Melt-blended thermoplastic composition

1. A melt-blended thermoplastic composition comprising

A) a polyamide composition comprising

a) 55 to 90 weight percent semi-crystalline semi-aromatic copolyamide having a melting point; wherein said semi-aromatic copolyamide comprises

a-1) about 15 to 50 mole percent aromatic repeat units derived from:

i) one or more aromatic dicarboxylic acids with 8 to 20 carbon atoms and a first aliphatic diamine with 4 to 20 carbon atoms;

and

a-2) 50 to 85 mole percent aliphatic repeat units derived from:

ii) a first aliphatic dicarboxylic acid with 8 to 20 carbon atoms and said first aliphatic diamine with 4 to 20 carbon atoms; or

iii) a first aliphatic aminoacid or lactam with 8 to 20 carbon atoms;

wherein the semi-aromatic copolyamide has a DMA tan delta peak value of greater than or equal to 0.23; and heat of fusion of at least 20 J/g as measured in first heat cycle of DSC;

b) 10 to 45 weight percent aliphatic homopolyamide having a melting point; wherein said aliphatic homopolyamide comprises repeat units derived from:

iv) a second aliphatic dicarboxylic acid with 8 to 20 carbon atoms and a second aliphatic diamine with 4 to 20 carbon atoms or

v) a second aliphatic aminoacid or lactam with 8 to 20 carbon atoms; and wherein the aliphatic homopolyamide has a DMA tan delta peak value of less than or equal to 0.21; and heat of fusion of at least 30 J/g as measured in first heat cycle of DSC;

wherein the weight percent of a) and b) are based on the total weight of a) and b); and said first and second aliphatic diamines can be the same or different;

B) 0 to 45 weight percent polymeric toughener;

C) 0 to 20 weight percent, preferably 0 to 12 weight percent, plasticizers; and

D) 0 to 45 weight percent reinforcing agent;

wherein the weight percent of B), C), and D) are based on the total weight of the melt-blended thermoplastic composition; and wherein said melt-blend composition has a glass transition and has a tan delta peak (E″/E′) value of 0.21 or lower at said glass transition.

2. The melt-blended thermoplastic composition of claim 1 wherein the semi-crystalline semi-aromatic copolyamide is selected from the group consisting of: PA 612/6T (85/15) to (55/45); PA 610/6T (85/15) to (55/45); PA1010/10T (85/15) to (55/45); PA 612/6I (90/10) to (70/30); and PA 612/6T/6I having a mole percent of 6T+6I of from 15 to 45 mol percent and the ratio of T to I is about 4:1 to 1:1.

3. The melt-blended thermoplastic composition of any one of the previous claims wherein said aliphatic homopolyamide is selected from the group consisting of PA 612, PA 610, PA1010, and PA 614.

4. The melt-blended thermoplastic composition of claim 1 wherein the semi-crystalline semi-aromatic copolyamide is PA 612/6T (85/15) to (55/45), and said aliphatic homopolyamide is PA 612.

5. The melt-blended thermoplastic composition of claim 1 wherein the semi-crystalline semi-aromatic copolyamide is PA 610/6T (85/15) to (55/45), and said aliphatic homopolyamide is PA 610.

6. The melt-blended thermoplastic composition of claim 1 wherein the semi-crystalline semi-aromatic copolyamide is PA 610/6T (85/15) to (55/45), and said aliphatic homopolyamide is PA 1010.

7. A method for providing a melt-blended thermoplastic composition comprising:

melt-blending

A) a polyamide composition comprising

a) 55 to 90 weight percent semi-crystalline semi-aromatic copolyamide having a melting point; wherein said semi-aromatic copolyamide comprises

a-1) about 15 to 50 mole percent, preferably 15 to 40 mole percent, aromatic repeat units derived from:

i) one or more aromatic dicarboxylic acids with 8 to 20 carbon atoms and a first aliphatic diamine with 4 to 20 carbon atoms;

and

a-2) 50 to 85 mole percent, preferably 60 to 85 mole percent, aliphatic repeat units derived from:

ii) an aliphatic dicarboxylic acid with 8 to 20 carbon atoms and said first aliphatic diamine with 4 to 20 carbon atoms; or

iii) an aliphatic aminoacid or a lactam with 8 to 20 carbon atoms;

b) 10 to 45 weight percent aliphatic homopolyamide having a melting point; wherein said aliphatic homopolyamide comprises repeat units derived from:

iv) an aliphatic dicarboxylic acid with 8 to 20 carbon atoms and a second aliphatic diamine with 4 to 20 carbon atoms or

v) an aliphatic aminoacid or a lactam with 8 to 20 carbon atoms; and

wherein the weight percent of a) and b) are based on the total weight of a) and b); and said first and second aliphatic diamines can be the same or different;

B) 0 to 45 weight percent polymeric toughener;

C) 0 to 20 weight percent, preferably 0 to 12 weight percent, plasticizers; and

D) 0 to 45 weight percent reinforcing agent;

wherein the weight percent of B), C), and D) are based on the total weight of the melt-blended thermoplastic composition; and wherein the melt-blending is performed at a melt temperature above the melting point of said semi-crystalline semi-aromatic copolyamide and said aliphatic homopolyamide and less than or equal to about 290° C.; to provide the melt-blended thermoplastic composition, and wherein said melt-blend composition has a glass transition and has a tan delta peak (E″/E′) value of 0.21 or lower at said glass transition.

8. The method of claim 7 wherein the semi-crystalline semi-aromatic copolyamide is selected from the group consisting of: PA 612/6T (85/15) to (55145); PA 610/6T (85/15) to (55/45); PA1010/10T (85/15) to (55/45); PA 612/6I (90/10) to (70/30); and PA 612/6T/6I having a mole percent of 6T+6I of from 15 to 45 mol percent and the ratio of T to I is about 4:1 to 1:1.

9. The method of any one of claims 7 - 8 wherein said aliphatic homopolyamide is selected from the group consisting of PA 612, PA 610, PA1010, and PA 614.

10. The method of any one of claims 7 - 8 wherein the semi-crystalline semi-aromatic copolyamide is PA 612/6T (85/15) to (55/45), and said aliphatic homopolyamide is PA 612.

11. The method of any one of claims 7 - 8 wherein the semi-crystalline semi-aromatic copolyamide is PA 610/6T (85/15) to (55/45), and said aliphatic homopolyamide is PA 610.

12. The method any one of claims 7 - 8 wherein the semi-crystalline semi-aromatic copolyamide is PA 610/6T (85/15) to (55/45), and said aliphatic homopolyamide is PA 1010.