Process and formulation for producing a polyamide having low caprolactam concentration and specific relative viscosity
A base polyamide composition comprising a nylon mixture having caprolactam units from 1 wppb to 50 wppm catalyst composition; and greater than 0.75 wt % residual caprolactam, wherein the base polyamide composition has a delta end group level ranging from 30 μeq/gram to 90 μeq/gram.
1. A base polyamide composition comprising:
a nylon mixture having caprolactam units;
from 1 wppb to 50 wppm catalyst composition; and
greater than 0.75 wt % residual caprolactam, based on the total weight of the base polyamide composition;
wherein the base polyamide composition has a delta end group level ranging from 30 μeq/gram to 90 μeq/gram.
2. The base polyamide composition of claim 1 , wherein the base polyamide composition has a delta end group level greater than or equal to 45 μeq/gram.
3. The base polyamide composition of claim 1 , wherein the base polyamide comprises greater than 1.4 wt % caprolactam units, based on the total weight of the base polyamide composition, and wherein the base polyamide has a relative viscosity less than 55.
4. The base polyamide composition of claim 1 , wherein the nylon mixture of the base polyamide composition comprises:
from 1 wt % to 50 wt % nylon-6; and
from 20 wt % to 99 wt % nylon-6,6, based on the total weight of the base polyamide composition.
5. The base polyamide composition of claim 1 , wherein the base polyamide composition has a color index ranging from −6 to 5, as measured by ASTM E313 (2018).
6. The base polyamide composition of claim 1 , wherein the base polyamide composition has a melting point ranging from 185° C. to 255° C.
7. The base polyamide composition of claim 1 , wherein the catalyst composition comprises phosphorous acid; phosphonic acid; alkyl-substituted phosphonic acids; aryl-substituted phosphonic acids; 2-pyridylethyl phosphonic acid; hypophosphorous acid; alkyl-substituted phosphinic acids; aryl-substituted phosphinic acids; alkyl-/aryl-substituted phosphinic acids; phosphoric acid; esters and salts of these phosphorous-containing acids; manganese hypophosphite; sodium hypophosphite; benzene phosphinic acid; monosodium phosphate; or any combinations thereof.
8. The base polyamide composition of claim 1 , wherein the base polyamide composition further comprises from 1 wppb to 25 wppm phosphorus.
9. The base polyamide composition of claim 1 , wherein the base polyamide composition comprises from 0.1 wppm to 35 wppm catalyst composition.
10. The base polyamide composition of claim 1 , wherein the base polyamide composition comprises greater than 1.5 wt % residual caprolactam.
11. The base polyamide composition of claim 1 , wherein the base polyamide composition comprises from 1 wt % to 8 wt % residual caprolactam.
12. The base polyamide composition of claim 1 , wherein the base polyamide composition has a delta end group level ranging from 50 μeq/gram to 75 μeq/gram.
13. A final polyamide composition prepared by polymerizing the base polyamide composition of claim 1 , wherein the final polyamide composition has a residual caprolactam concentration that is at least 5% less than the residual caprolactam concentration of the base polyamide composition.
14. The final polyamide composition of claim 13 , wherein the base polyamide composition has less than 0.6 wt % residual caprolactam.
15. The final polyamide composition of claim 13 , wherein the final polyamide composition has a color index ranging from −6 to 5, as measured by ASTM E313 (2018).