV filter which protects the interior of the article 
against UV light. The outer layer preferably comprises 5-15% by weight, 
especially 5-10% by weight, of at least one stabiliser of formula I. 
The invention therefore relates further to the use of the polymer 
composition according to the invention for the preparation of multi-layer 
systems, wherein the outer layer(s) is(are) a polymer composition 
according to the invention in a thickness of 10-100 .mu.m, while the inner 
layer consists of a polymer that may comprise little or no stabiliser of 
formula I. 
Of especial interest is the use of a polymer composition according to the 
invention wherein component (a) is a polycarbonate for the preparation of 
multi-layer systems. 
The polymers stabilised in that manner are distinguished by good fastness 
to weathering, and especially by a high degree of resistance to UV light. 
For that reason they retain their mechanical properties and their colour 
and lustre over a long period of time, even when used outside.

The Examples that follow serve to illustrate the invention in detail, 
without limiting it thereto. In the Examples parts and percentages are by 
weight; room temperature denotes a temperature from 20.degree. to 
25.degree. C. The following UV absorbers are used: 
Ph-1: 2,4-diphenyl-6-(2-hydroxy-4-propoxyphenyl)-1,3,5-triazine; 
Ph-2: 2,4-diphenyl-6-(2-hydroxy-4-benzyloxyphenyl)-1,3,5-triazine; 
Ph-3: 2,4-diphenyl-6-(2-hydroxy-4-butoxyphenyl)-1,3,5-triazine; 
Ph-4: 2,4-diphenyl-6-(2-hydroxy-4-hexyloxyphenyl)-1,3,5-triazine; 
Ph-5: 2,4-diphenyl-6-(2-hydroxy-4-methoxyphenyl)-1,3,5-triazine; 
To-1: 2,4-di-p-tolyl-6-(2-hydroxy-4-propoxyphenyl)-1,3,5-triazine; 
To-2: 2,4-di-p-tolyl-6-(2-hydroxy-4-benzyloxyphenyl)-1,3,5-triazine; 
To-3: 2,4-di-p-tolyl-6-(2-hydroxy-4-butoxyphenyl)-1,3,5-triazine; 
To-4: 2,4-di-p-tolyl-6-(2-hydroxy-4-hexyloxyphenyl)-1,3,5-triazine; 
To-5: 2,4-di-p-tolyl-6-(2-hydroxy-4-methoxyphenyl)-1,3,5-triazine; 
Xy-1: 
2,4-di(2,4-dimethylphenyl)-6-(2-hydroxy-4-propoxyphenyl)-1,3,5-triazine 
(comparison); 
Xy-2: 
2,4-di(2,4-dimethylphenyl)-6-(2-hydroxy-4-benzyloxyphenyl)-1,3,5-triazine 
(comparison); 
Xy-3: 
2,4-di(2,4-dimethylphenyl)-6-(2-hydroxy-4-butoxyphenyl)-1,3,5-triazine (co 
mparison); 
Xy-4: 
2,4-di(2,4-dimethylphenyl)-6-(2-hydroxy-4-hexyloxyphenyl)-1,3,5-triazine 
(comparison); 
Xy-5: 
2,4-di(2,4-dimethylphenyl)-6-(2-hydroxy-4-methoxyphenyl)-1,3,5-triazine 
(comparison). 
EXAMPLE 1 
With stirring at room temperature, 10 g of polycarbonate powder (Lexan.RTM. 
115) are dissolved in 50 g of methylene chloride, which takes several 
hours. 0.1 g, 0.2 g or 0.5 g of UV absorber, corresponding to additive 
concentrations of 1,2 and 5%, are added thereto. Films 20 .mu.m thick are 
cast from those solutions. 
The films are exposed in an Atlas Weatherometer CI 65 at a black panel 
temperature of 63.degree. C. and a relative humidity of 60%. At regular 
intervals the discolouration of the samples is tested by measuring the 
Yellowness Index (YI, ASTM D 1925 method). The exposure time required to 
reach a Yellowness Index of 7 is shown in Table 1. 
The films are then exposed further until they become brittle; this is 
indicated by the formation of cracks in the films. The exposure time 
required for the films to become brittle is also shown in Table 1. 
TABLE 1 
______________________________________ 
Exposure time (h) required to reach a Yellowness 
Index (YI) = 7 and for the films to become brittle 
Exposure time (h) until 
UV absorber YI = 7 films are brittle 
______________________________________ 
none 990 1100 
1% Xy-1 1700 3900 
1% Ph-1 2200 4100 
1% To-1 2100 4020 
2% Xy-1 1800 4500 
2% Ph-1 2300 7740 
2% To-1 2100 6680 
5% Xy-1 1900 6000 
5% Ph-1 5700 10990 
5% To-1 4000 10990 
______________________________________ 
EXAMPLE 2 
Films prepared in accordance with the instructions given in Example 1 are 
aged in a circulating-air furnace at 140.degree. C. As in Example 1 the 
ageing time required to reach a Yellowness Index of 7 and the time 
required for the films to become brittle are measured. 
