Cross-linked heat shrinkable film with flame retardant effect and preparation method thereof

The invention discloses a preparation method of a cross-linked heat shrinkable film with a flame retardant effect. The method comprises the following steps of: adding raw materials of an outer layer,a core layer and an inner layer, respectively melting and plasticizing, and obtaining a composite material by coextruding the layers; performing primary inflation on the composite material to obtain afilm bubble, and cooling and shaping the film bubble to form a film tube; drawing the film tube to an electron accelerator, and crosslinking linear molecular chains of the film tube through electronirradiation; preheating the cross-linked film tube, carrying out bidirectional stretching, and then carrying out secondary inflation on the film tube; and shaping the film tube subjected to secondaryinflation after being cooled by an air ring and subjected to heat treatment, and obtaining the cross-linked heat shrinkable film with the flame retardant effect by trimming and rolling. An organic flame retardant and an inorgani