GB2105731A - Copolymeric polyalkylpiperidines - Google Patents

Abstract

Copolymers of (a) at least one unsaturated polyalkylpiperidine derivatives of the formula I <IMAGE> and b) at least one comonorner of the formula II <IMAGE> in which R<1> is one of the groups of the formula III, IV, V, VI, VII or VIII <IMAGE> R<2> is one of the groups III to VIII or is N, alkyl, alkenyl, aralkyl or cycloalkyl, X and Y independently of one another are O or NR<10>, R<3> is H or CH3, R<4> is H, alkyl, phenyl Cl, CN, alkoxy, alkanoyloxy, -COOR<11>,- -CONH2 or -CON(R<12>) (R<13>) or of a) at least one malelmide of the formula Ia <IMAGE> in which R<15> is a group of the formula III or IX and b) at least one comonomer of the formula IIa CH2=CH-R16 in which R<16> is H or alkyl. The polymers may be prepared by direct copolymerisation or by analogous reactions introducing the piperidine moieties into preformed polymers. Typical monomers (a): bis-(1-benzyl-2,2,6,6-tetramethyl-piperid-4- yl)fumarate, N-(2,2,6,6-tetramethyl-piperid-4-yl)-maleimide. The copolymers are effective light stabilisers for plastics and lacquers. <IMAGE>

Description

SPECIFICATION Copolymeric polyalkylpiperidines The invention relates to novel copolymers of unsaturated derivatives of polyalkylpiperidines and one or more unsaturated comonomers, their preparation and their use as light stabilisers for organic polymers.

It is known that polyalkylpiperidine derivatives are outstanding light stabilisers which are particularly used for stabilising organic polymers. In this context, there is the problem that the stabiliser evaporates when the polymers undergo the shaping process, or migrates out of the polymer in the course of time. It is also known that this can largely be prevented by using a polymeric polyalkylpiperidine derivative as the stabiliser. However, the stabilisation of polymers using polymeric stabilisers presents the problem of the limited compatibility of polymers with one another. The compatibility is particularly influenced by the chemical structure and the molecular weight of the stabiliser. As is known from various publications, polymeric polyalkylpiperidine derivatives with a limited molecular weight are therefore preferred.Depending on the chemical structure, the molecular weights are therefore from about 1,000 to 20,000, which is always far below the molecular weight of the polymers to be stabilised.

It is relatively simple thus to limit the molecular weight of polycondensates; it can be done by using an excess of one component or by adding a monofunctional component. In contrast, it is more difficult to limit the molecular weight of polymers in a reproducible manner. European Patent Application 496 recommends the addition of regulators, for example mercaptans or aldehydes, to limit the molecular weight. Another solution is to use monomers which polymerise slowly and give only polymers of limited molecular weight. A process known for this is the copolymerisation of derivatives of maleic acid orfumaric acid with other unsaturated compounds, which usually proceeds in an alternating manner and gives copolymers of limited molecular weight.This principle has already been used also for the preparation of polymeric piperidine light stabilisers, as described in German Offenlegungsschrift 2,920,918. However, the copolymers thus obtained do not fulfil all the requirements in practice. In certain substrates, for example in lacquers, their compatibility or solubility is too low, and in other substrates they have a relatively weak light stabilising action.

Surprisingly, it has been found that the action and compatibility of such copolymeric maleic or fumaric acid derivatives of polyalkylpiperidines can be substantially improved if the piperidine nitrogen is substituted by certain substituents.

The invention relates to copolymers of a) at least one unsaturated polyalkylpiperidine derivative of the formula I

and b) at least one comonomer of the formula II

in which R1 is one of the groups of the formula Ill, IV, V, VI, VII or VIII

R is one of the groups III, IV, V, VI, VII or VIII or is hydrogen, C1-C18-alkyl, alkyl which is interrupted by -O-, or C3-C5-alkenyl, C7-C11-aralkyl or C5-C12-cycloalkyl, X and Y independently of one another are 0 or NR10, R3 is hydrogen or methyl, R4 is hydrogen, C1-C18-alkyl, phenyl, Cl, CN, C1-C18-alkoxy, C2-C5-alkanoyloxy, -COOR11, -CONH2 or -CON(R12)(R13), R5 is C3-C5-alkenyl, C3-C5-alkynyl, -CH2-CH(OH)-R7, -CH2CN, unsubstituted or C1-C4-alkyl-substituted C7-C11-aralkyl, C2-C18alkanoyl, C3-C5-alkenoyl, -OH, -O. (oxyl oxygen), -COOC1-C4-alkyl or -CON(R12)(R13), R6 is hydrogen or C1-C5-alkyl, R7 is hydrogen, C1-C3-alkyl, phenyl, C1-C4-alkoxy-methyl, phenoxy-methyl or C1-C4-alkyl-phenoxymethyl, R8 is hydrogen, C1-C18-alkyl, C3-C5-alkenyl, C3-C5-alkynyl, C2 C18-alkanoyl, C3-C5-alkenoyl, unsubstituted or C1-C4-alkyl-substituted C7-C11-aralkyl, -CH2CN,- -CH2-CH(OH)-R7 or -CON(R12)(R13), R9 is hydrogen, C1-C18-alkyl, C3-C5-alkenyl or C7-C11aralkyl, R10 is hydrogen, C1-C18-alkyl, cyclohexyl, C7-C11-aralkyl, phenyl or a group of the formula III, R11 is hydrogen, C1-C18-alkyl, C2-C4-hydroxyalkyl, glycidyl, a group of the formula III, IV, V, VI, VII or VIII or a group of the formula IX

in which R'4 is hydrogen or C1-18-alkyl, and R12 is C1-C12-alkyl, C5-C8-cycloalkyl, phenyl, benzyl or a group of the formula III or IX and R'3 is hydrogen, C1-C12-alkyl, C5-C8-cycloalkyl or benzyl, or R12 and R'3, together with the N atom to which they are bonded, form a 5-, 6- or 7- membered heterocyclic ring, R'7 is hydrogen, methyl or ethyl, p is zero or 1 and, if p is zero, q is one, or if p is 1 , q is zero or 1, or copolymers of a) at least one maleimide of the formula la

in which R15 is a group of the formula III or IX, and b) at least one comonomer of the formula ila CH2=CH-R16 (IIa) in which R18 is hydrogen or C1-C18-alkyl, the number-average molecular weight of the copolymer being from 1,000 to 50,000, and especially from 1 ,000 to 10,000.

An alkyl radical R, R4, R6, R7, R8, R9, R10, R11, R12, R13, R14 or R16 can be a branched or straight chain alkyl group. Examples are-taking into account the C-number defined-methyl, ethyl, iso-propyl, butyl, sec.-butyl, tert.-butyl, iso-amyl, n-hexyl, 2-ethylbutyl, n-octyl, 2-ethylhexyl, n-decyl, iso-decyl, n dodecyl, n-tetradecyl, n-pentadecyl and n-octadecyl.

An alkenyl radical R2, R5, R8 or R9 can be, for example, allyl, methallyl or dimethylaliyl.

An alkynyl radical R5 or R8 can be, for example, propargyl, but-2-ynyl or pent-2-ynyl.

An aralkyl radical R2, R5, R8 or R9 can be, for example, benzyl, phenethyl, phenylpropyl or naphthylmethyl.

A cycloalkyl radical R2, R12 or R13 can be, for example, cyclopentyl, cyclohexyl or cyclooctyl.

An alkanoyl or alkenoyl radical R5 or R8 can be, for example, acetyl, propionyl, butyryl, hexanoyl, lauroyl, acryloyl, methacryloyl or crotonoyl.

