AU668231B2 - Cycloolefin polymer molding composition of improved stability to chemical degradation - Google Patents

Description

141U01UI I 2WW01~ Rogulallon 3,2(2)

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT a Application Number: Lodged: 0* a a a Invention Title: CYCLOOLEFIN POLYMER MOLDING COMPOSITION OF IMPROVED STABILITY TO CHEMICAL DEGRADATION a.

a a a a a *0 The following statement is a full description of this invention, including the best method of performing it known to us HOECHST AKTIENGESELLSCHAFT HOE 92/F374 Dr.DA/St Description Cycloolefin polymer molding composition of improved stability to chemical degradation The invention relates to a cycloolefin polymer molding composition of improved stability to chemical degradation which comprises certain organophosphorus compounds as stabilizers.

Cycloolefin homo- and copolymers are a class of polymer 10 with outstanding properties. They are distinguished, inter alia, by a sometimes high heat distortion point, resistance to weathering and transparency. They can be processed in the melt, for example by melt pressing, kneading, extrusion or injection molding, and can be 15 used, for example, in the form of sheets, fibers, films and tubes. In particular, optical products, such as optical disks, optical lenses and optical fibers, can be produced from them.

For this, the polymers must have a good processing 20 stability, and if possible should not change their intrinsic color during processing. It is furthermore important that they do not comprise relatively large amounts of additives, since otherwise the transparency to light suffers. The additives employed should thus have a high activity in the polymer molding composition, cause little yellowing and be miscible with the polymer.

Efforts are therefore being made to stabilize cycloolefin polymers adequately for processing and use by very small amounts of additives.

It is known that synthetic polymers have to be protected against undesirable oxidative, thermal and photochemical damage during preparation, processing and use by means of stabilizers or stabilizer systems. Such stabilizers ii~ C- 2 comprise, for example, a phenolic antioxidant, which is intended to ensure, in particular, the long-term stability of th finished component during use, and one or more costabilizers, which regulate the processing stability and in some cases also synergistically intensify the action of the phenolic component.

Damage to the polymer during preparation, processing and use manifests itself in particular in the viscosity and appearance. The change in viscosity occurs in particular during processing of the polymer, while the appearance the intrinsic color can change chiefly during processing and use.

.Cycloolefin copolymer molding compositions comprising i 0.01 to 5% by weight of organic phosphite and/or phospho- 15 nite stabilizer systems and optionally 0.01-1% by weight of a higher fatty acid metal salt which can be used for optical materials are known (cf. JP 22 76 842, WO 90 08 173). Among the organic phosphorus-containing stabilizers, tris(2,4-di-t-butylphenyl) phosphite, tris(nonylphenyl) phosphite and tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylene diphosphonite are mentioned.

Such trivalent phosphorus compounds are in some cases not stable to hydrolysis and may lose their stabilizing property in the course of time.

The object of the present invention was therefore to discover suitable stabilizers for cycloolefin polymer molding compositions which ensure stability during processing and stability during use without changing the intrinsic color.

The object was achieved by using particular phosphoruscontaining stabilizers individually or in combination with other additives.

The present i nv ti nt AI.o therefore relates to the 3 cycloolefin polymer molding composition described in the claims, its preparation and its use.

The synthesis and properties of cycloolefin polymers have been the subject of many publications in recent times. It is known that these olefins can be polymerized by means of various catalysts. The polymerization here proceeds via ring opening or with opening of the double bond, depending on the catalyst. The cycloolefin polymerizations which proceed with opening of the double bond can be catalyzed either by more recent catalyst systems (cf.

EP 407 870, EP 485 893, EP 203 799) or by a conventional Ziegler catalyst system (cf. DD 222 317, DD 239 409).

The cycloolefin polymer molding composition according to 1 the invention comprises 90 to 99.99, preferably 95 to 99.975% by weight of a polymer which comprises structural units derived from at least one monomer of the formulae I to VII 4 4 CH 11 R -C-R 4

I

C H H C C H-,CH H2\ C-1 4

/CH

*CH CHR1 H C C H 'CH R -C-R R 5 CIR H C CH CH .0.C CH CHNCR H C C HCH

R

3

-C-R

4

R

5

-C-R

6 R 7 -C-R (I V H C CH CH CH2 C H C H C H

R

HC H HC I(v)

R

CH CH

R

6 5

R

R3C-R4 RC"-RaI

(VI),

H C

H

C H CC CCH C H C H' R 2

RR

CH CH C (VI I) CH In these formulae, R 2

R

3 R, R 5

R

6

R

7 and R 8 are identical or different and are a hydrogen atom or a CI-C e alkyl radical, it being possible for the same radicals in the various formulae to have a different meaning, and n 5 is an integer from 2 to In addition to the structural units derived from at least one monomer of the formulae I to VII, the cycloolefin polymers can comprise other structural units which are derived from at least one acyclic 1-olefin of the formula 10 VIII

*R

9 Rio c (viii) in which R 9

R

10

R

1 and R 12 are identical or different and are a hydrogen atom or a Ci-C-alkyl radical.

Preferred comonomers are ethylene or propylene. Copolymers of polycyclic clefins of the formula 1 or III and the acyclic olefins of the formula VIII are employed in particular. Particularly preferred cycloolefins are norbornene and tetracyclododecene, which can be substituted by C,-C,-alkyl, ethylene/norbornene copolymers being of particular importance. Of the monocyclic olefins of I~Lbl -6 the formula VII, cyclopentene, which can be substituted, is preferred. Polycyclic olefins, monocyclic olefins and open-chain olefins are also to be understood as mixtures of two or more olefins of the particular type. This means that cycloolefin homopolymers and copolymers, such as bi-, ter- and multipolymers, can be employed.

Those cycloolefin polymers which have been prepared by means of metallocene catalysts are preferably used for the cycloolefin polymer molding composition according to the invention. Cycloolefin homo- and copolymers which comprise structural units derived from monomers of the "'formulae I to VI or VII are preferably prepared with the aid of a homogeneous catalyst. This comprises a metallocene, the central atom of which is a metal from the group 15 comprising titanium, zirconium, hafnium, vanadium, niobium and tantalum, which forms a sandwich structure with two mono- or polynuclear ligands bridged with one another, and an aluminoxane.

The structure and also the polymerization of these cycloolefins are described in detail elsewhere (cf.

LP 407 870, EP 485 893, EP 501 370, EP 503 422, DE 42 05 416). These are cycloolefin polymers which in some cases differ in their chemical uniformity and their polydispersity.

