Flame retardant compositions

A flame retardant polymer composition which comprises

• (a) a polymer substrate, and
• (b) an effective flame retarding amount of a synergistic mixture of
• (i) a hindered amine and
• (ii) a brominated and/or phosphorus containing flame retardant;
• wherein the hindered amine of component (i) is selected from the group consisting of (A) and (B),
• wherein
• (A) is:
• wherein
• E is cyclohexyloxy,
• R is hydrogen or methyl,
• m is 1 to 4,
• when m is 1,
• R2 is hydrogen, C1-C18alkyl or said alkyl optionally interrupted by one or more oxygen atoms, C2-C12alkenyl, C6-C10aryl, C7-C18aralkyl, glycidyl, a monovalent acyl radical of an aliphatic, cycloaliphatic or aromatic carboxylic acid, or a carbamic acid, or:
• wherein x is 0 or 1, or:
• wherein y is 2-4;
• when m is 2,
• R2 is C1-C12alkylene, C4-C12alkenylene, xylylene, a divalent acyl radical of an aliphatic, cycloaliphatic, araliphatic or aromatic dicarboxylic acid or of a dicarbamic acid, or:
• wherein D1 and D2 are independently hydrogen, an alkyl radical containing up to 8 carbon atoms, an aryl or aralkyl radical including 3,5-di-t-butyl4-hydroxybenzyl radical, D3 is hydrogen, or an alkyl or alkenyl radical containing up to 18 carbon atoms, and d is 0-20;
• when m is 3, R2 is a trivalent acyl radical of an aliphatic, unsaturated aliphatic, cycloaliphatic, or aromatic tricarboxylic acid;
• when m is 4, R2 is a tetravalent acyl radical of a saturated or unsaturated aliphatic or aromatic tetracarboxylic acid including 1,2,3,4-butanetetracarboxylic acid, 1,2,3,4-but-2-enetetracarboxylic, and 1,2,3,5- and 1,2,4,5-pentanetetracarboxylic acid;
• wherein
• (B) is a mixture of N,N′,N′″-tris{2,4-bis[(1-hydrocarbyloxy-2,2,6,6-tetramethylpiperidin--4-yl)alkyl-amino]-s-triazin-6-yl}-3,3′-ethylenediiminodipropylamine;
• N,N′,N″-tris{2,4-bis[(1-hydrocarbyloxy-(2,2,6,6-tetramethylpiperidin-4-yl)alkylamino]-s-triazin-6-yl}-3,3′-ethylenediiminodipropylamine, and bridged derivatives as described by formulas I, II, IIA and III:
• R1NH—CH2CH2CH2NR2CH2CH2NR3CH2CH2CH2NHR4 (I)
• T—E1—T1 (II)
• T—E1 (IIA)
• G—E1—G1—E1—G2 (III)
• where in the tetraamine of formula I:
• R1 and R2 are the s-triazine moiety E;
• and one of R3 and R4 is the s-triazine moiety E with the other of R3 or R4 being hydrogen,
• E is:
• R is cyclohexyl,
• R5 is alkyl of 1 to 12 carbon atoms, where in the compound of formula II or IIA when R is cyclohexyl,
• T and T1 are each substituted by R1-R4 as is defined for formula I, where
• (1) one of the s-triazine moieties E in each tetraamine is replaced by the group E1 which forms a bridge between two tetraamines T and T1,
• E1 is:
• or
• (2) the group E1 can have both termini the same tetraamine T as in formula IIA where two of the E moieties of the tetraamine are replaced by one E1 group, or
• (3) all three s-triazine substituents of tetraamine T can be E1 such that one E1 links T and T1 and a second E1 has both termini in tetraamine T,
• L is cyclohexanediyl;
• where in the compound of formula III:
• G, G1 and G2 are each tetraamines substituted by R1-R4 as defined for formula I, except that G and G2 each have one of the s-triazine moieties E replaced by E1, and G1 has two of the triazine moieties E replaced by E1, so that there is a bridge between G and G1 and a second bridge between G1 and G2;
• which mixture is prepared by reacting two to four equivalents of 2,4-bis[(1-hydrocarbyloxy-2,2, 6,6-piperidin-4-yl)butylamino]-6-chloro-triazine with one equivalent of N,N′-bis(3-aminopropyl)-ethylenediamine;
• and
• with the proviso that when the polymer substrate is polypropylene, the flame retardant is not a halogenated hydrocarbyl phosphate or phosphonate;
• and with the proviso that when the polymer substrate is polypropylene, the flame retardant is not a brominated flame retardant when component (i) is di-(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl) sebacate or di-(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin4-yl) succinate.