Thermoplastic halogen-free flame retardant formulations
View Patent ↗Highly-mineral-filled, halogen-free, flame-retardant compositions made from or containing a polypropylene thermoplastic elastomer, a polypropylene, a metal hydroxide filler, and a polar-monomer-grafted polyolefin elastomer compatibilizer. Such compositions can be employed in preparing various articles of manufacture, including extruded articles and coated conductors, such as cables.
1. A halogen-free, flame-retardant composition comprising:
(a) a propylene polymer;
(b) a thermoplastic propylene/ethylene copolymer elastomer;
(c) a polar-monomer grafted polyolefinic elastomer compatibilizer; and
(d) a metal hydroxide filler,
wherein said thermoplastic propylene/ethylene copolymer elastomer is composed of a majority of propylene with a minor amount of ethylene.
2. The halogen-free, flame-retardant composition of claim 1 wherein
(a) the propylene polymer is present in an amount between about 10 to about 20 weight percent;
(b) the thermoplastic propylene/ethylene copolymer elastomer is present in an amount between about 15 to about 35 weight percent;
(c) the polar-monomer grafted polyolefinic elastomer compatibilizer is present in an amount between about 2.5 to about 7.5 weight percent; and
(d) the metal hydroxide filler is present in an amount greater than about 45 weight percent.
3. The halogen-free, flame-retardant composition of claim 1 or claim 2 wherein the polar-monomer grafted polyolefinic elastomer compatibilizer is a maleic-anhydride grafted polyolefin elastomer.
4. The halogen-free, flame-retardant composition of claim 1 or claim 2 wherein the metal hydroxide filler is magnesium hydroxide.
5. A cable comprising one or more electrical conductors or a core of one or more electrical conductors, each conductor or core being surrounded by a halogen-free, flame retardant layer comprising the halogen-free, flame-retardant composition according to claim 1 .
6. An extruded article comprising the halogen-free, flame-retardant composition according to claim 1 .
7. The halogen-free, flame-retardant composition of claim 1 , wherein said thermoplastic propylene/ethylene copolymer elastomer has an ethylene content of greater than 10 percent and less than 50 percent.
8. The halogen-free, flame-retardant composition of claim 1 , wherein said polar-monomer grafted polyolefinic elastomer compatibilizer consists of a maleic-anhydride-grafted polyolefin.
9. The halogen-free, flame-retardant composition of claim 1 , wherein said thermoplastic propylene/ethylene copolymer elastomer has a linear, single homogeneous macromolecular copolymer structure, wherein said thermoplastic propylene/ethylene copolymer elastomer is substantially devoid of intermolecular heterogeneity in tacticity and comonomer composition, wherein said thermoplastic propylene/ethylene copolymer elastomer is substantially free of diene, wherein said thermoplastic propylene/ethylene copolymer elastomer is substantially devoid of heterogeneity in intramolecular composition distribution.
10. A halogen-free, flame-retardant composition comprising:
(a) a propylene polymer;
(b) a thermoplastic propylene/ethylene copolymer elastomer;
(c) an organic peroxide;
(d) a polar graftable monomer; and
(e) a metal hydroxide filler,
wherein said thermoplastic propylene/ethylene copolymer elastomer is composed of a majority of propylene with a minor amount of ethylene.
11. A cable comprising one or more electrical conductors or a core of one or more electrical conductors, each conductor or core being surrounded by a halogen-free, flame retardant layer comprising the halogen-free, flame-retardant composition according to claim 10 .
12. An extruded article comprising the halogen-free, flame-retardant composition according to claim 10 .
13. The halogen-free, flame-retardant composition of claim 10 , wherein said thermoplastic propylene/ethylene copolymer elastomer has an ethylene content of greater than 10 percent and less than 50 percent.
14. The halogen-free, flame-retardant composition of claim 10 , wherein said polar graftable monomer consists of maleic anhydride.
15. The halogen-free, flame-retardant composition of claim 10 , wherein said thermoplastic propylene/ethylene copolymer elastomer has a linear, single homogeneous macromolecular copolymer structure, wherein said thermoplastic propylene/ethylene copolymer elastomer is substantially devoid of intermolecular heterogeneity in tacticity and comonomer composition, wherein said thermoplastic propylene/ethylene copolymer elastomer is substantially free of diene, wherein said thermoplastic propylene/ethylene copolymer elastomer is substantially devoid of heterogeneity in intramolecular composition distribution.