The molding composition comprises as a stabilizer at least one organophosphorus compound of the formula IX

R

13

-[P(OR

1 4)2] n

(IX)

in which n is 1 or 2,

R

14 is a linear or branched C 8

-C

20 -alkyl radical or a phenyl radical, which can be substituted by one or more linear or branched C,-C-alkyl radicals or by Cs-C,-cycloalkyl, C 6 -C1 0 -aryl or C 7 -Co 1 -aralkyl radicals,

R

13 if n 1, is a phenyl or benzyl radical, which can carry 1 to 3 substituents, an a-methylbenzyl, a,a-dimethylbenzyl or naphthyl radical or a naphthyl radical

I

7 which carries 1 to 5 substituents, the substituents being identical or different and being a linear or branched

C

1 -C-alkyl radical, a C,-Ca-alkoxy radical, a C-C 1 alkylthio radical, a C 1 -C.-dialkylamino radical, a C,-Co 0 aryl radical, a C-C 0 ,-aryloxy radical or halogen having an atomic number of 9 to 35, and R"3 if n 2, is a phenylene radical, a biphenylene radical, a naphthylene radical or a diphenylene oxide radical, which are unsubstituted or carry 1 to 4 linear or branched Cl-C.-alkyl radicals, one dibenzo-[c,e][1,2]-oxaphosphorine of the formula X

P--

I X), Y R or2,,J in which R 13 has the abovementioned meaning and m is 1 or 2, or one diarylphosphinous acid aryl ester of the formula 15 XI 11 (X I) R 9P in which the radicals R 16 independently of one another, as monovalent radicals, are a phenyl or naphthyl radical, which can carry in each case 1 to 5 substituents, the substituents being identical or different and being a non-aromatic hydrocarbon radical, an alkoxy radical, alkylthio radical or dialkylamino radical having in each case 1 to 8 carbon atoms, aryl or aryloxy having in each case 6 to 10 carbon atoms or halogen having an atomic I- -Y -8 numiber of 9 to 35, and

R

15 as a divalent radical is a phenylene, diphenylene oxide or biphenylene radical, which is unsubstituted or is substituted by up to 4 non-aromatic hydrocarbon radicals having 1 to 8 carbon atoms, or a naphthylene radical, which is unsubstituted or carries 1 to 4 nonaromatic hydrocarbon radicals having 1 to 8 carbon atoms as substituenti5, p is 1 or 2 and R" 6 has the abovementioned meaning.

Compounds of the formula IX which are preferably employed are 4-biphenylphosplionous acid bis- 4-di-t-butylphenyl.) ester, l-naphthyl-phosphonovis acid bis- (2 ,4-di-t-butylphenyl) ester, benzene- 1, 4-diphosphonous acid tetra-(2,4to to too di-t-butylphenyl) ester, 1-naphthyl-phosphonous acid bis- (2,4-di-t-butylphenyl) ester, tetrakis-(2,4-di-t-butyl- 9 phenyl) 4,4 '-biphenylenediphosphonite, 2,4, 6-trimethylphenylphosphonous acid bis- 4-di-t-butylphenyl) ester and tetrakis- 4-di-t-butylphenyl) -4,4 '-diphenylene to t oxide diphosphonite, which has been treated in each case with 0.01 to 5% by weight of an oxide, a carbonate, a bicarbonate or a carboxylate of a metal of groups la, 2a, 2b and 7b of the Periodic Table of the Elements.

Examples of suitable compounds of the formula X are 256-(2',4',6'-trimethylphenyl)-6H-dibenzo-[c,e][1.2]- 6-(4'-methoxy-phenyl)-6Hdibenzo[o,e][1.2]-oxaphosphorine, 5-(2'-tolyl)-6Hdibenzo-[c,e][1.2]-oxaphosphorine, 6-(3'-tolyl)-6Hdibenzo- (192] -oxaphosphorine, 6- (4 '-t-butyl-phenyl) 6H-dibenzo~c,eJ (1.2J-oxaphosphorine and 6-(4'-methyl-1'naphthyl) -6H-dibenzo-[c,eJ [1.2 3-oxaphosphorine.

Examples of suitable compounds of the formula XI are 2,4, 6-trimethylphenyl-phenylphosphinous acid 2, 4-di-tbutyiphenyl ester, 2,4, 6-trinethylphenyl-1-naphthylphosphinous acid 2,4-di-t-butylphenyl ester, bis-(4biphenyl)phosphinous acid 2.4-di-t-butylphenyl ester, bis- -naphthyl) phosphinous acid 2, 4-di-t-butylphenyl 9 1 9 ester, 4,4' -bphenylene-bis-( 1-naphthyl-phosphinous acid 2,4-di-t-butylphenyl ester), 2,4-trimethylphenyl-4methoxyphenylphosphinous acid 2,4,6-tri-t-butylphenyl ester, 2,4-bis-(4-chlorophenyl)phosphinous acid 2-tbutylphenyl ester, bis-(2-methoxyphenyl)-phosphinous acid 2,4-di-t-butylphenyl ester, 1,4-phenylene-bis-(l-naphthylphosphinous acid 2,4,6-tri-t-butylphenyl ester), 1,4naphthylene-bis-( 1-naphthylphosphinous acid 2,4-di-tbutylphenyl ester), bis-[4-(N,N-dimethylamino)phenyl]phosphinous acid 2,4-di-t-butylphenyl ester, 1-naphthyl- 2-methoxyphenylphosphinous acid 2,4-di-t-butylphenyl ester, 1-naphthyl-4-t-butylp' .,-lphosphinous acid 2,6-dit-butylphenyl ester and 4,4' -aphenylene-bis-(2,4,6-trimethylphenylphosphinous acid 2,4-di-t-butylphenyl ester).

15 Of the compounds of the formulae IX, X and XI, the oxaphosphorines and the phosphinous acid esters and phosphonous acid esters are particularly preferred, especially the phosphinous acid esters and phosphonous acid esters.

The stabilization system furthermore can comprise one or more phenolic antioxidants, one or more light stabilizers or alkali metal and alkaline earth metal salts of higher fatty acids or phenolates.

Since the individual stabilizers in the combination in 25 the polymer molding composition can react in an unknown manner during processing and use, they must be tested individually and in the stabilizer mixture.