A 5-, 6- or 7-membered heterocyclic ring formed by R12 and R13, together with the nitrogen to which they are bonded, can be, for example, a pyrrolidine, piperidine, morpholine or 4-alkylpiperazine ring.

Copolymers in which the polyalkylpiperidine groups are 2,2,6,6-tetramethylpiperidine groups are preferred. These are copolymers in which R6 in the groups of the formulae III, IV, V, VI, VII, VIII and IX is hydrogen.

Preferred copolymers are also those of a compound of the formula I and at least one comonomer of the formula II in which R is R, H or C1-C18-alkyl, R4 is hydrogen, C1-C6-alkyl, phenyl, C2-C6alkoxy, acetoxy or -COOR11, R5 is C3-C5-alkenyl, C2-C6-alkanoyl, C3-C5-alkenoyl, benzyl, -CH2CN or -CON(F12) (R13), R6 is hydrogen, R8 is hydrogen, C1-C6-alkyl, C3-C5-alkenyl, C2-C6-alkanoyl, C3-C5-alkenoyl, benzyl or-CH2CN, R9 is hydrogen, C1-C12-alkyl, ally or benzyl, R10 is hydrogen or C1-C8-alkyl, R1' is C1-C6-alkyl, C2-C4-hydroxyalkyl or a group of the formula Ill, IV, V, VI or IX, in which R14 is H or C1-C4-alkyl, and R12 and R13 are C1-C6-alkyl, cyclohexyl or benzyl and R1, X, Y, R3, R7, R15 and R16 are as defined above, the number-average molecular weight of the copolymer being from 1,000 to 10,000, and especially from 1,000 to 5,000.

Especially preferred copolymers are those of a) a compound of the formula I in which R1 is a group of the formula III, R is R1 or C1-C5-alkyl, X and Y are oxygen and, in formula Ill, R5 is allyl, benzyl or acetyl and R6 is hydrogen, and b) a compound of the formula II in which R3 is hydrogen or methyl and R-4 is hydrogen, C1-C6- alkyl or -COOR11, and R" is C1-C4-alkyl or a group of the formula Ill in which R5 is acetyl or benzyl and F6 is hydrogen, or R" is a group of the formula IX in which R6 is H and R14 is H or CH3, or of a) a compound of the formula la in which R15 is a group of the formula IX, in which F6 is hydrogen and R 4 is H or CH3, and b) a compound of the formula Ia in which R18 is as defined above.

The compounds of the formula I are maleic or fumaric acid derivatives of polyalkylpiperidinealcohols or -amines. Some of them are known compounds, such as those described, for example, in German Offenlegungsschriften 2,258,752, 2,623,422, 2,349,962 and 2,627,688. Compounds of the formula la are described in European Patent Application 496. Novei compounds of the formula I or la which are used in the present invention can be prepared in a manner similar to that for the known compounds.

Examples of monomers of the formula I are: bis-( 1 -acetyl-2,2,6,6-tetramethyl-piperid-4-yl) maleate, bis-(1-benzyl-2,2,6,6-tetramethyl-piperid-4-yl) fu marate, bis-( 1 -allyl-2 ,2,6,6-tetra methyl- piperid-4-yl) fu ma rate, bis-( 1 -a cryloyl-2 ,2,6,6-tetra methyl-piperid4-yl) fumarate, bis-( 1 -propargyl2,2,6,6-tetramethyl-piperid-4-yl) maleate, bis-( 1 -oxyl-2,2,6,6-tetra methyl-piperid-4-yl) maleate, bis (1 -hydroxyethyl-2,2,6,6-tetramethyl-piperid-4-yl) fuma rate, bis-[ 1 -(2'-phenoxy-2'-hydroxy)-ethyl- 2,2,6,6-tetramethyl-piperid-4-yl] fumarate, bis-(1-cyanomethyl-2,3,6-trimethyl-2,6-diethyl-piperid-4yl) fumarate, mono-(1-benzyl-2,2,6,6-tetramethyl-piperid-4-yl)maleate, mono-(1-acetyl-2,2,6,6tetra methyl-piperid-4-yl) monoethyl fu marate, N ,N'-bis-( 1 -benzyl-2,2,6,6-tetramethyl-piperid-4-yl)- fumarodiamide, N,N'-bis-( 1 -benzyl-2,2,6,6-tetramethyl-piperid-4-yl)-N,N'-dibutyl-fumarodiamide, bis [2-(2,2,6,6-tetramethylpiperidino)ethyl] fumarate, bis-[2-(2,2,6,6-tetramethylpiperidino)-propyl] fumarate, bis-[2-( 1 ,3,8-triaza-2,4-dioxo-7,7,8,9,9-penta methyl-spiro[4,Sjdec-3-yl)-ethyl] fumarate, bis-[2-( 1 ,3,8-triaza-2 ,4-dioxo-7,7,9,9-tetramethyl-3-dodecyl-spirn[4,Sjdec-8-yl)-prnpyl fu marate and monoethyl fumarate N-(1-butyryl-2,2,6,6-tetramethyl-piperid-4-yl)-monoamide.

Examples of monomers of the formula la are: N-(1,2,2,6,6-pentamethyl-piperid-4-yl)-maleimide, N-(2,2,6,6-tetramethyl-piperid-4-yl)-maleimide, N-(1-benzyl-2,2,6,6-tetramethyl-piperid-4-yl)-maleimide and N-( 1 acetyl-2,2,6,6-tetramethyl-piperid-4-yl)-maleimide.

The comonomers of the formula II or Ila which are free from piperidine radicals are commercially available monomers, for example ethylene, propylene, I -butene, isobutylene, 1-hexene, 1-octene, 1- octadecene, styrene, a-methylstyrene, vinyl chloride, vinyl acetate, vinyl alkyl ethers, alkyl (methacrylates, hydroxyalkyl (meth)acrylates, alkyl crotonates, acrylamide, N-alkylacrylamides, N-hydroxyalkylacrylamides, methacrylamide and acrylonitrile. Copolymers with ethylene as the comonomer in a molar ratio of 1:1 are particularly preferred.

The comonomers of the Formula II which are derivatives of polyalkylpiperidines (R4 is a -COOR11 group and R11 is a group of the formula Ill, IV, V, VI or IX) are known, for example, from German Offenlegungsschrift 2,040,983, 2,258,752 and 2,623,422, or they can be prepared in accordance with the instructions in those specifications.

Examples of such compounds of the formula II are: 2,2,6,6-tetramethyl-4-acryloxy-piperidine, 1 -allyl-2,2,6,6-tetramethyl-4-acryloxy-piperidine, 1 - acetyl-2,2,6,6-tetramethyl-4-acryloxy-piperidine, 1-cyanomethyl-2,2,6,6-tetramethyl-4-acryloxy piperidine, 1 -benzyl-2,2,6,6-tetra methyi-4-methacryloxy-piperidine, 1 ,2,2,6,6-pentameihyl-4- methacryloxy-piperidine, 2,2,6,6-tetramethyl-4-acrylamido-piperidine, 1 ,2,2,6,6-pentamethyl-4- acrylamido-piperidine, 1,2,2,6,6-pentamethyl-4-(N-butyl)-acrylamido-piperidine, 1-benzyl-2,2,6,6tetramethyl-4-methacrylamido-piperidine and 2,2,6,6-tetramethyl-4-(n-dodecyl)-methacrylamidopiperidine.

The copolymers according to the invention can be prepared either by direct copolymerisation of compounds of the formula I or la with compounds of the formula II or Ila or by polymer-analogous reaction of precopolymers with (polyalkyl)-piperidine derivatives.

