Flame resistant polymer blends
View Patent ↗Blends of siloxane copolymers, notably siloxane polyimides, with polyaryl esters or polyaryl ester carbonates containing linkages derived from resorcinol, show improved flame resistance, as measured by two minute and peak heat release, compared to conventional polycarbonates. In some instances transparent flame retardant blends can also be prepared. The compositions show good melt processability, high impact strength and high elongation, and can be used to make various flame retardant articles including sheets and films.
1. A composition comprising a resorcinol-based aryl polyester resin having greater than or equal to 40 mole % of its moieties derived from resorcinol and a siloxane copolymer, wherein the composition has a peak heat release, as measured by FAR 25.853, of less than 65 kW/m 2 , wherein the total content of all siloxane copolymers in the composition is from 0.1 to 9.0 weight percent based on the total weight of the composition, and wherein the composition has a tensile elongation at break, as measured by ASTM D638, of greater than or equal to 50%, and a notched Izod impact, as measured by ASTM method D256 of greater than or equal to 5.0 ft-lbs/in.
2. The composition of claim 1 wherein the composition has a percent transmittance at 3.1 mm, as measured by ASTM D1003, of greater than or equal to 50 percent.
3. The composition of claim 1 wherein the total siloxane block weight of the composition based on the total weight of the composition is from 0.02 to 1.8 weight percent.
4. The composition of claim 1 wherein the total content of all siloxane copolymers in the composition is from 0.1 to 5.0 weight percent based on the total weight of the composition.
5. The composition of claim 1 wherein the resorcinol-based aryl polyester resin has a hydrogen atom to carbon atom ratio of less than or equal to 0.75:1.
6. The composition of claim 1 wherein the siloxane copolymer is selected from the group consisting of polyimide siloxanes, polyetherimide siloxanes, polyetherimide sulfone siloxanes, polysulfone siloxanes, polyether sulfone siloxanes, polyphenylene ether sulfone siloxanes, and polyphenylene ether siloxanes.
7. The composition of claim 6 wherein the siloxane copolymer is selected from the group consisting of polyimide siloxanes, polyetherimide siloxanes, and polyetherimide sulfone siloxanes.
8. The composition of claim 1 wherein the total siloxane block weight of the composition based on the total weight of the siloxane copolymer is from 5 to 70 weight percent.
9. The composition of claim 1 wherein the resorcinol-based aryl polyester has the structure shown below:
wherein R is at least one of C 1-12 alkyl, C 6 -C 24 aryl, alkyl aryl, alkoxy or halogen, n is 0 to 4 and m is on average at least 8.
10. The composition of claim 1 wherein resorcinol-based aryl polyester has the structure shown below:
wherein R is at least one of C 1-12 alkyl, C 6 -C 24 aryl, alkyl aryl, alkoxy or halogen, n is 0 to 4, R 5 is at least one divalent organic radical, m is on average from 4 to 150, and p is on average from 2 to 200.
11. The composition of claim 10 wherein R 5 is a moiety derived from a bisphenol compound.
12. The composition of claim 1 wherein the composition has a haze at 3.1 mm, as measured by ASTM D1003, of less than or equal to 25 percent.
13. The composition of claim 1 further comprising a fluoropolymer.
14. The composition of claim 1 further comprising a second resorcinol-based polyester resin.
15. The composition of claim 1 wherein the composition has a melt flow, as measured by ASTM method D1238 at 300° C. with a 1.2 Kg weight, of from 1 to 30 g/10 min.
16. A composition comprising a resorcinol-based aryl polyester resin having greater than or equal to 40 mole % of its moieties derived from resorcinol and a siloxane copolymer, wherein the composition has a peak heat release, as measured by FAR 25.853, of less than 80 kW/m 2 , and wherein the composition has a percent transmittance at 3.1 mm, as measured by ASTM D1003, of greater than or equal to 50 percent, wherein the total content of all siloxane copolymers in the composition is from 0.1 to 9.0 weight percent based on the total weight of the composition, and wherein the composition has a tensile elongation at break, as measured by ASTM D638, of greater than or equal to 50%, and a notched Izod impact, as measured by ASTM method D256 of greater than or equal to 5.0 ft-lbs/in.
17. A composition comprising at least one resorcinol-based aryl polyester resin having greater than or equal to 40 mole % of its moieties derived from resorcinol and at least one siloxane copolymer, wherein the composition has a peak heat release, as measured by FAR 25.853, of less than 80 kW/m 2 and wherein the siloxane copolymer is selected from the group consisting of polyimide siloxanes, polyetherimide siloxanes, polyetherimide sulfone siloxanes, polysulfone siloxanes, polyether sulfone siloxanes, polyphenylene ether sulfone siloxanes, and polyphenylene ether siloxanes, and wherein the composition does not comprise a polycarbonate siloxane, wherein the total content of all siloxane copolymers in the composition is from 0.1 to 9.0 weight percent based on the total weight of the composition, and wherein the composition has a tensile elongation at break, as measured by ASTM D638, of greater than or equal to 50%, and a notched Izod impact, as measured by ASTM method D256 of greater than or equal to 5.0 ft-lbs/in.
18. A composition comprising at least one resorcinol-based aryl polyester resin having greater than or equal to 40 mole % of its moieties derived from resorcinol and from 0.1 to 5.0 wt % based on the total weight of the composition of at least one siloxane copolymer, wherein the composition has a peak heat release, as measured by FAR 25.853, of less than 65 kW/m 2 , and wherein the composition has a percent transmittance at 3.1 mm, as measured by ASTM D1003, of greater than or equal to 50 percent, and wherein the resorcinol-based aryl polyester resin has a hydrogen atom to carbon atom ratio of less than or equal to 0.75:1, wherein the total content of all siloxane copolymers in the composition is from 0.1 to 9.0 weight percent based on the total weight of the composition, and wherein the composition has a tensile elongation at break, as measured by ASTM D638, of greater than or equal to 50%, and a notched Izod impact, as measured by ASTM method D256 of greater than or equal to 5.0 ft-lbs/in.
19. An article comprising the composition of claim 1 .
20. An article comprising the composition of claim 16 .
21. An article comprising the composition of claim 17 .