CA1056095A - Synthetic polymers with 4,4'-dihydroxy-2,2,6,6,2',2',6',6',-octamethyl-4,4'-bipiperidyl derivatives - Google Patents

Abstract

ABSTRACT

Stabilization of synthetic polymers, such as polyolefins, by substituted bipiperidyl derivatives of formula:

Description

r ~

10561D~5 l The present invention relates to the stabi~ization of synthetic polymers against photo- and thermal-deterioration by the use of substituted bipiperidyl compounds.
i Synthetic polymers are widely used in various forms, for example as filaments, fibres, yarns, films, sheets, other moulded forms, latexes and foams. However, they sometimes suffer from poor thermal- and photo-stability and, although various stabilizers have been used in the past to overcome these difficulties, some problems still remain, and there is still a need for effective stabilizers.

Several 4, 4'-dihydroxy-4, 4'-bipiperidyl derivatives have been de~cribed in J. Org. Chem., 27, 1695 (1962) and are said to have pharmaceutical utility, but they have not previously been described as polymer stabilizers.

We have now discovered that certain bipiperidyl derivatives are unexpectedly effective as stabilizers for synthetic polymers, especially against photo- and thermal-degradation.

In accordance with the present invention, synthetic polymers are stabilized against photo- and thermal-deterioration by the addition of at least one of the bipiperidyl derivatives having the formula~

. , 1(~56095 3 >~

Y ~ O/~N--B' (I) wherein R and R' may be the same or different and each represents a hydrogen atom, an aLkyl group, an alkenyl group, an alkynyl group, an aralkyl group, a hydroxyalkyl group, an alkoxyalkyl group, an aliphatic or aromatic acyloxyalkyl group, a cyanoalkyl group, a halo-alkyl group, an epoxyalkyl group, an alkoxycarbonylalkyl group, an aliphatic acyl group, an alkoxycarbonyl group, or an aralkoxycarbonyl group, or an acid addition salt of said bipiperidyl derivative.

In formula (I), R and R' may each be, for example: a hydrogen atom; an alkyl group having from 1 to 8, preferably from 1 to 4, carbon atoms, such as a methyl, ethyl, propyl, butyl or octyl group;
an alkenyl group having from 3 to 6 carbon atoms, such as an allyl, crotyl or 2-hexenyl group, of which the allyl group is most preferred;
an alkynyl group having 3 or 4 carbon atoms, preferably a 2~propynyl group; an aralkyl group having 6 carbon atoms in the aryl moiety and 1 or 2 carbon atoms in the alkyl moiety, such as a benzyl or phenethyl group; a hydroxyalkyl group having from 1 to 4 carbon atoms, preferably a 2-hydroxyethyl group; an alkoxyallcyl group having from 1 to 8, J
,...... ~ . . , .; .

~05609S

preferably from 1 to 4, carbon atoms in the alkoxy moiety and from 1 to 4, preferably 1 or 2, carbon atoms in the alkyl moiety, such as a 2 ethoxyethyl, ethoxymethyl, 2-propoxyethyl or 3-methoxypropyl group; an aliphatic acyloxyalkyl group, in which the acyl moiety is il either saturated and has from 2 to 18 carbon atoms or is unsaturated and has from 3 to 6 carbon atoms and the alkyl moiety has from 1 to 4, preferably 2, carbon atoms, such as a 2-acetoxyethyl, 2-stearoyloxy-ethyl, 2-acryloyloxyethyl, 2-methacryloyloxyethyl, 2-crotonoyloxyethyl or 2-sorboyloxyethyl group; an aromatic acyloxyalkyl group (whose aromatic ring may be unsubstituted or may have from 1 to 3 substituents which are alkyl groups having from 1 to 4 carbon atoms and/or hydroxy groups, and whose alkyl moiety has from 1 to 4, preferably 2, carbon atoms), preferably a substituted or unsubstituted benzoy].oxyalkyl group, such as a 2-benzoyloxyethyl, 2-(p-t-butylben~oylo~y)-eth~,rl or

2-salicyloyloxyethyl group; a cyanoalkyl group having 2 or 3 carbGn atoms, such as a 2-cyanoethyl or cy-~nomethyl group; a haloalkyl group having from 1 to 3 carbon atoms, such as a 2-chloroethyl group; an epoxyalkyl group, preferably a 2, 3-epoxypropyl group; an alkoxy-carbonylalkyl group having from 1 to 18, preferably from 1 to 8, 2p carbon atoms in the alkoxy moiety and 1 or 2 carbon atoms in the alkyl moiety, such as an ethoxycarbonylmethyl, butoxycarbonylmethyl, hexylo~fycarbonylmethyl or octyloxycarbonylmethyl group; an aliphatic acyl grGup which, if saturated, has from 2 to 8 carbon atoms or, if unsaturated, as is preferred, has 3 or 4 carbon atoms, such as an .
~, l~S6~95 acetyl, propionyl, butyryl, acryloyl or methacryloyl group; an alkoxy-carbonyl group having from 2 to 9 carbon atoms, such as a methoxy-carbonyl, butoxycarbonyl or octyloxycarbonyl group; or an aralkoxy-carbonyl group, preferably a benzyloxycarbonyl group.

In the acid addition salts of compounds of formula (I), the acid may be, for example, an organic acid, such as benzoic acid, p-t-butylbenzoic acid, 3, 5-di-t-butyl-4-hydroxyphenylpropionic acid, maleic acid, oxalic acid, acetic acid, methylsulphonic acid, or p-toluene--sulphonic acid, or an inorganic acid, such as sulphuric acid, phosphoric acid or hydrochloric acid In the bipiperidyl compounds of formula (I) used as stabilizers in the present invention, we prefer that both R and R' should represent:
a hydrogen atom; an aLkyl group having from 1 to 4 carbon atomC; an allyl group; a benzyl group; an alkoxyalkyl group having from 1 to 4 carbon atoms in the alkoxy moiety and 1 or 2 carbon atoms in the alkyl .
moiety; an aliphatic acyloxyethyl group, in which the acyl moiety, if saturated, has from 2 to 18 carbon atoms or, if unsaturated, has from

3 to 6 carbon atoms; abenzoyloxyetHgroup, whose benzene ring may be unsubstituted or may have from 1 to 3 substituents which are alkyl groups having from 1 to 4 carbon atoms and/or hydroxy groups; or an alkoxycarbonylmethyl group having from 1 to 8 carbon atom~ in the alkoxy moiety, _ 4 --~, It is particularly preferred that R and R' should each represent: a hydrogen atom; an alkyl group having from 1 to 4 carbon atoms; an allyl group; a benzyl group; or an alkoxycarbonylmethyl group having from 1 to 8 carbon atoms in the alkoxy moiety.

