US 5,627,226 AGranted

Polypropylene/fiber composites

AssigneeExxon Research & Engineering Co.

InventorsArnold Lustiger, Cary N. Marzinsky, Yann Devorest

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Abstract

A composite is provided having improved toughness without reduction in stiffness comprising a polymer matrix having fibers embedded therein wherein the polymer of the matrix is substantially beta polypropylene or a beta polypropylene-olefin copolymer. The composite is made by combining a nucleating agent with a polymer composition selected from the group consisting of alpha polypropylene, an alpha polypropylene-olefin copolymer, alpha polypropylene containing fibers therein and an alpha polypropylene-olefin copolymer having fibers therein, and when the polymer is polypropylene or polypropylene-olefin copolymer, also independently adding fiber to the polymer or copolymer and thereafter inducing nucleation whereby a composite of improved stiffness with no reduction in toughness is formed.

Claims8

Dependent claims

A method of forming a composite having improved stiffness without reduction in toughness comprising:

providing a polypropylene polymer selected from the group consisting of polypropylene homopolymer, a polypropylene-olefin copolymer containing up to about 10 weight percent olefin, a polypropylene homopolymer having fibers dispersed therein and a polypropylene-olefin copolymer containing up to about 10 weight percent olefin having fibers dispersed therein;
combining a beta-nucleating agent with the polypropylene polymer in an amount ranging from about 50 to about 200 ppm based on the weight of polymer, the nucleating agent being capable of inducing the beta crystal form of the polypropylene polymer;
adding fibers to the polymer if the polymer does not already have fibers dispersed therein;
and
inducing nucleation whereby a composite of improved stiffness with no reduction in toughness is formed.

2 more elements

Dependencies are inferred from the claim text.