The invention discloses a directly-compoundable low-melting-point
polyester thin film preparation method for laminated steel. A core-layer
polyester slice is formed by mixing 60 to 80
mass percent of pure
polyester slice with a
melting point of 180 to 230 DEG C and 40 to 20
mass percent of
silicon dioxide additive type polyester slice. In order to avoid the degradation of PET (
polyethylene terephthalate) in a melting
extrusion process, the core-layer polyester slice is crystallized and dried, wherein primary
crystallization is carried out at 80 to 120 DEG C for 12 hours; secondary
crystallization is carried out at 150 DEG C; the
drying is carried out at 160 DEG C for not less than 6 hours. According to the preparation method, a polyester thin film has the advantages of
low melting point, high tensile property, high
machinability, resistance to high-temperature cooking, high barrier property, nontoxicity, anti-falling performance and the like, is used as an inner layer and an outer layer of a steel food and medicament can, and can be disinfected and sterilized at high temperature; in addition, the polyester thin film is free of adhesives and chemical solvents, so that safety in use can be ensured.