Stabilization of synthetic polymers by means of certain 1-substituted piperidine derivatives

This invention relates to the stabilization of synthetic polymers against photo- and thermal-deterioration by the use ojr !-substituted piperidine derivatives.

The compound 2, 2, 6, 6-tetramethylpiperidine, which is unsubstituted at the 1-position, is disclosed as a photo-stabilizer for polyolefins in Japanese Patent Publication No. 46-317^r3. On the other hand, various 1-substituted piperidine derivatives of the general formula

<img file="IL44629A_D0001.tif" />

wherein n = 1 or 2; and when n = 1, X represents an alkyl, allyl, propargyl, benzyl, ethoxycarbonylmethyl, 2-hydroxyethyl, 2-hydroxypropyl, 2-hydroxy-2-phenethyl, 2-acyloxyethyl, 2-acyloxy-2phenethyl, acetyl or methoxycarbonyl group; and when n 2 ־, X represents a hexamethylene group;

are !mow to have other utilities, especially as pharmaceuticals, but they have not previously been described as polymer stabilizers ־ see, for example, J. Pharmacol, 13 501-20 (1958), J. Med. Chem.

381-4 (1963), J. Org. Chem. 27 1695-1703 (1962), C.A. 62 9098h,

Beilstein 20 129, British Patent Specifications No. 834, 290 and

1,143, 371.

<img file="IL44629A_D0002.tif" />

We have now discovered that certain !-substituted piperidine 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 !-substituted piperidine derivatives having the formula:

<img file="IL44629A_D0003.tif" />

R¹ (I) wherein:

R^ and R^ represent methyl groups; or R&amp; and R^, together with the carbon atom to which they are attached, represent a cyclohexyl group;

R represents a methyl group, and R represents an alkyl ** Q group having from 1 to 5 carbon atoms; or R^ and R^, together with the carbon atom to which they are attached, represent a cyclopentyl group, a cyclohexyl group, a group of the formula

<img file="IL44629A_D0004.tif" />

or a group of the formula

<img file="IL44629A_D0005.tif" />

n = lor 2; and when n = 1: R represents an oxyl radical, a hydroxy group, an alkyl group, a substituted alkyl group, an alkenyl grov.p, an alkynyl group, an aralkyl group a substituted aralkyl group, or an acyl group; or when n - 2: R¹ represents an alkylene group (the chain of which may optionally be interrupted by an oxygen atom), a 2-butenylene group, a group of the formula -CH CO-O-R -O-COCH [wherein R represents an alkylene group or a xylylene group], or a group of the formula

-CH -CH -O-CO-(־R ־)—CO-O-CH -CH - [wherein m = 0 or 1; and R a z m&amp; u represents an alkylene group (the chain of which may optionally be interrupted by a sulphur atom), an alkenylene group, a phenylene group, or a 1, 4-cyclohexylene group].

A preferred sub-group of compounds within formula (I) are those wherein n = 1, that is to say the compounds of formula:

<img file="IL44629A_D0006.tif" />

(la) wherein R , R, , R a b c have the meanings previously given; and R represents an oxyl radical, a hydroxy group, an alkyl group, a substituted alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, a substituted aralkyl group, or an acyl group.

In formula (la), when R is an alkyl group it may be, for example, a methyl, ethyl, propyl, butyl, pentyl or hexyl group. When R^ is a substituted alkyl group it may be, for example: a haloalkyl group, such as 2~chloroethyl, 2-bromoethyl or 2-chloropropyl; an epoxyalkyl group, such as 2, 3-epoxypropyl; a hydroxyalkyl group, such as 2-hydroxyethyl, 2-hydroxypropyl or 3-hydroxypropyl; an alkoxy carbonylalkyl group, such as hexyloxycarbonylmethyl; an alkoxyalkyl group, such as 2-methoxyethyl, 2-ethoxyethyl, 2-propoxyethyl or 3-methoxypropyl; or an acyloxyalkyl group, such as 2-acetoxyethyl, 2-acetoxypropyl or 2stearoyloxyethyl. When R^ is an alkenyl group it may be, for example, allyl or methallyl. When R^ is an alkynyl group it may be, for example, propargyl. When R^ is an aralkyl group it may be, for example, benzyl or a-methylbenzyl. When R^ is a substituted aralkyl group it may be, for example, a hydroxyaralkyl group, such as 2-hydroxy-2-phenethyl. When r1 is an acyl group it may be, for example, an aliphatic acyl group, such as formyl or acetyl.

Those compounds of formula (la) are preferred wherein R is an oxyl radical, an alkyl group having from 1 to 8 carbon ato1^־^ja haloalkyl group having from 1 to 5 carbon atoms, a cyanoalkyl g^roup having from 1 to 5 carbon atoms, an epoxyalkyl group having 3 or 4 ' carbon atoms, a hydroxyalkyl group having from 2 to 5 carbon, atoms, an acyloxyalkyl group having from 4 to 20 carbon atoms, an aminoalkyl group having from 2 to 4 carbon atoms, an alkoxy carbonyl alkyl group having from 3 to 21 carbon atoms, an alkoxyalkyl group having from 3 to 20 carbon atoms, an alkenyl group having from 3 to 6 carbon atoms, an alkynyl group having from 3 to 6 carbon atoms, an aralkyl group having from 7 to 20 carbon atoms, a hydroxyaralkyl group having from 8 to 12 carbon atoms, or an acyl group having from 2 to 18 carbon atoms.

R^ and R^ are preferably methyl groups. R_c and R^ are preferably methyl groups or, together with the carbon atom to which they are attached, represent a cyclohexyl group or a group of the formula

<img file="IL44629A_D0007.tif" />

and, most preferably, they are methyl groups.

Another preferred sub-group of compounds within formula (I) are those having the formula:

<img file="IL44629A_D0008.tif" />

<img file="IL44629A_D0009.tif" />

wherein:

n = 1 or 2; and when n = 1, R represents:

an alkyl group having from 1 to 18 carbon atoms;

an alkenyl group having from 3 to 10 carbon atoms;

an alkynyl group having 3 or 4 carbon atoms;

a benzyl group whi ch may optionally be substituted with up to 3 substituents in its phenyl moiety, said substituents being the same or different and being one or more of chlorine, alkyl, θ alkoxy and hydroxy;

a phenethyl, group;

a 2,3-epoxypropyl group;

2 a group of the formula. -CH₉־C0-0-R (wherein R represents di an alkyl group having from 1 to 18 carbon atoms, an alkenyl group having from 3 to 6 carbon atoms, a phenyl group, a benzyl group, a cyclohexyl group, 01י a 2, 3-epoxypropyl group);

a group of the formula -CH -CHR R [wherein R* represents a hydrogen atom, a methyl group, or a phenyl group represents a hydroxy group, or a group of the formula

5

-O-COR ; R represents an alkyl group having from 1 to 17 carbon atoms, an alkenyl group having from 2 to 4 carbon atoms, a phenyl group which may optionally be substituted with up to 3 substituents (said substituents being the same or different, and being one or more of chlorine, alkyl, C, alkoxy and hydroxy), a benzyl group, a 3, 5-di-t-butyl-

