Method for the formation of composite articles comprised of thermotropic liquid crystalline polymers and articles produced thereby
AssigneeCelanese Corporation
InventorsKurt F. Wissbrun, Richard D. Orwoll
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Abstract
A method for the production of composite articles by pultrusion is provided wherein the articles comprise thermotropic liquid crystalline polymers and reinforcing fibers. The liquid crystalline polymers employed exhibit physical characteristics such that the negative slope of a dynamic viscosity-frequency curve (as defined) is less than about 0.35. The use of polymers having such rheological characteristics enables a composite material to be produced by pultrusion in which the polymer is uniformly dispersed among the reinforcing fibers.
Claims16
In a method for the production of a composite reinforced article by pultrusion whereby said article is formed by causing at least one continuous length bundle of reinforcing fibers to advance into a crosshead extruder die, forcing a molten thermoplastic matrix polymer into said die under pressure to impregnate said at least one fiber bundle, and continuously extruding and pulling said at least one impregnated bundle through at least one exit orifice of said die to shape said at least one impregnated fiber bundle into said composite reinforced article, the improvement wherein said polymer comprises a thermotropic liquid crystalline polymer which possesses rheological properties such that a dynamic viscosity-frequency curve based on such characteristics has a negative slope of less than about 0.35 when measured at a frequency of 1 sec.sup.-1.
Dependencies are inferred from the claim text.