The invention relates to the technical field of
polymer materials, and specifically relates to a high-
toughness high-water-steam-baffled completely-biodegraded composite multilayer film and a manufacturing method thereof. The film comprises a structure from the second layer to the seventh layer and is composed of a PBAT based high-
toughness high-barrier biodegradable material (A), a high-weatherability high-barrier biodegradable material (B), and a high-
toughness functional biodegradable material layer (C). A multi-layer co-
extrusion film blowing technology is adopted. Multiple material
layers are compounded to prepare the film. The film is highly tough, the tensile strength can reach 18 MPa, the horizontal / vertical breaking elongation rate can reach more than 500%, no prominent difference exists in the vertical direction and the horizontal direction, the water steam baffling performance is strong, the water steam
penetration rate of the film with a thickness of 10 [mu]m is 240 g / m2.24h; the
processing performance is good, the minimal thickness of the film can reach 5 [mu]m; the
processing equipment does not need frequent adjustment, and the film is used as a
package film, an agricultural cover film, and the like.