4-hydroxyphenethyl group, a styryl group, or a cyclohexyl group];

6 or a group of the formula -CO-R (wherein R represents a hydrogen atom, a methyl group, an alkenyl group having 2 or 3 carbon atoms, an alkoxy group having from 1 to 8 carbon atoms, a benzyloxy group, or a phenoxy group); or when n = 2, R¹ represents:

an alkylene group having from 1 to 6 carbon atoms (the chain of which may optionally be interrupted by an oxygen atom);

a 2־butenylene group;

7 a group of the formula -CH CO-O-R -O-COCH - (wherein R represents an alkylene group having from 2 to 6 carbon atoms, 01־ a xylylene group);

or a group of the formula -CH -CH,-O- cc4rV-co-o-ch -CH_z z m z &amp;

[wherein m 0 ־ or 1; and R represents an alkylene group having from 1 to 10 carbon atoms (the alkylene chain of which may optionally be interrupted by a sulphur atom), an alkenylene group having from 2 to 4 carbon atoms, a phenylene group, or a 1, 4-cyclohexylene group].

In formula (lb), when n = 1: When R¹ is an alkyl group it may be, for example, methyl, ethyl, propyl, butyl, isobutyl, isopentyl, hexyl, octyl, dodecyl or octadecyl; when it is an alkenyl group it may be, for example, allyl crotyl, 2-hexenyl or 2-decenyl; when it is an alkynyl group it may be, for example, propargyl or 2-butynyl; and when it is a benzyl or substituted benzyl group it may be, for example, ano-, m-or jo-chlorobenzyl, p-methylbenzyl, p-ethylbenzyl, p-isopropylben.zyl, p-methoxybenzyl, p-butoxybenzyl, p-octoxybenzyl or 3, 5-di-t-butyl-4-hydroxybenzyl group.

When R is an alkyl group it may be, for example, methyl, ethyl, butyl, isopentyl, octyl, dodecyl or octadecyl; and when it is an alkenyl group it may be, for example, allyl, crotyl or 2-hexenyl.

When R is an alkyl group it may be, for example, methyl, ethyl, propyl, isopropyl, heptyl, 1-ethylpentyl, undecyl, pentadecyl or heptadecyl; when it is an alkenyl group it may be, for example, vinyl, 1-propenyl, isopropenyl or 2-methyl-l-propenyl; and when it is a substituted or unsubstituted phenyl group it may be, for example, phenyl, m- or p-chlorophenyl, 2, 4-dichlorophenyl, o- or p-methylphenyl, p-isopropylphenyl, p-t-butylphenyl, p-ethoxyphenyl, pbutoxyphenyl, p-octoxyphenyl, 3, 4, 5-trimethoxyphenyl, o-hydroxyphenyl or 3, 5-di-t-butyl-4-hydroxyphenyl.

When R is an alkenyl group it may be, for example, vinyl or 1-propenyl; and when it is an alkoxy group it may be, for example, methoxy, ethoxy, isobutoxy or octoxy. ^?

In formula (lb), when n = 2:When R¹ is an alkylene group it may be, for example, methylene, ethylene, tetramethylene or hexamethylene; and when it is an alkylene group the chain of which is interrupted by an oxygen atom it may be, for example, oxydiethyl,

When R is an alkylene group it may be, for example, ethylene, tetramethylene or hexamethylene; and when it is a xylylene group it may be, for example, m- or p-xylylene.

When R is an alkylene group it may be, for example, methylene, ethylene, tetramethylene, octamethylene or de camethylene; when it is an alkylene group the chain of which is interrupted by a sulphur atom it may be, for example, thiodiethyl; when it is an alkenylene group it may be, for example, vinylene, 2-propene-l, 2ylene or 2-butenylene; and when it is a phenylene group it may be, for example, m- or p-phenylene.

The following groups are preferred for R¹ in formula (lb) when n = 1: An alkyl group having from 4 to 12 carbon atoms, particularly butyl, octyl or dodecyl.

An allyl group.

44629/2

A benzyl group which may optionally be substituted sillcyl in the phenyl moiety with methoxy or 3,5-di-t-but^K4hydroxy, and particularly unsubstituted benzyl.

2

A group of formula -C^CO-QR , particularly when M is an alkyl group having from 1 to 18 carbon atoms or an allyl group*

A group of formula -SHg-ClR^R⁴, particularly when , p.

R is a hydrogen atom, a methyl group or a phenyl group (and most preferably a hydrogen atom), and when E⁴ is a hydroxy group or the group -O-COR^ (wherein R® is an alkyl group having from 1 to 17 carbon atoms, or a 3,5*־di-t-butyl-4-hydroxyphenethyl group, an alkenyl group having 2 or 3 carbon atoms, a phenyl group, which may optionally be substituted with alkyl, C_1->Q alkoxy or hydroxy, and particularly an unsubstituted phenyl group).

®he following groups are preferred for in formula (lb) when n = 2:An alkylene group having from 2 to 6 carbon atoms, particularly ethylene or hexamethylene.

Z A group of the formula -C^-CO-O-R^-O-OO-CHg“»wherein 7--LR _: 4^s preferably an alkylene group having from 2 to 6 carbon

;'־;דך־־ atoms, particularly ethylene or hexamethylene*

A group of the formula -CHg-CHj-O-CO-^-CO-O-CHg-CHg-, 8wherein B is preferably an alkylene group having from 1 to 8 carbon atoms, particularly methylene, ethylene, tetramethylene or octamethylene, or an m- or p-phenylene group.

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 Examples 1 to 7.