The direct copolymerisation can be carried out in the presence or absence of solvents, preferably in an organic solvent or in aqueous dispersion. The polymerisation can be initiated by ionic catalysts, the reaction being carried out at room temperature or only slightly elevated temperature. However, the copolymerisation is preferably initiated by means of free radical catalysts, for example peroxy compounds or azo compounds. In this case, the reaction is carried out at elevated temperature, preferably at 40 -150 C. If the comonomer is gaseous at the polymerisation temperature, the copolymerisation is carried out under increased pressure, advantageously in an autoclave.

At least an equimolar amount, and preferably an excess, of the comonomer II or Ila is used. Even if an excess of II or Ila is used, predominantly alternating copolymers which contain the two components in an approximate molar ratio of 1:1 are obtained. If II is an acrylic or methacrylic acid derivative, copolymers having a component ratio corresponding to the ratio of the monomers used are obtained.

In particular cases, it may be advantageous to copolymerise more than one compound of the formula I or la or more than one compound of the formula II or Ila. In these cases also, predominantly alternating copolymers are formed.

The polymerisation is generally carried out by a procedure in which all of the monomeric components together with the initiator are dissolved in an organic solvent or dispersed in water and polymerisation is initiated by slowly warming the solution or dispersion. However, it is also possible initially to start the polymerisation with only some of the two components and then to continuously add the monomer mixture dropwise. In general, the copolymerisation of I with II and of la with Ila is relatively slow and requires a polymerisation time of several hours at elevated temperature until all the monomers of the formula I or la have been copolymerised. Accordingly, the resulting copolymers have a relatively low molecular weight, which is the intention of the invention.In general, copolymers with a number-average molecular weight of from about 1 ,000 to 20,000 are obtained; the molecular weight can also be higher in individual cases. However, copolymers with a number-average molecular weight of from 1,000 to 1 0,000, and especially of from 1 ,000 to 5,000, are preferred.

Organic solvents in which the copolymerisation can be carried out are, for example, hydrocarbons, such as toluene or xylene, esters, such as ethyl acetate or butyl acetate, and ethers, such as dibutyl ether or dioxan. If the copolymerisation is carried out in aqueous dispersion, an emulsifier, for example sodium lauryl-sulfate or sodium do-decylbenzenesulfonate, is advantageously added. The copolymer can be isolated from the solution, for example, by precipitation with a non-solvent or by evaporation. If the copolymer is insoluble in the solvent used, it separates out in the form of a dispersion and can be isolated by simple filtration, as is also the case with aqueous dispersions. The copolymers according to the invention are usually solid and soften above 600, which is desirable for their use as stabilisers.

As already mentioned, the copolymers according to the invention can also be prepared by an indirect route, by first preparing a precopolymer which is then converted into the copolymer according to the invention by a polymer-analogous reaction. For example, a precopolymer I'/ll can be prepared by copolymerisation of a monomer I' with the comonomer II and can then be converted into a copolymer l/il or la/ll by a polymer-analogous chemical reaction.

Suitable monomers 1' are, for example, maleic anhydride, dialkyl maleates and dialkyl fumarates, precopolymers with maleic anhydrides have the structure X

and can be converted into the polymer-analogous half-esters or half-amides having the structure XI or

by reaction with a piperidine derivative of the formula F1-XH.

In a second reaction stage, if excess F1-XH is used, a product having the structure XII can be obtained:

Alternatively, if a reagent R2--YH which differs from F1-XH is used in the second stage, polymers having the structure XIII or Xllla are obtained:

Starting from a maleic anhydride/olefin copolymer having the structure XIV, a la/lla copolymer having the structure XV is obtained, via the intermediates XlVa, by reaction with a primary amine of the formula F15-NH2:

Copolymers of maleic anhydride having the structure X or XIV and a relatively low molecular weight are commercially available.Reactions of such precopolymers with F1-XH, R2--YH or F15- NH2 are preferably carried out in a solvent. The ring-opening of the precopolymers with 1 mol equivalent of F1-XH to form half-esters or half-amides having the structure Xl already occurs quantitatively within a short time at relatively low temperatures, for example at 50-100 .

Higher temperatures, for example 80-160 , are required for the second stage of the reaction to give XII or XIII or the imide formation to give XV. The second stage can also be carried out under milder conditions if the intermediates having the structure Xl are first reacted with an equimolar amount of thionyl chloride and the second mol equivalent of R-XH or R-YH is then added.

As well as the precopolymers of maleic anhydride with comonomers of the formula II or Ila, precopolymers of dialkyl maleates orfumarates with this comonomer can also be used. Such copolymers have the structure XVI

and are also known compounds, some of which are commercially available.

They can be converted into the corresponding mixed diesters or ester-amides by reaction with 1 mol equivalent of F1-XH. The copolymers having the structure XII are obtained by reaction with 2 mol equivalents of F1-XH. If the precopolymers having the structure XVI are reacted first with one mol equivalent of F1-XH and then with a compound R-YH which differs from F1-XH, products having the structure XIII are obtained. If less than 1 mol equivalent of R-YH is used in the second reaction stage or if the precopolymer is reacted with more than 1 but less than 2 mol equivalents of F1-XH, partially reacted copolymers are obtained. These copolymers are likewise the subject of the invention and can be used as light stabilisers.

These reactions can be carried out without solvents or in organic solvents. If F1-XH or R-YH is an alcohol, the reaction is carried out by general trans-esterification procedures. The reaction is preferably carried out in the presence of trans-esterification catalysts and at temperatures from 110 to 1800. If F1-XH or R-YH is an amine, the reaction is carried out by the general procedures for amidation of esters. In this case, the reaction is preferably carried out with basic catalysts, for example alkali metal alkoxides, and at temperatures from 120 to 1 700.

If a precopolymer having the structure (XVII)

is reacted with one mol equivalent of a primary amine F15--NH2, an ester-amide is initially obtained, and this product can be converted into an imide copolymer having the structure XV by heating to temperatures of from 130 to 1800, for example in dimethylformamide.

Finally, the substituents R5, R8 and R'4 on the piperidine nitrogen can also be introduced by reaction with a precopolymer. For this, it is possible to use a precopolymer in which R5, R8 or R14 is hydrogen and to react this precopolymer, for example, with an alkyl, alkenyl, alkynyl, aralkyl, alkanoyl or alkenoyl halide. An acetyl radical can be introduced by means of acetic anhydride, a cyanomethyl radical can be introduced by reaction with CH2O/HCN and a methyl group can be introduced by reaction with CH2O/HCOOH. Some of these conversions of precopolymers into copolymers according to the invention are described in more detail in the Examples.

The copolymers according to the invention are effective light stabilisers for organic polymers which are sensitive to light, especially UV light. Examples of such light-sensitive polymers are: 1. Polymers of monoolefins and diolefins, for example polyethylene (which may be crosslinked), polypropylene, polyisobutylene, polybut-1-ene, polymethylpent-1-ene, poly-isoprene and polybutadiene, and polymers of cycloolefins, for example of cyclopentene or norbornene.

2. Mixtures of the polymers mentioned under 1), for example mixtures of polypropylene with polyethylene or with polyisobutylene.

3. Copolymers of monoolefins and diolefins with one another or with other vinyl monomers, for example ethylene/propylene copolymers, propylene/but-l-ene copolymers, propylene/isobutylene copolymers, ethylene/but-l-ene copolymers, propylene/butadiene copolymers, isobutylene/isoprene copolymers, ethylene/alkyl acrylate copolymers, ethylene/alkyl methacrylate copolymers, ethylene/vinyl acetate copolymers and ethylene/acrylic acid copolymers and salts thereof (ionomers), as well as terpolymers of ethylene, propylene and a diene, such as hexadiene, dicyclopentadiene or ethylidenenorbornene.

