Thermoformable polycarbonate/polyester compositions and uses
View Patent ↗The melt strength and hence the processing window of blends of polycarbonate and PBT can be enhanced without degradation in the surface appearance of the article produced when relatively minor amounts of certain selected polymers are added to the blend. For example, a composition that has a thermoforming processing window of at least 15° C. for an article having a weight that is more than 100 grams, may contain 15 to 80% by weight of a polycarbonate resin; 10 to 80% by weight of polybutylene terephthalate, and 1 to 15% by weight of a semicrystalline melt strength enhancer. The melt strength enhancer is polyethylene terephthalate (PET), polycyclohexane-dimethyl terephthalate (PCT), polycyclohexanedimethyl terephthalate glycol (PCT-G), and (poly)ethylene co 1,4 cyclohexanedimethylene terephthlate (PET-G), or a combination thereof.
1. A thermoformable composition comprising: (a) 15 to 80% by weight of a polycarbonate resin; (b) 10 to 80% by weight of polybutylene terephthalate, and (c) 1 to 15% by weight of a semicrystalline melt strength enhancer selected from the group consisting of polycyclohexanedimethyl terephthalate, polycyclohexanedimethyl terephthalate glycol, and (poly)ethylene co 1,4-cyclohexane-dimethylene terephthlate), and combinations thereof; wherein the composition has a thermoforming processing window of at least 15° C.
2. The composition of claim 1 , wherein the composition has a thermoforming processing window of at least 30° C.
3. The composition of claim 1 , wherein the composition has a thermoforming processing window of at least 15° C. for an article having a weight that is more than 500 grams.
4. The composition of claim 1 , wherein the composition has a thermoforming processing window of at least 15° C. for an article having a weight that is more than 1000 grams.
5. The composition of claim 1 , wherein the composition has a thermoforming processing window of at least 15° C. for an article having a weight that ranges from 100 grams to 50 kilograms.
6. The composition of claim 1 , wherein the composition is substantially free of melt strength enhancers other than the melt strength enhancer of component (c).
7. The composition of claim 1 , wherein the composition is substantially free of styrene acrylontirile encapsulated polytetrafluoroethylene, polyamide, polyetheretherketone, PPO, polyetherketone, and PPS.
8. The composition of claim 1 , further comprising an impact modifying component.
9. The composition of claim 8 , wherein the impact modifying component is selected from the group consisting of ethylene/methyl acrylate/glycidyl methacrylate terpolymer, acrylonitrile styrene butadiene terpolymer, butyl acrylate impact modifier, and combinations thereof.
10. The composition of claim 9 , wherein the impact modifying component is present in an amount of from 1 to 5% by weight.
11. The composition of claim 9 , wherein the impact modifying component further comprises methyl methacrylate-butadiene-styrene terpolymer.
12. The composition of claim 1 , wherein the melt strength enhancer is polycyclohexanedimethyl terephthalate.
13. The composition of claim 12 , wherein the composition has a processing window of at least 30° C.
14. The composition of claim 12 , wherein the composition is substantially free of melt strength enhancers other than the melt strength enhancer of component (c).
15. The composition of claim 12 , wherein the composition is substantially free of styrene acrylontirile encapsulated polytetrafluoroethylene.
16. The composition of claim 12 , further comprising an impact modifying component.
17. The composition of claim 16 , wherein the impact modifying component comprises ethylene/methyl acrylate/glycidyl methacrylate terpolymer.
18. The composition of claim 17 , wherein the ethylene/methyl acrylate/glycidyl methacrylate terpolymer is present in an amount of from 1 to 5% by weight.
19. The composition of claim 18 , wherein the impact modifying component further comprises methyl methacrylate-butadiene-styrene terpolymer.
20. The composition of claim 1 , wherein the melt strength enhancer is polyethylene terephthalate.
21. The composition of claim 20 , wherein the composition has a processing window of at least 30° C.
22. The composition of claim 20 , wherein the composition is substantially free of melt strength enhancers other than the melt strength enhancer of component (c).
23. The composition of claim 20 , wherein the composition is substantially free of styrene acrylontirile encapsulated polytetrafluoroethylene.
24. The composition of claim 20 , further comprising an impact modifying component.
25. The composition of claim 24 , wherein the impact modifying component comprises ethylene/methyl acrylate/glycidyl methacrylate terpolymer.
26. The composition of claim 25 , wherein the ethylene/methyl acrylate/glycidyl methacrylate terpolymer is present in an amount of from 1 to 5% by weight.
27. The composition of claim 26 , wherein the impact modifying component further comprises methyl methacrylate-butadiene-styrene terpolymer.
28. The composition of claim 1 , wherein the melt strength enhancer is present in an amount of 2 to 15% by weight.
29. The composition of claim 1 , wherein the melt strength enhancer is present in an amount of 5 to 15% by weight.
30. A molded article formed by thermoforming a composition according to claim 1 , wherein said molded article is substantially free of visual defects.
31. The article of claim 30 , wherein the article is an automotive body part or a seat.
32. The article of claim 30 , wherein the melt strength enhancer in the composition is polycyclohexanedimethyl terephthalate.
33. The article of claim 30 , wherein the melt strength enhancer in the composition is polyethylene terephthalate.
34. The article of claim 30 , wherein the molded article has a measured gloss of 80 or greater.
35. A molding composition consisting essentially of: (a) 20 to 45% by weight of a polycarbonate resin; (b) 20 to 40% by weight of polybutylene terephthalate, (c) 5 to 13% by weight of polycyclohexanedimethyl terephthalate; (d) 1 to 15% by weight of an impact modifying component; and(e) 0 to 30% by weight of additional components selected from the group consisting of colorants, flame retardants, stabilizers, quenchers, and combinations thereof; wherein the composition has a thermoforming processing window of at least 15° C. for an article having a weight that is more than 100 grams; and wherein the composition is substantially free of styrene acrylontirile encapsulated polytetrafluoroethylene, polyamide, polyetheretherketone, PPO, polyetherketone, and PPS.
36. The molding composition of claim 35 , wherein the polycarbonate resin comprises a branched polycarbonate resin.
37. The molding composition of claim 36 , wherein the branched polycarbonate resin is 1,1,1,tris p hydroxyphenylethane (TBPE) branched polycarbonate.
38. The composition of claim 37 , the impact modifying component comprises ethylene/methyl acrylate/glycidyl methacrylate terpolymer.
39. The composition of claim 38 , wherein the ethylene/methyl acrylate/glycidyl methacrylate terpolymer is present in an amount of from 1 to 5% by weight.
40. The composition of claim 38 , wherein the impact modifying component further comprises methyl methacrylate-butadiene-styrene terpolymer.
41. A molded article formed by thermoforming a composition according to claim 35 , wherein said molded article is substantially free of visual defects.