1) 1, 2, 2, 6, 6-Pentamethylpiperidine

2) l-Butyl-2, 2, 6, 6-tetramethylpiperidine

3) l-Octyl-2, 2,6, 6-tetramethylpiperidine

4) l-Dodecyl-2, 2, 6, 6-tetramethylpiperidine

5) 1-Octade cyl-2, 2, 6, 6-tetramethylpiperidine

6) l-Allyl-2, 2, 6, 6-tetramethylpiperidine

7) l-Crotyl-2, 2, 6, 6-tetramethylpiperidine

8) 1-Propargyl-2, 2, 6, 6-tetramethylpiperidine

9) l-Benzyl-2, 2, 6, 6-tetramethylpiperidine

10) 1-Phenethyl-2, 2, 6, 6-tetramethylpiperidine

11) l-(o-Chlorobenzyl)-2, 2, 6, 6-tetramethylpiperidine

12) l-(m־Chlorobenzyl)-2, 2, 6, 6-tetramethylpiperidine

13) l-(£-Chlorobenzyl)-2, 2, 6, 6-tetramethylpiperidine

14) l-(p-Methylbenzyl)-2, 2, 6, 6-tetramethylpiperidine

15) 1-(3, 5-di-t-Butyl-4-hydroxybenzyl)-2, 2, 6, 6-tetramethylpiperidine

16) l-(p-Methoxybenzyl)-2, 2, 6, 6-tetramethylpiperidine

17) 1-(2, 3-Epoxypropyl)-2, 2, 6, 6-tetramethylpiperidine

18) l-Methoxycarbonylmethyl-2_; 2, 6, 6-tetramethylpiperidine

19) l-Ethoxycarbonylmethyl-2, 2, 6, 6-tetramethylpiperidine

20) l-Butoxycarbonylmethyl-2, 2, 6, 6-tetramethylpiperidine

21) l-Octoxycarbonylmethyl-2, 26 _צ6 _צ-tetramethylpiperidine

22) l-Dodecyloxycarbonylmethyl-2, 2, 66 _נ-tetramethylpiperidine

23) 1-Octade cyloxycarbonylmethyl-2, 2,5, 6-tetramethylpiperidine

24) l-Allyloxycarbonylmethyl-2, 2, 6, 6-tetramethylpiperidine

25) l-Benzyloxycarbonylmethyl-2, 2, 6, 6-tetramethylpiperidine

26) 1-Cyclohexyloxycarbonylmethyl-2, 2, 6, 6-tetramethylpiperidine

27) 1-(2-Hydroxyethyl)-2, 2, 6, 6-tetramethylpiperidine

28) 1-(2-Hydroxypropyl)-2, 2, 6, 6-tetramethylpiperidine

29) 1-( 2-Hydroxy-2-phenylethyl)-2.2, 6. 6-tetramethylpiperidine

30) l-(2-Acetoxyethyl)-2, 2, 6, 6-tetramethylpiperidine

31) l-^-Acetoxypropyl)^, 2, 66 _נ-tetramethylpiperidine

32) l-(2-Acetoxy-2-phenylethyl)-2, 2, 6, 6-tetramethylpiperidine

33) l-(2-Prpionyloxy-2-phenylethyl)-2, 2, 6, 6-tetramethylpiperidine

Λ

34) l-(2-Butyryloxypropyl)-2_J 2, 6, 6-tetramethylpiperidine

35) l-(2-Lauroyloxyethyl)-2, 2, 6, 6-tetramethylpiperidine

36) l-(2-Lauroyloxypropyl)-2, 2, 6, 6-tetramethylpiperidine

37) l-(2-Lauroyloxy-2-phenylethyl)-2, 2, 66 _ג-tetramethylpiperidine

38) 1-(2-Stearoyloxyethyl)-2, 2, 6, 6-tetramethylpiperidine

39) 1-(2-Stearoyloxy-2-phenylethyl)-2, 2, 6, 6-tetramethylpiperidine

40) 1-(2-Acryloyloxyethyl)-2, 2, 6, 6-tetramethylpiperidine

41) 1-(2-Crotonoyloxyethyl)-2, 2, 66 _ג-tetramethylpiperidine

42) l-(2-Crotonoyloxypropyl)-26 ,6 ,2 _־-tetramethylpiperidine

43) 1-(2-Methacryloyloxyethyl)-2, 2, 6, 6-tetramethylpiperidine

44) 1-(2-Benzoyloxyethyl)-2, 2, 6, 6-tetramethylpiperidine

45) l-(2-Benzoyloxypropyl)-2, 2, 6, 6-tetramethylpiperidine

46) l~(2-Benzoyloxy-2-phenylethyl)-2, 2, 6, 6-tetramethylpiperidine

47) l-[2-(m-Ch.lorobenzoyloxy)ethyl]-2, 2, 6, 6-tetramethylpiperidine,

48) l-[2 -(p-Chlorobenzoyloxy)-2-phenylethyl]-2, 2, 6, 6-te tram ethylpiperidine

49) 1-(2-(p-Toluoyloxy)propyl]-2, 2, 6, 6-tetramethylpiperidine

50) l-[2-(p-t-Butylbenzoyloxy)ethyl]6 ,6 ,2 ,2־-tetramethylpiperidine

51) 1-(2-(3, 5-di-t-Butyl-4-hydroxybenzoyloxy)propyl]-2, 2, 6, 6tetramethylpiperidine

52) 1-(2-(p-Methoxybenzoyloxy)-2-phenylethyl]-2, 2, 6, 6-tetramethylpiperidine

53) 1-(2-(3, 4, 5-Trimethoxybenzoyloxy)ethyl]-2, 2, 6, 6-tetramethylpiperidine

54) l-[2-(p-Butoxybenzoyloxy)ethyl]-2, 2, 6, 6-tetramethylpiperidine

55) l-[2-(p-Octoxybenzoyloxy)propyl]-2, 2, 6, 6-tetramethylpiperidine

56) l-(2-Salicyloyloxyethyl)-2, 2, 6, 6-tetramethylpiperidine

57) 1-( 2-Phenylacetoxyethyl)-2, 2,6, 6-tetramethylpiperidine

58) 1- [2-(3-(3, 5-di-t-Butyl-4-hydroxyphenyl)propionyloxy]ethyl] -

2, 2, 6, 6-tetramethylpiperidine

59) l-(2-Cinnamoyloxy-2-phenylethyl)-2, 2, 6, 6-tetramethylpiperidine

60) 1-(2-Cyclohexanecarbonyloxypropyl)-2, 2, 6, 6-tetramethylpiperidine

61) l-Formyl-2, 2, 6, 6-tetramethylpiperidine

62) l-Acetyl-2, 2, 6, 6-tetramethylpiperidine

63) l-Acryloyl-2, 2, 6, 6-tet.ramethylpiperidine

64) l-Crotonoyl-2, 2, 6, 6-tetramethylpiperidine

65) 1-Me th oxycarbonyl-2, 2, 6, 6-tetramet.hylpiperidine

66) l-Octoxycarbonyl-2, 2, 6, 6-tet.ramethylpiperidine

67) l-Benzyloxycarbonyl-2, 2, 6, 6 -tetramethylpiperidine

68) 1, 2-Bis(2, 2, 6, 6-tetramethylpiperidino)ethane '

60) 1,4-Bis(2, 2,6, 6-tetramethylpiperidino)butane

70) 1, 6-Bis(2, 2, 6, 6-tetramethylpiperidino)hexane

71) 2, 2' -Bis( 2, 2, 6, 6-tetramethylpiperidino)ethyl ether

72) 1, 4-Bis(2, 2, 6, 6-tetramethylpiperidino)-trans-2-butene

73) 1, 2-Bis(2, 2,6, 6-tetramethylpiperidino-acetoxy)ethane

74) 1, 6-B1s(2, 2, 6, 6-tetramethylpiperidino-acetoxy)hexane

75) 1,4-Bis(2, 2, 6, 6-tetramethylpiperidino-acetoxy)benzene

76) Bis[2-(2, 2, 6, 6-tetramethylpiperidino)ethyl] oxalate

77) Bis[2-(2, 2, 6, 6-tetramethylpiperidino)ethyl] malonate

78) Bis[2-(2, 2, 6, 6-tetramethylpiperidino)ethyl] succinate

79) Bis[2-(2, 2, 6, 6-tetramethylpiperidino)ethyl] adipate,

80) Bis[2-(2, 2, 6, 6-tetramethylpiperidino)ethyl] sebacate

81) Bis[2-(2, 2, 6, 6-tetramethylpipe.ridino)ethyl]-1,10-decane-dicarboxylate

82) Bis[2-(2, 2, 6, 6-tetramethylpiperidino)ethyl]thiodipropionate

83) Bis[2-(2, 2, 6, 6-tetramethylpiperidino)ethyl]maleate

84) Bis[2-(2, 2, 6, 6-tetramethylpiperidino)ethyl]terephthalate

85) Bis[2-( 2, 2, 6, 6-tetramethylpiperidino)ethyl] isophthalate

86) Bis[2-(2, 2, 6, 6-tetramethylpiperidino)ethyl]-1, 4-cyclohexanedicarboxylate.