4. Polystyrene.

5. Copolymers of styrene or a-methylstyrene and dienes or acrylic derivatives, for example styrene/butadiene, styrene/acrylonitrile, styrene/ethyl methacrylate, styrene/butadiene/ethyl acrylate and styrene/acrylonitrile/methyl acrylate; high impact strength mixtures of styrene copolymers and another polymer, for example a polyacrylate, a diene polymer or an ethylene/propylene/diene terpolymer; and block copolymers of styrene, for example styrene/butadiene/styrene, styrene/isoprene/styrene, styrene/ethylene and/or butylene/styrene and styrene/ethylene and/or propylene/styrene.

6. Graft copolymers of styrene, for example styrene on polybutadiene, styrene and acrylonitrile on polybutadiene, styrene and maleic anhydride on polybutadiene, styrene and alkyl acrylates or alkyl methacrylates on polybutadiene, styrene and acrylonitrile on ethylene/propylene/diene terpolymers, styrene and acrylonitrile on polyalkyl acrylates or polyalkyl methacrylates, and styrene and acrylonitrile on acrylate/butadiene copolymers, and mixtures thereof with the copolymers mentioned under 5), for example the mixtures known as so-called ABS, MBS, ASA or AES polymers.

7. Halogen-containing polymers, for example polychloroprene, chlorinated rubber, chlorinated or chlorosulfonated polyethylene, epichlorohydrin homopolymers and copolymers, and especially polymers of halogen-containing vinyl compounds, for example polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride and polyvinylidene fluoride; and copolymers of these vinyl compounds, such as vinyl chloride/vinylidene chloride, vinyl chloride/vinyl acetate and vinylidene chloride/vinyl acetate.

8. Polymers which are derived from a,P-unsaturated acids and their derivatives, such as polyacrylates and polymethacrylates, and polyacrylamides and polyacrylonitriles.

9. Copolymers of the monomers mentioned under 8) with one another or with other unsaturated monomers, for example acrylonitrile/butadiene copolymers, acrylonitrile/alkyl acrylate copolymers, acrylonitrile/alkoxyalkyl acrylate copolymers, acrylonitrile/vinyl halide copolymers and acrylonitrile/alkyl methacrylate/butadiene terpolymers.

1 0. Polymers which are derived from unsaturated alcohols and amines or their acyl derivatives or acetals, such as polyvinyl alcohol, polyvinyl acetate, stearate, benzoate or maleate, polyvinyl butyral, polyallyl phthalate and polyallylmelamine.

11. Homopolymers and copolymers of cyclic ethers, such as polyalkylene glycols, polyethylene oxide and polypropylene oxide, and copolymers thereof with bisglycidyl ethers.

12. Polyacetals, such as polyoxymethylene, and polyoxymethylenes which contain comonomers, for example ethylene oxide.

1 3. Polyphenylene oxides and sulfides.

14. Polyurethanes which are derived on the one hand from polyethers, polyesters and polybutadienes with terminal hydroxyl groups and on the other hand from aliphatic or aromatic polyisocyanates, and intermediates thereof (polyisocyanates, polyols and prepolymers).

1 5. Polyamides and copolyamides which are derived from diamines and dicarboxylic acids and/or from aminocarboxylic acids or the corresponding lactams, such as polyamide 4, polyamide 6, polyamide 6/6, polyamide 6/10, polyamide 11, polyamide 12, poly-2,4,4-trimethylhexamethylene terephthalamide and poly-m-phenylene-isophthalamide, and copolymers thereof with polyethers, for example with polyethylene glycol, polypropylene glycol or polytetramethylene glycol.

1 6. Polyureas, polyimides and polyamide-imides.

17. Polyesters which are derived from dicarboxylic acids and diols and/or from hydroxycarboxylic acids or the corresponding lactones, such as polyethylene terephthalate, polybutylene terephthalate, poly-1 ,4-dimethylolcyclohexane terephthalate, poly-L2,2-bis-(4-hydroxyphenyl)-propanei terephthalate and polyhydroxybenzoates, and block polyether/esters which are derived from polyethers with hydroxyl end groups, dialcohols and dicarboxylic acids.

1 8. Polycarbonates.

1 9. Polysulfones and polyether-sulfones.

20. Crosslinked polymers which are derived from aldehydes on the one hand and phenols, urea or melamine on the other hand, such as phenol/formaldehyde resins, urea/formaldehyde resins and melamine/formaldehyde resins.

21. Drying and non-drying alkyd resins.

22. Unsaturated polyester resins which are derived from copolyesters of saturated and unsaturated dicarboxylic acids with polyhydric alcohols, and vinyl compounds as crosslinking agents, as well as their halogen-containing, low-burning modifications.

23. Crosslinkable acrylic resins which are derived from substituted acrylic acid esters, for example from epoxyacrylates, urethane/acrylates or polyester-acrylates.

24. Alkyd resins, polyester resins and acrylate resins which are crosslinked with melamine resins, urea resins, polyisocyanates or epoxide resins.

25. Crosslinked epoxide resins which are derived from polyepoxides, for example from bisglycidyl ethers or from cycloaliphatic diepoxides.

26. Natural polymers, such as cellulose, natural rubber and gelatin, and their polymerhomologous chemically modified derivatives, such as cellulose acetates, propionates and butyrates, and the cellulose ethers, such as methyl-cellulose.

Stabilisation of polyolefins, styrene polymers, polyamides, polyurethanes and varnish gums, such as alkyd, acrylic and polyester resins, is of particular importance.

The copolymeric stabilisers are added to the plastics in a concentration of 0.01 to 5% by weight, based on the material to be stabilised. 0.1 to 2% by weight of the compounds, based on the material to be stabilised, are preferably incorporated into this material.

The compounds can be incorporated during or after the polymerisation; for example the compounds and, where relevant, further additives can be mixed into the melt by the methods customary in the art before or during shaping, or the dissolved or dispersed compounds can be applied to the polymer, if necessary with subsequent evaporation of the solvent.

The polymers to be stabilised can also be treated with the novel compounds in the form of a master batch, which contains these compounds, for example, in a concentration of 2.5 to 25% by weight.

The invention thus also relates to the polymers which have been stabilised by addition of 0.01 to 5% by weight of a compound of the formula I and which, if desired, can also contain other known and usual additives. The plastics thus stabilised can be used in many different forms, for example as films, fibres, narrow tapes or profiies, or as binders for lacquers, adhesives or putty.Examples which may be mentioned of other additives with which the stabilisers which can be used according to the invention can be conjointly employed are: antioxidants, such as 2,6-dialkylphenols, derivatives of alkylated hydroquinones, hydroxylated diphenyl thioethers, alkylidene-bis-phenols, 0-, N- and S-benzyl compounds, hydroxybenzylated malonates, hydroxybenzyl aromatics, s-triazine compounds, amides of A-(3,5-di-tert.-butyl-4-hydroxyphenyl)-propionic acid, esters of ,B-(3,5-di-tert.-butyl-4-hydroxy-3- methylphenyl)-propionic acid, esters of 3,5-di-tert.-butyl-4-hydroxyphenylacetic acid, acylaminophenols, benzylphosphonates and aminoaryl derivatives, UV absorbers and light stabilisers, such as 2-(2'-hydroxyphenyl)-benzotriazoles, 2,4-bis-(2'-hydroxyphenyl)-6-alkyl-s-triazines, 2- hydroxybenzophenones, 1 ,3-bis-(2'-hydroxybenzoyl)-benzenes, esters of substituted or u nsubstituted benzoic acids and acrylates, and furthermore nickel compounds, sterically hindered amines, oxalic acid diamides, metal deactivators, phosphites, compounds which destroy peroxide, polyamide stabilisers, basic co-stabilisers, PVC stabilisers, nucleating agents or other additives, for example plasticisers, lubricants, emulsifiers, fillers, carbon black, asbestos, kaolin, talc, glass fibres, pigments, fluorescent brighteners, flameproofing agents and antistatic agents.

