Abstract: The present invention discloses and claims a novel process for the formation of high denier as-spun and heat-treated multilobal filaments of a thermotropic liquid crystalline polymer. Preferred embodiments include process for the formation of as-spun and heat treated octalobal monofilaments of a few wholly aromatic polyesters and polyesteramides. The process involves (a) heating of a thermotropic liquid crystalline polymer to above its melting transition temperature; (b) passing said molten polymer through an extrusion chamber equipped with an extrusion capillary having a multilobal cross-section to form a multilobal filament; and (c) winding the filament at a suitable draw-down. The filaments so formed are of at least 50 denier per filament (dpf) and feature essentially uniform molecular orientation across their cross-section. In a final optional step, the filaments are heat treated in stages to form filaments exhibiting excellent tensile properties.

Abstract: The present invention discloses and claims a novel process for the heat treatment of high denier filaments of a thermotropic liquid crystalline polymer. Preferred embodiments include process for the formation of heat treated filaments of a few wholly aromatic polyesters and polyesteramides. The process involves: (a) heating of a thermotropic liquid crystalline polymer to above its melting transition temperature; (b) passing said molten polymer through an extrusion chamber equipped with an extrusion capillary of an aspect ratio of greater than about 1 and less than about 15 to form a filament; (c) winding the filament on to a bobbin at a low tension and draw-down ratio of at least about 4; and (d) heat treating the filament directly on the bobbin at suitable temperature and pressure conditions for a sufficient period of time. The filaments so formed are of at least 50 denier per filament (dpf) and feature essentially uniform molecular orientation across the cross-section.

Abstract: A process for making a transparent film comprising a liquid crystalline polymer, and a transparent film made thereby having high barrier properties. In this process, the LCP is dissolved in an appropriate solvent, then cast into a film at ambient or near-ambient temperatures. The film optionally may be dried at elevated temperatures and/or reduced pressures to remove the solvent. The film is then annealed at a temperature between the glass transition temperature (T.sub.g) and the melting point temperature (T.sub.m) of the polymer. The result is a highly transparent film having liquid crystalline morphology and high barrier properties.

Abstract: A miscible blend comprising from about 5 to about 95 weight percent of a polybenzimidazole and from about 95 to about 5 weight percent of a polyamide-imide having fluorine-containing linking groups, total weight percent of the two polymers being 100. A process for preparing the blends comprises dissolving in a mutual solvent from about 5 to about 95 weight percent of the aromatic polybenzimidazole to about 95 to about 5 weight percent of the polyamide-imide having fluorine-containing linking groups, based on the total weight of those polymers and subsequently evaporating the solvent, thereby producing a dried blend of a polybenzimidazole and a polyamide-imide having fluorine-containing linking groups. The blends, particularly in the form of films, fibers or fibrets, may be post-treated with heat or sulfuric acid in order to minimize their shrinkage when subsequently subjected to heat and in order to increase their resistance to solvents and acid.

Abstract: A compatible polymer blend containing a polyacetal, a hydroxylated polyacetal, polypropylene, and an acid-grafted polyolefine such as a muconic acid-polypropylene graft copolymer. The polyacetal is preferably a polyoxymethylene polymer such as Celcon.RTM.. The preferred hydroxylated polyacetal is one having a structure very similar to the polyacetal. The invention also includes a process for forming a compatible blend containing polypropylene and polyacetal by melt mixing polypropylene and polyacetal with an acid grafted polyolefin and hydroxylated polyacetal.

Abstract: Miscible compositions comprising from about 1 part by weight to about 99 parts by weight of an aromatic polyimide and from about 99 parts by weight to about 1 part by weight of an aromatic polybenzimidazole. Preferably, the composition comprises from about 5 parts by weight to about 95 parts by weight of an aromatic polyimide and from about 95 parts by weight to about 5 parts by weight of an aromatic polybenzimidazole. In a composition mostly comprised of an aromatic polybenzimidazole, it is preferred that the aromatic polyimide be thermoplastic and be present in the composition in an amount sufficient to make the aromatic polybenzimidazole more processable for molding purposes and also less susceptible to moisture. More preferably, such compositions are comprised of from about 65 parts by weight to about 95 parts by weight of an aromatic polybenzimidazole and from about 35 parts by weight to about 5 parts by weight of a thermoplastic aromatic polyimide.

Abstract: Miscible compositions comprising from about 1 part by weight to about 99 parts by weight of an aromatic polyetherimide and from about 99 parts by weight of about 1 part by weight of an aromatic polybenzimidazole. Preferably, the composition comprises from about 5 parts by weight to about 95 parts by weight of an aromatic polyetherimide and from about 95 parts by weight to about 5 parts by weight of an aromatic polybenzimidazole. In a composition mostly comprised of an aromatic polybenzimidazole, it is preferred that the aromatic polyetherimide be present in the composition in an amount sufficient to make the aromatic polybenzimidazole more thermally processable and also less susceptible to moisture. More preferably, such compositions are comprised of from about 65 parts by weight to about 95 parts by weight of an aromatic polybenzimidazole and from about 35 parts by weight to about 5 parts by weight of an aromatic polyetherimide.

Abstract: An article is provided comprised of a thermotropic liquid crystalline polymer having an inherently weak weld line incorporated therein which renders the article suitable for use as a breakaway part.

Abstract: The present invention discloses and claims a novel process for the formation of high denier as-spun and heat-treated filaments of a thermotropic liquid crystalline polymer. Preferred embodiments include process for the formation of as-spun and heat treated monofilaments of a few wholly aromatic polyesters and polyesteramides. The process involves (a) heating of a thermotropic liquid crystalline polymer to above its melting transition temperature; (b) passing said molten polymer through an extrusion chamber equipped with an extrusion capillary of an aspect ratio of greater than about 1 and less than about 15 to form a filament; and (c) winding the filament at a draw-down ratio of at least about 4. The filaments so formed are of at least 50 denier per filament (dpf) and feature essentially uniform molecular orientation across the cross-section. In a final optional step, the filaments are heat treated in stages to form filaments exhibiting excellent tensile properties.