Dynamics and structure development for biaxial stretching PA6 films

The biaxial stretching film of polyamide 6 (PA6) is widely used for food and industrial products packaging, because it has good physical properties, such as high toughness and gas barrier properties. It is expected to improve film formability and performance for a larger market. So, in this research, both the stretching methods and PA6 blends were investigated in terms of dynamics and structure development for biaxial stretching films. There are three different stretching methods which can produce polyamide 6 films, namely the simultaneous biaxial stretching, the sequential biaxial stretching, and the double bubble tubular process. There are no reports which describe the difference among the three stretching methods and film properties, so it was not clarified why the films have big differences in their properties. For this reason, the higher order structure and stretching behaviours of the three stretching methods were studied. As a result, the sequential biaxial stretching shows strong stretched effect and molecular orientation in the transverse direction. In the simultaneous biaxial stretching, the molecule orientation was equal both in the machine direction and in the transverse direction of the stretched plane. The double bubble tubular process produced well balanced film and equal orientation in any directions, in terms of the phase difference in the plane of film. Blends of PA6 to meta-Xylene diamine (MXD6) improved the properties of easy straight line cut and high barrier, but did not have good stretchability. For this reason, they were also studied to develop the biaxial stretching film of polyamide which improved stretchability and physical properties. Furthermore, blend effects of MXD6 to PA6 and dynamics analyses were investigated.