Examples of other additives with which the stabilisers which can be used according to the invention can be conjointly employed can be found in German Offenlegungsschrift 2,427,853, on pages 18-24.

If known stabilisers are also used, synergistic effects may occur, which is frequently the case especially if UV absorbers are also used.

The copolymers according to the invention can also be used in the form of their salts. If R5 and R8 are not acyl groups, the piperidine groups of the copolymers according to the invention are capable of forming salts with acids, for example with hydrochloric acid, phosphoric acid or sulfonic acids. Those copolymers which have free carboxyl groups, for example those in which the group -YR2 in component I is -OH, or those in which the group R4 in component II is -COOH, can also form salts with strong bases, in particular alkali metal salts.

The copolymers according to the invention can also be used in the form of their complexes with heavy metal compounds, in particular nickel or cobalt compounds. Examples of these complexes are those with nickel acetate, nickel stearate or nickel acetylacetonate.

The Examples which follow illustrate the preparation of the copolymers according to the invention and their use as light stabilisers. The temperatures given in the Examples are in OC.

Example 1: 34.5 g (0.06 mol) of bis-(1-benzyl-2,2,6,6-tetramethyl-piperid-4-yl) fumarate (melting point: 177-178 ), dissolved in 250 ml of butyl acetate, are introduced into a 1 litre autoclave (of Hastelloy B) with a magnetically driven propellor stirrer, and 1.0 g of azo-isobutyronitrile (AIBN) is added.

Ethylene is then forced in until the pressure is 50 bars, and the reaction mixture is warmed at 8890 for 8 hours, while stirring, a final pressure of 75 bars at 900 being established. The reaction mixture is then evaporated, the residue is dissolved in chloroform and the solution is filtered through a layer of kieselguhr (Hyflo). The filtrate is concentrated to about 100 ml and the concentrate is stirred into about 1 litre of methanol at room temperature, while stirring vigorously at a high speed, and the colourless, fine powder which thereby separates out is filtered off and dried under a high vacuum at Soc.The bis (1 -benzyl-2,2,6,6-tetramethyl-piperid-4-yl) fumarate/ethylene copolymer thus obtained has a softening point (Tg) of 1000 and has a mean molecular weight (Mn) of 7,300 (copolymer No. 1).

(C38Hs4N204)n Calculated: N 4.65% (602.8)n Found: N 4.4%.

Example 2: By a method analogous to that in Example 1,33.3 g (0.07 mol) of bis-(1 -allyl-2,2,6,6- tetramethylpiperid-4-yl) fumarate (melting point: 1211220), 250 ml of butyl acetate and 0.8 g of AIBN are introduced into a 1 litre autoclave. Ethylene is forced in until the pressure is 50 bars and copolymerisation is carried out at 8890 for 7 hours, while stirring vigorously. The final pressure is 84 bars (at 900). The bis-(1-allyl-2,2,6,6-tetramethylpiperid-4-yl) fumarate/ethylene copolymer is isolated by a method analogous to that in Example 1. The copolymer (No. 2) is obtained as a colourless powder having a softening point of about 650 and an Mn of 3,900.

Example 3: By a method analogous to that in Example 1,31.1 g (0.065 mol) of bis-(1-acetyl-2,2,6,6- tetramethylpiperid-4-yl) fumarate (melting point: 1 51--1520; prepared by transesterification of diethyl fumarate with 2 mol equivalents of 1 -acetyl-4-hydroxy-2,2,6,6 tetramethylpiperidine of melting point 129130 ) and 1.0 g of AIBN in 250 ml of butyl acetate are introduced into the reaction vessel, ethylene is forced in until the pressure is 50 bars, and the mixture is heated at 88900 for 6 hours, while stirring, an end pressure (at 900) of 77 bars being established. The crude copolymer is then freed from the solvent under a waterpump vacuum, the residue is dissolved in methylene chloride and the solution is clarified by filtration through a layer of Hyflo.The filtrate is concentrated and a precipitate is obtained by stirring the concentrate vigorously in 500 ml of n-hexane at a high speed at room temperature, the precipitate is dissolved in a little methylene chloride and the solvent is removed completely in vacuo, whereupon the bis-(1-acetyl-2,2,6,6-tetramethylpiperid-4-yl) fumarate/ethylene copolymer is obtained as a white, pulverisable mass having a softening point of 900 and an Mn of 5,300 (copolymer No. 3).

Example 4: By a method analogous to that in Example 1, 10 g (0.04 mol) of N-(1 ,2,2,6,6-pentamethyl- piperid-4-yl)-maleimide (melting point: 1 18--1 190, prepared from maleic anhydride and 4-amino 1 ,2,2,6,6-pentamethylpiperidine) and 0.2 g of AIBN in 80 ml of butyl acetate are introduced into a 0.3 litre autoclave. Ethylene is forced in until the pressure is 50 bars, and copolymerisation is then carried out at 8890 for 5 hours, while stirring vigorously. The final pressure at 880 is 70 bars.

To isolate the N-(1,2,2,6,6-pentamethyl-piperid-4-yl)-maleimide/ethylene copolymer, the reaction mixture is filtered over Hyflo, the filtrate is washed with methylene chloride and evaporated, the residue is dissolved again in a little methylene chloride and the copolymer solution is poured into 400 ml of acetonitrile, while stirring vigorously at a high speed. The precipitated copolymer (No. 4) is dried at 500 under a high vacuum; it has a softening point of about 1900 and a mean molecular weight Mn of 7.300.

By an analogous method, 10 g (0.04 mol) of N-(1,2,2,6,6-pentamethyl-piperid-4-yl)-maleimide and 0.5 g of AIBN in 80 ml of butyl acetate are copolymerised with ethylene at 900 and the copolymer is isolated by a method analogous to that in Example 4. The resulting copolymer has a softening point of 1 500 and a mean molecular weight of 1,900 (copolymer No. 4a).

Example 5: A) Bis-(2,2,6,6-tetramethyl-piperid-4-yl) fumarate/ethylene copolymer: By a method analogous to that in Example 1, 31.6 g (0.08 mol) of bis-(2,2,6,6-tetramethylpiperid-4-yl) fumarate (melting point: 1 57-1 580) and 0.35 g of AIBN in 250 ml of butyl acetate are copolymerised with ethylene under a pressure of 40 bars at 750 in a 1 litre autoclave and the copolymer is isolated. Softening point: about 800--820.

B) Bis-( 1 -a llyl-2,2,6,6-tetra methyl-piperid4-yl) fumarate/ethylene copolymer obtained by polymer-analogous allylation of A): A solution of 9.3 g (0.022 mol) of the copolymer prepared in A) in 50 ml of methyl ethyl ketone is treated with 6 g of allyl bromide and 7 g of anhydrous potassium carbonate (finely powdered) and the mixture is heated at 7880 under nitrogen for 28 hours. The reaction mixture is then filtered hot and the filtrate is freed from the solvent in vacuo. The residue is dissolved in a little methylene chloride and the solution is poured slowly into 300 ml of methanol, while stirring vigorously at a high speed. The precipitate is separated off and dried at room temperature under a high vacuum.The copolymer (No. 5) which has been allylated by a polymer-analogous reaction has a softening point of about 90" and an Mn of 11,800.

