| 摘要 |
PURPOSE:To obtain a film permeable for gas such as air but impermeable for water such as storm water, useful as growth guide cylinder material for artificial plantation bottle for champignon and adhesive plaster tapes, by perforating an oriented drawn film with, e.g. laser beams. CONSTITUTION:The objective film can be obtained by perforating an oriented film made by drawing a thermoplastic resin film by a factor of four or more in one direction so that 500,000-3,000,000 pores per m<2> of the oriented film with a pore size 20-300mu are penetrated through the film. The resin surrounding these pores is melted in the perforation process, thus being nonoriented. This film perforated has the water permeability (JIS, L-1079) and oxygen permeability (JIS, Z-1707) of 0% and infinite, respectively, determined at 25 deg.C under atmospheric pressure. The structure of this film is such that, on a biaxially oriented film from inorganic fine powder-contg. polyolefin resin as base material, is laminated a uniaxially oriented film of the same origin. |
