Polypropylene multi-layer sealant films for retort packaging

Abstract

Polypropylene multi-layer sealant films for retort packaging, each including a multi-layer film composed mainly of at least one polypropylene polymer and to be laminated on one surface of a heat-resisting film, the multi-layer film having a first surface facing the heat-resisting film when laminated therewith and further having a second surface on the other side, the first surface having a surface roughness as defined below in (1), and the second surface having a surface roughness as defined below in (2): (1) (i) center-line mean roughness (Ra): 0.020 to 0.250 μm; (ii) maximum height (Rmax): 0.3 to 2.9 μm; and (iii) ten-point mean roughness (Rz): 0.2 to 2.4 μm; (2) (i) center-line mean roughness (Ra): 0.050 to 0.300 μm; (ii) maximum height (Rmax): 3.0 to 13.0 μm; and (iii) ten-point mean roughness (Rz): 2.5 to 11.5 μm.

Dependencies are inferred from the claim text.