Table 2 shows the results obtained. 
TABLE 2 
______________________________________ 
Ageing time (h) required to reach a Yellowness Index 
(YI) = 7 and for the films to become brittle 
Time in hours at 140.degree. C. until 
UV absorber YI = 7 films are brittle 
______________________________________ 
1% Xy-1 500 2100 
1% Ph-1 3250 3250 
1% To-1 2440 2900 
2% Xy-1 300 1500 
2% Ph-1 3350 3350 
2% To-1 1300 2350 
5% Xy-1 120 700 
5% Ph-1 2940 3000 
5% To-1 1150 1700 
______________________________________ 
EXAMPLE 3 
Polycarbonate powder is mixed with 0.3% of different UV absorbers and 
processed in a double screw extruder at a mass temperature of 275.degree. 
C. and at 25 rpm to form granules. 
The granules are processed on an injection-moulding machine 
(240.degree./300.degree. C./75 bar) to form sheets measuring 
67.times.43.times.2 mm. The sheets are exposed in an Atlas Weatherometer 
CI 65 as in Example 1. Table 3 indicates the exposure time required to 
reach a Yellowness Index of 25 (YI measured in accordance with ASTM 
D-1925). 
TABLE 3 
______________________________________ 
Exposure time (h) required to reach a 
Yellowness Index (YI) = 25 
Exposure time (h) 
UV absorber until YI = 25 
______________________________________ 
none 900 
0.3% Xy-1 2700 
0.3% Ph-1 3500 
0.3% To-1 3100 
______________________________________ 
EXAMPLE 4 
Polycarbonate films comprising 2% by weight of UV absorber are prepared and 
exposed in accordance with the method given in Example 1. Table 4 
indicates the exposure time after which a Yellowness Index of 7 has been 
reached. 
The films are then exposed further until they become brittle. The exposure 
time required for this is likewise given in Table 4. 
TABLE 4 
______________________________________ 
Exposure time (h) required to reach a Yellowness 
Index (YI) = 7 and for the films to become brittle 
Exposure time (h) until 
UV absorber YI = 7 films become brittle 
______________________________________ 
none 990 1100 
2% Ph-2 2480 8040 
2% Ph-3 2560 5900 
2% Ph-4 2560 5550 
2% Ph-5 2690 7540 
2% To-2 2270 5900 
2% To-3 2400 5550 
2% To-4 2375 5060 
2% Xy-2 1850 3900 
2% Xy-3 1860 3900 
2% Xy-4 1950 3900 
______________________________________ 
EXAMPLE 5 
Films prepared in accordance with the instructions given in Example 4 are 
aged in a circulating-air furnace at 130.degree. C. As in the Example 
referred to, the ageing time required to reach a Yellowness Index of 7 and 
the time required for the films to become brittle are measured. 
Table 5 shows the results obtained. 
TABLE 5 
______________________________________ 
Ageing time (h) required to reach a Yellowness Index 
(YI) = 7 and for the films to become brittle 
Time in hours at 130.degree. C. until 
UV absorber YI = 7 films become brittle 
______________________________________ 
2% Ph-2 1840 7000 
2% Ph-3 5030 7000 
2% Ph-4 4170 7000 
2% Ph-5 5580 8000 
2% To-2 2460 4720 
2% To-3 2790 4720 
2% To-4 2750 4720 
2% Xy-2 750 3030 
2% Xy-3 790 2530 
2% Xy-4 820 3030 
______________________________________ 
EXAMPLE 6 
Polycarbonate films comprising 2% by weight of UV absorber are prepared and 
exposed as described in Example 1. At regular intervals the tensile 
strength of the films is measured at room temperature (cross-speed 20 
mm/min, dumb-bell according to DIN 53448/1, width of sample 10 mm, 
thickness of sample 20 .mu.m). Table 6 shows the exposure time after which 
only 50% of the original tensile strength has been reached. 
TABLE 6 
______________________________________ 
Exposure time (h) 
UV absorber until 50% tensile strength 
______________________________________ 
none 690 
2% Xy-1 1420 
2% Ph-1 1670 
2% To-1 1860 
______________________________________ 
EXAMPLE 7 
3 kg of polybutylene terephthalate powder (Crastin.RTM. S 600) are mixed 
dry for 2 minutes in a Henschel mixer with each of 0.1% by weight of 
pentaerythritol 
tetrakis(3-[3',5'-di-tert-butyl-4'-hydroxyphenyl]-propionate), 0.4% by 
weight tris(2,4-di-tert-butylphenyl)phosphite and 0.5% by weight of the UV 
absorber shown in Table 7 and then processed to form granules in a 
Berstorff double screw extruder at a speed of 100/min and at a temperature 
setting of 230.degree. C./240.degree. C./250.degree. C./250.degree. C. 