The piperidine derivatives of formula (I) can be prepared by known methods, such as the following reactions (A) - (F). The products of these reactions, having the formulae (Π), (V), (Va), (VIII), (X), (Xa), (XII), (XIV) and (XVI), are all sub-groups of the compoundsof formula (I).

(A). Compounds of formula (II) can be prepared by reacting a substituted piperidine (III) with a halide (IV), by the method described in British Patent Specification No. 834, 290, in which the piperidine (III) is reacted with allyl bromide: -

<img file="IL44629A_D0010.tif" />

(III) (IV) (II) wherein:

R , R, , R and R, have the meanings already defined;

abed n = 1 or 2; and when n = I: R represents an alkyl group, an alkenyl group, an alkynyl group, a substituted or unsubstituted benzyl group, a phenethyl group, a 2, 3-epoxypropyl group, a cyanoalkyl group, an aminoalkyl group, an alkoxyalkyl group, or the group -CH CO-OR (wherein R has the meaning already defined); or when n 2 ־: R represents an alkylene group (which may optionally be interrupted by an oxygen atom), or a 2-butenylene group;

and

Y represents a halogen atom.

(B). Compounds of formulae (V) and (Va) can be prepared by transesterification of a substituted piperidine of formula (VI) with an alcohol of formula (VII) or diol of formula (Vila):-

<img file="IL44629A_D0011.tif" />

<img file="IL44629A_D0012.tif" />

(VI) (Vila) (Va) wherein:

7

R , R , R , R ,, R and R have the meanings already abed defined; and

R^O represents an alkyl group.

Compounds of formula (VIII) can be prepared by reacting a (C).

substituted piperidine (III) with an epoxide (IX), by the method described in British Patent Specification No. 1,143, 371:R R

<img file="IL44629A_D0013.tif" />

(ΠΙ) (IX) (VIII) wherein R , R, , R , R and R have the meanings already defined, cl D C u.

(D). Compounds of formulae (X) and (Xa) can be prepared by reacting a substituted piperidine of formula (VIII) or (Villa) with a reactive derivative of an appropriate acid, e.g. an acid halide of formula (XI) or (Xia), by the method described in British Patent

Specification No. 1,143,371:-

<img file="IL44629A_D0014.tif" />

<img file="IL44629A_D0015.tif" />

<img file="IL44629A_D0016.tif" />

(VIII) (XI) (X)

R

<img file="IL44629A_D0017.tif" />

+ yco4r^{5 * * 8}4-coy m

(Villa) (Xia)

<img file="IL44629A_D0018.tif" />

(Xa)

5 8 wherein R , R, , R , R ״ R , R , R , Y and m have the meanings abed already defined.

(E). Compounds of formula (XII) can be prepared by reacting a substituted piperidine (III) with a reactive derivative of an appropriate acid, e.g. an acid halide of formula (XIII), by the method described in

J. Med. Chem. (5, 381-4 (1963):-

<img file="IL44629A_D0019.tif" />

(III) (XIII) (ΧΠ) wherein:

R , R,, R and R , have the meanings already defined: abed ״ j ,>

*

R represents a methyl group or an alkenyl group; and represents a halogen atom.

Compounds of formula (XIV) can be prepared by a similar method, except that a chlorocarbonate (XV) is used in place of the acid halide (XIII): -

<img file="IL44629A_D0020.tif" />

(III) (XV) (XIV) wherein:

R_gJ R^, R^ and R^ have the meanings already defined; and

R ^ώ represents an alkyl group, a benzyl group or a phenyl group.

(F). Compounds of formula (XVI) can be prepared by reacting a substituted piperidine (III) with ethyl orthoformate in the presence of an acid catalyst: - 20 -

<img file="IL44629A_D0021.tif" />

+ CH(OC_H )

Δ Ο Ο

<img file="IL44629A_D0022.tif" />

c (III) (XVI) wherein R^, R_c and have the meanings already defined.

Reactions (A), (D) and (E), which proceed with the formation of a hydrogen halide, are conveniently performed in the presence of an acid binding agent. The conventional organic or inorganic bases can be added to the reaction system as acid binding agents, or alternatively an excess of the piperidine starting material can serve the same purpose. The reactions can be performed by heating the reactants in an inert solvent, or in the absence of a solvent.

The transesterification reaction (B) is performed with heating in the presence of a catalyst, such as an alkali metal alkoxide, amide or hydroxide. The alcohol formed during the reaction is preferably removed from the reaction system.

The compounds of formula (I) impart to synthetic polymeric materials an exceptionally high degree of stability against photoand thermal-deterioration. Moreover, this improved stability is achieved without discoloration of the polymeric material, and without adverse effects on other light-protection agents, stabilizers, plasticizers of pigments which may also be added to the polymer. Accordingly, the invention provides a composition comprising a synthetic polymerjseprti at least one of said compounds of formula (I).

Synthetic polymers which can be stabilized by means of the compounds of formula (I) include:olefin, diene and styrene polymers including homopclymers of olefins, dienes and styrene (e. g. low and high density polyethylenes, polypropylene, polystyrene, polybutadiene and polyisoprene), and copolymers of olefins, dienes and styrene with each other or with other ethylenically-unsaturated monomers (e.g.

ethylene/propylene copolymers, ethylene/butene copolymers, ethylene/vinyl acetate copolymers, styrene/butadiene copolymers and acrylonitrile/butadiene/styrene copolymers);

vinyl chloride and vinylidene chloride polymers including homopolymers of vinyl chloride and vinylidene chloride, vinyl chloride/vinylidene chloride copolymers, and copolymers of vinyl chloride or vinylidene chloride with vinyl acetate or other ethylenicallyunsaturated monomers;

polyacetals

e.g. polyoxymethylene and polyoxyethylene;

polyesters

e. g. polyethylene terephthalate;

polyamides

e.g. nylon-6, nylon-6, 6, nylon-6.10 and nylon-12;

polyurethanes

e.g. polyether polyurethanes and polyester polyurethanes; and epoxy resins

e. g. reaction products of epichlorohydrin with polyphenols.

The synthetic polymers stabilized by the compounds of formula (I) 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.

The amount of stabilizer of formula (I) needed foi' effective stabilization of the synthetic polymer will depend on a variety of factors, such as the type and properties of the polymer concerned, its intended 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%, preferably from 0.1% to 2%, by weight of stabilizer or stabilizers of formula (I), based on the weight of the synthetic polymer.

