JPS6484850A - Slightly permeable packaging bag - Google Patents

Abstract

PURPOSE:To obtain a controlled permeability for vapor or other gases by a method in which groups of minute scars are dispersed over a bag main body by pressing a file-like roughened surface against the surface of a film constituting the bag in such a manner that the film material are secured. CONSTITUTION:Groups of minute scars are dispersed over a bag main body by pressing a file-like roughened surface against the surface of a film constituting the bag in such a manner as to secure the film material. It is preferable to use a processing implement comprising a metal disc having projections provided on its circumferential surface as a file because it is durable and grinding particles are least likely to come off. When pressing the file-like roughened surface against the film surface, the portions on the film with which the projections of the file-like roughened surface are brought into abutment are extended by the projections and hence become thinner, leading to breakage of the film at the extremely thin portions. However, since the broken film portions are surrounded by the extended film portions, the expansion of breakage can thus be prevented. The density, size, total volume and so forth of scars can be freely adjusted, and the permeability of vapor, various odor components and gases can be adjusted according to applications.