ES378258A1 - Procedure for the obtaining of polypropylene bands. (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Procedure for obtaining polypropylene strips, which comprises extruding polypropylene, at a mass temperature of 180 to 360ºC to a sheet of 0.03 to 4mm thick and 150 to 3000mm wide, cutting the sheet at a temperature of the surface from 10 to 100ºC, in primary bands from 2 to 70 mm wide and stretch the primary bands monoaxially and longitudinally at a surface temperature that is above 10ºC but below the melting point of the crystallites of the polypropylene used in a ratio of 1: 4 to 1:15, characterized in that a mixture of (a) 70 to 80 parts by weight of a polypropylene of which (with a weight ratio between polypropylene: toluene) is used as polypropylene 5:95) less than 1% by weight (under normal conditions) is soluble in boiling toluene, and (B) 20 to 30 parts by weight of a polypropylene of which (with a weight ratio of polypropylene: toluene of 5 : 95) more than 99% in weight (under normal conditions) is soluble in boiling toluene, under the conditions of (I) that the sum of the parts by weight of (a) and (b) is respectively 100, (II) that the polypropylenes of (a) and (b) have both (approximately) the same intrinsic viscosities and (approximately) the same molecular weight distributions determined according to the gel permeation chromatography method) and (III) as the absolute values of the intrinsic viscosities [η ] (measured in decalin at 130ºC) are respectively in the zone from 1 to 10. (Machine-translation by Google Translate, not legally binding)