The phenolic antioxidnt is, for example, an ester of 3-3-bis-(3'-t-butyl-4'-hydroxyphenyl)-butanoic acid of the formula XII 10 S- C 4 H 9 0 H C C C H 17 (X I I) -C-0H-- OH r *in which R' 7 is a r 1

-C

2 -alkyl radical or a Cl-C 1 -alkylene *radical and r is 1 or 2. Preferably, R 7 is a C 2 -C,,alkylene radical, in particular a C 2 -alkylene radical.

However, the phenolic antioxidant can also be an ester of 03- 5-di-t-butyl-4-hydroxy-phenyl) -propionic acid of the formula XIII t-C 4

NI

H 2 -CR 2 H (XI II) t

.M

in which the alcohol component is a mono- or polyhydric alcohol, such as, for example methanol, octade--anol, 1, 6-hexanediol, neopentyi glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris-hydroxyethyl isocyanurate or di-hydroxyethyl-oxalic acid diamide.

The cycloolefin polymer mrolding composition to be stabilized can additionally also comprise the following 11 antioxidants, such as, for example: 1. Alkylated monophenols, for example 2, 6-di-t-butyl-4-methylphenol, 2-t-butyl-4, 6-dimethylphenol, 2, 6-di-t-butyl-4-ethylphenol, 2, 6-di-t-butyl-4-ibutyiphenol, 2,6-di-cyclopentyi-4-methylphenol, 2-(amethylcyclohexyl) 6-dimethyiphenol, 2, 6-di-octadecyl-4methyiphenol, 2,4, 6-tri-cyclohexyiphenol a J- 2, 6-di-tbutyl-4-methoxymethylphenol.

Alkylated hydroquinones, for example 2, 6-di-t-butyl-4-methoxyphenol, 2, quinone, 2, 5-di-t-amylhydroquinone and 2, 6-diphenyl-4octadecyloxyphenol.

Hydroxylated thiodiphenyl ethers, for example 2,2 '-thio-bis- (6-t-butyl-4-methylphenol), 2,2 '-thic-bis- 15 (4-octyiphenol), 4,4'-thio-bis-(6-t-butyl-3-methylphenol) and 4,4'-thio-bis-(6-t-butyl-2-methylphenol).

4. Alkylidene-bisphenols, for example 2,2' -methylene-bis- (6't-butyl-4-methylphenol) iethylene-bis- (6-t-butyl-4-ethylpheiol), 2,2 '-methylenebis-[4-inethyl-6-(c-methylcyclohexyl)-phenol], 2,2'inethylene-bis- (4-methyl-6-cyclohexylphenol), 2,2 '-methylene-bis-(6-nonyl-4-methylphenol), 2,2 '-methylene-bis- 6-di-t-butylphenol), 2,2 '-ethylidene-bis- 6-di-t- ~.:butyiphenol) 2,2 '-ethylidene-bis-(6-t-butyl-4-isobutylphenol), 2,2 '-methylene-bis-[6- (a-methylbenzyl) -4-nonylphenol), 2,2 '-methylene-bis-[6-(a,ac-dizethylbenzy.) -4nonyiphenol], 4,4 '-methylene-bis-(2 ,6-di-t-butylphenol), 4,4 '-methylene-bis- (6-t-butyl-2-methylphenol), 1, 1-bis- (5-t-butyl-4-hydroxy-2-nethylphenyl) -butane, 2, 6-di- (3-tbutyl-5-methyl-2-hydroxybenzyl) -4-methylphenol, 1,1,3tris- (5-t-butyl-4-hydroxy-2-methiylphenyl)-butane, 1,1bis- (5-t-butyl-4-hydroxy-2-methylphenyl) -3-n-dodecylmercaptobutane, di- (3-t-butyl-4-hydroxy-5-methylphenyl) dicyclo-pentadit,.-ne, di- (3 '-t-butyl-2 xethyl-benzyl )-6-t-butyl-4-methyl-phenyl] terephthalate -12 and ethylenet glycol bis-[3, 3-bis-(3 '-t-butyl-4 '-hydroxyphenyl) butyrate).

Benzyl compounds, for example 1,3,5-tri-(3, 5-di-t-butyl-4-hydroxybenzyl) 6-trimethylbenzene, di- (3 ,5-di-t-butyl-4-hydroxybenzyl) sulfide, isooctyl 3, 5-di-t-butyl-4-hydroxybenzylmercaptciacetate, bis-'(4-t-butyl-3-hydroxy-2, 6-dimethylbenzyl)--dithiol terephthalate, 1,3, 5-tris--(3, 5-di-t-butyl-4-hydroxybenzyl) isocyanurate, 1,3, 5-tris- (4-t-butyl-3-hydroxy- 2, 6-dimethylbenzyl) isocyanurate, 3, 5-di-t-butyl-4hydroxybenzyl-phosphonic acid dioctadecyl ester and the calcium salt of 3, 5-di-t-butyl-4-hydroxybenzylphosphonic monoethyl ester.

6. Acylaminophenols, for example 4-hydroxy-lauric acid anilide, 4-hydroxy-stearic acid anilide, 2,4-bis-octylmercapto-6-(3,5-di-t-butyl-4hydroxy-anilino) -s-triazine and octyl N- 4-hydroxyphenyl) -carbamate.

7. Esters of 1-(5-t-butyl-4-hydroxy-3-methylphenyl)propionic acid with mono- or polyhydric alcohols, such as, for example, with methanol, diethylene glycol, octadecanol, triethylene glycol, 1, 6-hexanediol, pentaerythritol, neopentylglycol, tris-hydroxyethyl isocyanurate, thiodiethylene glycol and 9*9: 25 dihydroxyethyl-oxalic acid diamide.

8. A~mides of P3- 5-di-t-butyl-4-hydroxyphenyl) -propionic acid, such as, tor example, N,VN'-di- 5-di-t-butyl-4-hydiroxyphenylpropionyl) -hexamethylenediamine, N,N' -di- 5-di-t-butyl-4-hydroxyphenylpropionyl) -trimethylenediamine and N,N' -di- t-butyl-4-hydroxvphenylpropionyl) -hydrazine.

In addition, the polymers to be stabilized can also contain other additives, such as, for example: I I -13 1. UV absorbers and light stabilizers 1.1 2 (2 -Hydroxyphenyl) -ben zotria zole s, such as, for example, the 5 '-methyl, 3',5 '-di-t-butyl, 5 '-t-butyl, 3-tetramethylbutyl), 5-chloro-3 5 '-di-t-butyl, 5-chloro-3 '-t-butyl-5 '-methyl, 3 '-sec-butyl-5 '-t-butyl, 4'-octoxy, 3',5'-di-t-anyl and dimethylbenzyl) derivative.

