Phosphazene flame retardant polycarbonate compounds
View Patent ↗A non-halogenated flame retardant polycarbonate compound is disclosed. The compound comprises a polycarbonate, a non-halogenated, non-migrating, non-plasticizing flame retardant adduct. The compound can achieve a UL 94 rating of V-0 at a thickness of at least 3.2 mm and otherwise achieves no dripping/igniting of the cotton indicator during that test. The adduct is formed from an allyl-functional phenoxyphosphazene and a hydride-functional polysiloxane.
1. A flame retardant polycarbonate compound, comprising:
(a) polycarbonate homopolymer or copolymer,
(b) a crosslinked phosphorous-containing silicone formed without solvent from an allyl-functional phenoxyphosphazene derivative and a hydride-functional siloxane.
2. The compound of claim 1 , wherein the hydride-functional siloxane comprises a homopolymer or copolymer of methyl hydrosiloxane moieties, and/or hydride terminated poly-disubstituted siloxanes, which optionally contain phenyl and other alkyl substitution, in linear, cyclic, or oligomeric configuration.
3. The compound of claim 1 , wherein the polycarbonate is a combination of linear polycarbonate and branched carbonate.
4. The compound of claim 1 , wherein the hydride functional siloxane is poly(methyl hydrosiloxane) homopolymer or methylhydrosiloxane-dimethylsiloxane copolymer, or both, in which the percentage of methylhydrosiloxane and/or hydride terminal poly-dimethyl siloxane moieties can range from about 1 to about 99 weight percent.
5. The compound of claim 1 , further comprising talc.
6. The compound of claim 1 , further comprising a second non-halogenated flame retardant.
7. The compound of claim 6 , wherein the second non-halogenated flame retardant is selected from the group consisting of bisphosphate esters, polyphosphonates, polyphosphazenes, and combinations thereof.
8. The compound of claim 1 , wherein the reaction of the allyl-functional phenoxyphosphazene derivative and a hydride-functional siloxane occurs in situ during melt mixing with the polycarbonate via hydrosilylation with a platinum catalyst.
9. The compound of claim 8 , wherein the compound when injection molded and tested at a thickness of 3.2 mm passes the dripping/igniting portion of UL 94 test.
10. The compound of claim 9 , wherein the allyl-functional phenoxyphosphazene comprises
(a) cyclic phosphazenes of Formula (1)
wherein m is an integer of 3 to 25, two R 1 groups are the same or different and each represents a phenyl group substituted with at least one group selected from the class consisting of alkyl groups having 1 to 6 carbon atoms and an allyl group or an unsubstituted phenyl group, or a hydroxy substituted phenyl or
(b) straight-chain phosphazenes of Formula (2)
wherein n is an integer of 3 to 1000, R 1 is as defined above, X represents a group —N=P(OR 1 ) 3 or a group —N=P(O)OR 1 , and Y represents a group —P(OR 1 ) 4 or a group—P(O)(OR 1 ) 2 or
combinations thereof.
11. The compound of claim 1 , further comprising adhesion promoters; biocides; anti-fogging agents; anti-static agents; bonding, blowing or foaming agents; dispersants; fillers or extenders; smoke suppressants; impact modifiers; initiators; lubricants; micas; colorants; plasticizers; impact modifiers; processing aids; release agents; silanes; titanates; zirconates; slip or anti-blocking agents; stabilizers; stearates; ultraviolet light absorbers; viscosity regulators; waxes; catalyst deactivators; or combinations of them.
12. The compound of claim 1 , wherein the polycarbonate homopolymer is a mixture of a branched polycarbonate of virginal source, recycled source, or both, and a linear polycarbonate of virginal source, recycled source, or both and wherein the polycarbonate copolymer is polyphosphonate-co-carbonate.
13. The compound of claim 11 , wherein the compound has ingredients in amounts expressed in weight percent:
Polycarbonate Matrix
50-99.9
Allyl functional phenoxyphosphazene
0.1-25
Hydride-functional Polysiloxane
0.1-25
Platinum Catalyst Complex (1-2.5% Platinum)
0.01-1
Optional Non-Halogenated Char Former
0-2
Optional Talc
0-9
Optional Non-Halogenated Flame Retardant
0-10
Optional Other Additives
0-5.
14. A shaped article made from the compound of claim 1 , wherein the shaping occurs by extrusion, molding, calendering, thermoforming, and additive manufacturing.
15. A method of using the compound of claim 1 , comprising the step of shaping the compound into an article designed to resist combustion or molten dripping in the presence of flame.