Rigid and impact resistant compositions containing poly (propylene) or poly (ethylene / propylene) and calcium carbonate for closures

摘要

"Rigid and impact-resistant compositions containing poly (propylene) or poly (ethylene / propylene) and calcium carbonate for closures". Hard and impact resistant closures (10) derived from hard and impact resistant mixtures including poly (propylene) or polyethylene / propylene and calcium carbonate; rigid and impact resistant compositions including poly (propylene) or (polyethylene / propylene) and calcium carbonate; methods for increasing the stiffness and impact resistance of a poly (propylene) or (polyethylene / propylene) resin or a closure (10); and a method for measuring the impact strength of a closure (10) or resin at a reduced temperature are described. A presently preferred mixture contains from about 40 to about 60 percent by weight of poly (propylene) or (polyethylene / propylene) and from about 25 to about 35 percent by weight of fatty acid-treated calcium carbonate particles. treated having a particle size of approximately 2.5 to approximately 3.5 microns.