(C30H50N2O4)n Calculated: N 5.57% (502.7)n Found: N 5.3%.

Example 6: A solution of 1 7.3 g (0.03 mol) of bis-( 1 -benzyl-2,2,6,6-tetramethyl-piperid-4-yl) fumarate, 12 g (0.12 mol) of ethyl acrylate and 0.6 g of tert.-butyl perbenzoate in 50 ml of butyl acetate is subjected to copolymerisation at 11 5-11 60 in a nitrogen atmosphere for 26 hours, while stirring. After this period, monomeric educts can no longer be detected in the polymerisation mixture. The reaction mixture is then concentrated and the concentrate is stirred into 400 ml of methanol at room temperature, while stirring vigorously at a high speed. The bis-(1 -benzyl-2,2,6,6-tetramethyl-piperid-4-yI) fumarate/ethyl acrylate copolymer (No. 6) which has precipitated is separated off from the supernatant methanol and dried at 400 under a high vacuum.Softening point: 8890 ; Mn: 3,700.

Example 7: By a method analogous to that in Example 6, a solution of 24 g (0.05 mol) of bis-( 1 -acetyl- 2,2,6,6-tetramethyl-piperid-4-yl) fumarate, 22.5 g (0.1 mol) of 1 ,2,2,6,6-pentamethyl-piperid-4-yl acrylate and 0.6 g of tert.-butyl perbenzoate, as the initiator, in 100 ml of anhydrous toluene is subjected to copolymerisation at 1100 under an argon atmosphere for 30 hours.The toluene is then distilled off in a rotary evaporator, the residue is dissolved in a little methylene chloride, the solution is poured into 800 ml of acetonitrile, while stirring vigorously at a high speed, and the bis-(1 -acetyl- 2,2,6,6-tetramethyl-piperid-4-yl) fu ma rate/1 ,2,2 ,6,6-penta methylpiperid-4-yl acrylate copolymer which has precipitated is separated off and dried at 500 under a high vacuum. It has a softening point of 108-1 100 and an Mn of 2,900 (copolymer No. 7).

Example 8: By a method analogous to that in Example 6, a solution of 14.24 g (0.03 mol) of bis-( 1 -allyl- 2,2,6,6-tetramethyl-piperid-4-yl) fumarate, 6 g (0.06 mol) of ethyl acrylate and 0.3 g of tert.-butyl perbenzoate, as the initiator, in 130 ml of butyl acetate is subjected to copolymerisation at 110 under nitrogen for 20 hours. The copolymer solution is then evaporated in vacuo, the residue is dissolved in methylene chloride, the solution is clarified by filtration and a precipitate is obtained by pouring the concentrated filtrate into 1 litre of methanol at --100, while stirring vigorously at a high speed. The precipitate is filtered off and dried under a high vacuum.The bis-( 1 -allyl-2,2,6,6-tetramethyl-piperid-4- yl) fumarate/ethyl acrylate copolymer thus obtained has a softening point of about 1350 and a mean molecular weight (Mn) of 8,000 (copolymer No. 8).

Example 9: By a method analogous to that in Example 6, a solution of 20.11 g (0.035 mol) of bis-( 1 -benzyl 2,2,6,6-tetramethyl-piperid-4-yl) fumarate, 3.93 g (0.035 mol) of 1-octene and 0.2 g of tert.-butyl perbenzoate in 200 ml of toluene is heated under reflux for 28 hours under nitrogen.

The copolymer is precipitated by pouring the solution into cold acetonitrile and is purified by being again dissolved, in methylene chloride, and precipitated with acetonitrile. After being dried in vacuo, the bis-( 1 -benzyl-2,2,6,6-tetramethyl-piperid-4-yI) fumarate/octene copolymer has a softening point of 1250 and an Mn of 2,600.

Example 10: A) Diethyl maleate/ethylene copolymer: 126.1 g (1 mol) of a maleic anhydride/ethylene copolymer (EMA-1 103 resin from Monsanto) in 600 ml of absolute ethanol, with the addition of 0.4 g of p-toluenesulfonic acid, are heated under reflux for 8 hours. The now completely clear, homogeneous solution is then cooled to 450 and 131 g (1.1 mols) of distilled thionyl chloride are added dropwise over a period of 4 hours, while stirring vigorously.

Stirring is then continued for 14 hours, at 5557 . The reaction mixture is cooled to 00, and separates into 2 phases after it has stood for a short time. The lower phase is separated off, washed three times with 100 ml of ethanol at 0 and freed completely from the solvent under a high vacuum.

The diethyl maleate/ethylene copolymer thus obtained still contains 8x 10-5 equivalent of free carboxyl groups per gram, i.e. about 99.2% of all the carboxyl groups are in the form of the ethyl ester.

B) Bis-(1-benzyl-2,2,6,6-tetramethyl-piperid-4-yl) maleate/ethylene copolymer: 20 g (0.1 mol) of the copolymer obtained in A) are trans-esterified with 50 g of 1-benzyl-4hydroxy-2,2,6,6-tetramethylpiperidine and 0.4 ml of tetrabutyl orthotitanate in 400 ml of anhydrous xylene under a weak stream of nitrogen at about 130-135 over a period of 24 hours, the ethanol detached being continuously distilled out of the reaction mixture. The xylene is then completely distilled out and the residue is heated for a further 8 hours, at 1 65-1 700 under a pressure of about 100 mbars.The copolymer is then dissolved again in 150 ml of hot xylene and this solution is poured into 1 litre of a methanol/ethanol (1:1) mixture, while stirring vigorously at a high speed, whereupon the bis-(1-benzyl-2,2,6,6-tetramethyl-piperid-4-yl) maleate/ethylene copolymer is precipitated as a powder. The precipitate is filtered off, washed with a 1:1 mixture of methanol and ethanol and dried at 6070 under a high vacuum. Softening point: about 1200; Mn: 15,300 (copolymer No. 10).

(C38Hs4N204)n Calculated: N 4.65% (602.8)n Found: N 4.35%.

Example 11: A) Dibutyl maleate/ethylene copolymer: By a method analogous to that in Example 1 OA), 63.1 g (0.5 mol) of a commercially available maleic anhydride/ethylene copolymer (EMA-1 103 resin, Monsanto) are reacted with 300 ml of nbutanol and then with 77.4 g of thionyl chloride (freshly distilled) to give the dibutyl maleate/ethylene copolymer. For purification, the excess n-butanol is distiled off and the crude copolymer is repeatedly washed with cold methanol and then freed completely from all the volatile components under a high vacuum, at 1300/0.01 bar. The resinous dibutyl maleate/ethylene copolymer has a residual content of free acid of 7x10-5 equivalent/gram.

B) Bis-(1-allyl-2,2,6,6-tetramethyl-piperid-4-yl) maleate/ethylene copolymer: The method of preparation is analogous to that in Example 1 OB), the copolymer prepared in 1 1A) being reacted with 1 -allyl-4-hydroxy-2,2,6,6-tetramethylpiperidine and the butanol being continuously distilled off. The bis-( 1 -allyl-2,2,6,6-tetramethyl-piperid-4-yl) maleate/ethylene copolymer thus obtained has a softening point of about 1000 and a molecular weight (Mn) of about 1 1,500 (copolymer No.11).

(C30HsoN204)n Calculated: N 5.57% (502.7)n Found: N 5.1.

