MACROPOROUS POLYETHYLENE FILM AND METHOD OF PREPARING THEREOF Russian patent published in 1999 - IPC

FIELD: products from high-molecular compounds such as chemical current sources, diaphragms for electric capacitors, two-layer membranes, substrates for various coatings, test objects in biological research, medical clothes and wrappings. SUBSTANCE: microporous polyethylene film has through pore size of 0.01-0.08 mcm and total porosity of 40-60%. Film thickness is 10-15 mcm, tensile strength along fabric is 1700-2000 kg/sq.cm. Film has shrinkage with micropores fully closed at 100 C. Method comprises extrusion of polyethylene melt, hardening, heat treatment, longitudinal extension of semifinished product and thermofixation of the resulting microporous film. Longitudinal extension is carried out in one stage in the form of cold extension of 100-300 % at room temperature of product extension rate of 450-1000%/min. EFFECT: improved properties of the microporous polyethylene film. 3 cl, 1 ex, 1 tbl