Polyamide formulations for long term high temperature performance
Provided herein is a polymer composition comprising an aromatic polyamide comprising terephthalic units and isophthalic units or a 6T/DT copolymer and having an overall high aromaticity, with a heat stabilizer and/or a lubricant. The polymer composition demonstrates improved electrical performance in terms of volume resistivity and dielectric strength.
1 . A polymer composition comprising:
an aromatic polyamide consisting essentially of: 6T units, 6I units, and 66 units, the aromatic polyamide having an overall aromaticity greater than 31%, the aromatic polyamide containing from 15 wt % to 85 wt % 66 units based on the weight of the aromatic polyamide;
a heat stabilizer; and
an optional lubricant,
wherein the polymer composition demonstrates a volume resistivity greater than 1.0E+10 Ohm-cm, as measured via IEC 62631 at 150° C.
2 . The polymer composition of claim 1 , wherein the polymer composition demonstrates a dielectric strength of greater than 25 KV/mm as measured via IEC 60243 at 150° C.
3 . The polymer composition of claim 1 , wherein the polymer composition retains dielectric strength under humidity aging.
4 . The polymer composition of claim 1 , wherein the aromatic polyamide has an overall aromaticity greater than 35%.
5 . The polymer composition of claim 1 , wherein the aromatic polyamide has an overall aromaticity of 42.5%.
6 . The polymer composition of claim 1 , wherein aromatic polymer is PA6T/6I/66 or PA6T/66/6I or a combination thereof.
7 . The polymer composition of claim 1 , wherein the difference in content of terephthalic units and isophthalic units, combined, and adipic units ranges from 25 wt % to 70 wt %.
8 . The polymer composition of claim 1 , further comprising from 0.1 wt % to 10 wt % of PA6.
9 . The polymer composition of claim 1 , wherein the polymer composition comprises from 50 wt % to 60 wt % aromatic polyamide aromatic polyamide, based on the total weight of the polymer composition.
10 . The polymer composition of claim 1 , wherein the heat stabilizer is a hindered phenol.
11 . The polymer composition of claim 1 , wherein the heat stabilizer is N,N′-hexamethylene bis[3-(3,5-dit-butyl-4-hydroxyphenyl) propionamide.
12 . The polymer composition of claim 1 , wherein the lubricant is a montanate.
13 . The polymer composition of claim 1 , wherein the composition demonstrates a tensile strength greater than 85 MPa when moisture treated for 1K hours at a temperature of 85° C. and 85% relative humidity, and a volume resistivity greater than 5.0E+13 Ohm-cm, when moisture treated for 1K hours at a temperature of 85° C. and 85% relative humidity.
14 . The polymer composition of claim 1 , wherein the aromatic polyamide comprises from 45 wt % to 60 wt % 6T units, from 15 wt % to 25 wt % 6I units, and from 15 wt % to 35 wt % 66 units, based on the weight of the aromatic polyamide.
15 . A polymer composition comprising:
a 6T/DT copolymer having an overall aromaticity greater than 25%;
a heat stabilizer;
a non-halogenated flame retardant; and
an optional lubricant,
wherein the polymer composition demonstrates a volume resistivity greater than 1.0E+10 Ohm-cm, as measured via IEC 62631 at 150° C.
16 . The polymer composition of claim 15 , wherein the polymer composition demonstrates a dielectric strength of greater than 25 KV/mm as measured via IEC 60243 at 150° C.
17 . The polymer composition of claim 15 , wherein the heat stabilizer is a hindered phenol.
18 . The polymer composition of claim 15 , wherein the lubricant is a montanate.
19 . The polymer composition of claim 15 , wherein the polymer composition comprises from 10 wt % to 20 wt % non-halogenated flame retardant based on the total weight of the polymer composition, and wherein the non-halogenated flame retardant comprises a phosphonate flame retardant.
20 . The polymer composition of claim 15 , wherein the 6T/DT copolymer comprises from 45 wt % to 55 wt % 6T units based on the weight of the 6T/DT copolymer.