The following is a non-limiting list of individual preferred compounds of formula (I). The numbers appended to the compounds in the list will be used to identify them hereinafter in the Examples.

1) 4, 4'-dihydroxy-2,2.6, 6, 2', 2', 6', 6'-octamethyl-4, 4'-bipiperidyl 2) 4, 4'-dihydroxy-1, 2, 2, 6, 6,1', 2', 2', 6', 6'-decamethyl-

4, 4'_bipiperidyl 3) 4, 4'-dihydroxy-2, 2, 6, 6, 2', 2', 6', 6'-octamethyl-1, 1'-dioctyl-4, 4'-bipiperidyl 4) 1,1'-diallyl-4J 4'-dihydroxy-2, 2, 6, 6, 2', 2', 6', 6'-octamethyl-4, 4'-bipiperidyl ., I

5) 4, 4'-dihydroxy-2, 2,6, 6, 2', 2', 6', 6'-octamethyl-1, 1'-~ di( 2-propynyl)-4, 4' -bipiperidyl

6) 1, 1'-dibenzyl-4, 4'-dihydroxy-2, 2, 6, 6, 2', 2', 6', 6'-octamethyl-4, 4'-bipiperidyl '

7) 4, 4'-dihydroxy-1, 1'-bis(2-hydroxyethyl)-2, 2, 6, 6, 2', 2', 6', 6'-octamethyl-4, 4'-bipiperidyl ~D

8) 1, 1'-bis(2-ethoxyethyl)-4, 4'-dihydrcxy-2, 2, 6, 6, 2', 2', 6', 6'-octamethyl-4, 4' -bipiperidyl \

~5~;09~

9) 1,1'-bis(2-acetoxyethyl)-4, 4'-dihydroxy-2, 2, 6, 6, 2', 2', 6', 6'-octamethyl-4, 4'-bipiperid~l

10) 4, 4'-dihydroxy-2, 2, 6, 6, 2', 2', 6', 6'-octamethyl-1, 1'~
bis~2-stearoyloxyethyl)-4, 4'-bipiperidyl

11) 1,1'-bis(2-acryloyloxyethyl)-4, 4'-dihydroxy-2, 2, 6, 6,2', 2', 6', 6'-octamethyl-4, 4'-bipiperidyl

12) 4, 4'-dihydroxy-1, 1'-bis(2-methacryloyloxyethyl)-: 2, 2, 6, 6, 2', 2', 6', 6'-octamethyl-4, 4'-bipiperidyl

13) 1J l'-bis(2-crotonoyloxyethyl)-4, 4'-dihydroxy-2, 2, 6, 6, 2', 2', 6', 6'-octamethyl-4, 4'-bipiperidyl

14) 4, 4'-dihydroxy-2, 2, 6, 6, 2', 2', 6', 6'-octamethyl-1, 1'-bis(2-sorboyloxyethyl)-4, 4'-bipiperidyl

15) 1,1'-bis(2-benzoyloxyethyl)-4, 4'-dihydroxy-2, 2, 6, 6, 2', 2', 6', 6'-octamethyl-4, 4'-bipiperidyl

16) 1, 1'-bis(2-p-t-butylbenzoyloxyethyl)-4, 4'-dihydroxy-2, 2, 6, 6, 2', 2', 6', 6'-octamethyl-4, 4'-bipiperidyl

17) 4, 4'-dihydroxy-2, 2, 6, 6, 2', 2', 6', 6'-octamethyl-l, 1'-bis (2-salicyloyloxyethyl)-4, 4'-bipiperidyl

18) 1,1'-bis(cyanomethyl)-4, 4'-dihydroxy-2, 2, 6, 6, 2', 2', 6', 6'-!! 20 octamethyl-4, 4'-bipiperidyl

19) 1, l'~bis(2-chloroethyl)-4, 4'-dihydroxy-2, 2, 6, 6, 2', 2', 6', 6'-octamethyl-4, 4'-bipiperidyl

20) 1,1'-bis(2, 3-epoxypropyl)-4, 4'-dihydroxy-2, 2, 6, 6, 2', 2', 6', 6'-octamethyl-4, 4'-bipiperidyl . - 6 -~0560~5

21 ) 1, 1 ' - bis( ethoxycarbonylm ethyl) - 4, 4 ' - dihydroxy-2, 2, 6, 6, 2', 2', 6', 6'-octamethyl-4, 4'-bipiperidyl

22) 4, 4'-dihydroxy-2, 2, 6, 6, 2', 2', 6', 6'-octamethyl-1, 1 ' -bis( octyloxycarbonylmethyl) - 4, 4' -bipiperidyl

23) 1-acetyl-4, 4'-dihydroxy-2, 2, 6, 6, 2', 2', 6', 6'-octamethyl-4, 4'-bipiperidyl

24) 1,1'-diacetyl-4, 4'-dihydroxy-2, 2, 6, 6, 2', 2', 6', 6'-octamethyl-4, 4'-bipiperidyl

25) 1,1'-diacryloyl-4, 4'-dihydroxy-2, 2, 6, 6, 2', 2', 6', 6'-octamethyl-4, 4' -bipiperidyl

26) 1,1'-bis(butoxycarbonyl)-4, 4'-dihydroxy-2, 2, 6, 6, 2', 2', 6', 6'-t octamethyl-4j 4' -bipiperidyl

27) 1, 1' -bis( benzyloxycarbonyl) -4, 4' -dihydroxy-2, 2, 6, 6, 2', 2', 6', 6'-octamethyl-4, 4'-bipiperidyl.

Of the bipiperidyl derivatives of formula (I) used in the present invention, those in which R and R' are the same and each represents a hydrogen atom or a methyl group have been described in J. Org. Chem., 27, 1695 (1962), referred to above. However~, the remaining compounds falling within formula (I) and their acid addition salts are novel and also form part of the present invention, .
The bipiperidyl derivatives of formula (I) can be synthesized by known methods, as summarized in the following reaction scheme:

' ' ~ ' - ` -10~i0~5 ~ ~NH~ N~NH

(II) (III) (IV) \ 2R-X ¦R'-~

R-N~N-R(R') R
(V) (~/I) in which R and R' are as defined above and X is a halogen atom.

