GB934071A - Textured polypropylene sheets - Google Patents

Abstract

A polypropylene film having one creped and one smooth surface is made by calendering polypropylene at least 90% of which is isotactic and which has a melt index of 0,5-5,0, at a temperature of 170 DEG -190 DEG C. The polypropylene may have a melt index of about 1, and may contain an antistatic agent, at least one stabilizing ingredient, and at least one material which absorbs ultra-violet light. As antistatic agents, condensates of long-chain alkyl phenols with alkylene oxides may be used, for example a condensate of 6-10, especially about 8,5 molecular proportions of ethylene oxide with one molecular proportion of p-octyl phenol. Specified stabilizing ingredients include a mixture of a condensate of 3 molecules of 3-methyl-6-tert. butyl phenol with 1 molecule of crotonaldehyde suitably together with a diester of a thiodialkanoic acid, e.g. dilaurylb -thio-dipropionate or g -thiodibutyrate, a sulphide or di-sulphide, e.g. octadecyl sulphide, or a polycondensate containing sulphur, e.g. a polycondensate of ethylene glycol with b -thiodipropionic acid, or other phenols, other sulphur compounds, or aromatic amines may be used. 2-hydroxy benzophenone and carbon black are specified as ultra-violet light absorbers. Other ancillary ingredients which may be present include processing aids, e.g. soaps of calcium or zinc, pigments, e.g. carbon black, dyes and fillers. The surface which has been concave between the second and third nips of the calender, i.e. uppermost, emerges creped, the other side being smooth. The films have good heat resistance and are useful as lamp shades.ALSO:A polypropylene film having one creped and one smooth surface is made by calendering polypropylene at least 90% of which is isotactic and which has a melt index of 0.5-5.0, at a temperature of 170-190 DEG C. The polypropylene may have a melt index of about 1, and may contain an antistatic agent, at least one stabilising ingredient, and at least one material which absorbs ultra-violet light. As antistatic agents, condensates of long-chain alkyl phenols with alkylene oxides may be used, for example a condensate of 6-10, especially about 8,5 molecular proportions of ethylene oxide with one molecular proportion of p-octyl phenol. Specified stabilizing ingredients include a mixture of a condensate of 3 molecules of 3-methyl -6-tert.-butyl phenol with 1 molecule of crotonaldehyde suitably together with a diester of a thiodialkanoic acid e.g. dilauryl-b -thio-dipropionate or g -thiodibutyrate, a sulphide or di-sulphide e.g. octadecyl sulphide, or a polycondensate containing sulphur e.g. a polycondensate of ethylene glycol with b -thiodipropionic acid, or other phenols, other sulphur compounds, or aromatic amines may be used. 2-hydroxy benzophenone and carbon black are specified as ultra-violet light absorbers. Other ancillary ingredients which may be present include processing aids, e.g. soaps of calcium or zinc, pigments e.g. carbon black, dyes and fillers. The surface which has been concave between the second and third nips of the calendar, i.e. uppermost, emerges creped, the other side being smooth. The films have good heat resistance and are useful as lamp shades.