The stabilizers of formula (I) 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 slurry of the stabilizer in a suitable solvent or dispersant (e. g. an inert organic solvent, such as methanol, ethanol or acetone) can be added to the 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 stabilized synthetic polymer compositions of the invention may optionally also contain, various conventional additives, such׳ as the following: Antioxidants

Simple, 2, 6-dialkylphen.ols, such as, for example, 2, 6-di-t־-butyl-4methylphenol, 2-t-butyl-4, 6-dimethylphenol, 2, 6-di-t-butyl4־methoxymethylphenol and 2, 6-dioctadecyl-4-methylphenol.

Derivatives of alkylated hydroquinones, such as, for example,

2, 5-di-t-butylhydroquinone, 2, 5-di-t-amylhydroquinone, 2, 6-di-tbutylhydroquinone, 2, 5-di-t-butyl-4-hydroxyanisole, 3, 5 - di-t-butyl4-hydroxyanisole, tris( 3, 5 -di-t-butyl-4-hydroxyphenyl)phosphite,

3, 5-di-t“butyl-4-hydroxyphenylstearate and di-(3, 5~di-t-butyl-4hydroxyphenyl)adipate.

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

Alkylidene-bisphenols, such as, for example, 2, 2'-methylene-bis(6-t-butyl-4-methylphenol), 2, 2' -methylene-bis( 6-t-butyl-4-ethylphc-nol),

4, 4' -methylene-bis(6־t-butyl-2-methylphenol), 4, 4' -methylene-bis(2, 6-di-t-butyIphenol), 2, 6-di-(3־t-butyl-5־.methyl-2-hydroxybenzyl)-

4-methylphenol., 2,2' -methylene -bis[4 -methyl-6 -(a-methyleyclohexyl)- 24 phenol], 1, l-bis(3, 5-dimethyl-2-hydroxyphenyl.) butane, l,l-bis(5-tbutyl-4-hydroxy-2-methylphenyl)butane, 2, 2-bis(5-t-butyl-4-hydroxy2-methylphenyl)butane, 2, 2-bis(3, 5-di-t-butyl-4-hydroxyphenyl^ropane,

1,1, 3-tris(5-t״butyl-4-hydroxy-2-methylphenyl)butane, 2, 2-bis(5-t5 butyl - 4 - hyd r oxy - 2 - m e thy Iphenyl) - 4 -n - dode cylme r captobutane,

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].

Ο-, N- arid S-benzyl compounds, such as, for example, 3,5, 3', 5'tetra-t-butyl-4,4'-dihydroxydibenzyl ether, 4-hydroxy5 ,3־-dimethyl10 benzyl-mercaptoacetic acid octadecyl ester, tri(3, 5-di-t-butyl-4hydroxybenzyl)amine, and bis(4-t-butyl-3-hydroxy-2, 6-dimethylbenzyl)dithiolterephthalate. .

Hydroxybenzylated malonic esters, such as, for example, 2,2-bis(3,5di-t-butyl-2־hydroxybenzyl)malonic acid dioctadecyl ester, 2-(3-t15 ׳ butyl-4-hydroxy-5-methylbenzyl)malonic acid dioctadecyl ester,

2, 2-b.is(3, 5-di-t-butyl4־-hydroxybenzyl)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-di20 t-butyl-4-hydroxybenzyl)-2, 4, 6-trimethylbenzene, l,4-di(3, 5-di-tbutyl-4-hydroxybenzyl)-2, 3, 5, 6-tetramethylbenzene, and 2, 4, 6-tri- (3, 5-di-t-butyl-4-hydroxybenzyl)phenol.

s“Triazine compounds, such as, for example, 2, 4-bis-octylmcrcapto-

6-(3, 5-di-.t-butyl-4_rhydroxyanilino)-s-triazine, 2-octylmercaptp-4, 6bis(3, 5-di-t-butyl-4־hydroxyanilino)-s-triazine, 2-octylmercapto~4, 6bis(3, 5-di-t-butyl-4-hydroxyphenoxy)-s-triazine, 2, 4, 6-tris(3, 5-dit-butyl-4-hydroxyphenoxy)-£-triazine, 2, 4, 6-tris(3, 5-di-t-butyl4־hydroxyphenylethyl)-s-triazine, and 1, 3, 5-tris(3, 5-di-t-butyl-4hydroxybenzyl)isocyanurate.

Amides of 3, 5-di-t-butyl-4-hydroxyphenylpropionic acid, such as, for example, 1, 3, 5-tris(3, 5-di-t-butyl-4-hydroxyphenyl-propionyl)hexahydro-s-triazine, and N,Ν' -bis(3, 5-di-t-butyl-4-hydroxyphenylpropionyl )hexamethylenediamine.

Esters of 3, 5-di-t-butyI-4-hydroxyphenylpropionic acid with monohydric or polyhydric alcohols, such as, for example, those with methanol, ethanol, octadecanol, 1, G-hexanediol, 1, 9-nonanediol, ethyleneglycol, 1, 2-propanediol, diethylene glycol, thiodiethylene glycol, neopentyl glycol, pentaerythritol, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolethane, trimethylolpropane, trishydroxyethyl isocyanurate, and 4-hydroxymethyl-l-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, ethyleneglycol, 1, 2-propanediol, diethylene glycol, thiodiethylene glycol, neopentyl glycol, pentaerythritol, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolethane, trimethy^olpropane, trishydroxyethyl isocyanurate, and 4-hydroxymethyl-I-phospha-2, 6, 7trioxabicyclo[2, 2, 2]octane.

Esters of 3, 5-di-t-butyl-4-hydroxyphenylacetic acid with monohydric or polyhydric alcohols, such as, for example, those with methanol, ethanol, octadecanol, 1, 6-hexanediol, 1, 9-nonane diol, ethyleneglycol, 1, 2-propane diol, diethyleneglycol, thiodiethyleneglycol, neopentyl glycol, pentaerythritol, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolethane, trimethylolpropane, trishydroxyethyl isocyanurate, and 4-hydroxymethyl-l-phospha-2, 6,7 -trioxabicyclo[2, 2, 2]octane, _ /

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

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-butyl-4-hydroxybenzylphosphonic acid dioctadecyl ester, and 5-t-butyl-4-hydroxy-3-methylbenzylphosphonic acid dioctadecyl ester.

Aminoaryl derivatives, such as, for example, phenyl-1-naphthylamine, phenyl-2-naphthylamine, N, Ν' -diphenyl-p-phenylenediamine, N, Ν' - 27 di-2 -naphthyl-p-phenylencdiamine, N, Ν' -di-s-butyl-p-phenylenediamine,

6-ethoxy-2, 2, 4-triinethyl-l, 2-dihydroquinoline, 6-dodecyl-2, 2,4-trimethyl-1, 2-dihydroquinoline, mono- and di-octyliminodibenzyl, )*©rd polymerized 2, 2, 4-trimethyl-1, 2־dihydroquinoline.

