Antislip, heat sealable plastic flexible packaging bag and method and apparatus for its production

Abstract

An antislip, heat sealable plastic packaging bag, is formed from an antislip flexible packaging material whose wall has an average surface weight of at most 500 g/m. The packaging material includes a multiplicity of randomly distributed, separate antislip protrusions of a first substance. The protrusion height is between 50 micrometres and 10000 micrometres, with an average of top-plan-view aspect ratios of the antislip protrusions being at most 5.0. Some antislip protrusions have a hidden surface portion being a portion of a free surface of the antislip protrusion, which the antislip protrusion covers from a viewer in a top plan view of the wall. The first substance is a thermoplastic polymer, and the wall's outer surface is of a substance at least somewhat different from the first substance. It is an important feature that the first substance has a melt mass flow rate of at least 0.6 g/10 min. An apparatus, for producing the packaging material, includes a film blowing die head, a cooling air ring, and a particle dispersing unit therebetween, for dispersing polymer particles on the bubble neck at a place in, or closely under, an expanding area where the bubble has a divergent shape.