The invention claimed is:
1. A method for imparting flame retardancy to a plastic material such that it has a flame retardancy rating of V-2 or better and for synergistically enhancing the flame retardancy of a plastic material, the method comprising incorporating into the plastic material (i) an organic oxyimide comprising at least one structural element of Formula I
wherein the organic oxyimide is halogen-free and is selected from the group consisting of
a) oxyimides comprising at least one structural element of Formula II,
wherein R 1 is hydrogen or a substituted alkyl-, cycloalkyl-, aryl-, heteroaryl-, or acyl radical, and
b) bridged oxyimides comprising at least one structural element of Formula III,
wherein R 2 is a substituted alkylene-, cycloalkylene-, arylene-, heteroarylene-, or bridging acyl radical, and
(ii) a flame retardant selected from the group consisting of (a), (b), (c), (d), and (e), and combinations thereof, wherein:
(a) is a phosphinate of the formula:
wherein R 1 and R 2 are identical or different and are selected from the group consisting of linear or branched C 1 -C 6 alkyl and aryl; M is selected from the group consisting of Mg, Ca, Al, Sb, Sn, Ge, Ti, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K, Zn, and a protonated nitrogen base; m =1-4; n=1-4; and x=1-4;
(b) is metal salt of hypophosphorous acid of the formula:
wherein Met is a metal selected from groups I, II, III, and IV of the periodic table of elements, and n is a number from 1 to 4 which corresponds to the charge of the corresponding metal ion Met;
(c) is a phosphonate or phosphonic acid diaryl ester of the formula:
wherein R 8 and R 10 ═H or alkyl, R 9 ═C 1 —C 4 alkyl, u=1-5, and v=1-5;
(d) is one or more of the following compounds:
wherein M is a metal selected from the group consisting of second, third, twelfth and thirteenth group of the periodic table of the elements, x=2 or 3, n≥10, m =0-25, R═H, halogen or an aliphatic or aromatic radical with 1-32 C atoms and R 1 ═H or C 1 -C 6 alkyl; and
(e) is a cyclic phosphonate of the following formulae:
wherein A l and A 2 , independently of each other, representing a substituted or unsubstituted, straight-chain or branched alkyl group with 1 to 4 carbon atoms, substituted or unsubstituted benzyl, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, and A 3 and A 4 , independently of each other, is methyl or ethyl and A 5 is a straight-chain or branched alkyl group with 1 to 4 carbon atoms or a phenyl- or benzyl group which can have respectively up to 3 methyl groups;
such that the plastic material, after incorporation of the organic oxyimide and the flame retardant or flame retardants, has a flame retardancy rating of V-2 or better, wherein the flame retardancy is measured according to DIN EN 60695-11-10, and wherein the flame retardancy is greater than the flame retardancy of the plastic material containing only a phosphorus-containing flame retardant, a nitrogen-containing flame retardant, or a sulphur-containing flame retardant, or combination thereof.
2. The method according to claim 1 , wherein R 2 is selected from radicals of the group consisting of
—(CH 2 ) n — with n=1 to 18, —CH(CH 3 )—, —C(CH 3 ) 2 , —O—, —S—, —SO 2 —, —NHCO—, —CO—and the following groups:
the cycloaliphatic or aromatic ring systems contained in the above groups being unsubstituted or substituted by one or more alkyl- and/or alkoxy groups,
Q upon each occurrence, being the same or different and being selected from the group consisting of a chemical bond and radicals —(CH 2 ) n — with n=1 to 18, —CH(CH 3 )—, —C(CH 3 ) 2 , —O—,—S—, —SO 2 —, —NHCO—, —CO—, and
m being 0 or 1 to 18.
3. The method according to claim 1 , wherein the oxyimide has one of the following formulae,
respectively R 1 is hydrogen or a unsubstituted or substituted alkyl-, unsubstituted or substituted cycloalkyl-, unsubstituted or substituted aryl- or unsubstituted or substituted heteroaryl- or unsubstituted or substituted acyl radical, and
R 2 is a substituted alkylene-, cycloalkylene-, arylene-, heteroarylene- or bridging acyl radical.
4. The method according to claim 3 , wherein R 1 ═H or acyl.
5. The method according to claim 1 , wherein the plastic materials are thermoplastic, elastomeric or duroplastic polymers.
6. The method according to claim 5 , wherein the plastic materials are thermoplastic polymers selected from the group consisting of
a) polymers made of olefins or diolefins and polyalkylene-carbon monoxide copolymers;
b) polystyrene, polymethylstyrene, polyvinylnaphthalene, styrene-butadiene (SB), styrene-butadiene-styrene (SBS), styrene-ethylene-butylene-styrene (SEBS), styrene-ethylene-propylene-styrene, styrene-isoprene, styrene-isoprene-styrene (SIS), styrene-butadiene-acrylonitrile (ABS), styrene-acrylonitrile-acrylate (ASA), styrene-ethylene, styrene-maleic anhydride polymers including corresponding graft copolymers, graft copolymers made of methylmethacrylate, styrene-butadiene, styrene-butadiene-acrylonitrile (ABS), and methyl methacrylate-acrylonitrile-butadiene-styrene (MABS),
c) halogen-containing polymers,
d) polymers of unsaturated esters, polyacrylonitrile, polyacrylamides, and copolymers thereof,
e) polymers made of unsaturated alcohols and derivatives thereof, polyacetals,
g) polyphenylene oxides and blends with polystyrene or polyamides,
h) polymers of cyclic ethers,
i) polyurethanes made of hydroxy-terminated polyethers or polyesters and aromatic or aliphatic isocyanates,
j) polyamides, partially or fully aromatic polyamides, and aromatic polyamides,
k) polyimides, polyamideimides, polyetherimides, polyesterimides, poly(ether)ketones, polysulphones, polyethersulphones, polyarylsulphones, polyphenylenesulphide, polybenzimidazoles, and polyhydantoins,
l) polyesters made of aliphatic or aromatic dicarboxylic acids and diols or made of hydroxycarboxylic acids,
m) polycarbonates, polyester carbonates, and blends thereof,
n) cellulose derivatives,
o) non-thermoplastic or duroplastic plastic materials, and
p) polyureas,
q) mixtures, combinations or blends made of two or more of the previously mentioned polymers.
7.