UV-absorbers and light protection agents

2-(2¹ -Hydroxyphenypbenztriazoles, such as, for example, the 5'-methyl, 3', 5'-di-t-butyl, 5'-t-butyl, 5'-(1,1, 3, 3-tetramethylbutyl), 5-chloro-3', 5'di-t-butyl, 5-chloro-3'-t-butyl-5'-methyl, 3'-s-butyl-5'-t-butyl, 3'-[amethylbenzyl] -5' -methyl, 3' -[a-methylbenzyl] -5' -methyl-5-chloro, 4' hydroxy, 4'-methoxy, 4'-octoxy, 3', 5'-di-t-amyl, 3'-methyl-5’-carbomethoxyethyl and 5-chloro-3’, 5'-di-t-amyl derivatives.

2.4-)315(2¹ -hydroxypheriyl)-6-alkyl־s-triazines, such as, for example, the 6-ethyl, 6-undecyl and 6-heptadecyI derivatives.

2-Hydroxybenzophenones, such as, for example, the 4-hydroxy, 4-methoxy, 4-octoxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy,

4, 2', 4' -trihydroxy and 2' -hydroxy-4,4' -dimethoxy derivatives.

1, 3-Bis(2* -hydroxybenzoyl)benzenes, such as, for example, 1,3-bis (2' -hydroxy-4' -hexyloxybenzoyl)benzene, 1, 3-bis(2' -hydroxy-4' octoxybenzoyl)benzene and 1, 3-bis(2' -hydroxy-4' -dodecyloxybenzoyl)benzene.

Esters of optionally substituted benzoic acids, such as, for example, phenyl salicylate, octylphenyl salicylate, dibenzoylresorcinol, bis(4-t-butylbenzoyl)resorcinol, benzoylresorcinol and 3, 5-di-t-butyl4-hydroxybenzoic acid 2, 4-di-t-butylphenyl ester,' octadecyl ester or

2-methyl-4, 6-di-t-butylphenyl ester.

Acrylates, such as, for example, a-cyano-β, β-diphenylacrylic acid ethyl ester or iso-octyl ester, a-carbomethoxycinnamic acid methyl ester, u-cyano-3-methyl-p-1nethoxycinnamic acid methyl ester or butyl ester, and N-(3־carbomethoxyvinyl)2־-methyIindoline.

Nickel compounds, for example, nickel complexes of 2, 2' -thiobis(4t-octylphenol), such as the 1:1 and 1:2 complexes,' optionally with other ligands such as n-butylamine, triethanolamine or N-cyclohexyldiethanolamine; nickel complexes of bis(4-t-octylphenyl)sulphone, such as the 2:1 complex, optionally with other ligands such as 2-ethylcaproic acid; nickel dibutyldithiocarbamate; nickel salts of 4-hydroxy-3, 5. ׳״. . di-t-butylbenzylphosphonic acid monoalkyl esters, such as the methyl, ethyl or butyl ester; the nickel complex of 2-hydroxy4־methylphenyl undecyl ketonoxime; and nickel 3, 5-di-t-butyl-4hydroxybenzoate.

Oxalic acid diamidcs, such as, for example, 4,4' -di-octyloxyoxanilide, 2, 2' -dioctyloxy-5, 5' -di-t-butyloxanilide, 2, 2' -di-dodecyloxy-5, 5' di-t-butyloxanilide, 2-ethoxy-5-t-butyl-2'-ethyloxanilide, 2-ethoxy- 29 2' -ethyloxanilide, N, Ν' -bis( 3 -dimethylaminopropy] )oxalamide, mixtures of 0- and p-methoxy and 0- 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 bis phenylhydrazide, bisbenzylidene oxalic acid dihydrazide, N, Ν'-diacetyladipic acid dihydrazide, N,N׳bis-salicyloyloxalic acid dihydrazide, N, N¹-bis-salicyloylhydrazine, and N,N¹ -bis5 ,3)־-di-t-butyl-4-hydrcxyphenylpropionyl)hydrazine.

Phosphites, such as, for example, triphenyl phosphite, diphenyl alkyl phosphites, phenyl dialkyl phosphites, trinonyl phenyl phosphite, trilauryl phosphite, trioctadecyl phosphite, 3,9-di-isodecyloxy2,4, 8,10-tetraoxa-3, 9-diphosphaspiro[5, 5]undecane, and tris(4hydroxy - 3, 5 - di -t -butylphenyl)phosphite.

Peroxide de activators, such as, for example, esters of β-thiodi.‘ . propionic acid (e. g., the lauryl, s+earyl, myristyl and tridecyl esters), salts of 2-mercaptobenzimidazole (e. g., the zinc salt), and diphenylthiourea.

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

Basic co-stabilizers, such as, for example, polyvinyl-pyrrolidone, melamine, benz oguanam ine, triallyl cyanurate, dicyandiamide, urea derivatives, hydrazine derivatives, amines, polyamides, polyurethanes, and alkali metal salts and alkaline .earth metal salts of higher saturated or unsaturated fatty acids, (e. g., Ca stearate, Mg laurate, Na ricinoleate, K palmitate and Zn stearate).

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

Nucleating agents, such as, for example, 4-t־butylbenzoic acid, adipic acid, and diphenylacetic acid.

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

The use of the stabilizers of formula (I) with the abovelisted antioxidants is particularly effective for the stabilization of olefin polymers.

The invention is illustrated by the following Examples 1 to 7, in which the stabilizers of formula (I) are identified by means,״ of the numbers appended to them in the list given hereinbefore.

Preparations 1 to 6, which follow the Examples, illustrate the preparation of the stabilizers of formula (I). All parts and percentages are by weight, unless otherwise specified. The stabilizers used for comparative purposes in the Examples and identified by the Trade Marks ״Tinuvin-327 and ״Tinuvin P are products of Ciba-Geigy AG and have the following chemical identity: 10 Tinuvin-327: 2-(2-Hydroxy-3, 5-di-t-butylphenyl)-6־chlorobenzo1, 2, 3-triazole;

Tinuvin P : 2-(2-Hydroxy-5־methylphenyl)benzo-l, 2,3-triazole.

Example 1

Mixtures were made from 1,000 parts of polypropylene powder with a melt index of 20 (230 C, 2160 g), 2 parts of β-(3, 5di-t-butyl-4-hydroxyphenyl)propionic acid octadecyl ester and

2.5 or 5 parts of each in turn of the stabilizers of the invention indicated in Table 1. The mixtures were homogenized in a Brabender Kneader at 200°C, then pre-pressed in a toggle press into sheets

2-3 mm thick. The sheets were pressed in a platen press at 260°C, using suitable dies, first into films 0. 3 mm thick and then into films 0.1 ״ mm thick. A control film, containing no stabilizer, was also made.

44629/2

The films were annealed for 1 hour at 150 C, while preventing them from cooling below this temperature, and immediately afterwards quenched in water at 15°C. The resulting films exhibited a homogeneous, fine spherulitic structure. Test specimens punched 5 from the films had an elongation at break of approximately 900%.

