Polypropylene and other polymer composite, thermal sealing and barrier properties can be improved, however, in the compound and in the process, often damage film transparency and surface smoothness. To solve this problem, it was suggested that an improved method, the principle of transparent polypropylene film as described below.
As the basement membrane orientation of polypropylene film remains a melting or tensile State, melting point of its surface is covered in less than an a (low melting point is about 5 c) b, polyolefin film, this film before b in the compound will remain unstretched State or just a one-way stretch. After the two film lamination adhesive, then proceeds to film heated stretch, then by a stereotyped treatment immediately to more than 200 c/s speed cooling until the film temperature is below low melting-point temperature the maximum crystallization polyolefin (low 10 ° c above), to prevent thin film Crystal effects and transparency. The resulting composite thin film polymer were amorphous, heat sealing properties at low temperature and has high transparency and surface smoothness.