Multilayer coextruding pyrocondensation film

2499. The invention provides a multilayer coextrusion heat shrinking film which comprises a surface layer, a sandwich layer and a heat-sealing layer. The surface layer and the heat-sealing layer are respectively bonded with the sandwich layer through a bonding layer; the sandwich layer comprises a mixture composed of 98Wt% of PVDC resin and 2Wt% of processing aid, wherein, the PVDC resin is a VDC-MA copolymer, the melting point is 150 DEG C, the density is 1.7g/cm , and the processing aid is epoxidized soybean oil or other plasticizing agent systems. The proposal increases the shrinkage factor of the multilayer coextrusion heat shrinking film, and improves the barrier property; the multilayer coextrusion heat shrinking film has excellent heat sealing performance, and is widely applied to the vacuum shrink package.