If a compound of formula (III) is reacted with a halide (R-X) in the presence of an organic or inorganic base (which combines with the acid liberated during the reaction and thus effectively removes it from the reaction mixture), where equimolar quantities of compound (III) and halide are used, a compowld of formula (IV) is obtained; on the other hand, if the molar ratio of halide to compound (III) is about 2:1, then compounds of formula (VI) are obtai.ned. By a similar reaction, compounds of formula (VI) can be prepared from compounds of formula (IV) and this gives the possibility of producing compounds in which R and R' are different. A compound of formula (VI) in which R and R' are each a methyl group can also be obtained in good yield by ' .:

~56~95 reacting the compound of formula (III) with formic acid and formalin.
Moreover, a compound of formula (~TI) in which R and R' are each a 2-hydroxyethyl group can be prepared by reacting compound (III) with cthylene oxide in the presence of an acid.

However, we have found that compounds of formula (III) or (VI) can be prepared from compounds of formula (II) or (V), respectively, more advantageously than by the conventional method and in yields exceeding 80%, by heating the compound of formula (II) or (V) dissolved in a non-polar solvent with metallic sodium and an acid.
The compound of formula (II) or (V) IS first dissolved in the non-polar ~olvent, e.g. benzene, toluene or xylene, after which metallic sodium and an acid are added to cause the reaction. The metallic sodium is preferably employed in an amount of from 2 to 3 moles per mole of compound (II) or (V).

In this reaction, the presence of an acid is of particular importance, in order to increase the yield of the desired product. In general, in the abæence of an acid, synthesis of a pinacol compound from a ketone gives only low yields (:E3ull. Soc. Chim. France, 1946, 25~). The acid is preferably used in an amount of from 1 to 1. 2 moles per mole of metallic sodium. Examples of suitable acids are organic acids, such as acetic acid, benzoic acid and_-toluene-sulphonic acid, and inorganic acids, such as hydrogen chloride (gas).

_ g _ `~' ' .. . . . , . ... .. . .. , . . , .. .. ... _ . _ . _ . ., . .. , .. _ .. . ~ . _ .. ., .. . . _ . _ .. _ . _ .
. _ .. .. .

1~56~gS

l'he reaction temperature is not particularly critical, but we prefer that the reaction should be carried out at the boiling point of the solvcnt employed. In general, the reaction will go substantially to completion by heating at a temperature of from 50 to 100 C for a period of from 30 minutes to 5 hours. At the end o~ the reaction, the desired product may be recovered by conventional procedures; thus, for example, the reaction mixture may be filtered, the filtrate concentrated and residual crystals collected and, if necessary, purified by recrystallization.

Synthetic polymers which can be stabilized by means of the compounds of formula (I) or their acid addition salts include:
olefin, diene and styrene polymers .
including homopolymers of olefins, dienes and styrene (e.g. low and high density polyethylenes, polypropylene, polystyrene, poly~utadiene and polyisoprene), and copolymers of olefins, dienes and styrene with each other or with other ethylenically un~aturated monomers (e.g. ethylene/propylene copolymers, ethylene/butene copolymers, ethylene/vinyl acetate copolymers, styrene/
~utadiene copolymers and acrylonitrile/butadiene/styrene copolymers);
vinyl chloride and vinylidene chloride polymers including homopolymers of vinyl chloride and vinylidene , 1~56~95 chloride, vinyl chloride/vinylidene chloride copolymers, and copolymers of vinyl chloride or vinylidene chloride with vinyl acetate or with other ethylenically unsaturated monomers;
polyac etals e.g. polyoxymethylene and polyoxyethylene;
polyesters e . g . polyethylene terephthalate;
polyester ethers ~yamid es e.g. nylon-6, nylon-6,6, nylon-6,10, nylon-lOandnylon-12;
polyurethanes e,g, polyether polyurethanes and polyester polyurethanes;
polycarbonates epoxy resins e. g, react on products of epichlorhydrin witll polyphenols, Synthetic polymers stabili~ed by the compounds of formula (I) ' or their acid addition salts can be used in the manufacture of a wide variety of products, for example filaments, fibres, yarns, films, sheets, other moulded forms, latexes, foams and paints i The amount of bipiperidyl derivative of formula (I) or salt , thereof needed for effective stabilization of the synthetic polymer will '' `
' `\

- - -1~5~0~5 depend upon a variety of factors, such as the type and properties of the polymer concerned, its likely use, the likely duration and intensity of exposure to heat and light, and the presence of other stabilizers . However, it is generally satisfactory to use from 0 . 01%
to 5. 0% by weight of the bipiperidyl derivative or derivatives of formula (I) or their acid addition salts, based on the weight of the synthetic polymer. In practice, the amount used may vary within this range depending upon the type of synthetic polymer thus, for example, if the synthetic polymer is an olefin, diene or styrene polymer, the stabilizer is preferably used in an amount of from 0. 01 to 2. 0%
by weight, more preferably from 0. 02 to 1. 0% by weight, based on the weight of the polymer. In the case of a vinyl chloride or vinylidene chloride polymer, the amount of stabilizer is preferably from 0. 01 to ¦ 1. 0% by weight, more preferably from 0 . 02 to 0. 5% by weight and in the case of a polyurethane or polyamide, the amount of stabili7.er is ¦ preferably from 0. 01 to 5. 0% by weight, more preferably from 0. 02 to 2, 0% by weight.

The stabilizers of formula (I) and their acid addition salts can readily be incorporated with synthetic polymers by conventional techniques, at any convenient stage prior to the manufacture of shaped articles therefrom. For example, the stabilizer and the polymer can be compounded in a mixer, in dry form; or a solution or emulsion of the stabilizer in a suitable solvent or dispersant can be added to the ~056~95 powdered polymer, and the whole intimately mixed. As a further alternative, the stabilizer can be added during the preparation of the polymer, for instance at the latex stage of polymer production, to provide a pre-stabilized polymer material.

The bipiperidyl stabilizers of the present invention can be used alone or in combination with other conventional additives, such as antioxidants, UV-absorbers, metal deactivators, fillers or organic pigments. The bipiperidyl stabilizers of the present invention are particularly useful in combination with a UV-absorber in a polymer containing an organic pigment, since the reduction in light stabilization of the UV-absorber caused by the presence of the organic pigmer.t is prevented and thu~ particularly good results can be obtained.

, .
.

~ - 1 3 , . .