1.2 2-Hydroxybenzophenones, for example the 4-hydroxy, 4-inethoxy, 4-octoxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy, 4,2' ,4 '-trihydroxy and 2' -hydroxy-4, 4'-dimethoxy derivative.

Esters of optionally substituted benzoic acids, for example 4 -t-butyl-phenylsalicylate, phenyl salicylate, octylphenyl .salicylate, dibenzoylresorcinol, bis- (4-tbutylbenzoyl)resorcinol, benzoylresorcinol, 2,4-di-tbutylphenyl 3, 5-di-t-butyl-4-hydroxybenzoate and hexadecyl 3, 5-di-t-butyl-4-hydroxybenzoate.

1.4 Acrylates, for example ethyl and isooctyl a-cyano-f343-diphenylacrylate, methyl 20 a-carbomethoxycinnamate, methyl and butyl cz-cyano-pmethyl p-methoxycinnamate, methyl a-carbomethoxy-pmethoxycinnamat.- and N- (P-carbomethoxy-9-cyano-vinyl) -2wmethyl-indoline.

Nickel compounds, for example nickel complexes of 2, 2 1 -thio-bis [4 113, 3-tetramethylbutyl)-phenol], such as the 1:1 or 1:2 complex, if appropriate with additional ligands, such as n-butylamine, triethanolamine or N-cyclohexyldiethanolamine, nickel alkyldithiocarbauates, nickel salts of 4-hydroxy- 3, 5-di-t-butyl -ben zylphosphonic acid monoalkyl esters, such as of the methyl or ethyl ester, nickel complexes of ketoximes, such as of 2 -hydroxy-4-methyl-phenyl undecyl ketoxime, nickel complexes of hydroxypyrazole, if appropriate with additional ligands, 14 and nickel salts of 2-hydroxy-4-alkoxybenzophenones.

1.6 Sterically hindered amuines, for example 1.6.1 bis(2,2,6,6-tetramethylpiperidyl) sebacate, bis- (1,2,2,6,6-pentamethylpiperidyl) sebacate, bis-(2,2,6,6tetramethylpiperidyl) glutarate, bis-( 1,2 ,2,6,6-pentamethylpiperidyl) glutarate, bis- 6-tetramethylpiperidyl) succinate, bis-( 1,2,2,6, 6-pentaniethylpiperidyl) succinate, 4-stearyloxy-2, 2,6, 6-tetraniethylpiperidine, 4-stearyloxy-1 6-pentamethylpiperidine, 4-stearoyloxy-2 6-tetraniethylpiperidine, 4-stearoyloxy-1 ,2,2,6 ,6-pentamethylpiperidine, 2,2,6, 6-tetramnethylpiperidyl behenate, 1,2,2,6, 6-pentamnethylpiperidyl behenate, 2, 2,4,4-tetramnethyl-7-oxa-3,20-diazadispiro- [5.1.11.2]-heneicosan-21-one, 2,2,3,4,4-pentamethyl-7oxa-3,20-diazadispiro-[5.1.11.2]-heneicosan-21-one, 2,2 4-tetramethyl-3-acetyl-7 -oxy-3 ,2 0-diazadispiro- 11.2J-heneicosan-21-one, 2,2,4,4-tetramethyl-7-oxa- 3, 20-diaza-20- -lauryl-oxycarbonylethyl) -21-oxo-dispiro- [5.1.11.2]-heneicosane, 2,2,3,4,4-pentamethyl-7-oxa-3,20diaza-20-(f-lauryloxycarbonylethyl)-21-oxo-dispiro- 11.2]-heneicosane, 212,4,4-tetramethyl-3-acetyl-7oxa-3 ,20-diaza-20- 1-lauryloxycarbonyl-ethyl) -21-oxodispiro-[5.1.11.2]-heneicosane, 1,1',3,3',5,5'-hexahydro- 2,2' ,4 ,4 '-hexaaza-2 ,6,6 '-bismethano-7 ,8-dioxo- 25 4,4'-bis-(1,2,2,6,6-pentamethyl-4-piperidyl)biphenyl, N4,N',N",N"'-tetrakis-[2,4-biB-[N-(2,2,6,6-tetramethyl-4piperidyl) -butylamino] 5-triazin-6-yl]J-4, 7-diazadecane-1,10-diamine, N,N',N"l,N"'l-tetrakiB[2,4-bis[N- 6-pentamethyl-4-piperidyl) butylamino] -1,3,5triazin-6-ylJ-4,7-diazadecane-1,10-diaiine, N,N',N',NI'Itetrakis- 4-bis- 6-tetraniethyl-4-piperidyl) methoxypropylaxninoJ-1,3,5-triazin-6-yl]-4 ,7-diazadecane- 1, 10-diamine, N,N' '-tetrakis-[2,4-bis-[N- 6-pentamethyl-4-piperidyl )methoxypropylaminoj 1,3,5-triazin-6-yl]-4,7-diazadecane-1,1-diamine, bis- 6-pentamethyl-piperidyl) -n-butyl 3, 4-hydroxy-benzylmalonate, tris-(2 6, 6-tetramnethyl-4-

I

piperidyl) nitrilotriacetate, tetrakis- 6-tetramethyl-4-piperidyl) 4-butanetetracarboxylic acid and 1,1'-(1,2-ethanediyl)-bis-(3,3,5,5-tetramethylpiperazinone).

1.6.2 Poly-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,8diazadecylene, the condensation product of 1-(2-hydroxyethyl) 6-tetramethyl-4-hydroxypiperidine and succinic acid, the condensation product of N,N'-bis- 6-tetramethyl-4-piperidyl) -hexamethylenedianine and 4-t-octylamino-2,6-dichloro-l,3,5-triazine and the condensation product of N,N'-bis-(2,2,6,6-tetramethyl-4piperidyl) -hexamethylenediamine and 4-morpholino-2 ,6dichloro-1, 1.7 Oxalic acid diainides, for example 4,4 '-di-octyloxy-oxanilide, 2,2 '-di-octyloxy-5,5 '-di-tbutyl-oxanilide, 2,2 '-didodecyloxy-5, anilide, 2 -ethoxy-2 I -ethyl -oxanilide N, N I-bis- (3-dimethylaxninopropyl) -oxalainide, 2-ethoxy-5-t-butyl-2 '-ethyloxanilide and its mixture with 2-ethoxy-2'-ethyl-5,4-di-tbutyl-oxanilide, and mixtures of o- and p-methoxy- and of o- and p-ethoxy-di-substituted oxanilides.

