Highly active beta-nucleating agent for polypropylene

Producing a stable dispersion of a non-aqueous liquid phase and a dispersed dicarboxylic acid salt, comprises: reacting an aliphatic dicarboxylic acid with a divalent metal salt in an aqueous solution to form a dicarboxylic acid salt; separating and drying the dicarboxylic acid salt; and subsequently suspending the dried dicarboxylic acid salt in a non-aqueous liquid phase, and crushing until a stable dispersion is formed. Independent claims are also included for: (1) producing a compound of polypropylene and nanoscale dicarboxylic acid salts, comprising either removing the non-aqueous liquid phase from the dispersion, mixing the remaining powder of dicarboxylic acid salts with polypropylene, and then melting the obtained pre-mixture, and extruding into a granulated compound, or mixing the dispersion with polypropylene, removing the non-aqueous liquid phase from the mixture, and then melting the obtained pre-mixture, and extruding into a granulated compound; (2) producing polypropylene with an increased proportion of beta -crystalline polypropylene, comprising mixing the nanoscale dicarboxylic acid salts and polypropylene, or optionally mixing the compound obtained by the above method with polypropylene and/or an additional polymer, melting at a temperature of at least 1500[deg] C, and then cooling in such a manner that the cooled polypropylene melt exhibits an increased proportion of beta -crystalline polypropylene; (3) producing a biaxially oriented polypropylene film with at least one porous layer or a layer, comprising optionally mixing the compound obtained by the above method with polypropylene, additional polyolefins and/or the additional additives, melting at a temperature of at least 1500[deg] C, extruding through a flat nozzle, and cooling on a cooling roller in such a manner that the cooled precursor film exhibits an increased proportion of beta -crystalline polypropylene, then heating the precursor film, and stretching in longitudinal and transverse directions, where the temperature during the stretching is chosen in such a way that the beta -crystalline polypropylene of the precursor film is converted into an alpha -modification of polypropylene, and the layer forms an outer layer of the film, and exhibits an increased surface roughness on the outer surface; and (4) a porous, biaxially oriented film comprising polypropylene and nanoscale dicarboxylic acid-alkaline earth metal salts, where the film exhibits a Gurley value of less than 100 seconds, a thickness of less than 25 mu m, and a porosity of more than 50%.