The stabilized synthetic polymer compositions of the ~-invention may optionally also contain various conventional additives, such as the following:- :
_ ioxidants_ Simple, 2,6-dialkylphenols, such as, for example 2,6-di-t-butyl-4 : :
-methylphenol, 2-t-butyl-4,6-dimethylphenol, 2,6-di-t-butyl-4 methoxymethylphenol and 2,6-dioctadecyl-4-methylphenol.

Derivati-~es of alkylated hydroquinones, such as for example, 2,5~di-t-butylhydroquinone, 2,5-ti-amylhydroquinone, 2,6-di-t -butylhydroquinone, 2,5-di-t-butyl-4-hydroxyanisole, 3,5-di-t-butyl-4-hydroxyanisole, tris(3,5-di-t-butyl-4-hydroxyphenyl) :~
phosphite, 3,5Tdi-t-butyl-4-hydroxyphenylstearate and di-(3, : s 5-di-t-butyl-4-hydroxyphenyl)adipate.

Hydroxylated thiodiphenyl ethers,such as, for example 2,2'-thiobis -(6,t-butyl-4-methylphenol), 2,2'-thiobis(4-octylphenol), 4,4'-thiobis(3,6-di-s-amylphenol), 4,4'-thiobis(6-t-butyl-2-methyl-phenol) and 4,4'-bis(2,6-dimethyl-4-hydroxyphenyl)disulphide.

~. , .
Alkylidene-bisphenols, such as, for example 2,2'-methylene-bis-: (6-t-butyl-4-methylphenol), 2,2'methylene-bis(6,t-butyl-4-ethyl-phenol), 4,4'methylene-bist6-t-butyl-2-methylphenol), 4,4'-methylene-bis-(2,6-di-t-butylphenol), 2,6-di-(3-t-butyl-5-~ methyl-2-hydroxybenzyl)-4-methylphenol, 2,2'methylene-bis ; [4-methyl-6-( a methylcyclohexyl)-.

'.

' -14- ~:

,~

phenol , l,l-bis(3,5-dimethyl-2 hydroxyphenyl)butane, l,l -bis(5-t-butyl-4-hydroxy-2-methylphenyl)butane, 2,2-bis (5-t-butyl-4-hydroxy-2-methylphenyl)butane, 2,2-bis(3,5-di-t-butyl-4-hydroxyphenol) propane, 1,1,3-tris(5-t-butyl-4-hydroxy-2-methylphenyl)butane, 2,2-bis(5-t-butyl-4-hydroxy-2-methylphenyl)-4-n-dodecylmercaptobutane, 1,1,5,5-tetra(5-t-butyl-4-hydroxy-2-methylphenyl)pentane and ethylene glycol bis 3,3-bis(3'--t-butyl-4'hydroxyphenyl)butyrate .

O-, N- and S benzyl compounds, such as, for example, 3,5, 3',5'-tetra-t-butyl-4,4'-dihydroxydibenzyl ether, 4-hydroxy-3,5-dimethylbenzyl-mercaptoacetic acid octadecyl ester, tri(3,5-di-t-butyl-4-hydroxybenzyl)amine, and bis (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-dithiolterephthalate.

Hydroxybenzylated malonic esters, such as, for example, 2,2-bis(3,5-di-t-butyl-2-hydroxybenzyl)malonic acid dioct-adecyl ester, 2-(3-t-butyl-4-hydroxy-5-methylbenzyl)malonic acid dioctadecyl ester, 2,2-bis(3,5-di-t-butyl-4-hydroxyben-zyl)malonic acid di-dodecylmercaptoethyl ester, and 2,2-bis(3,5-di-t-butyl-4-hydroxybenzyl)-malonic acid di(4-t-octylphenyl)ester.

Hydroxybenzyl aromatics, such as, for example 1,3,5-tri(3, 5-di-t-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene, 1,4 -di(3,5-di-t-butyl-4-hydroxybenzyl)2,3,5,6-tetramethylben-zene, and Z,4,6-tri-(3,5-di-t-b~tyl-4-hydroxybenzyl)phenol.

,, ' 1~56~95 s-Tria~ e comr)ourld.s, such as, for example, 2, fi~-~is-octylmcl-capto-_ 6-(3, 5-di-t-butyl-~-hydroxyanilino)-s-tl iazine, 2-octylmercaplo-4, G-bis(3, 5-di-t-butyl-4-hydroxyanilino)-s-tria%inc, 2-octylme} capto-4, G-bis(3, 5-di-t-1,utyl-4-hydroxyphenoxy)-s-triazine, 2, 4, 6-tris(3, 5-di-t-butyl-4-hydroxyphenoxy)-s-triazine, 2, 4, 6-tris(3, 5-di-t-butyl-4-hydroxyphenylcthyl)-s-tria~ine, and 1, 3, 5-tris(3, 5-di-t-butyl-4-hydroxybenzyl)isocyanurate .

Amides of 3, 5-di-t-butyl-4-hydroxyphenylpropionic acid such as, for example, I, 3, 5-tris(3, 5-di-t-butyl-4-hydroxyphenyl-propionyl)-hexahydro-s-triazine, and N, N' -bis(3, 5-di-t-butyl-4-hydroxyphenyl-propionyl)hexamethylenediamine Esters of 3, S-di-t-butyl-4-hydroxyphenylpropic-nic acid urith monohydric or polyhydric alcohols, such as, for example, those with methanol, ethanol, octadecanol, 1,6-hexanediol, l,9-n~nanedioi, ethylene glycol, 1, 2-propanediol, diethylene glycol, thiodiethylene glycol, neopentyl glycol, pentaerythritol, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolethane, trimethylolpropane tri~3-hydroxyethyl isocyanurate, and 4 -hydroxymethyl-1-phospha-2, 6, 7 -trioxabicyclo[2, 2, 2]octane.

. .
Esters of 5-t-butyl-4-hydroxy-3-methylphenylpropionic acid with monohydric or polyhydric alcohols, such as, for example, those with methanol, ethanol, octadecanol, 1, 6-hexanediol, 1, 9-nonanediol, ethylene glycol, 1, 2-propanediol, dietllylene glycol, thiodiethylene . . .
- .

~0 ~609 5 glycol, neopentyl glycol, pentaerythritol, 3-thiaundecanol, 3-thia-pentadecanol, trimethylhexanediol, trime-thylolethane, trimethylolpropane, trishydroxyethyl isocyanurate, and 4-hydroxymethyl-l-phospha-2,6,7-trioxabicyclo r 2,2,2~ octane.

