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:

(i) one or more monomers having the structure

HO-A 1 -Y 1 -A 2 -OH

wherein each of A 1 and A 2 comprise a monocyclic divalent arylene group, and Y 1 is a bridging group having one or more atoms, and wherein the structure is free of halogen atoms; or

(ii) polyester monomer units having the structure

wherein D comprises one or more alkyl containing C 6 -C 20 , aromatic group(s), or one or more C 6 -C 20 aromatic group(s), and T comprises a C 6 -C 20 aromatic group; and

(b) a second polycarbonate wherein the second polycarbonate is a polysiloxane block copolymer derived from

(i) the structure

wherein R comprises a C 1 -C 30 aliphatic, a C 1 -C 30 aromatic group, or a combination thereof, wherein Ar comprises one or more C 6 -C 30 aromatic group(s), one or more alkyl containing C 6 -C 30 aromatic group(s), wherein E has an average value of 20-75; or

(ii) the structure

wherein R comprises a C 1 -C 30 aliphatic, a C 1 -C 30 aromatic group, or a combination thereof, wherein R 6 comprises C 7 -C 30 aromatic group, or a combination of a C 7 -C 30 aromatic group and a C 7 -C 30 aliphatic group, wherein E has an average value of 20-75;

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.

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 second polycarbonate further comprises a carbonate unit derived from the polysiloxane blocks having the structure

wherein E has an average value of between 20 and 75.

4. The blend composition of claim 1 , wherein the first polycarbonate comprises carbonate units derived from at least one of the following monomers 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).

5. The blend composition of claim 4 , 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).

6. The blend composition of claim 5 , 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.

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

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

9. The blend composition of claim 1 , wherein the first polycarbonate comprises aromatic ester units derived from isophthalic acid or terephthalic acids or isophthalic acid esters or terephthalic esters or a combination isophthalic acid or terephthalic acids or isophthalic acid esters or terephthalic acid esters.

10. The blend composition of claim 9 , wherein the first polycarbonate further comprises carbonate units or ester units derived from Bisphenol-A.

11. 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.

12. 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.

13. 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.

14. 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.

15. The blend composition of claim 1 , wherein the second polycarbonate comprises greater than 75 wt % of the polycarbonate blend composition and wherein the first polycarbonate comprises less than 25 wt % of the polycarbonate blend composition based on the sum of the first and second polycarbonates being equal to 100 wt %.

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

17. 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 free of halogens and having the structure

HO-A 1 -Y 1 -A 2 -OH

wherein each of A 1 and A 2 comprises a monocyclic divalent arylene group, and Y1 comprises at least one of the following: —O—, —S—, —S(O)—, —S(O) 2 —, methylene, cyclohexyl-methylene, 2-[2.2.1]-bicycloheptylidene, ethylidene, isopropylidene, neopentylidene, cyclohexylidene, cyclopentadecylidene, cyclododecylidene, and adamantylidene, wherein A 1 , A 2 , and Y 1 are free of halogen atoms; 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.

18. The blend composition of claim 17 , wherein the first polycarbonate is derived from at least Bisphenol-A and one or more of the monomers, 3,3-bis(4-hydroxyphenyl)-2-phenylisoindolin-1-one (PPPBP), Bisphenol-AP, Bisphenol-TMC or a combination of isophthalic and phthalic acids or a combination of isophthalic and phthalic acid esters.

19. The blend composition of claim 18 further comprising at least one of the following additives: mold release agents, thermal stabilizers, UV stabilizers, or colorants.

20. 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.

21. The method of claim 20 , wherein

(a) the first polycarbonate comprises carbonate units derived from at least Bisphenol-A and one or more of the following monomers

(i) PPPBP;

(ii) Bisphenol-A;

(iii) Bisphenol-TCM;

(iv) a combination of isophthalic and phthalic acids; and

(v) a combination of isophthalic and phthalic acid esters; and

(b) the second polycarbonate comprises carbonate units 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.

22. The method of claim 21 , wherein step (c) comprises extrusion.

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

24. The article of claim 23 , wherein the article is a component of a cell phone cover or computer housing.