Using an injection-moulding apparatus (type Arburg L, material temperature 
260.degree. C., tool temperature 70.degree. C.), sheets measuring 67 
mm.times.43 mm and having a thickness of 1 mm are made from each mixture. 
After being stored for 30 days at room temperature, the sheets are exposed 
in an Atlas Weatherometer CI 65 at a black panel temperature of 63.degree. 
C. and a relative humidity of 60%, a rain cycle of 102 min dry/18 min wet 
being set. At regular intervals the discolouration of the samples is 
tested by measuring the Yellowness Index (YI, ASTM D 1925 method). Table 7 
shows the exposure time in which an increase in the Yellowness Index of 
.DELTA.YI=10 takes place. 
TABLE 7 
______________________________________ 
Exposure time (h) 
UV absorber until 6YI = 10 
______________________________________ 
0.5% Xy-1 1520 
0.5% To-1 2850 
0.5% Ph-1 3130 
______________________________________ 
EXAMPLE 8 
Polyamide-6 powder (Ultramid.RTM. B3S, manufactured by BASF) is mixed dry 
for 2 minutes in a Henschel mixer with the stabilisers shown in Table 8 
and then processed in a Berstorff double screw extruder at a speed of 
95/min and a temperature setting of 230.degree. C./235.degree. 
C./240.degree. C./240.degree. C. The amounts of stabiliser are given in % 
by weight, based on the amount of polyamide used. Sheets 2 mm thick are 
prepared from each mixture using an injection-moulding apparatus (type 
Arburg L, material temperature 240.degree. C., tool temperature 80.degree. 
C.). 
The sheets are exposed in an Atlas Weatherometer CI 65 at a black panel 
temperature of 63.degree. C. and a relative humidity of 60%, a rain cycle 
of 102 min dry/18 min wet being set. The time required for the cracks on 
the sheets to become visible is measured. The results of the measurements 
are shown in Table 8. 
In addition to the stabilisers according to the invention mentioned above, 
the following additional stabilisers are used: 
N,N'-bis(3-[3',5'-di-tert-butyl-4'-hydroxyphenyl]-propionyl)hexamethylened 
iamine, 
B tris(2,4-di-tert-butyl phenyl)phosphite, 
C condensation product of 
N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 
4-tert-octylamino-2,6-dichloro-1,3,5-s-triazine having a melting point of 
120.degree.-150.degree. C. 
TABLE 8 
______________________________________ 
Time (h) required for cracks to appear 
Stabilisers time (h) 
______________________________________ 
none 1050 
0.2% A + 0.2% B 2620 
0.2% A + 0.2% B + 0.3% Xy-1 
2950 
0.2% A + 0.2% B + 0.3% To-1 
3320 
0.2% A + 0.2% B + 0.3% Ph-1 
3930 
0.2% A + 0.2% B + 0.3% Xy-1 + 0.3% C 
5900 
0.2% A + 0.2% B + 0.3% To-1 + 0.3% C 
6200 
0.2% A + 0.2% B + 0.3% Ph-1 + 0.3% C 
&gt;6200 
______________________________________ 
EXAMPLE 9 
Polyoxymethylene (Hostaform.RTM. C) is kneaded for 7 minutes at 190.degree. 
C. and 30 rpm in a Brabender Plasticorder with each of 0.3% by weight of 
calcium stearate, 0.3% by weight of a stabiliser of the formula 
##STR6## 
and 0.3% by weight of the UV absorber given in Table 9. The material is 
then compressed at 190.degree. C. under a pressure of 3000 psi to form 
sheets 1 mm thick; the processing time in this step is 3 minutes. 
The sheets are exposed at 60.degree. C. and a humidity of 23% to a UV-A 
source at a distance of 20 cm. The UV-A source comprises 5 TL/09 
fluorescent lamps and 5 TL/12 lamps (wave-length range 295-400 nm). At 
regular intervals the Yellowness Index (YI, ASTM D 1925 method), which 
passes through a maximum in the case of UV exposure of polyoxymethylene, 
is measured. That maximum is caused by a first occurrence of micro-cracks 
that are not yet visible. On further exposure, at a later point in time 
cracks in the sheets can be seen. Table 9 shows the exposure times in 
weeks required to reach the maximum of the Yellowness Index and for 
visible cracks to appear. 
TABLE 9 
______________________________________ 
Exposure time in weeks to YI maximum and to the appearance 
of visible cracks in the test sheets 
Exposure time (weeks) to 
UV absorber YI maximum crack formation 
______________________________________ 
0.3% Xy-5 8 16 
0.3% To-5 10 20 
0.3% Ph-5 16 25 
______________________________________ 
The test results shown in Examples 1-9 show markedly improved properties 
when using the stabilisers according to the invention (diphenyl- and 
di-p-tolyl derivatives of 1,3,5-triazine) as compared with the known 
dixylyl derivatives.