Esters of 3,5-di-t-butyl -4hydroxyphenylacetic acid with monohydric or pol~ydric alcohols, such as, for example, those with methanol, ethanol, octadecanol, l,6-hexanediol, l,9-nonanediol, ethylene glycol, l,2-propanediol, diethyl-ene glycol, thiodiethylene glycol, neopentyl glycol, pentaerythritol, 3-thiaundecanol, 3-thiapentadecanol, tri-methyl-hexanediol, trimethylolethane, trimethylolpropane, trishydroxyethyl isocyanurate, and 4-hydroxymethyl-1-phos-pha-2,6,7-trioxabicyclo-~2,2,2~octane.

Acylaminophenols, such as, for example, N-(3,4-di-t-butyl-4-hydroxyphenyl)stearic acid amide and N, N'-bis(3,5-di-t-butyl-4-hydroxyphenyl)thiobisacetamide.

Benzylphosphonates, such as, for example, 3,5-di-t-butyl-4-hydroxybenzylphosphonic acid dimethyl ester, 3,5-di-t-butyl-4-hydroxybenzylphosphonic acid diethyl ester, 3,5-di-t-3,5-di-t-butyl-4-hydroxybenzylphosphonic acid dioctadecyl ester, and 5-t-butyl-4-hydroxy-3-methylbenzylphosphonic acid dio-ctadecyl ester, Aminoaryl derivatives, such as, for example, phenyl-l-nap-hthylamine, phenyl-2-naphthylamine, N,N'-diphenyl-~-phenyl-enediamine, N,N'-:`, . -17-, ~ . .

.

lO5~09S
di-2-n~p1~ yl-p-1~henylenedian~inc, N, N' -di-~ -butyl-p-~ enylcnediaInille, 6-etho~y-2, 2, 4-trimethyl-1, 2-dihydr~quinoline, 6-dodc cyl-2, 2, 4-tri-roethyl-l, 2-dihydroc1uinoline, mono- and di-octyliminodibenzyl, and polymerized 2, 2, 4-trimethyl-l, 2-dihydroquinoline.

UV-absorbers and light protection agents 2-(2'-I~ydroxyphenyl)bcnztriazol~s, such as, for example, the 5'-methyl, 3', 5'-di-t-butyl, 5'-t-butyl, 5'-(l,l, 3, 3-tetramethylbutyl), 5-chloro-3', 5'-di-t-butyl, 5-chloro-3'-t-butyl-5'-methyl, 3'-s-blltyl-5'-t-butyl, 3'-[~-methylbenzyl]-5'-methyl, 3'-l~-methylbenzyl]-5'-methyl-5-chloro, 4'-hydroxy, 4'-methoxy, 4'-octoxy, 3', 5'-di-t-amyl, 3'-methyl-5'-carbo-methoxyethyl and 5-chloro-3', 5'-di-t-amyl derivatives.

,~ _~ ,. such as, for example, the 6 -ethyl, ~ -unde cyl and 6 -heptade cyl de rivatives .

_-Hydroxybenzophenones, such as, for example, the 4-hydroxy, 1~ 4-methoxy, 4-octoxy, 4-decyloxy, 4-dodecyloxy, 4-benzylox~, 4,2',4'-trihydroxy and 2'-hydroxy-4,4'-dimethoxy derivatives.
. I ' .

, !l 1, 3-Bis(2' -hydroxybenzoyl)benzenes, such as, for example, l, 3-bis 2' -hydroxy-4' -he~syloxybenzoyl)benzene, 1, 3-bis(2' -hydroxy-4' -octoxybenzoyl)benzene and l, 3 -bis( 2' -hydroxy -4' -dode cyloxybenzoyl) -benzene.

' ~5609~

Esters of optionally substituted benzoic acids, such as, for example7 phenyl salicylate~ octylphenyl salicylate, dibenzoylresorcinol, bis(4_t-butylbenzoyl)resorcinol, benzoylresorcinol and 3,5-di-t-butyl-4-hydroxybenzoic acid 2,4-di-t-butylphenyl ester, octadecyl ester or 2-methyl-4,6-di-t-butylphenyl ester.

Acrylates, such as, for example, ~-cyano-~,~ diphenylacrylic acid ethyl ester or iso-octyl ester, ~-carbomethoxycinnamic acid methyl ester, c-cyano-~-methyl-~_methoxycinnamic acid methyl ester or butyl ester, and N-(~-carbomethoxyvinyl)-2-methylindoline.

Nlckel compounds~ for example~ nickel complexes of 2,2'-thiobis(4-t-octylphenol)~ such as the 1:1 and 1:2 complexes, optionally with other ligands such as n-butylamine, triethanolamine or N-cyclohexyldi-ethanolamine; nickel complexes of bis(4-t-octylphenyl)sulphone, such as the 2:1 complex, optionally with other ligands such as 2-ethylcaproic acld; nickel dibutyldithiocarbamate; nickel salts of 4-hydroxy-3,5-di-t-butylbenzylphosphonic acid monoalkyl esters, such as the m~thyl1,tethyl or butyl ester; the nickel complex of 2-hydroxy-4-methylphenyl undecyl ketonoxime; and nickel 3,5-di-t-butyl-4-hydroxybenzoate.

Oxslic acid diamides~ such as~ for example~ 4~4'-ti-octyloxyoxanilide~
2,2'-dioctyloxy-5,5'-di-t-butyloxanilide, 2,2'-di-dodecyloxy-5,S'-dl-t-butyloxsnillde~ 2-ethoxy-5-t-butyl_2~_ethyloxanilide~ 2-ethoxy-.

., .

~1.05~iO95 2t-ethyloxanilide~ N~NI-bis(3-dimethylaminopropyl)oxalamide, mixtures of o- and p-methoxy and o- and p-ethoxy-di-substituted oxanilides, and mixtures of 2-ethoxy-5-t-butyl-2'-ethyloxanilide with 2-ethoxy-2~-ethyl-5,4~-di-t-butyloxanilide.

Metal deactivators, such as, for example, oxanilide, isophthalic acid dihydrazide, sebacic acid bisphenylhydrazide, bisbenzylidene oxalic acid dihydrazide, N,N'-diacetyladipic acid dihydrazide, N,Nl-bis_sallcyloyloxalic acid dihydrazide, N,N'_bis_salicy~oylhydrazine, and N,N'-bis-(3,5-di-t-butyl-4-hydroxyphenylpropionyl)hydrazine.

