Impact-modified injection-molded polyamide
An impact-modified polyamide composition comprising from 5 wt % to 85 wt % of polyamide polymer; from 10 wt % to 60 wt % glass fiber; from 3 wt % to 30 wt % of an impact modifier; and a melt stabilizer at a concentration less than 5 wt %; wherein the weight ratio of the impact modifier to the melt stabilizer ranges from 1.0:1 to 100:1; and wherein the polyamide composition demonstrates an un-notched Charpy impact energy loss at 23° C. that is greater than 80 kJ/m 2 and a tensile strength greater than 135 MPa.
1. An impact-modified polyamide composition comprising:
from 13 wt % to 68 wt % PA66 polyamide polymer;
reinforcing filler consisting of from 25 wt % to 40 wt % glass fiber;
from 11.1 wt % to 27.3 wt % of a maleic anhydride modified impact modifier an impact modifier;
from 1 wt % to 2 wt % nigrosine;
from 0.1 wt % to 1 wt % heat stabilizer;
less than 20 wt % PA6 polyamide polymer;
less than 3 wt % carbon black; and
from 0.5 wt % to 1 wt % of a melt stabilizer, wherein the melt stabilizer is stearic acid;
wherein the weight ratio of the maleic anhydride modified impact modifier to the melt stabilizer ranges from 12:1 to 35:1; and
wherein the weight ratio of the PA66 polyamide polymer to the maleic anhydride modified impact modifier is less than 12; and
wherein the polyamide composition demonstrates an un-notched Charpy impact energy loss at 23° C. that is greater than 80 kJ/m 2 and a tensile strength greater than 135 MPa.
2. The polyamide composition of claim 1 , wherein the weight ratio of the PA66 polyamide polymer to the glass fiber ranges from 0.1:1 to 10:1.
3. The polyamide composition of claim 1 , wherein the polyamide composition demonstrates a tan delta at 60° C., as measured using dynamic mechanical analysis greater than 0.04.
4. The polyamide composition of claim 1 , wherein the polyamide composition demonstrates a tan delta at 90° C., as measured using dynamic mechanical analysis greater than 0.1.
5. The polyamide composition of claim 1 , wherein the maleic anhydride modified impact modifier comprises a maleic anhydride-modified acrylate.
6. The polyamide composition of claim 1 , wherein the maleic anhydride modified impact modifier comprises a maleic anhydride-modified olefin.
7. The polyamide composition of claim 1 , wherein the maleic anhydride modified impact modifier has a glass transition temperature less than 0° C.
8. The polyamide composition of claim 1 , wherein the weight ratio of the glass fiber to the maleic anhydride modified impact modifier ranges from 0.3:1 to 20:1.
9. The polyamide composition of claim 1 , wherein the composition comprises a heat stabilizer and the weight ratio of the maleic anhydride modified impact modifier to the heat stabilizer ranges from 0.5:1 to 300:1.
10. The polyamide composition of claim 1 , wherein the polyamide composition demonstrates a tensile elongation greater than 2.5%; and an un-notched Charpy impact energy loss at −40° C. that is greater than 65 kJ/m 2 .
11. The polyamide composition of claim 1 , wherein the number average molecular weight of each of the PA66 polyamide polymers is independently greater than 26,000.
12. The polyamide composition of claim 1 , wherein
the polyamide composition has a notched Charpy impact energy loss at 23° C. greater than 11 kJ/m 2 .
13. An injection molded article comprising the polyamide composition of claim 1 .
14. The polyamide composition of claim 1 , wherein the composition comprises nigrosine and the weight ratio of the maleic anhydride modified impact modifier to the nigrosine is greater than 13.