Example 12: 39 g of a commercially available methyl vinyl ether/maleic anhydride copolymer of Mn 16,000 (Gantrez AN-1 19 resin, GAF Corp.) are dissolved in 350 ml of methyl ethyl ketone, a solution of 72 g of 4-butylamino-1-benzyl-2,2,6,6-tetramethylpiperidine is added dropwise at 700 (under N2) over a period of 4 hours, while stirring, and stirring is continued for 8 hours, at 7075 . The fine-particles precipitate which has separated out during the reaction is filtered off, washed with methyl ethyl ketone and dried at 600 under a high vacuum. The maleic acid [1-benzyl-2,2,6,6-tetramethyl-piperid-4-ylj- monoamide/methyl vinyl ether copolymer thus obtained has a softening point of 2000 (copolymer No.

12).

(C27H42N2O4)n Calculated: N 6.11% (458.6)n Found: N 5.75%.

Example 13: A solution of 38.3 g (0.08 mol) of bis-( 1 -acetyl-2,2,6,6-tetramethyl-piperid-4-yl) fumarate (melting point 151-152 ) and 16.8 g (0.12 mol) of 1-decene in 200 ml of pure toluene is copolymerised with 0.4 g of tert.-butyl perbenzoate at 106108 under nitrogen for 24 hours.

Thereafter, about half of the toluene is distilled off in vacuo and the concentrated solution is poured slowly into 500 ml of hexane, while stirring vigorously at a high speed, at room temperature. The precipitated copolymer is separated off, washed with hexane and dried completely at 600 under a high vacuum. This bis-( 1 -acetyl-2,2,6,6-tetramethyl-piperid-4-yl) fumarate/1 -decene copolymer thus obtained has a softening point of about 900 and a mean molecular weight (Mn) of 3,300 (copolymer No. 13).

(C36H62N20)n Calculated: N 4.53% (618.6)n Found: N 4.8%.

Example 14: By a a method analogous to that in Example 13, 10 g (0.04 mol) of N-( 1 2,2,6,6-pentamethyl- piperid-4-yl)maleimide and 8.75 g (0.052 mol) of 1-dodecene in 70 ml of pure toluene are copolymerised, with addition of 0.2 g of tert.-butyl perbenzoate, at 106107 under argon for 24 hours. The toluene is then distilled off in vacuo, the residue is dissolved in a little methylene chloride and the solution is poured slowly into 500 ml of acetonitrile at 0-5 , with vigorous stirring at a high speed. The initially resinous copolymer precipitated is separated off, washed with acetonitrile and dried completely at about 700 under a high vacuum.The N-(1,2,2,6,6-pentamethyl-piperid-4-yl) maleimide/1 -dodecene copolymer thus isolated has a softening point of about 140 and an #n of 1,850 (copolymer No. 14).

Example 15: 35.1 g (0.1 mol) of a commercial 1:1 copolymer of 1 -octadecene and maleic anhydride (Gulf PA18) and 17.1 g (0.1 mol) of 4-amino-1,2,2,6,6-pentamethylpiperidine, dissolved in 250 ml of dimethylformamide, are heated to about 1 600 in an N2 atmosphere for 17 hours, with stirring, the water formed and the dimethylformamide being slowly distilled off. When most of the dimethylformamide has been distilled off, the bath temperature is increased to 1 75-1 800 for 2 hours, and the mixture is finally kept at 1 800 under a vacuum of 30 mm Hg for another hour.The product is then cooled to about 800 and dissolved in 1,2-dichloroethane and this viscous solution is poured slowly into 1 litre of methanol, with vigorous stirring at a high speed, whereupon the copolymeric imide precipitates. The supernatant methanol is separated off and the product is dried in vacuo and then under a high vacuum at 800/0.02 mm Hg. The copolymeric imide thus obtained, having the structure

has a softening point of about 1300 and an #n of 10,500 (copolymer No. 1 5). It is readily and clearly soluble in n-hexane. The 1C-NMR spectrum is in agreement with the given structure.

Example 16: By a method analogous to that in Example 14, the copolymeric imide having the recurring structural unit

is prepared from 42.1 g (0.12 mol) of 1 -octadecene/maleic anhydride copolymer (Gulf PA-18) and 18.8 g (0.12 mol) of 4-amino-2,2,6,6-tetramethylpiperidine in dimethylformamide. Precipitation in 1.2 litres of methanol gives a virtually colourless powder, which is dried under a high vacuum at SO0. It has a softening point of 120130 and an #n of 11,000. It is clearly soluble in hexane (copolymer No.

16).

Examples 17-28: By a method analogous to that in Example 13, 1:1 copolymers are prepared from the following monomer pairs: Copolymer No. 17 Bis-(1-benzyl-2,2,6,6-tetramethyl-piperid-4-yl) fumarate and 1-octadecene, softening point (Ts) about 640, #n 2,600.

Copolymer No. 18 N,N'-Bis-(1-benzyl-2,2,6,6-tetramethyl-piperid-4-yl)-fumarodiamide and 1-octene, softening point (T8) about 140 , #n 2,260.

Copolymer No. 19 Bis-2-(2,2,6,6-tetramethylpiperidino)-ethyl fumarate and 1-octene, softening point (T5) 57 65 , #n 1,930.

Copolymer No.20 Bis-(1-allyl-2,2,6,6-tetramethyl-piperid-4-yl) fumarate and butyl vinyl ether, softening point (T3) about 900, #n 3,000.

Copolymer No. 21 Bis-(1-benzyl-2,2,6,6-tetramethyl-piperid-4-yl) fumarate and vinyl acetate, softening point (Ts) about 142 , #n 3,100 Copolymer No. 22

and 1-decene, softening point (Ts) 11 00, #n 3,030 Copolymer No. 23 Bis-(1-acetyl-2,2,6,6-tetramethyl-piperid-4-yl) fumarate and N-vinylpyrrolidone, softening point (Ts) about 1700, #n 4,600.

Copolymer No. 24

and 1-octene, softening point (Ts) about 980, #n 4,200.

Copolymer No. 25 Bis-( 1 -benzyl-2,2,6, 6-tetra methyl-piperid-4-yl) fumarate and styrene, softening point (Ts) 1 400, #n 2,250.

Copolymer No. 26 Bis-( 1 -benzyl-2,2,6,6-tetramethyl-piperid-4-yl) fumarate and 1-octene, softening point (Ts) about 125 , #n 2600.

Copolymer No. 27 Bis-(1-benzyl-2,2,6,6-tetramethyl-piperid-4-yl) fumarate and 1-dodecene, softening point (Ts) about 1000, #n 2,100.

Copolymer No. 28 Bis-( 1 -acetyl-2,2,6,6-tetramethyl-piperid-4-yl) fumarate and 1 -acetyl-2,2,6,6-tetramethylpiperid-4-yl acrylate, softening point (Ts) about 860, #n 1,960.

Examples 29 and 30 By a method analogous to that in Example 4, 1:1 copolymers having the following structures are prepared: Copolymer No. 29 Ts about 2300, #n about 16,000

Copolymer No. 30

Ts about 2100, #n about 2,200 Example 31: By a method analogous to that of Example 12, a half-ester copolymer (No. 31) of the structure

which has a softening point of 1900 and is sparingly soluble in most solvents, is prepared from a commercial maleic anhydride/octadecene 1:1 copolymer (Gulf P-1 8) and 1 -acetyl-2,2,6,6-tetramethyl piperidin-4-ol.

Example 32: Light stabilising action in polypropylene film.