2. Metal deactivators, for example N, N I'-diphenyloxalic acid diamide, N-salicylyl-N I -salicyloyl-hydrazine, N,N'-bis-salicyloyl-hydrazine, N,N'-bis- 25 5-di-t-butyl-4-hydroxyphenylpropionyl)-hydrazine, 3-salicy-loylamino-1, 2,3-triazole and bis-benzylideneoxalic acid dihydrazide.

3. Phosphites and phosphonites, for example triphenyl phosphite, diphenyl alkyl phosphites, phenyl dialkyl phosphites, trisnonyiphenyl phosphite, trilauryl phosphite, trioctadecyl. phosphite, distearylpentaerythrityl diphosphite, tris- 4-di-t-butylphenyl) phosphite, diisodecyl-pentaor ythrityl diphosphite, bis- 4-di-t-butylphenyl) -pentaerythrityl diphosphite, tr is t ear y1- s o rb ityl1 tr ip ho sp h ite 16 3,9-bis-(2,4-di-t-butylphenoxy)-2,4,8,10-tetraoxa-3,9diphosphaspiro- 5.5 ]-undecane and tris- (2-t-butyl-4-thio- (2'-methenyl-4'-hydroxy-5'-t-butyl)-phenyl-5-methenyl)phenyl phosphite.

4. Peroxide-destroying compounds, for example esters of p-thio-dipropionic acid, such as, for example, the lauryl, stearyl, myristyl or tridecyl ester, mercaptobenzimidazole, the zinc salt of 2-mercaptobenzimidazole, zinc alkyl-dithiocarbamates, dioctadecyl sulfide, dioctadecyl disulfide and pentaerythritol tetrakis-(p-dodecylmercapto)-propionate.

5. Basic co-stabilizers, for example melamine, polyvinylpyrrolidone, dicyandiamide, triallyl cyanurate, urea derivatives, hydrazine derivatives, 15 amines, polyamines, polyurethanes, alkali metal and alkaline earth metal salts of higher fatty acids or phenolates, for example Ca stearate, Zn stearate, Mg stearate, Na ricinoleate, K palmitate, antimony pyrocatecholate or tin pyrocatecholate, and hydroxides and 20 oxides of alkaline earth metals or of aluminum, for example CaO, MgO or ZnO.

6. Nucleating agents, for example 4-t-butylbenzoic acid, adipic acid, diphenylacetic acid and dibenzylidenesorbitol.

7. Fillers and reinforcing agents, for example calcium carbonate, silicates, glass fibers, asbestos, talc, kaolin, mica, barium sulfate, metal oxides and hydroxides, carbon black, graphite and high modulus fibers.

8. Other additives, for example plasticizers, lubricants, emulsifiers, pigments, optical brighteners, flameproofing agents, antistatics and blowing agents.

17 The various additional additives of the abovementioned groups 1 to 6 are added to the polymers to be stabilized in an amount of from 0.01 to 10, preferably 0.01 to 5% by weight, based on the total weight of the molding composition. The proportion of additives of groups 7 and 8 is 1 to 80, preferably 10 to 60% by weight, based on the total molding composition.

The stabilizers are incorporated into the cycloolefin polymers by generally customary methods. Incorporation can be carried out, for example, by mixing the compounds and if appropriate other additives into the melt before or during shaping. Incorporation can also be carried out by application of the dissolved or dispersed compo'l;;ds to the polymer directly or by mixing in a solution, suspension or emulsion of the polymer, if appropriate with subsequent evaporation of the solvent. The amount to be added to the polymers is 0.01 to 10, preferably 0.025 to in particular 0.02 .to 2% by weight, based on the cycloolefin polymer to be stabilized.

The stabilizers can also be added to the polymers to be stabilized in the form of a masterbatch which comprises these compcunds, for example, in a concentration of from 1 to 50, preferably 2.5 to 20% by weight.

The organophosphorus compounds used according to the invention maintain the melt viscosity of the molding composition at the highest level (very small deviation from the starting value). Moreover, they lead to the best initial colors of test specimens and to relatively little change in color after kneading experiments.

The cycloolefin polymer molding composition stabilized according to the invention can be used in various forms, for example in the form of sheets, fibers, films and tubes, or as binders for paints, adhesives or putties.

The folloing polymers were prepared by standard methods 18 for the examples.

Cycloolefin copolymer Al [COC Al] A clean and dry 75 dm 3 polymerization reactor with a stirrer was flushed with nitrogen and then with ethylene.

37 dm 3 of benzine fraction (100/110) and 10700 g of norbornene melt were then initially introduced into the polymerization reactor. The reactor was brought to a temperature of 70 0 C, while stirring, and 2.9 bar of ethylene were forced in.

Thereafter, 500 cm 3 of a toluene solution of methylaluminoxane (10.1% by weight of methylaluminoxane of u..o molecular weight of 1300 g/mol according to cryoscopic determination) were metered into the reactor and the mixture was stirred at 70°C for .15 minutes, the ethylene pressure being kept at 2.9 bar by subsequent metering in.

In parallel, 350 mg of diphenylmethylene-(9-fluorenyl)cyclopentadienyl zirconium dichloride were dissolved in 500 cm 3 of a toluene,solution of methylaluminoxane (for the concentration and quality, see above) and were preactivated by being left to stand for 15 minutes. The solution of the metallocene (catalyst solution) was then metered into the reactor. The mixture was polymerized at for 135 minutes, while stirring, the ethylene pressure being kept at 2.9 bar by subsequent metering in.

S 25 The contents of the reactor were then drained rapidly into a stirred vessel ipto which 40 dm 3 of benzine fraction (100/110), 1000 g of kieselguhr (®Celite J 100) and 200 cm 3 of ice-water had been initially introduced at 0 C. The mixture was filtered, so that the filter auxiliary was retained and a clear polymer solution resulted as the filtrate. The clear solution was precipitated in acetone, the mixture was stirred for 10 minutes and the suspended polymeric solid was then filtered off.

To remove residual solvent fom the polymer, the polymer was extracted by stirring twice more with acetone and 19 filtered off. Drying was carried out at 80 0 C in vacuo in the course of 15 hours. 3400 g of polymer were obtained.

Preparation of cycloolefin copolymer A2 [COC A2] A clean and dry 75 dm 3 polymerization reactor with a stirrer was flushed with nitrogen and then with ethylene.

20550 g of norbornene melt were then initially introduced into the polymerization reactor. The contents of the reactor were brought to a temperature of 70°C, while stirring, and 3.5 bar of ethylene were forced in.

