The Example polyadipamide polymer containing added succinic acid(cas:110-15-6)

In this Example, varying amounts of succinic acid are added to nylon 66 polymer made in a continuous polymerization unit and spun into industrial yarn to illustrate the effects on tenacity, transfer line pressure, relative viscosity, and spin breaks per kilogram (kg). The results are reported in Table 1.

To a 51% by weight aqueous solution of hexamethylenediammonium adipate at an initial pH of .about. 7.40 as measured at a 9.5 weight % concentration at 25° C. are added 2-(2'-pyridyl)ethylphosphonic acid (PEPA) to comprise 0.042 weight % of the polymer to be formed, potassium bromide to comprise approximately 0.10 weight % of the polymer to be formed, potassium iodide to comprise approximately 0.05 weight % of the polymer to be formed, cupric acetate to comprise approximately 0.021 weight % of the polymer to be formed, and potassium bicarbonate to comprise approximately 0.16 weight % of the polymer to be formed. The succinic acid(cas:110-15-6) present in the raw materials is approximately 0.0014 of the polymer to be formed (14 ppm).

The resulting nylon salt solution is then polymerized as in U.S. Pat. No. 3,947,424 and spun into 1260 denier industrial yarn using a process as disclosed in U.S. Pat. No. 3,311,691.

The process of Item A is repeated except that additional succinic acid(cas:110-15-6) is added to the nylon salt solution to comprise a total of 0.0081 weight % of the polymer to be formed (81 ppm).

The process of Item A is repeated except additional succinic acid(cas:110-15-6) is added to the nylon salt solution to comprise a total of 0.0134 weight % of the polymer to be formed (134 ppm).

For items A, B and C above, pressure drop of the high viscosity polymer is monitored between the finisher vessel and the spinning manifold, yarn RV is measured, spin breaks are monitored, and yarn properties are measured and the results are reported in Table 1 below.

Items B and C compared to Item A show a reduction in transfer line pressure drop at constant polymer RV with the added succinic acid(cas:110-15-6). Item C compared to Item A also demonstrates an improvement in yarn tenacity and decreased spin breaks.

In this Example, an amount of succinic acid(cas:110-15-6) as indicated in Table 1 are added to nylon 66 polymer made in a continuous polymerization unit similarly to Example 1. In this example, however, transfer line pressure was maintained constant by increasing the RV. Transfer line pressure and RV are monitored and are reported in Table 2 below.

The process of Example 1, Item A is repeated (no additional succinic acid(cas:110-15-6) is added). As in Item A, succinic acid(cas:110-15-6) is present in the raw materials to comprise 0.0014 weight % of the polymer to be formed (14 ppm).

The process of Item D is repeated except that additional succinic acid(cas:110-15-6) is added to the nylon salt solution to comprise 0.0134 weight % of the polymer to be formed (134 ppm) and the RV was increased by approximately 3 RV units to a level which maintains the transfer line pressure constant.

Item E when compared to Item D illustrate that RV can be increased by employing the invention without increasing transfer line pressures.