Porous, powdery polypropylene

Abstract

Process for the production of porous, powdery polypropylene, and utilization thereof. Hot solutions of polypropylene in pentaerythrol ester are slowly cooled down to approximately room temperature, forming a solidified mass, after which it is extracted with an extractant in which pentaerythrol is soluble. Before extracting, the size of the solidified mass may be reduced mechanically. After extracting, the pentaerythrol may be removed from the extractant to a high degree. Preferred embodiments include using solutions of polypropylene in pentaerythrol esters of fatty acids, more specifically, of synthetic fatty acids with 8-10 carbon atoms; using ethanol for the extraction; using solutions with a weight ratio of polypropylene to pentaerythrol ester of 30:70 to 10:90; having cooling of the solutions within the range of 260.degree. to 120.degree. C. proceed at an average rate of 1.degree. to 20.degree. C. per minute; using polypropylene with an admixture of up to 10% by weight of polyethylene. The porous, powdery polypropylene is characterized by an apparent density of 0.1 to 0.3 g/cm.sup.3, a particle size of 50-700 .mu.m, and an externally accessible porosity of 70-85%. The product may be used for the separation of hydrophobic substances from aqueous systems, in particular the separation of oil; for the adsorption of liquids, in particular, as oil adsorbent; as additive to paints, particularly to protective paints; and as carrier of substances for long-term release, in particular, odorants, and more specifically, as carrier of sexual attractants for insects.

Dependencies are inferred from the claim text.