Heat resistant clear polycarbonate-polysiloxane compounds

1. A polycarbonate blend composition comprising:

(a) a first polycarbonate having a glass transition temperature of greater than 170° C. as measured using a differential scanning calorimetry method, wherein the first polycarbonate is derived from at least one monomer selected from the group consisting of 3,3-bis(4-hydroxyphenyl)-2-phenylisoindolin-1-one (PPPBP), 1,1-bis (4-hydroxyphenyl)-1-phenyl-ethane (Bisphenol-AP), and 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethyl-cyclohexane (Bisphenol-TMC); and

(b) a second polycarbonate wherein the second polycarbonate is a polysiloxane block copolymer derived from bisphenol-A and

 wherein the average value of E is between 30 and 50, or

 wherein the average value of E is between 30 and 50,

wherein the blend composition has a glass transition temperature (Tg) between 148° C. and 155° C. as measured using a differential scanning calorimetry method;

wherein the blend composition has a percent (%) haze of less than 3.5% and a % transmission of greater than 80% as measured using a method of ASTM D 1003-07;

wherein the blend composition possesses 80% or greater ductility in a notched izod test at −20° C. at a thickness of 0.125 inches according to ASTM D 256-10; and

wherein the second polycarbonate composes greater than 75 wt % of the polycarbonate blend composition and wherein the first polycarbonate composes less than 25 wt % of the polycarbonate blend composition based on the sum of the first and second polycarbonates being equal to 100 wt %.

2. The blend composition of claim 1 , wherein the composition has an MVR of between 6 and 12 cm 3 /10 minute as measured at 300° C. at 1.2 kilograms using the method of ASTM D 1238-10.

3. The blend composition of claim 1 , wherein the first polycarbonate comprises greater than 30 wt % of carbonate units derived from at least one of the following 3,3-bis(4-hydroxyphenyl)-2-phenylisoindolin-1-one (PPPBP), 1,1-bis(4-hydroxyphenyl) -1-phenyl-ethane (Bisphenol-AP), and 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethyl-cyclohexane (Bisphenol-TMC).

4. The blend composition of claim 3 , wherein the first polycarbonate has a % haze of less than 1.5% as measured using the method of ASTM D 1003-07 at 0.125 inches in part thickness.

5. The blend composition of claim 1 , wherein the first polycarbonate further comprises carbonate units derived from 2,2-bis(4-hydroxyphenyl)propane (Bisphenol-A).

6. The blend composition of claim 3 , wherein the first polycarbonate further comprises carbonate units derived from 2,2-bis(4-hydroxyphenyl)propane (Bisphenol-A).

7. The blend composition of claim 1 , wherein the second polycarbonate has a haze of less than 3% as measured using the method of ASTM D 1003-07 at 0.125 inches in part thickness having 100% ductility at -20° C. as measured using the method of ASTM D 256-10 at 0.125 inches in part thickness.

8. The blend composition of claim 1 , wherein the first and second polycarbonates are made from either an interfacial polymerization process and/or a melt polymerization process.

9. The blend composition of claim 1 , wherein the wt % siloxane in the second polycarbonate is between 5 wt % and 7 wt % based on the total weight of the second polycarbonate.

10. The blend composition of claim 1 , wherein the wt % of the siloxane in the blend composition is between 4 wt % and 6 wt % based on the total weight of the polycarbonate blend composition.

11. The blend composition of claim 1 , wherein the first polycarbonate comprises 4,4′-(3,3,5-trimethylcyclohexane-1,1-diyl)diphenol.

12. A polycarbonate blend composition comprising:

(a) a first polycarbonate, which is a copolycarbonate having a glass transition temperature of 170° C. or greater as measured using differential scanning calorimetry and derived from a combination of bisphenol-A and a second monomer that is selected from the group consisting of 3,3-bis(4-hydroxyphenyl)-2-phenylisoindolin-1-one (PPPBP), 1,1-bis(4-hydroxyphenyl)-1-phenyl-ethane (Bisphenol-AP), and 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethyl-cyclohexane (Bisphenol-TMC); and

(b) a second polycarbonate, which is a polysiloxane block copolycarbonate derived from at least bisphenol-A and

 wherein the average value of E is between 30 and 50, or

 wherein the average value of E is between 30 and 50,

 wherein the siloxane content in the polysiloxane block co-polycarbonate is between 2 wt % and 10 wt % siloxane based on the total weight of the polysiloxane block co-polycarbonate;

wherein the polycarbonate blend composition comprises between 10% and 20% of the first polycarbonate and between 90 wt % and 80 wt % of the second polycarbonate based on the sum of the first and the second polycarbonate being equal to 100 wt %;

wherein the polycarbonate blend composition has a glass transition temperature (Tg) of between 148° C. and 155° C. as measured using a differential scanning calorimetry method;

wherein the polycarbonate blend composition has a % haze of less than 3% and a transmission of greater than 80% as measured using the method of ASTM D 1003-07; and

wherein the polycarbonate blend composition possesses at least 75% ductility in a notched izod test at -20° C. at a thickness of 0.125 inches according to ASTM D 256-10.

13. The blend composition of claim 12 further comprising at least one of the following additives: mold release agents, thermal stabilizers, UV stabilizers, or colorants.

14. A polycarbonate blend composition comprising:

(a) a first polycarbonate comprising carbonate units derived from a bisphenol-A and 3,3-bis(4-hydroxyphenyl)-2-phenylisoindolin-1-one (PPPBP), wherein the first polycarbonate has a mole % of carbonate units derived from PPPBP between 30-35 mole % and a mole carbonate units derived from Bisphenol-A between 65 and 70 mole ° %, and

(b) a second polycarbonate comprising carbonate units derived from Bisphenol-A and carbonate units derived from

wherein, E has an average value of between 40 and 50 and wherein the wt % siloxane in the second polycarbonate is between 5 wt % and 7 wt % based on the weight of the second polycarbonate being 100%;

wherein, the polycarbonate blend composition comprises between 10% and 20% of the first polycarbonate and between 80 wt % and 90 wt % of the second polycarbonate based on the sum of the first and the second polycarbonate being equal to 100 wt %;

wherein, the polycarbonate blend composition has a glass transition temperature (Tg) of between 148° C. and 155° C. as measured using a differential scanning calorimetry method;

wherein, a molded article of the polycarbonate blend composition has a % haze of less than 3% and a % transmission of greater than 80% as measured using the method of ASTM D 1003-07 at 0.125 inches in part thickness;

wherein the polycarbonate blend composition possesses at least 75% ductility in a notched izod test at -20° C. at a thickness of 0.125 inches according to ASTM D 256-10.

15. A method for making the polycarbonate blend composition of claim 1 comprising the step of

(a) Selecting the first polycarbonate of claim 1 ;

(b) Selecting the second polycarbonate of claim 1 ; and

(c) Blending the first polycarbonate with the second polycarbonate to form a composition having a glass transition temperature (Tg) of between 145° C. and 155° C. as measured using a differential scanning calorimetry method, a % haze of less than 3.5% and a % transmission of greater than 80% as measured using the method of ASTM D 1003-07; and, possesses 80% or greater ductility in a notched izod test at -20° C. at a thickness of 0.125 inches according to ASTM D 256-10.

16. The method of claim 15 , wherein step (c) comprises extrusion.

17. An article molded from the polycarbonate blend composition of claim 1 .

18. The article of claim 17 , wherein the article is a component of a cell phone cover or computer housing.

19. An article molded from the polycarbonate blend composition of claim 14 .