Phosphites~ such as, for example, triphenyl phosphite, diphenyl alkyl phosphites, phenyl dialkyl phosphites, trinonyl phenyl phosphite, trilauryl phosphite, trioctadecyl phosphite, 3,9-di-isodecyloxy-2,4J8,10-tetraoxa-3,9-diphosphaspiro[5,5~undecane, and tris(4-hydroxy-3~5-di-t-butylphenyl)phosphite.

Peroxlde deactivators, such afi, for example, esters of ~-thiodi-propionic acld (e.g., the lauryl, stearyl, myristyl and tridecyl esters), salts of 2-mercaptobenzimldazole (e.g., the zinc salt), and diphenylthiourea.

Polvamide stabilizers, such as, for example, copper salts in combination with iodides and/or phosphorus compounds and salts of divalent manganese.

':

I -20_ .

;.

~i 1~56~95 e Basic co stabili~,ers, such as, for e~iample, polyv;nyl-pyrro]idolle, !
melamine, benzoguanamine, triallyl cyanurate, dicyandiamide, urea derivatives, hydrazine derivativcs, amines, polyamides, pol~urethanes, and alkali mctal salts and alkaline carth metal salts of higher saturated or unsaturated fatty acids, (e. g., Ca stearate, Mg laurate, Na ricinoleate, K palmitate and Zn stearate).

f PVC stabilizers, such as, for example, organic tin compounds, __ organic lead compounds and Ba~Cd salts of fatty acids.

uclea'Ling agents, such as, for example, 4-t-butylbenzoic acid~
0 adipic acid, and diphenylacetic acid.

C)ther additives, such as, for example, plasticizers, lubricants~
(e. g., ,glycerol monostearate), emulsifiers, antistatic agcnts, flameproofing agents, pigments, carbon black, asbestos, glass fibre, kaolin and talc.

The invention is illustrated by the following Examples 1 to 6, in which the stabilizers of formula (I) are identified by means of the numbers appended to them in the list given hereinbefore. Preparations . I , .
1 and 2, which follow the Examples, illustrate the preparation of the stabilizers of formula (I). All parts and percentages are by weight, unless otherwise specified.

.

1~56~95 Example l Mixtures were made from lG0 parts of polypropylene ("Noblen JHII-G", a trademark of Mitsui Toatsu Chemicals Inc., Japan, employed after two recrystallizations from monochloro-benzene~ and 0.25 part of each in turn of the stabilizers of the invention, indicated in Table l. The resulting mixtures were blended, melted, and moulded under heat and pressure to form sheets 0.5 mm thick. A control sheet containing no stabilizer was also made.
The sheets thus formed were exposed to ultraviolet irradiation at 45C in the "Standard Fade Meter Type FA-l"
manufactured and sold by Toyo Rika Instruments Inc., Japan (a modification of the Atlas Fade-O-Meter Type FDA-R which meets the requirements of paragraph 3.8 of Japanese Industrial Standard 1044-L). The brittleness time (i.e. the time required for the sheet to become brittle) for each sheet is shown in Table 1.
Example 2 Mixtures were made from lO0 parts of high-density polyethylene ("Hi-Zex", a trademark of Mitsui Toatsu Chemicals Inc., Japan, employed after two recrystallizations from toluene) and 0.25 part of each in turn of the stabilizers of the inven-tion indicated in Table 1. The resulting mixtures were moulded under heat and pressure to form sheets 0.5 mm thick. A control sheet, containing no stabilizer, was also made.

` 30 , .

.

1~56~95 The brittleness time of each sheet was measured by the same method as in Example 1, and the results are shown in Table 1.

Table 1 Brittleness time (hours) Stabiliz er High - d ensity No . Polypropylene polyethylene _ 1 , 900 2060 4 1120 23~0 None L 60 400 Example 3 Mixtures were made from 100 parts of polystyrene ("Styron", r ~ fra~ ,~ o,~' A~ 15 l~vailablc fr~m Asahi~ow Limited, Japan, employed after recrystall-ization from a mixture of benzene and methanol) and 0. 25 part of each in turn of the stabilizers of the invention indicated in Table 2, The resulting mixtures were moulded under pressure at 180C into plates 1. 5 mm thick. A control plate, containing no stabilizer, was also made.

1056~95 The plates thus formed were irradiated for 3, 000 hours in a xenon Fade-Meter (1. 5 KW, Model FX-1 manufactured by Toyo Rika Instruments Inc., Japan). The difference in colour before and after the exposure to radiation was measured in test pieces taken from the plates, by the method prescribed in Japanese Industrial Standard K-7103, using a colour-difference colourimeter; and the change in their yellowness index was calculated by means of the equation:

~YI = YI - YI

in which ~YI is the change in the yellowness index, YI is the yellowness index after exposure, and YIo is the initial yellowness index of the test piece.

The results are shown in Table 2.
.
Table 2 Stabilizer No . YIo ~ YI

1 1.8 + 8.0 .~l 2 1.9 + 8.6 4 2.0 + 8.2 6 1 1.8 +7.8 .

None 1 1. 8 + 35. 2 .

~, ~, _ 24 .
.

.. . . . . . .

1056~95 Example 4 Mixtures were made from 100 parts of nylon-6 ("CM 1011", r~e ~G~ rk o ~
ML~ aveilQblc fr~m Toray Industries Inc ., Japan) and 0. 25 part of each in turn of the stabilizers of the invention indicated in Table 3. The resulting mixtures were melted and further mixed whilst molten, and were then moulded under pressure into films about 0.1 mm thick in a compression-moulding machine. A control film, containing no stabilizer, was also made.

The films thus formed were subjected to accelerated ageing under the conditions described below, and their retention of ultimate tensile strength and of ultimate elongation were then measured. The results are shown in Table 3.

A~eing Conditions 1) Exposure to ultraviolet irradiation for 200 hours at 45C
in the Fade-Meter described in Example 1.

2) Ageing for 2 hours at 160C in a forced air oven.
' 1 [356095 Table 3 _ Fade-Meter Air oven Stabilizer Retenlion of I~ Retention of Retention of No. elongation tensile strength elongation tensile strength (%) __ (%) (%) (%) l 6 '~2 75 69 73 __ ..
Non e 2 0 5 3 18 5 5 .

