Polyamide blends for polymer films

1. A film comprising a polyamide composition, the polyamide composition comprising:

from 15 wt % to 85 wt % of a PA6 polymer; and

from 15 wt % to 85 wt % of a PA66/6 copolymer,

wherein weight percentages are based upon total polyamide composition;

wherein the total of caprolactam units in the PA66/6 copolymer ranges from 5 wt % to 40 wt %, and

wherein the film demonstrates puncture resistance that is greater than 800 N/mm, as measured in accordance with standard test method ASTM F1306-16 (2016).

2. The polymer film of claim 1 , wherein the PA66/6 copolymer is a statistical copolymer.

3. The polymer film of claim 1 , wherein the film is a biaxially oriented film.

4. The polymer film of claim 1 , wherein the film has a heat deflection temperature greater than 190° C.

5. The polymer film of claim 1 , wherein the film thickness is less than 26 microns and wherein the film demonstrates a puncture resistance that is greater than 825 N/mm.

6. The polymer film of claim 1 , wherein the total of caprolactam units in the polyamide composition ranges from 26 wt % to 74 wt %.

7. The polymer film of claim 1 , wherein the PA66/6 copolymer comprises:

from 75 wt % to 85 wt % adipic acid-hexamethylene diamine units; and

from 15 wt % to 25 wt % caprolactam units;

wherein wt % is based upon total PA66/6 copolymer, and

wherein the melting point of the PA66/6 copolymer ranges from 215° C. to 223° C.

8. The polymer film of claim 1 , wherein the PA66/6 copolymer comprises:

from 80 wt % to 90 wt % adipic acid-hexamethylene diamine units; and

from 10 wt % to 20 wt % caprolactam units;

wherein wt % is based upon total PA66/6 copolymer, and

wherein the melting point of the PA66/6 copolymer ranges from 230° C. to 238° C.

9. The polymer film of claim 1 , wherein the film demonstrates transverse direction elongation that is greater than 85%, as measured in accordance with standard test method ASTM D882-18 (2018).

10. The polymer film of claim 1 , wherein the film demonstrates impact resistance that is greater than 9.6 N, as measured in accordance with standard test method ASTM D1709-16ae1 (2016).

11. The polymer film of claim 1 , wherein the film demonstrates a transverse direction tensile strength that is greater than 250 MPa, as measured in accordance with standard test method ASTM D882-18 (2018) or a transverse direction tensile modulus that is less than 3800 MPa, as measured in accordance with standard test method ASTM D882-18 (2018).

12. The polymer film of claim 1 , wherein the polyamide composition comprises:

from 55 wt % to 85 wt % of the PA6 polymer; and

from 15 wt % to 45 wt % of the PA66/6 copolymer; and

wherein the film demonstrates puncture resistance that is greater than 850 N/mm and transverse direction elongation that is greater than 90%.

13. The polymer film of claim 1 , further comprising diatomaceous earth and silica microparticles.

14. The polymer film claim 1 , wherein the film is oriented by stretching in the machine direction at a machine direction stretch ratio ranging from 3 to 3.8, and stretching in the transverse direction at a transverse direction stretch ratio ranging from 3.1 to 5.

15. The polymer film of claim 1 , having a heat shrinkage less than 2%.

16. The polymer film of claim 1 , wherein the polymer film exhibits a maximum stretch ratio no greater than the maximum stretch ratio of a corresponding film comprising no PA66/6 copolymer, and wherein the polymer film exhibits a heat shrinkage no greater than the heat shrinkage of the corresponding film.

17. A method of preparing a polymer film, the method comprising:

providing from 15 wt % to 85 wt % of a PA6 polymer and from 15 wt % to 85 wt % a PA66/6 copolymer, wherein weight percentages are based upon total polyamide composition, and wherein the total of caprolactam units in the PA66/6 copolymer ranges from 5 wt % to 40 wt %;

blending the PA6 polymer and the PA66/6 copolymer to create a polyamide composition;

casting the created polyamide composition to form a film; and

stretch orienting the formed film, thereby preparing the polymer film, wherein the film demonstrates puncture resistance that is greater than 850 N/mm.

18. An article comprising the film of claim 1 wherein the film is biaxially oriented.

19. A film comprising a polyamide composition, the polyamide composition comprising:

from 15 wt % to 70 wt % of a PA6 polymer; and

from 30 wt % to 85 wt % of a PA66/6 copolymer, wherein weight percentages are based upon total polyamide composition,

wherein the total caprolactam content in the polyamide composition ranges from 26 wt % to 74 wt %; and

wherein the film demonstrates puncture resistance that is greater than 800 N/mm, as measured in accordance with standard test method ASTM F1306-16 (2016).

20. The polymer film of claim 19 , further comprising diatomaceous earth and silica microparticles.