Abstract: A method for forming a liquid crystalline thermoplastic composition is provided. The method comprises blending at least one thermotropic liquid crystalline polymer and a plurality of fibers within an extruder. The extruder contains at least one rotatable screw received within a barrel (e.g., cylindrical barrel) and defines a feed section and a melting section located downstream from the feed section along the length of the screw. Relatively long fibers are initially supplied to the feed section of the extruder, but at a location downstream from the liquid crystalline polymer so that the polymer is still in a solid state when it initially contacts the fibers. In this manner, the present inventors have discovered that the polymer can act as an abrasive agent for reducing the length of the fibers.

Abstract: A thermoplastic composition for use in a fine pitch electrical connector is provided. The thermoplastic composition contains a liquid crystalline polymer and a plurality of fibers. The volume average length of the fibers in the thermoplastic composition is selectively controlled according to the present invention so that it is within a certain range, such as from about 80 to about 250 micrometers. The fibers also have a narrow length distribution. That is, at least about 70% by volume of the fibers have a length within a certain range. Through the use of a liquid crystalline polymer and fibers of a certain weight average length and narrow length distribution, the present inventors have discovered that the resulting thermoplastic composition is able to achieve a desirable combination of strength and flowability, which enables it to be uniquely suited for the walls of a fine pitch connector.

Abstract: A system and process for injection molding polymer articles is described. The system and process are designed to reduce gate blush. In one embodiment, an injection molding device injects a molten polymer composition into a runner that extends from an injection point to a gate. The gate is positioned adjacent to an opening leading into a mold cavity. In accordance with the present disclosure, the system includes one or more overflow passages that divert flow of the polymer composition so as to temporarily reduce the flow rate and pressure of the polymer composition entering the mold.

Abstract: A thermoplastic composition that comprises a low-naphthenic, thermotropic liquid crystalline polymer blended with a combination of flow modifiers is provided. More particularly, one of the flow modifiers is a hydroxy-functional compound that contains or more hydroxyl functional groups. Without intending to be limited by theory, it is believed that the hydroxyl functional groups can react with the polymer chain to shorten its length and thus reduce melt viscosity. Aromatic dicarboxylic acids are also employed as a flow modifier in the thermoplastic composition. Again, without intending to be limited by theory, it is believed that such acids can combine smaller chains of the polymer together after they have been cut by hydroxy-functional compounds. This helps maintain the mechanical properties of the composition even after its melt viscosity has been reduced.

Abstract: A thermoplastic composition that contains a unique combination of a thermotropic liquid crystalline polymer, dielectric material, laser activatable additive, and a fibrous filler is provided. The nature of the components and/or their concentration are selectively controlled in the present invention to maintain a high dielectric constant, good mechanical properties (e.g., deflection under load), and good processibility (e.g., low viscosity), yet still be laser activatable. Thus, the thermoplastic composition can be readily shaped into a thin substrate and subsequently applied with one or more conductive elements using a laser direct structuring process (“LDS”).

Abstract: Polymer springs are described having a closed cell geometry. The polymer springs are well adapted for replacing metal springs in various applications, such as in seat cushions. In one embodiment, the polymer springs include columns of closed cells, in which each cell has a curvilinear shape. A method for designing polymer springs is also described.

Abstract: A polymer composition containing a polyacetal resin, a metallic pigment, and an ultraviolet light stabilizer is disclosed that exhibits a metallic brilliant appearance. The metallic pigment, the ultraviolet light stabilizer and the polyacetal resin can be mixed in a high intensity mixer prior to being used to mold polymer articles.

Abstract: Polyoxymethylene polymer compositions are disclosed that contain an impact modifier. In accordance with the present disclosure, the impact modifier is attached to the polyoxymethylene polymer and comprises a thermoplastic elastomer containing carbonate groups, such as polycarbonate groups. In one embodiment, a coupling agent bonds the impact modifier to the polyoxymethylene polymer. Incorporation of an impact modifier containing carbonate groups has been found to produce articles having good impact resistance properties while also preserving the permeability of the material. The polymer composition is well suited to producing containment devices, especially fuel tanks.

Abstract: A multi-stage process for forming a liquid crystalline polymer is provided. More particularly, the process includes acetylating one or more precursor monomers and melt-polymerizing the acetylated monomers to form a prepolymer in the form of a solid particulate material. Thereafter, the prepolymer is solid-state polymerized in a fluidized bed reactor that contains a porous surface (e.g., bed, plate, grate, etc.) on which the prepolymer is supported. While supported by this porous surface, the prepolymer can become “fluidized” with a heated stream of a gas (e.g., nitrogen). In this manner, a sufficient degree of turbulence is created to distribute heat evenly around the prepolymer and cause it to rapidly reach the target reaction temperature.

Abstract: Metal coated molded polymer articles are described made from a polyoxymethylene polymer. In accordance with the present disclosure, the molded articles are produced from a polymer composition containing a functionalized polyoxymethylene polymer combined with a metal pigment. The functionalized polyoxymethylene polymer may comprise a polyoxymethylene polymer that has a significant amount of hydroxyl groups present in the terminal positions. The terminal positions can be on the end of the polymer chain or on the side of the polymer chain. In one embodiment, the metal coating is applied to the molded article using an electrolytic plating process. Electrolytic coatings applied to substrates made in accordance with the present disclosure have displayed excellent peel strengths.

Abstract: An overmolded composite structure that contains a metal component and a resinous component adhered to a surface thereof is provided. The resinous component is formed from a thermoplastic composition that contains at least one polyarylene sulfide and at least one mineral filler. The present inventors have discovered that the nature and relative concentration of the polyarylene sulfides, mineral fillers, and/or other materials in the thermoplastic composition can be selectively tailored so that the resulting resinous component has a coefficient of linear thermal expansion and/or color that is similar to the metal component.

Abstract: Melt processed polyarylene sulfide compositions are described as are methods of forming the melt processed polyarylene sulfide compositions. The melt processed polyarylene sulfide compositions are formed according to a melt processing method that includes melt processing a mixture that includes a starting polyarylene sulfide, a disulfide compound and a filler. The melt processed polyarylene sulfide compositions may provide low chlorine content products having excellent strength characteristics.

Abstract: Methods for forming a low chlorine content washed polyarylene sulfide are described. Methods include washing a polyarylene sulfide that includes aryl halide endgroups with a solution that includes a disulfide compound. The solution can also include a catalyst and an organic solvent. During the disulfide wash, a nucleophilic substitution reaction occurs between the disulfide compound and aryl halides endgroups of the polyarylene sulfide. The nucleophilic substitution reaction is carried out at conditions to prevent chain scission of the polyarylene sulfide that includes the aryl halide endgroups. Compositions and products formed with the low chlorine content disulfide washed polyarylene sulfide are also described.

Abstract: Polyarylene sulfide/liquid crystal polymer alloys are described as are methods of forming the polyarylene sulfide/liquid crystal polymer alloys. The polyarylene sulfide/liquid crystal polymer alloys are formed according to a melt processing method that includes melt processing a polyarylene sulfide with a reactively functionalized disulfide compound and a liquid crystal polymer in a one or two step process. The reactively functionalized disulfide compound is added in a stoichiometric amount to react with a portion of the polyarylene sulfide. The melt processing forms a polyarylene sulfide/liquid crystal polymer copolymer that is a compatibilizer in the alloy. The polyarylene sulfide/liquid crystal polymer alloys may provide low chlorine content products having excellent strength characteristics.