Example 5 Mixtures were made from 100 parts of a polycaprolactone-type c~ ~f~ e r~a"~
polyurethane resin ( "Elastollan E- 5080 ", ~_Nippon Elastollan Industries Limited) and (1. 5 part of each in turn of the stabilizers of the invention indicated in Table 4. The resulting mixtures were melted and moulded into sheets about 0. 5 mm thick. A control sheet, containing no stabilizer, was also made.

The sheets thus formed were exposed to ultraviolet irradia~ion in a Fade-Meter at 45 C and the brittleness times were measured;
the retention of ultimate elongation and OI ultimate tensile strength were then measured as described Example 4. The results are shown in Table 4.

.. . .

10560~5 Table 4 !

Stabilizer Retention of Retention of No. elongation (%) tensile strength (%) _ _____ _ _ None 7 2 53 I

Example 6 Mixtures were made from 100 parts by weight of a polyester r~a~ rk o~
re~in ( "Ester - Gl 3 ", availabl~ffl Mitsui Toatsu Chemicals Inc . J
Japan), 1 part of benzoyl peroxide and 0. 2 part of each in turn of the stabilizers of the invention indicated in Table 5. The mixture was stirred thoroughly and then heated at 60C for 30 minutesJ
after which it was cured by heating at 100 C for 1 hour to produce plates 3 mm thick.
!
The plates thus formed were exposed for 60 hours in the "Sunshine Weather-Ometer" and the change in yellowness index !1, was then determined in the manner described in Example 3.

~;

The results are shown in Table 5.

_ 27 -lQ56095 o Table 5 Stabiliz er No . YI ~ YI

1 2.6 +8.4 4 2 4 +8.1 6 2.2 +8.7 bone 1 . 9 +13. 3 Preparation 1 4,4'-dihydroxy-2, 2,6,6, 2', 2',6',6'-octamethyi-4, 4 ' -bipiperidyl 31 g of triacetoneamine were dissolved in 300 ml of toluene, and 18 g of acetic acid were then added to the solution. The mixture was heated at 90-105C, with stirring. 7 g of metallic sodium, in the form of small pieces, were then slowly added to this solution.
l 5 After the metallic sodium had completely dissolved, the reaction mixture was cooled and crystals, which had precipitated, were separated by filtration. The filtrate was concentrated and the residual crystals were recrystallized from benzene, yielding 27.4 g of 4,4'-dihydroxy-2, 2,6,6, 2', 2',6',6'-octamethyl-4,4'-bipiperidyl, in the form of white crystals melting at 177-178C, The yield was 87.7%.
'

- 28 -10560gS

Elementary analysis:
Calculated for C1 8H36N 20 2 : C ,6 9 . 1 8%; H. 1 1 . 6 1 17o; N, 8 . 7 7% .F ound : C,69. 05%; H,ll . 53%; N~8. 73%.
IR spectrum (Nujol mull) : \~OH ~ 3J 500 cm and 3, 370 cm ~)N~-I = 3J 280 cm and 3, 240 cm Preparation 2 1, 1 '-diallyl-4, 4 ' -dihydroxy- 2, 2, 6, 6, 2', 2', 6 ~, 6 ' -octamethyl-4, 4 ' -bipiperidyl 3.1 g of the 4,4'-dihydroxy-2,2,6,6,2',2',6',6'-octamethyl-4,4'-bipiperidyl obtained in Preparation 1, 3.6 g of allyl bromide, 4. 5 g of potassium hydrogen carbonate and 0. 5 g of p-toluenesulphonic acid were added to 30 ml of dimethylformamide, and the mixture was heated at 120-130C for 5 hours, with stirring. The reaction mixture was then concentrated and the residue dissolved in benzene, washed with a 5% aqueous sodium hydrogen carbonate solution and with water, dried over anhydrous potassium carbonate, and concentrated.
The residual crystals were recrystallized from benzene, giving the desired 1,1'-diallyl-4,4'-dihydroxy-2,2,6,6,2',2',6',6'-octamethyl-4,4'-bipiperidyl, in the form of white crystals melting at 127-128 C.

Elementary analysis:
Calculated for C24H44N22 Found : C, 73. 33%; H, 11. 24%; N, 7. 21%.

_ 29 -.
:

;: .
~' .

-l~S6095 IR spectrum (Nujol mull) : ~OH = 3~ 52~ cm ~)C=C ~ 1,640 cm The following compounds were then obtained following substantially the same method as described in Preparation 2, except that the allyl bromide was replaced by other appropriate halides:
4,4'-dihydroxy-1, 2, 2,6,6, 1 ', 2', 2',6 ',6 '-decamethyl-4,4'-bipiperidyl mp 148- 149C;
1,1'-dibenzyl-4,4'-dihydroxy-2,2,6,6,2',2',6',6'-octamethyl-4,4 ' -bipiperidyl mp 21G - 217 C;
4,4'-dihydroxy-1, 1'-bis(2-hydroxyethyl)-2, 2,6,6, 2', 2',6',6'-octamethyl-4,4'-bipiperidyl mp 286-288C;
1,1'-bis(2-ethoxyethyl)-4,4'-dihydroxy-2,2,6,6,2',2',6',6'-octamethyl-4,4'-bipiperidyl mp 167-169C;
1,l'^bis(2-acetoxyethyl)-4,4'-dihydroxy-2, 2,6,6, 2', 2',6',6'-octamethyl~4,4'-bipiperidyl mp 206-207. 5C;
big(2-crotonoylox~ethyl)-4.4 ' -dihydroxy- 2, 2,6,6, 2', 2',6',6'-octamethyl-4,4'-bipiperidyl mp 146.5-148 C;
4,4'-dihydroxy-1, 1'-bis(2, 3-epoxypropyl)-2, 2,6,6, 2', 2',6',6'-octamethyl-4,4'-bipiperidyl mp 167-169C;
1-acetyl-4,4'-dihydroxy-2, 2,6,6, 2', 2',6~,6~-octamethyl-4,4'-bipiperidyl mp 139-140C.

. .

:- ' ' ., ~ , .

Claims (11)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. A synthetic polymer composition stabilized against photo-and thermal-deterioration, comprising a synthetic polymer and an effective amount of at least one stabilizing compound having the formula:

(I) wherein R and R' are the same or different and each represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, a hydroxyalkyl group, an alkoxyalkyl group, an aliphatic or aromatic acyloxyalkyl group, a cyanoalkyl group, a haloalkyl group, an epoxyalkyl group, an alkoxycarbonylalkyl group, an aliphatic acyl group, an alkoxycarbonyl group, or an aralkoxy-carbonyl group, or of an acid addition salt of said compound.

