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 inorganic flame retardant are compounded, so that the flame retardant effect is improved, the defects that the
smoke amount of the organic flame retardant is too large in the
combustion process and the like are avoided, and the phenomenon that the affinity with the cross-linked heat shrinkable film is poor due to the fact that too much inorganic flame retardant is added, and the
processing and mechanical properties are poor is avoided.