Fiber reinforced thermoplastics are well known. Reinforcing fibers may be short (e.g. chopped fiberglass) or long continuous fibers. Cogswell, "The Processing Science of Thermoplastic Structural Composites", Intern. Polymer Processing,l (1987) 4, pp. 157-165 illustrates the latter. Specifically, Cogswell describes polyether etherketone (PEEK) reinforced with carbon fibers. Cogswell further teaches that the composite may be in the form of a laminate of two or more layers or plies, and that the carbon fibers in adjacent layers may be oriented in different directions. Carbon fibers are formed separately and are thereafter incorporated into the thermoplastic matrix by conventional means.
U.S. Pat. No. 4,820,568 to Harpell et al discloses a multilayer composite comprising a plurality of prepreg layers, in which layer comprises high strength performed fibers of conventional materials (e.g., carbon, graphite, cellulose or metal) in a polymer matrix. The fibers are oriented in the same direction.
U.S. Pat. Nos. 4,728,698 and 4,835,047, both to Isayev, et al., disclose liquid crystal fiber reinforced polymer composites in which the liquid crystal fibers are formed in situ in a matrix of flexible chain thermoplastic polymer. The essentially unidirectionally oriented fibers are formed by application of high strain rate mixing conditions.
M. P. De Meuse and M. Jaffe Polymer Preprints, vol. 30, no. II, Sep. 19, 1989 pp 540-541 discloses LCP/LCP blends which are miscible in both the melt and solid states.
Application Ser. No. 07/695,507, now abandoned describes and claims blends of two thermotropic liquid crystal polymers, one having a melting point and the other having a glass transition temperature, which are both melt processable with overlapping processing temperature ranges, one of which has a higher minimum processing temperature than the other and which are phase separated in the solid phase. The second liquid crystal polymer forms fibers in situ in a matrix of the first polymer under appropriate mixing conditions over at least a part of the composition range.
U.S. Pat. No. 4,902,369 to Avramova et al discloses a process for laminating a liquid crystal polymer film having a high degree of molecular orientation while maintaining such orientation, and to the resulting multi-layer laminate. The liquid crystal polymer film is prepared from a single liquid crystal copolymer, i.e., a copolymer of poly(ethyleneterephthalate) (PET) with p-hydroxybenzoic acid.
USPTO Backgrounds
USPTO Backgrounds