摘要:
Disclosed is a method of modifying polyethylene to increase its ability to resist the transmission of water vapor. The polyethylene is modified to increase long chain branching resulting in lower water vapor transmission rates in films prepared with the modified polyethylene. The polyethylene can be modified using peroxides, air and even by admixture with high long chain branching content polyethylene. The polyethylene, particularly when in the form of films, can be used for preparing packaging where sorption of flavor, aroma, or colorant compounds must be minimized.
摘要:
A polypropylene material may be prepared from a blend of heterophasic propylene copolymers and propylene homopolymers. The material may be prepared by blending the polymers while they are in a molten state, and forming a film or sheet from the polymer blend. The materials may also be formed as coextruded materials or as ternary blends with a polyethylene or a single phase random propylene copolymer. The blends and neat polymers have particular application to forming slit film tapes and similar materials. The resultant materials may exhibit increased tenacity, elongation and toughness and greater surface roughness as compared to those materials prepared solely from propylene homopolymers.
摘要:
A method of processing a high ethylene random copolymer comprising nucleating a high ethylene random copolymer to form a high ethylene polymeric composition, melting and extruding a high ethylene polymeric composition, spinning a high ethylene polymeric composition to form a fiber, cooling the fiber, guiding the fiber with an aspirator, and recovering the fiber.
摘要:
Process for the production of an oriented polyolefin film using multi-component polymer compositions. One polymer component comprises an isotactic propylene homopolymer produced by the polymerization of propylene with a Ziegler-Natta catalyst. A secondary component is a Ziegler-Natta polymerized ethylene-propylene random copolymer or a metallocene-polymerized ethylene-propylene random copolymer produced by the polymerization of propylene and ethylene in the presence of a metallocene polymerization catalyst. The Ziegler-Natta polymerized copolymer is produced by the polymerization of ethylene and propylene in the presence of a Ziegler-Natta catalyst and contains no more than 0.5 wt. % ethylene and has a xylene solubles content of at least 2 wt. %. The primary and secondary polymer components are mixed together to provide a blend in which, when the secondary component is a Ziegler-Natta polypropylene, is present in an amount within the range of 5–25 wt. % and the secondary polymer component is a metallocene-based copolymer present in an amount of less than 5 wt. %. After mixing the two polymer components together, the mixture is extruded and the formed into a biaxially oriented film.