Recyclable thermoplastic insulation with improved breakdown strength

摘要

The disclosure provides a process for producing a material with improved breakdown strength. The process includes heating a polymeric composition composed of a low density polyethylene (LDPE) and a minority amount of a high density polyethylene (HDPE). The polymeric composition is heated to at least the melting temperature of the HDPE. The process includes control-cooling the heated polymeric composition at a cooling rate from 0.1° C./min to 20° C./min, and forming a polymeric composition. The control-cooled polymeric composition has a unique morphology which improves breakdown strength. Also provided is a coated conductor with an insulating layer composed of the polymeric composition with the unique morphology. The insulating layer exhibits improved breakdown strength.

主权项

1. A process comprising:
heating a polymeric composition consisting of (i) a low density polyethylene having a melting temperature of at least 105° C. to 125° C. (LDPE) (ii) a minority amount of a high density polyethylene having a melting temperature of at least 130° C. to 134° C. (HDPE), and (iii) optional antioxidant, to at least the melting temperature of the HDPE; control-cooling the heated polymeric composition at a cooling rate from 0.1° C./min to 10° C./min; and forming a polymeric composition having a space-filling array of HDPE lamellae, which are separated by the LDPE, the polymeric composition having an AC breakdown strength greater than 170 kV/mm as measured on 85 micrometer thin films in accordance with ASTM D 149.