The polypropylene films thus formed were mounted on sample carriers and exposed in a Xeno~150* test apparatus. At regular intervals, pieces of film were removed from the apparatus, 5 test specimens were punched out from them, and their residual י elongation was measured. The exposure time after which the elongation at break of the film had declined to 50% of its value before irradiation was determined and was taken as a measure of the effectiveness of the stabilizers.

* The Xeno-150 test apparatus is described in Japanese Industrial Standard L0843.

The results are shown in Table 1.

Table 1

<td colspan="2"> Stabilizer</td><td> Exposure time for elongation at break to decline to 50% of its initial</td>

<td> Compound No.</td><td> Amount added (parts)</td><td> value (hours) s</td>

<td> 3</td><td> 2. 5</td><td> 4700</td>

<td> 4</td><td> 2.5</td><td> 5140</td>

<td> 8</td><td> 2.5 .</td><td> 2200</td>

<td> 21</td><td> 2. 5</td><td> 4920</td>

<td> 27</td><td> 5</td><td> 8900</td>

<td> 29 /</td><td> 5 :</td><td> __________. 4350 -___________</td>

Table 1 cont'd

<td colspan="2"> Stabilizer</td><td rowspan="2"> Exposure time for elgonation at break to decline to 50% of its initial/ value (hours)</td>

<td> Compound No.</td><td> Amount added (parts)</td>

<td> 38</td><td> 5</td><td> 10500</td>

<td> 39</td><td> 5</td><td> 6250</td>

<td> 70</td><td> 2.5</td><td> &gt; 6000</td>

<td> None</td><td></td><td> 800</td>

Example 2

Mixtures were made from 100 parts of polypropylene (Noblen JHH-G״, available from Mitsui Toatsu Chemicals Inc., Japan, employed after 2 recrystallizations from monochlorobenzene) and 0. 25 part of each in turn of the stabilizers of the invention indicated in Table 2 or, as a control, of Tinuvin-327. The resulting mixtures were blended, melted, and moulded under healing and pressure into sheets 0. 5 mm thick. A control sheet, containing no stabilizer, was also made.

The sheets thus formed were exposed to ultraviolet irradiation at 45°C in the Standard Fade-Meter Type FA-1 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 time required for each sheet to become brittle is shown in Table 2.

Example 3

Mixtures were made from 100 parts of high-density polyethylene (Hi-Zex, available from Mitsui Toatsu Chemicals Inc., Japan, employed after two recrystallizations from toluene) and 0. 25 part of each in turn of the stabilizers of the invention indicated in Table 2 or, as a control, of Tinuvin-327. The resulting mixtures were moulded under heating and pressure into sheets 0. 5 mm thick. A control sheet, containing no stabilizer was also made.

The brittleness time of each sheet was measured by the same method as in Example 2, and the results are shown in Table 2.

Table 2

<td rowspan="2"> Stabilizer No.</td><td colspan="2"> Brittleness time (hours)</td>

<td> Polypropylene</td><td> High-density polyethylene</td>

<td> 1</td><td> 560</td><td> ד</td>

<td> 4</td><td> 520</td><td> 1400</td>

<td> 6</td><td> 640</td><td> 1540</td>

<td> 9</td><td> 540</td><td> -</td>

<td> 14</td><td> 520</td><td> 1340</td>

<td> 21</td><td> 500</td><td> -</td>

<td> 27</td><td> 900</td><td> 1</td>

<td> 29</td><td> 480</td><td> -</td>

<td> 38</td><td> 1060</td><td> 1860</td>

<td> 62</td><td> 340</td><td> -</td>

Table 2 cont'd

<td rowspan="2"> Stabilizer No.</td><td colspan="2"> Brittleness time (hours)</td>

<td> Polypropylene</td><td> High-density polyethylene</td>

<td> 70</td><td> 860</td><td> 1600</td>

<td>⁸¹</td><td> 1100</td><td> 1900</td>

<td> 84</td><td> 820</td><td> ׳-</td>

<td> Tinuvin-327</td><td> 340</td><td> 700</td>

<td> None</td><td> 60</td><td> 400</td>

Example 4

Mixtures were made from 100 parts of polystyrene (״Styron, available from Asahi-Dow Limited, Japan, employed after recrystallization from a mixture of benzene and methanol) and 0. 25 part of each in turn of the stabilizers of the invention indicated in

Table 3. The resulting mixtures were moulded under pressure at

180°C into sheets 1 mm thick. A control sheet, containing no stabilizer, was also made.

The sheets thus formed were exposed to ultraviolet irradiation for 500 hours at 45°C in the Fade-Meter described in

Example 2. The difference in colour before and after the exposure to ultraviolet irradiation was measured on test-pieces of the sheets, by the method prescribed in Japanese Industrial Standard K-7103, using a colour-difference colorimeter; and the change in their yellowness index was calculated by means of the equation:

Δ YI = YI - YI 0 wherein ΔΥΙ is the change in the yellowness index, YI is the yellowness index after exposure, and YI is the initial yellowness index of the test piece.

The results are shown in Table 3.

Table

<td> Stabilizer No.</td><td> YI 0</td><td> ΔΥ1</td>

<td> 9</td><td> 4.4</td><td> +5.1</td>

<td> 38</td><td> 4.7</td><td> +5.9</td>

<td> 70</td><td> 4. 6</td><td> +6.1</td>

<td> 84</td><td> 4. 5</td><td> +5. 3</td>

<td> None</td><td> 4. 4</td><td> +17.1</td>

Example 5

Mixtures were made from 100 parts of acrylonitrile/butadiene/־ styrene resin (״Kane-Ace B-12, available from Kanegafuchi Chemical Industries Ltd., Japan) and 0. 5 part of each in turn of the stabilizers of the invention indicated in Table 4 or, as a control, of ״Tinuvin P. The resulting mixtures were kneaded for 6 minutes on kneading rolls at 160°C, and then moulded into sheets about 0. 5 mm thick. A control sheet, containing no stabilizer, was also made.

The sheets thus formed were exposed for 50 hours in the ״Sunshine Weather-ometer prescribed in Japanese Industrial

Standard Z-0230, entitled Accelerated Weathering Test of Rust5 proofing Oils, paragraph 2. The retention of ultimate elongation and of ultimate tensile strength of the sheets were then measured.

The results are shown in Table 4.

Table

<td> Stabilizer No.</td><td> Retention of elongation (%)</td><td> Retention of tensile strength (%)</td>

<td> 6</td><td> 73</td><td> 81</td>

<td> 38</td><td>⁷⁶</td><td> 80</td>

<td> 70</td><td> 75</td><td> 83</td>

<td> 84</td><td> 71</td><td> 78</td>

<td> Tinuvin-P</td><td> 61</td><td> 71</td>

<td> None</td><td> 54</td><td> 71</td>

Example 6

Mixtures were made from 100 parts of nylon-6 (CM 1011, available from Toray Industries Inc., Japan) and 0. 25 part of each in turn of the stabilizers of the invention indicated in Table 5 or, as a control, of ״Tinuvin-P. The resulting mixtures were melted,, and 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 aged 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 5.