2. A composition according to claim 1, comprising at least one stabilizer of said formula (I) or an acid addition salt thereof, wherein R and R' may be the same or different and each represents:

a hydrogen atom; an alkyl group having from 1 to 8 carbon atoms;
an alkenyl group having from 3 to 6 carbon atoms; an alkynyl group having 3 or 4 carbon atoms; an aralkyl group having 6 carbon atoms in the aryl moiety and 1 or 2 carbon atoms in the alkyl moiety; a hydroxyalkyl group having from 1 to 4 carbon atoms; an alkoxyalkyl group having from 1 to 8 carbon atoms in the alkoxy moiety and from 1 to 4 carbon atoms in the alkyl moiety; an aliphatic acyloxyalkyl group, in which the acyl moiety is either saturated and has from 2 to 18 carbon atoms or is unsaturated and has from 3 to 6 carbon atoms and in which the alkyl moiety has from 1 to 4 carbon atoms; an aromatic acyloxyalkyl group (whose aromatic ring is unsubstituted or has from 1 to 3 substituents which are alkyl groups having from 1 to 4 carbon atoms and/or hydroxy groups, and whose alkyl moiety has from 1 to 4 carbon atoms); a cyanoalkyl group having 2 or 3 carbon atoms;
a haloalkyl group having from 1 to 3 carbon atoms; a 2-3-epoxypropyl group;
an alkoxycarbonylalkyl group having from 1 to 18 carbon atoms in the alkoxy moiety and 1 or 2 carbon atoms in the alkyl moiety; an aliphatic acyl group which, if saturated, has from 2 to 8 carbon atoms or, if unsaturated, has 3 or 4 carbon atoms; an alkoxycarbonyl group having from 2 to 9 carbon atoms; or a benzyloxycarbonyl group.

3. A composition according to claim 1, comprising at least one compound of said formula (I) or an acid addition salt thereof wherein both R and R' ares a hydrogen atom; an alkyl group having from 1 to 4 carbon atoms; an allyl group; a benzyl group; an alkoxyalkyl group having from 1 to 4 carbon atoms in the alkoxy moiety and 1 or 2 carbon atoms in the alkyl moiety; an aliphatic acyloxyethyl group, in which the acyl moiety, if saturated, has from 2 to 18 carbon atoms or, if unsaturated, has from 3 to 6 carbon atoms; a benzoyloxyethyl group, whose benzene ring is unsubstituted or has from 1 to 3 substituents, which arc alkyl groups having from 1 to 4 carbon atoms and/or hydroxy groups; or an alkoxycarbonylmethyl group having from 1 to 8 carbon atoms in the alkoxy moiety.

4. A composition according to claim 1, comprising at least one compound of said formula (I) or an acid addition salt thereof, in which both R and R' are: a hydrogen atom; an alkyl group having from 1 to 4 carbon atoms; an allyl group; a benzyl group; or an alkoxy-carbonylmethyl group having from 1 to 8 carbon atoms in the alkoxy moiety.

5. A composition according to claim 1, comprising at least one of the following compounds of said formula (I):
4,4'-dihydroxy-2,2,6,6,2',2',6',6'-octamethyl-4,4'-bipiperidyl, 4,4'-dihydroxy-1,2,2,6,6,1',2',2',6',6'-decamethyl-4,4' -bipiperidyl, 1,1'-diallyl-4,4'-dihydroxy-2,2,6,6,2',2',6',6'-octamethyl -4,4'- bipiperidyl, 1,1'-dibenzyl-4,4'-dihydroxy-2,2,6,6,2',2',6',6'-octamethyl-4,4'-bipiperidyl, and 1,1'-bis(ethoxycarbonylmethyl)-4,4'-dihydroxy-2,2,6,6, 2',2',6',6'-octamethyl-4,4'-bipiperidyl.

6. A composition according to claim 1, comprising from 0.01% to 5.0% by weight of a compound or compounds of said formula (I) or acid addition salts thereof, based on the weight of the synthetic polymer.

7. A composition according to claim 1, wherein said synthetic polymer is an olefin, diene or styrene polymer.

8. A composition according to claim 1, wherein said synthetic polymer is a vinyl chloride or vinylidene chloride polymer, a polyacetal, a polyester, a polyester ether, a polyamide, a polyurethane, a polycarbonate, or an epoxy resin.

9. A composition as claimed in claim 1, wherein R and R' are the same or different and each represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, a hydroxyalkyl group, an alkoxyalkyl group, an aliphatic or aromatic acyloxyalkyl group, a cyanoalkyl group, a haloalkyl group, an epoxyalkyl group, an alkoxycarbonylalkyl group, an aliphatic acyl group, an alkoxycarbonyl group, or an aralkoxy-carbonyl group, provided that R and R' are not the same and hydrogen atoms or methyl groups, and acid addition salts thereof.

10. A composition as claimed in claim 1, containing at least one of the following compounds, 4,4'-dihydroxy-1,1'-bis(2-hydroxyethyl)-2,2,6,6,2',2', 6',6'-octamethyl-4,4'-bipiperidyl, 1,1'-bis(2-ethoxyethyl)-4,4'-dihydroxy-2,2,6,6,2',2', 6',6'-octamethyl-4,4'-bipiperidyl, 1,1'-bis(2-acetoxyethyl)-4,4'-dihydroxy-2,2,6,6,2',2', 6',6'-octamethyl-4,4'-bipiperidyl, 1,1'-bis(2-crotonoyloxyethyl)-4,4'-dihydroxy-2,2,6,6, 2',2',6',6'-octamethyl-4,4'-bipiperidyl, 4,4'-dihydroxy-1,1'-bis(2,3-epoxypropyl)-2,2,6,6,2',2', 6',6'-octamethyl-4,4'-bipiperidyl, 1-acetyl-4,4'-dihydroxy-2,2,6,6,2',2',6',6'-octamethyl-4,4'-bipiperidyl.

11. A composition as claimed in claim 9, containing at least one acid addition salt of compounds set forth in claim 9, wherein the acid is benzoic acid, p-t-butylbenzoic acid, 3,5-di-5-butyl-4-hydroxyphenylpropionic acid, maleic acid, oxalic acid, acetic acid, methylsulphonic acid, p-toluenesulphonic acid, sulphuric acid, phosphoric acid or hydrochloric acid.