Thereafter, 1000 cm 3 of a toluene solution of methylaluminoxane (10.1% by weight of methylaluminoxane of molecular weight 1300 g/mol according to cryoscopic determination) were then metered into the reactor and the mixture was stirred at 70 0 C for 15 minutes, the ethylene 15 pressure being kept at 3.5 bar by subsequent metering in.

0: In parallel, 350 mg of diphenylmethylene-(9-fluorenyl)cyclopentadienyl-zirconium dichloride were dissolved in 500 cm 3 of a toluene solution of methylaluminoxane (for the concentration and quality, see above) and were 20 preactivated by being left to stand for 15 minutes. The solution of the metallocene (catalyst solution) was then metered into the reactor. The mixture was polymerized at 70 0 C for 233 minutes, while stirring, the ethylene pressure being kept at 3.5 bar by subsequent metering in.

25 The contents of the reactor were then drained rapidly into a stirred vessel into which 40 dm 3 of benzine fraction (100/110), 1000 g of kieselguhr (eCelite J 100) and 200 cm 3 of ice-water had been initially introduced at 0 C. The mixture was filtered, so that the filter auxiliary was retained and a clear polymer solution resulted as the filtrate. The clear solution was precipitated in acetone, the mixture was stirred for 10 minutes and the polymeric solid was then filtered off.

To remove residual solvent from the polymer, the polymer was extracted by stirring twice more with acetone and filtered off. Drying was carried out at 80°C in vacuo in the course of 15 houzs. f polymer were obtained.

The physical parameters of cycloolefin copolymers Al and A2 can be found in Table 1.

Table 1 Cycloolefin copolymer incorporation* of ethylene norbornene VlN Tg [mol%] (mol%] [cm 3

[CC]

4~ 0 Al 54 46 143 145 10 A2 55 45 141 139 determined by "C-nuclear magne-'-,c resonance spectroscopy VN: viscosity number in accordance wit)-, DIN 53 728 Tg: glass stage during the 2nd heating up; heating up and cooling rate: 20 0 /minute Examples The organophosphorus compounds listed below were employed for the experiments.

Tetrakis- (2 ,4-di-t-butylphenyl)4,4-biphenylene diphosphonite, conmmercial product \0/P Content 40% 3

'P-NMR)

Tetrakis- (2 ,4-di-t-butylphenyl)-4,4-biphenylene diphosphonite, stabilized toward hydrolysis according to DE 42 18 411 with MgO Content 40% 31 p-NMR) 21 Tetrakis- 4-di-t-butylphenyl -biphenyleie diphosphonite, according to Examuple 2a DE 42 18 411 Content 70% (31519YP-IIMR) 6-(2'-Tolyl)-6H-dibenzcp-[c,e][i.21-oxaphosphorine

OV

U

Content about 97% 31 p-NMR) Bis- -naphthyl)phosphinous acid 2 ,4-di-t-butylphenyl ester Content about 90% 31

P-NMR)

].-4laphthyl-phosp-ocnous acid bis-(2,4-di-t-buty,phenyl) ester 22 S* Content about 98% ("P-NMR) The preparation of these compounds is described in US 5,109,043, EP 472 564 and WO 92/00306. Other prepara- S tion methods are proposed in DE 41 24 790 and DE 42 18 411.

The amounts of stabilizers shown in the tables were applied as solutions to the powder of the cycloolefin polymers described above and the mixture was dried (130 0 C, 24 hours, vacuum). The polymers pretreated in this way were kneaded with the aid of a measuring kneader (®Rheocord System 40/®Rheomix 600; Haake, Karlsruhe) under the conditions mentioned. Portions of the resulting kneaded products were pressed (vacuum press: ®Polystat 200 S; Schwabenthan, Berlin) to sheets (110 x 1 mm).

Sheets were additionally produced from the starting powder of the cycloolefin copolymers (without/with stabilizers).

The yellowing of the sheets produced was measured as the Yellowness Index in accordance with ASTM D 1925-70.

The other portion of the kneaded products was ground and dried (130 0 C, 24 hours, vacuum) and the melt flow index was determined in accordance with DIN 53 735.

The yellowing after storage in heat '7 days at 100 0

C)

1 -23 furthermore was measured.

The stated a-mounts of additives employed are parts by weight per 100 parts by weight (phr) of cycloolef in copolymer.

The results are to be found in Tables 2 to 12.

The symbols in the tables have the following meanings: phenol') ethylene glycol. 3, 3-bis-(3 '-t-butyl-4 '-hydroxyphenyl) -butanoate 2) HALS Hindered Amine Light Stabilizer 2,2,4,4-tetramethyl-7-oxa-3,20-diazadispiro-[5.l.ll.

2

J-

heneicosan-2 1-one 3oligomerized 2,2,4,4-tetramethyl-7-oxa-3,20-diaza-2O- 3-epoxypropyl) -dispiro- -heneicosan-21-one 4) N,N',N",N"'f-tetrakis-{2,4-biB-[N-(1,2,2,6,6-pentanethyl-4-piperidyl )-butylainino]-1, 3,5-triazin-6-yl}-4,7diazadecane-1, lO-diamine bis- 6-tetrainethyl-piperidy.) -E;ebacalte 6condensation product of N,N'-bis-(2,2,6,6-tetramethyl- 4-piperidyl) -hexamethylenediamine and 4-t-octylanino-2, 6- 20 dichloro-1,3,5-s-triazine Table 2 Action of phosphorus compounds on the processing stability of cycloolef in copolymer Al Kneading conditions: 280*C, 40 revolution-s per minute, 60 minutes Melt flow index MFI 280/5 (melting time of 5 minutes) bef ore kneading: 5 CM 3 /10 minutes I C 24 Example Phosphorus compound Parts by by weight Other additives Parts by by weight MFI after kneading cm 3 /10 minues Comparison I Comparison II la Ib Ic Id none 0.1 (A) 0.1 (B) 0.1 (C) 0.1 (B) 0.1 (C) 39.1 52.5 47.0 32.1 51.0 26.6 0.05 phenol') 0.05 phenol') r r r sc o r e sc o s r e e s~ o sc Table 3 Change in color (Yellowness Index in accordance with ASTM D 1925-70) after the extreme kneading experiment (280 0 C, 40 revolutions per minute, 60 minutes) on cycloolefin copolymer Al Example Phosphorus compound Parts by weight Comparison I none Comparison II 0.1 (A) la 0.1 (B) lb 0.1 (C) Ic 0.1 (B) Id 0.1 (C) Other additives Parts by weight