Aging conditions

1. Exposure to ultraviolet irradiation for 200 hours at 45°C, in the fade-meter described in Example 2.

2. Aging for 2 hours at 160°C in the Geer's aging tester prescribed in Japanese Industrial Standard K-6301 entitled ”Physical Testing Methods for Vulcanized Rubber”, paragraph 6. 5.

Table 5

<td rowspan="2"> Stabilizer No.</td><td colspan="2"> Fade-Meter</td><td colspan="2"> Geer's aging tester</td>

<td> Retention of elongation (%)</td><td> Retention of tensile strength (%)</td><td> Retention of elongation (%)</td><td> Retention of tensile strength (%)</td>

<td> 9</td><td> 68</td><td> 75</td><td> 60</td><td> 67</td>

<td> 81</td><td> 76</td><td> 78</td><td> 62</td><td> 68</td>

<td> Tinuvin-P</td><td> 52</td><td> 65</td><td> 34</td><td> 59</td>

<td> None</td><td> 23</td><td> 51</td><td> 27</td><td> 55</td>

44629/2

Example 7

Mixtures were made from 100 parts of polycaprolactonetype polyurethane resin (’Έ-5Ο8Ο״, available from the Nippon ו

Elastollan Co. Ltd., Japan) and 10.5 part of each in turn of the stabilizers of the invention indicated in Table 6. 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 irradiation for 15 hours at 45°C in the fade-meter described in

Example 2, and their retention of ultimate elongation and of ultimate tensile strength were then measured.

The results are shown in Table 6.

Table

<td> Stabilizer No.</td><td> Retention of elongation ^x (%)</td><td> Retention of tensile strength (%)</td>

<td> 1</td><td> 81</td><td> 78</td>

<td> 9</td><td> 83</td><td>¹⁵ 80</td>

<td> None</td><td> 78</td><td> 52</td>

Preparation l-Octyl-2, 2, 6, 6-tetramethylpiperidine

A mixture of 56. 4 parts of 2, 2, 6, 6-tetramethylpiperidine and

38. 6 parts of l-bromo-octane was heated at 125 - 130°C for 120 hours.

After cooling, the reaction mixture was filtered, to remove 2,2,64.6tetramethylpiperidine hydrobromide formed during the reaction.

Fractional distillation of the filtrate gave the desired product, having a boiling point of 168°C/17 Torr.

Preparation l-n-Dodecyl-2, 2, 6, 6-tetramethylpiperidine

The procedure of Preparation 1 was repeated, except that the l-bromo-octane was replaced by an equivalent amount of 1-bromo« dodecane. The desired product was obtained, having a boiling point of 115°C/0.004 Torr.

Preparation l-Ethoxycarbonylmethyl-2, 2, 6, 6-tetramethylpiperidine

The procedure of Preparation 1 was repeated, except that the l-bromo-octane was replaced by an equivalent amount of ethyl chloroacetate. The desired product was obtained, having a boiling point of 129-130°C/13 Torr.

Preparation

- O ct oxy carbonylmethyl-2, 2, 6, 6-tetramethylpiperidine

A mixture of 45. 4 parts of l-ethoxycarbonylmethyl-2. 2, 6, 6tetramethylpiperidine, 36. 5 parts of 1-octanol and 0. 5 part of lithium amide was heated at 110-115°C for 48 hours, the ethyl alcohol formed during the reaction being removed by distllation. Fractional distillation of the reaction mixture gave 1-octoxycarbonylmethyl0 t

2, 2, 6, 6-tetramethylpiperidine having a boiling point of 120 C/0. OFT

Torr.

Preparation l-(2-Stearoyloxyethyl)-2_J 2, 6, 6-tetramethylpiperidine g (0. 092 mole) of 1-(2-hydroxyethyl)-2, 2, 6, 6-tetramethylpiperidine in 30 g of chloroform were saturated with dry hydrogen chloride, under cooling. A solution of 27. 9 g (0. 092 mole) of stearoyl chloride in 30 g of chloroform was added, and the reaction mixture was heated under reflux for 12 hours. The chloroform was removed from the reaction mixture, under reduced pressure; and the residual syrup was treated with an excess of 10% sodium carbonate solution, and then extracted with benzene. The benzene was evaporated off from the extract in vacuo, and the residue was chromatographed on a column of silica gel, giving 25 g of the desired product with a melting point of 30°C (50% yield). The identity of the product was confirmed from its nuclear magnetic resonance spectrum.

Preparation

1-(2-Stearoyloxy-2-phenylethyl)-2, 2, 6, 6-tetramethylpiperidine

The procedure of Preparation 5 was repeated, except that the 1-(2-hydroxyethyl)-2, 2, 6, 6-tetramethylpiperidine was replaced by l-(2-hydroxy-2-phenylethyl)-2, 2, 6, 6-tetramethylpiperidine. The column chromatography on silica gel yielded a liquid product which was shown, by elementary analysis .and NMR spectrography, to be essentially

P' pure l-(2-stearoyloxy-2-phenylethyl)-2, 2, 6, 6-tetramethylpiperidine.

Elementary analysis:

Calculated for C_oKH״N0 ׳ C, 79. 63%; H, 11. 65%; N, 2. 65%.

3b bi 2

Found : C, 79.36%; H, 11.91%; N, 2.68%.

Preparation

Bis-2-(2, 2, 6, 6-tetramethylpiperidino)ethyl-succinate

18. 4 g (0.1 mole) of 1-(2-hydroxyethyl)-2, 2, 6, 6rtetramethylpiperidine in 30 g of chloroform were saturated with dry hydrogen chloride, under cooling. A solution of 7. 5 g (0. 049 mole) of succinoyl chloride in 30 g of chloroform was added, and the reaction mixture was heated under reflux for 15 hours. The mixture was then washed with three portions of 10% sodium carbonate solution, and then with water, and dried over anhydrous sodium sulphate. The volatile constituents were evaporated off, leaving a residue which was recrystallized from ethanol, giving 18 g of the pure desired product with a melting point of 77-78°C (80% yield).

Preparation l-Formyl-2, 2, 6, 6-tetramethylpiperidine

A mixture of 5. 0 g of 2, 2, 6, 6-tetramethylpiperidine p-toluenesulphonate, 70 g of ethyl orthoformate and 15 ml of dimethylformamide was heated under reflux for 3 hours. After completion of the reaction, the excess ethyl orthoformate and dimethylformamide were distilled off under reduced pressure. The

5residue was filtered, to remove the crystalline matter which was washed with ether. The filtrate and washings were combined, and washed with aqueous sodium hydrogen carbonate solution, and then withwater. The organic phase was dried over anhydrous magnesium sulphate, and the volatile constituents were evaporated off, leaving

5. 4 g of residue. The residue was chromatographed on a column of silica gel, eluted with a 10:1 mixture of benzene and ethyl acetate, and further purified by sublimation, giving the pure desired product melting at 51. 5-52. 5°C.

Elementary analysis:

Calculated for C H NO: C, 70.96%; H, 11.32%; N, 8.28%. XU lu

Found : C, 71.14%; H, 11.36%; N, 8.26%.