Thermoplastic elastomer compositions comprising intumescent flame retardants and non-phosphorous-based flame retardant synergists
Compositions comprising a thermoplastic elastomer, e.g., a polyurethane, a nitrogen and/or phosphorus-based, intumescent flame retardant, e.g., a polyphosphate, a non-phosphorus-based burn synergist, e.g., carbon black or a metal oxide, and an optional olefin polymer, EVA are provided. Color-stable, halogen-free, flame retardant compositions comprising a thermoplastic elastomer polymer, a phosphorus-based flame retardant, at least 3 weight percent TiO2 and a UV stabilizer are also provided.
1. A coating for a wire or cable comprising a color-stable, halogen-free, flame retardant composition, the composition comprising, based on the weight of the composition:
(a) a thermoplastic elastomer consisting of a thermoplastic polyurethane and, optionally, an olefin-based polymer;
(b) 5-60 weight percent of a phosphorus-based flame retardant;
(c) at least 5 weight percent TiO 2 ; and
(d) a UV stabilizer;
the composition having a CIE 94 ΔE of no greater than 3 after 300 hours of exposure to a xenon arc lamp according to ASTM-D-4459-06.
2. The composition of claim 1 in which the thermoplastic polyurethane comprises a polycarprolactone ester based thermoplastic polyurethane.
3. The composition of claim 1 comprising at least 9 weight percent TiO 2 .
4. The composition of claim 3 in which the phosphorus-based flame retardant is a phosphoric acid ester.
5. The composition of claim 4 in which the thermoplastic polyurethane is an aromatic polyurethane.
6. The composition of claim 1 having a 5% secant modulus of no greater than 20,000.
7. The composition of claim 2 , wherein the composition comprises up to 40% by weight percent of an olefin-based polymer.
8. The composition of claim 7 in which the olefin-based polymer is at least one of ethylene/acrylic acid (EAA), ethylene/methacrylic acid (EMA), ethylene/acrylate or methacrylate, ethylene/vinyl acetate (EVA), poly(ethylene-co-vinyltrimethoxysilane) copolymer, or a maleic anhydride- or silane-grafted olefin polymer.
9. A coated wire comprising an electrically conductive wire having a surface that is at least partially coated with the flame retardant composition of claim 1 .
10. A method of making a coated wire, the method comprising coating at least a portion of the surface of an electrically conductive wire with the flame retardant composition of claim 1 .
11. The composition of claim 1 , wherein the composition comprises 20-85 weight percent thermoplastic polyurethane.