YI

unkneaded kneaded 5.3 6.7 8.5 6.7 8.4 5.8 85.9 70.9 72.2 74.6 68.3 71.9 0.05 phenol 1 0.05 phenol') I I--11- 25 Table 4 Action of phosphorus compounds on the processing stability of cycloolefin copolymer Al Kneading conditions: 240°C, 40 revolutions per minute, 60 minutes Melt flow index MFI 240/21.6 (melting time of 5 minutes) before kneading: 19.2 cm 3 /10 minutes Example Phosphorus Other MFI after compound additives kneading 10 Parts by Parts by cm 3 /10 minutes by weight by weight Comparison III none 33.0 2a 0.1 28.7 2b 0.1 0.05 phenol') 26.6 2c 0.1 0.05 phenol 1 0.3 HALS 2 21.0 2d 0.1 0.05 phenol' 0.3 HALS 3 18.6 20 2e 0.1 0.05 phenol) 0.3 HALS 4 20.3 26 Table Change in color (Yellowness Index in accordance with ASTM D 1925-70) after the kneading experiment (240*C, revolutions per minute, 60 minutes) on cycloolef in copolymer Al Example Phosphorus compound Parts by weight 9@ *0 10 Comparison III 2a 2b 2c none 0.1 0.1 0.1 Other additives Parts by weight 0.05 phenoll 0.05 phenol') 0.3 HALS') 0.05 phenol') 0.3 HALS') 0.05 phenol') 0.3 HALS 4 5.3 5.0 6.3 6.1 6.6 19.4 54.8 33.6 52.0 30.5 44.3 55.2

YI

unkneaded kneaded to. I *00.0 0. 1 (C) 0. 1 (C) 27 Table 6: Action of phosphorus compounds on the processing stability of cycloolefin copolymer A2 Kneading conditions: 190°C, 40 revolutions per minute, 60 minutes Melt flow index MFI 190/10 (melting time of 5 minutes) before kneading 10 cm 3 /10 minutes S I o Example 10 Comparison IV 3a 15 3b 3c 3d 20 3e 3f 3g Phosphorus compound Parts by by weight Other additives Parts by by weight none 0.1 0.1 0.1 0.1 (D) 0.1 (D) 0.1 (D) 0.1 (D) 0.05 phenol 1 0.05 phenol 1 0.3 HALS 2 0.05 phenol' 0.3 HALS 3 0.05 phenol 1 0.3 HALS 5 0.05 phenol"' 0.3 HALS 6 0.05 phenol 1 0.3 HALS 4 MFI after kneading 22.6 15.4 12.1 13.0 12.4 19.9 12.8 12.2 28 Table 7: Change in color (Yellowness Index in accordance with ASTM D 1926-70) of cycloolefin copolymer A2 after the kneading experiment (190 0 C, 40 revolutions per minute, 61) minutes) Example Phosphorus compound Parts by weight Other additives Parts by weight

YI

unkneaded kneaded o 0* *0e 10 Comparison IV 3a 3b 3c 3d 3e 3f 3g none 0.1 0.1 0.1 0 0 0* *0 0 0. 1 (D) 0. 1 (D) 0. 1 (D) 0. 1 (D) 0.05 0.05 0.3 0.05 0.3 0.05 0.3 0.05 0.3 0.05 0.3 phenol' phenol') Aims 2 phenol')

HALS')

phenol')

HALS

5 phenol')

HAIJS"

phenol')

HALSO

3A, 2.1 1.0 3.2 1.4 3.1 1.6 1.4 13.8 12.9 25.1 20.9 26.6 16.2 16.4 15.8 0 *00 00 0~ 0.

29 Table 8: Action of phosphorus compounds on the processin,; stabil.ity of cycloolefin copolymer A2 Kneading conditions: 190*C, 40 revolutions per minute, 60 minutes Melt flow index MFI 190/10 (melting time of 5 minutes) before kneading 10 cm 3 /10 minutes 0 .0.6.

see* Example Comparison IV 4a 15 4b 4c 4d 4e 4f 4- Phosphorus compound Parts by by weight Other additives Parts by by weight none 0.1 0.1 0.1 0. 1 (E) 0. 1 (E) 0. 1 (E) 0. 1 (E) 0.05 phenol) 0.05 phenol') 0.03 HAIJS 2 0.05 phenol') 0.03 HAIJS3 0.05 phenol') 0.3

HAIJS

5 0.05 phenol') 0.3 HALS 6

O

0.05 phenol') 0.3 HAILS 4 XFl after kneading 22.6 12.1 13.2 16.4 12.0 13.3 13.2

S.

S. S 0S

S.

18.6 30 Table 9: Change in color (Yiellowness Index in accordance with ASTM D 1925-70) of cycloolefin copolymer A2 after the kneading experiment (190 0 40 revolutions per minute, 60 minutes) Example Phosphorus compound Parts by weight Other additives Parts by weight

YI

unkneaded kneaded 10 Comparison IV 4a 4b 4c 4d 4e 20 4f 4g none 0.1 0.1 0.1

SO

00 5

*SSSS.

S

0. 1 (E) 0. 1 (E) 0. 1 (E) 0. 1 (E) 0.05 0.05 0.3 0.05 0.3 0.05 0.3 0.05 0.3 0.05 0.3 phenol') phenol') MAS2) phenol') HAS3) phenol')

HALS

5 phenol')

HALS

6 phenol')

MAS

4 3.4 2.2 13.8 6.1 22.3 10.2 18.3 28.6 19.7 1.5 1.7 1.6 31 Table Action of phosphorus compounds on the processing stability of cycloolefin copolymer A2 Kneading conditions: 190 0 C, 40 revolutions per minute, 60 minutes Melt flow index MFI 190/10 (melting time of 5 minutes) before kneading 10 cm 3 /10 minutes Example Comparison IV 5b 20 5e 5g Phosphorus compound Parts by by weight Other additives Parts by by weight MFI after kneading none 0.1 0.1 0.1 ooo.oo o ooooo *eoo* *o 0.1 (F) 0.1 (F) 0.1 (F) 0.1 (F) 0.05 phenol' 0.05 phenol 0.03 HALS 2 0.05 phenol' 0.03 HALS 3 0.05 phenol' 0.3 HALS s 5 0.05 phenol' 0.3 HALS 6 0.05 phenol' 0.3 HALS 4 22.6 12.3 9.9 19.6 12.5 13.0 16.3 13.8 32 Table 11: Change in color (Yellowness Index in accordance with ASTM D 1925-70) of cycloolefin copolymer A2 after the kneading experiment (190WC: 40 revolutions per minute, 60 minutes) Example Phosphorus compound Parts by weight .10 Comparison IV none 0.1 (F) Sb 0.1 (F) Sc 0.1 MF Other additives Parts by weight

