The jacket's name is PrimaLoft, but why does the insulation label say 100% polyester?

Looking first at the 100% figure, the PrimaLoft Long Jacket from HELINOX WEAR lists not only the outer shell and pocket lining, but also the inner insulation as 100% polyester^[1].

PRIMALOFT in the name is a synthetic microfiber insulation developed to overcome the limitations of natural feathers, which clump when wet. No matter how proprietary the insulation technology is, if the raw material is synthetic fiber, standard labeling regulations typically require the base material classification, polyester, to be listed on the official composition label rather than the trademarked brand name.

This fine polyester structure traps air tightly between the fibers to help maintain body heat even in humid environments. The smooth 100% nylon lining and polyester outer fabric also stably encase the functional insulation from both the inside and outside^[2].

hmmm, while it might read like ordinary padding on the surface, it is closer to the result of honestly representing outdoor thermal insulation that is resilient against snow and rain in accordance with regulated ingredient labeling.