Method for identifying a blend of nucleators useful for preparing a nucleated polyolefin material

摘要

A method for identifying nucleators blends that provide reduced haze in a nucleated polyolefin comprises (i) providing blends containing first and second nucleators in which the first nucleator is a major component in one blend and a minor component in another, (ii) determining the minimum dissolution temperature at which each blend dissolves in the same molten polyolefin, and (iii) identifying a blend with a dissolution temperature that is lower than other blends. The nucleators may be substituted dibenzylidene sorbitol derivatives, 1,3,5-benzenetrisamides, trans- or dimethylquinacridone, or N,N-di-C5-8-cycloalkyl-2,6-naphthalene dicarboxamides. Preferably, each nucleator blend is melt compounded with the polyolefin to form a composition, without dissolving the blend in the polyolefin. The dissolution temperature may be determined using a microscope having a light source to transmit light through the composition, a heating platform for heating the composition, and an image capturing device for continuously capturing microscope images of the composition. The image capturing device may be linked to an analysis unit that determines the brightness of the images. The temperature at which a peak in relative brightness is observed will typically indicate the minimum dissolution temperature.