YI

unkneaded kneaded 0 0 0 20 5f 0. 1 (F) 0. 1 (F) 0. 1 (F) 0. 1 (F) 0.05 phenol') 0.0S phenol') 0.3 BALS 2 0.0S phenol') 0.3 EALS') 0.05 phenol') 0.3 HAIJS 5 0.05 phenol') 0.3 HALSO~ 0.05 phenol') 0.3 HALS') 3.4 0.8 1.3 1.0 1.3 1.4 1.8 1.7 13.8 7.3 13.8 11.4 10.3 11.4 20.3 33 Table 12: Color development on 1 mm pressed sheets immediately after production and after conditioning (7 days at 100 0

C)

e 0 e Example Comparison I 2a 2b 2c 2d 2e Comparison IV 3a 3b 3c 3d 3e 3f 3g 4a 4b 4c 4d 4e 4f 4g 5e YI immediately 5.3 5.0 6.3 6.1 6.6 19.4 Yi after 7 days 6.1 6.7 7.1 6.7 15.0 3.4 2.1 1.0 3.2 1.4 3.1 1.6 1.4 2.2 1.1 1.1 1.7 1.5 1.7 1.6 0.8 1.3 1.0 1.3 1.4 1.8 1.7 4.7 4.3 5.3 3.3 5.3 3.2 3.9 3.3 2.7 2.3 2.2 2.9 2.6 3.3 1.4 1.7 1.8 2.4 2.9 r oi o

Claims (7)

1. A cycloolefin polymer molding composition of improved stability to chemical degradation, comprising to 99% by weight of a polymer which comprises structural units derived from at least one monomer of the formulae I to VII HO CH -CHR1 R 3 -C-R 4 MI) HC "I "OH OH ~R CI H _CH 2 I I HC R 3 CH H I I oo H COH ~CH 2 C OH C H HC I %OH OI- H R HO I R -ICH I 5 H CH R HOCC~H OCH O H Il 1R :R--RI R- 5 -O-R 6 I R 7 -O-R 8 I (IV), *HC. IQ ,CHJ I CH IJ COHN OH OH OHR HO-1I C H 11OLH .R 1 I I R 3 -r.-R 4 I I R 3 -C-R 4 R 7 R 8 1 (VI), HO CH C I CH CH CH R 6 CH\ O/CH (VII) (CH 2 )n in which Ri, R2, R3, R4, R51 R6, R7 and R8 are identical or different and are a hydrogen atom or a C 1 -C 8 -alkyi radical, it being possible for the same radicals in the various formulae to have a different meaning, and n is an integer from 2 to and 0.01 to 10% by weight of at least one organophosphorus compound as a stabilizer from the group formed by compounds a) of the formula IX R3-[P(OR14) 2 ]n (IX) in which n is 1 or 2, R14 is a linear or branched C 8 -C 2 0 -alkyl radical or a phenyl radical, which is optionally substituted by one or more linear or branched C1-C-alkyl radicals or br C 5 -C 8 -cycloaikyl, CO 6 -C 1 0 -aryl or C 7 -Clo-aralkyl radicals, R13 if n 1, is a phenyl or benzyl radical, which optionally carries 1 to 3 substituents, an cx-methylbenzyl, c,a-dimethylbenzyl or naphthyl radical or a naphthyl radical which carries 1 to 5 substituents, the substituents being identical or different and being a linear or branched Ci-C 8 -alkyl radical, a C- CO-alkoxy radical, a C-C1 2 -alkylthio radical, a C-C8- dialkylamino radical, a C6- Clo-ayl radical, a CO 6 -Clo-aryloxy radical or halogen having an atomic number of 9 to 35, and R13 if n 2, is a phenylene radical, a biphenylene radical, a naphthylene Is I I Is L p p 6 p e e p p p p e 0 p.* e e p p re r «e radical or a diphenylene oxide radical, which are unsubstituted or carry 1 to 4 linear or branched Ci-C 8 -alkyl radicals, b) oxaphosphcrines of the formula X 0 [P R 13 in which Ra 1 has the abovementioned meaning and m is 1 or 2.

2. A molding composition ,s claimed in claim 1, wherein the cycloolefin polymer comprises, in addition to the structural units which are derived from at 2east one monomer of the formulae I to VII, other structural units which are derived from at least one cyclic 1-olefin of the formula Vm R 9 Rio (VIII) R C7 C 11)12 in which R9, Rio, R11 and R12 are identical or different and are a hydrogen atom or a Ci*C 8 -alkyl radical.

3 A moding composition as clai,ned in claim 1, which comprises, in addition to the phosphorus compounds, customary additives.

4. A molding composition as claimed in claim 1, wherein the organo- phosphorus compound is a derivative of oxaphosphorine or phosphonous acid ester.

A molding composwLlon as claimed in claim 4, wherein the organo- phosphorus compound is a phosphonous acid ester.

6. The use of a molding composition as claimed in claim 1 for the production of sheets, fibers, films and tubes or as a binder for paints, adhesives or putties.

7. The use of a molding composition as claimed in claim 3 fo the productions of sheets, fibers, films and tubes or as a binder for paints, adhesives or putties. DATED this 15th day of February, 1996 HOECHST AKTIENGESELLSCHAFT WATERMARK PATENT TRADEMARK ATTORNEYS 290 BURWOOD ROAD HAWTHORN VICTORIA 3122 AUSTRALIA CJH/SH DOC 6 AU5193993.WPC ea a v• -111 Abstract HOE 92/F 374 Cycloolefin polymer molding composition of improved stability to chemical degradation. A cycloolefin polymer molding composition which comprises organophosphorus compounds of the formula IX R3-[P(OR14) 2] (IX) of the formula X o *0 S .R1 3 5 0* 6 *5*6S* S* S S 55* S 0* S 0* 4* or of the formula XI RR 6 0- 1 R P (X if appropriate in addition to other additives, shows an improved stability to chemical degradation. The organophosphorus compounds used according to the invention maintain the melt viscosity of the molding composition at the highest level (very small deviation from the starting value). They furthermore lead to the best initial colors of test specimens and to a relatively low change in color after kneading experiments. II ~e r r~