100 parts of polypropylene powder (Moplen, fibre grade, Montedison) are homogenised with 0.2 part of octadecyl ss-(3,5-di-tert.-butyl-4-hydroxyphenyl)-propionate, 0.1 part of calcium stearate and 0.25 part of a stabiliser from Table 1 , which follows, at 2000C in a Brabender plastograph for 10 minutes. The resulting composition is removed from the kneader as rapidly as possible and is pressed to a 2-3 mm thick sheet in a toggle press. A piece is cut out of the resulting crude moulding and is pressed between two high-gloss hard aluminium sheets at 260 for 6 minutes in a hydraulic laboratory press operated manually, to give a 0.1 mm thick film, which is immediately quenched in cold water.

Pieces of this film are now stamped out and exposed in a Xenotest 1 200. These test pieces are removed from the exposure apparatus at regular intervals of time, and their carbonyl content is examined in an IR spectrophotometer. The increase in carbonyl extinction at 5.85 m throughout exposure is a measure of the photo-oxidative degradation of the polymer (cf. L. Balaban et al., J.

Polymer Sci, Part C; 22, 1059-1071(1969), and, and, from experience, is associated with a deterioration of the mechanical properties of the polymer. The time required for the carbonyl extinction to reach about 0.3, at which the comparison film is brittle, is a measure of the stabilising action. In a nonstabilised sample, this time is about 900 hours.

Stabiliser Exposure test copolymer no. in hours 1 3220 2 4900 3 3600 4 4200 5 3730 6 3720 8 3000 13 4800 14 > 5500 17 > 4300 19 > 5000 20 > 4500 21 3870 22 > 3000 23 > 2900 24 > 4400 25 4360 26 > 5500 27 5770 28 > 2350

Claims (14)

Claims

1. A copolymer of a) at least one unsaturated polyalkylpiperidine derivative of the formula I and

b) at least one comonomer of the formula II

in which R1 is one of the groups of the formula III, IV, V, VI, VII or VIII

R2 is one of the groups III, IV, V, VI, VII or VIII or is hydrogen, C1-C18-alkyl, alkyl which is interrupted by -O-, or C3-C5-alkenyl, C7-C11-aralkyl or C5-C12-cycloalkyl, X and Y independently of one another are 0 or NR10, R3 is hydrogen or methyl, R4 is hydrogen, C1-C18-alkyl, phenyl, CI, CN, C1-C18-alkoxy, C2-C5-alkanoyloxy, -COOR11, -CONH2 or -CON(R12)(R13), R5 is C3-C5-alkenyl, C3-C5-alkynyl, -CH2-CH(OH-R7, -CH2CN, unsubstituted or C1-C4-alkyl-substituted C7-C11-aralkyl, C2-C18alkanoyl, C3-C5-alkenoyl, -OH, -O.(oxyl oxygen), -COOC1-C4-alkyl or CON(R12)(R13), R6 is hydrogen or C1-C5-alkyl, R7 is hydrogen, C1-C3-alkyl, phenyl, C1-C4-alkoxymethyl, phenoxymethyl or C1-C4-alkyl-phenoxymethyl, R8 is hydrogen, C1-C18-alkyl, C3-C5-alkenyl, C3-C5-alkynyl, C2 C18-alkanoyl, C3-C5-alkenoyl, unsubstituted or C1-C4-alkyl-substituted C7-C11-aralkyl, -CH2CN, -CH2-CH(OH)-R7 or CON(R12)(R13), R9 is hydrogen, C1-C18-alkyl, C3-C5-alkenyl or C7-C11 aralkyl, R10 is hydrogen, C1-C18-alkyl, cyclohexyl, C7-C11-aralkyl, phenyl or a group of the formula III, R'1 is hydrogen, C1-C18-alkyl, C2-C4-hydroxyalkyl, glycidyl, a group of the formula III, IV, V, VI, VII or VIII or a group of the formula IX

in which R'4 is hydrogen or C1-C18-alkyl, and R12 is C1-C12-alkyl, C5-C8-cycloalkyl, phenyl, benzyl or a group of the formula III or IX and R13 is hydrogen, C1-C12-alkyl, C5-C6-cycloalkyl or benzyl, or R12 and R'3, together with the N atom to which they are bonded, form a 5-, or 7-membered heterocyclic ring, R'7 is hydrogen, methyl or ethyl, p is zero or 1 and, if p is zero, q is one, or if p is 1 , q is zero or 1, or copolymers of a) at least one maleimide of the formula is

in which R15 is a group of the formula III or IX, and b) at least one comonomer of the formula Ila CH2=CH-R16 (lea) in which R16 is hydrogen or C1-C18-alkyl, the number-average molecular weight of the copolymer being from 1,000 to 50,000.

2. A copolymer according to claim 1 wherein the number-average molecular weight of the copolymer is from 1000 to 10,000.

3. A copolymer according to claim 1 or 2, in which R6 in the formulae III, IV, V, VI, VII, VIII and IX is hydrogen.

4. A copolymer according to claim 1, in which R2 is R1, H or C1-C18-alkyl, R4 is hydrogen, C1-C6- alkyl, phenyl, C2-C6-alkoxy, acetoxy or-COOR11, R5 is C3-C5-alkenyl, C2-C6-al kanoyl, C3-C5- alkenoyl, benzyl, -CH2CN or -CON(R12) (R'3), R6 is hydrogen, R8 is hydrogen, C1-C0-alkyl, C3-C5- alkenyl, C2-C6-alkanoyl, C3-C5-alkenoyl, benzyl or H2CN, R9 is hydrogen, C1-C12-alkyl, allyl or benzyl, R10 is hydrogen or C1-C6-alkyl, R11 is C1-C8-alkyl, C2-C4-hydroxyalkyl or a group of the formula Ill, IV, V, VI or IX, in which R'4 is H or C1-C4-alkyl, and R12 and R13 are C1-C8-alkyl, cyclohexyl or benzyl and R', X, Y, R3, R7, R15 and R16 are as defined in claim 1, the number-average molecular weight of the copolymer being 1 000 to 10,000.

5. A copolymer according to claim 4 wherein the number-average weight of the copolymer is from 1,000 to 5,000.

6. A copolymer according to claim 1, of a) a compound of the formula I in which R1 is a group of the formula III, R2 is R1 or C1-C8-alkyl, X and Y are oxygen and, in formula Ill, R5 is allyl, benzyl or acetyl and R6 is hydrogen, and b) a compound of the formula II in which R3 is H or CH3 and R4 is H, C1-C6-alkyl or -COOR11, and R11 is C1-C4-alkyl or a group of the formula III in which R5 is acetyl or benzyl and R6 is hydrogen, or or R" is a group of the formula IX, in which R6 is H and R'4 is H or CH3, or of a) a compound of the formula la in which R'5 is a group of the formula IX, in which R6 is H and R'4 is H or CH3, and b) a compound of the formula Ila in which R16 is as defined in claim 1, the number-average molecular weight of the copolymer being 1,000 to 10,000.

7. A copolymer according to claim 6 wherein the number-average molecular weight of the copolymer is from 1,000 to 5,000.

8. A copolymer according to claim 1, of a) a compound of the formula I or la according to claim 1 and b) ethylene, in an approximate molar ratio of 1:1.

9. A copolymer according to claim 1 substantially as described with reference to any of Examples 1 to 31.

10. A polymer which has been stabilised against damage by the action of light and which contains, as the light stabiliser, 0.01 to 5% by weight of at least one copolymer according to claim 1.

11. A polymer according to claim 10 containing 0.1 to 2% by weight of at least one copolymer according to claim 1.

12. A stabilised polymer according to claim 10, which is a polyolefin, a styrene polymer, a polyamide, a polyurethane or a varnish gum.

13. A stabilised polymer according to claim 10, which also contains other additives, in addition to the copolymeric light stabiliser.

14. A stabilised polymer according to claim 10 substantially as described with reference to Example 32.