Thermoplastic composite materials made by rotational shear
OwnerLawrence V. Montsingerinventor
Life of this patent
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Abstract
A composite with a thermoplastic matrix and fiber reinforcement is made by rotation of an exit die about a roving of continuous fiber in the presence of a thermoplastic melt. The rotation causes opposing inner and outer helical flow conditions which reduce the melt viscosity of the polymer by shear thinning while dragging and directing the polymer into the fiber roving thereby wetting and dispersing the fiber. A composite structure is formed with a polymer rich skin and a core region of unidirectionally aligned polymer and fiber. The polymeric skin is composed of helically aligned polymer chains which are coiled by the rotation around the core to compress the core region and enhance fiber wet out.
Claims30
A method of producing a fiber reinforced thermoplastic material comprising:
- directing continuous filaments along a predetermined advancing path of travel into and through an impregnation chamber;
- directing molten thermoplastic polymer material from an extruder into the impregnation chamber and into intimate contact with the advancing fiber for wetting and impregnating the filaments with the molten thermoplastic material;
- and
- pulling the polymer impregnated filaments from the impregnation chamber through an exit die while imparting relative rotation between the exit die and the filaments advancing therethrough.
An apparatus for producing a fiber reinforced thermoplastic material comprising:
- an impregnation chamber having an entrance end and an exit end, the exit end including an exit die;
- means for directing continuous filaments along a predetermined advancing path of travel into and through said impregnation chamber, entering through said entrance end and exiting through the exit die;
- an extruder for providing a supply of molten, thermoplastic polymer;
- means for directing molten thermoplastic material from said extruder into the impregnation passageway and into intimate contact with the filaments to promote wetting and impregnating of the filaments with the molten thermoplastic polymer;
- and
- means for imparting relative rotation between the exit die and the filaments advancing therethrough.
A fiber reinforced thermoplastic material comprising a core region including a plurality of unidirectionally aligned fibers which are substantially fully impregnated with a thermoplastic polymer and a skin region including the thermoplastic polymer which is substantially free of said fibers, the polymer chains in said core region being substantially aligned with said fibers and the polymer chains in said skin region being substantially helically arranged about said core region.
Dependencies are inferred from the claim text.