Stabilizing polycarbonates

A method of stabilising a transparent, solid and vitreous moulded article which is transparent at a wavelength of 350 to 700 nm and composed of a polycarbonate, polyester or polyketone or their mixtures against oxidative, thermal and/or light-induced degradation, which comprises incorporating therein, or applying thereto, at least one benzofuran-2-one compound of formula I

• wherein,
• if n=1,
• R1 is naphthyl, phenanthryl, anthryl, 5,6,7,8-tetrahydro-2-naphthyl, 5,6,7,8-tetrahydro-1-naphthyl, thienyl, benzo[b]thienyl, naphtho[2,3-b]thienyl, thianthrenyl, dibenzofuryl, chromenyl, xanthenyl, phenoxathiinyl, pyrrolyl, imidazolyl, pyrazolyl, pyrazinyl, pyrimidinyl, pyridazinyl, indolizinyl, isoindolyl, indolyl, indazolyl, purinyl, quinolizinyl, isoquinolyl, quinolyl, phthalazinyl, naphthyridinyl, quinoxalinyl, quinazolinyl, cinnolinyl, pteridinyl, carbazolyl, β-carbolinyl, phenanthridinyl, acridinyl, perimidinyl, phenanthrolinyl, phenazinyl, isothiazolyl, phenothiazinyl, isoxazolyl, furazanyl, biphenyl, terphenyl, fluorenyl or phenoxazinyl, each of which is unsubstituted or substituted by C1-C4alkyl, C1-C4alkoxy, C1-C4alkylthio, hydroxy, halogen, amino, C1-C4alkylamino, phenylamino or di(C1-C4-alkyl)amino, or R1 is a radical of formula II
• and,
• if n=2,
• R1 is unsubstituted or C1-C4alkyl- or hydroxy-substituted phenylene or naphthylene;
• or —R12—X—R13—, R2, R3, R4 and R5 are each independently of one another hydrogen, chloro, hydroxy, C1-C25-alkyl, C7-C9phenylalkyl, unsubstituted or C1-C4alkyl-substituted phenyl;
• unsubstituted or C1-C4alkyl-substituted C5-C8cycloalkyl;
• C1-C18alkoxy, C1-C18alkylthio, C1-C4alkylamino, di(C1-C4-alkyl)amino, C1-C25alkanoyloxy, C1-C25alkanoylamino, C3-C25alkenoyloxy;
• C3-C25alkanoyloxy which is interrupted by oxygen, sulfur or
• C6-C9cycloalkylcarbonyloxy, benzoyloxy or C1-C12alkyl-substituted benzoyloxy;
• or R2 and R3, or R3 and R4, or R4 and R5, together with the linking carbon atoms, form a benzene ring, R4 is additionally —(CH2)p—COR15 or —(CH2)qOH or, if R3, R5 and R6 are hydrogen, R4 is additionally a radical of formula III
• wherein
• R1 is as defined above for n=1,
• R6 is hydrogen or a radical of formula IV
• wherein
• R4 is not a radical of formula III, and R1 is as defined above for n=1
• R7, R8, R9, R10 and R11 are each independently of one another hydrogen, halogen, hydroxy, C1-C25alkyl which is interrupted by oxygen, sulfur or
• C1-C25alkoxy;
• C2-C25alkoxy which is interrupted by oxygen, sulfur or
• C1-C25alkylthio, C3-C25-alkenyl, C3-C25alkenyloxy, C3-C25alkynyl, C3-C25alkynyloxy, C7-C9phenylalkyl, C7-C9phenylalkoxy, unsubstituted or C1-C4alkyl-substituted phenyl;
• unsubstituted or C1-C4alkyl-substituted phenoxy;
• unsubstituted or C1-C4alkyl-substituted C5-C8cycloalkyl;
• unsubstituted or C1-C4alkyl-substituted C5-C8cycloalkoxy;
• C1-C4alkylamino, di(C1-C4alkyl)amino, C1-C25alkanoyl;
• C3-C25alkanoyl which is interrupted by oxygen, sulfur or
• C1-C25alkanoyloxy;
• C3-C25alkanoyloxy which is interrupted by oxygen, sulfur or
• C1-C25alkanoylamino, C3-C25alkenoyl;
• C3-C25alkenoyl which is interrupted by oxygen, sulfur or
• C3-C25alkonoyloxy, C3-C25alkenoyloxy which is interrupted by oxygen, sulfur or
• C6-C9cycloalkylcarbonyl C8-C9cycloalkylcarbonyloxy, benzoyl or C1-C12alkyl-substituted benzoyl;
• benzoyloxy or C1-C12alkyl-substituted benzoyloxy;
• or in formula II,
• R7 and R8, or R8and R11, together with the linking carbon atoms, form a benzene ring,
• R12 and R13 are each independently of the other unsubstituted or C1-C4alkyl-substituted phenylene;
• or naphthylene,
• R14 is hydrogen or C1-C8alkyl,
• R15 is hydroxy,
• C1-C18alkoxy or
• R16 and R17 are each independently of the other hydrogen, CF3, C1-C12alkyl or phenyl, or R16 and R17, together with the linking carbon atom, are a C5-C8cycloalkylidene ring which is unsubstituted or substituted by 1 to 3 C1-C4alkyl;
• R18 and R19 are each independently of the other hydrogen, C1-C4alkyl or phenyl,
• R20 is hydrogen or C1-C4alkyl, R21 is hydrogen, unsubstituted or C1-C4alkyl-substituted phenyl;
• C1-C25alkyl;
• C2-C25alkyl which is interrupted by oxygen, sulfur or
• C7-C9phenylalkyl which is unsubstituted or substituted at the phenyl moiety by 1 to 3 C1-C4alkyl;
• C7-C25phenylalkyl which is interrupted by oxygen, sulfur or
• and which is unsubstituted or substituted at the phenyl moiety by 1 to 3 C1-C4alkyl, or R20 and R21, together with the linking carbon atoms, form a C5-C12cycloalkylene ring which is unsubstituted or substituted by 1 to 3 C1-C4alkyl;
• R22 is hydrogen or C1-C4alkyl,
• R23 is hydrogen, C1-C25alkanoyl, C3-C25alkenoyl;
• C3-C25alkanoyl which is interrupted by oxygen, sulfur or
• C2-C25 alkanoyl which is substituted by a di(C1-C6alkyl)phosphonate group;
• C6-C9cycloalkylcarbonyl, thienoyl, furoyl, benzoyl or C1-C12alkyl-substituted benzoyl;
• R24 and R25are each independently of the other hydrogen or C1-C18alkyl,
• R26 is hydrogen or C1-C8alkyl,
• R27 is a direct bond, C1-C18alkylene;
• C2-C18alkylene which is interrupted by oxygen, sulfur or
• C2-C18alkenylene, C2-C20alkylidene, C7-C20phenylalkylidene, C5-C8cyclo alkylene, C7-C8bicycloalkylene, unsubstituted or C1-C4alkyl-substituted phenylene,
• or
• R28 is hydroxy,
• C1-C18alkoxy or
• R29 is oxygen, —NH— or
• R30 is C1-C18alkyl or phenyl,
• R31 is hydrogen or C1-C18alkyl,
• M is an r-valent metal cation,
• X is a direct bond, oxygen, sulfur or —NR31 —,
• n is 1 or 2,
• p is 0, 1 or 2,
• q is 1, 2, 3, 4, 5 or 6,
• r is 1, 2 or 3, and
• s is 0, 1 or 2.