Thanks guys,

As it turns out, several years ago we had run samples with the "correct" colorant, so now we are just trying to find that part number and get some more of it. We'll have 3 different gray colorants in the facility (1 for PBT, 1 for nylon 6,6, and 1 for nylon 4,6) so hopefully we won't get them mixed up. You know how sometimes "black is black" :-).

The application is automotive, so we didn't want to rush through and use a sample material that was not intended to be used for production also. Once you get something approved, it takes a global crisis to get it changed, and then only temporarily. We decided to take the extra time and use the "correct" colorant, now that we've identified it.