Patent application number | Description | Published |
20130048908 | Heat-Resistant Liquid Crystalline Polymer Composition having a Low Melting Temperature - A thermotropic liquid crystalline polymer composition capable of exhibiting both a low melting temperature and good heat resistance without the use of conventional naphthenic acids is provided. The melting temperature may, for example, range from about 250° C. to about 400° C. Even at such low melting temperatures, the present inventors have surprisingly discovered that the ratio of the deflection temperature under load (“DTUL”), a measure of short term heat resistance, to the melting temperature may remain relatively high. The specific DTUL values may range from about 200° C. to about 300° C. The ability to form a polymer composition with the properties noted above may be achieved, at least in part, by the use of an aromatic amide oligomer. | 02-28-2013 |
20130052446 | Melt-Extruded Substrate for Use in Thermoformed Articles - A melt-extruded substrate that can be readily thermoformed into a shaped, three-dimensional article is provided. The substrate is formed from a polymer composition that contains a thermotropic liquid crystalline polymer and a unique aromatic amide oligomer. The present inventors have discovered that the oligomer can help increase the “low shear” complex viscosity of the resulting polymer. The ability to achieve enhanced low shear viscosity values can lead to polymer compositions with an increased melt strength, which allows the resulting substrate to better maintain its shape during thermoforming without exhibiting a substantial amount of sag. Due to its relatively high degree of melt strength, the polymer composition is particularly well suited for forming thin extruded substrates for use in thermoforming processes. | 02-28-2013 |
20130053531 | Method for Minimizing Process Disruptions During Formation of a Liquid Crystalline Polymer - A method for lowering melt viscosity of a liquid crystalline polymer as it is formed in a reactor vessel. More particularly, a reaction mixture is initially supplied to the reactor vessel that contains two or more precursor monomers (e.g., acetylated or non-acetylated). The reaction mixture is heated to an elevated temperature under agitation to initiate formation of the polymer. After a certain period of time, an aromatic amide oligomer is added to the reaction mixture. Among other things, the present inventors have discovered that such an oligomer can serve as a flow aid by altering intermolecular polymer chain interactions, thereby lowering the overall viscosity of the polymer matrix under shear. This minimizes the likelihood of “freeze off” of the polymer within the reactor vessel and limits the impact of process disruptions on the production of the liquid crystalline polymer. | 02-28-2013 |
20130053532 | Melt Polymerization of Low Melt Viscosity Liquid Crystalline Polymers - A method for forming a high molecular weight liquid crystalline polymer is provided. The method include melt polymerizing two or more precursor monomers (e.g., acetylated or non-acetylated) in the presence of an aromatic amide oligomer. The present inventors have discovered that such an oligomer can lower the melt viscosity of the viscous polymer as it is formed. The ability to lower melt viscosity in situ during melt polymerization enables the formation of high molecular weight polymers that display low melt viscosity and can still be removed from the reactor vessel without solidifying therein. This not only improves the ease of processing, but also allows molecular weights to be reached that are even higher than conventionally practical. | 02-28-2013 |
20130053533 | Solid-State Polymerization of a Liquid Crystalline Polymer - A method for forming a high molecular weight thermotropic liquid crystalline polymer is provided. The method includes melt polymerizing two or more monomers in the presence of a unique aromatic amide oligomer to form a prepolymer, and then solid-state polymerizing the prepolymer to achieve a target molecular weight. The present inventors have discovered that a unique aromatic amide oligomer can be employed to help increase the “low shear” complex viscosity of the resulting solid-state polymerized composition. This allows for the attainment of higher than conventional “low shear” complex viscosity values and/or a substantial reduction in the solid-state polymerization time needed to achieve a target complex viscosity. In addition, the oligomeric flow aid can also accelerate the extent to which the “high shear” melt viscosity is increased during solid-state polymerization, which may also contribute to a substantial reduction in the solid-state polymerization time needed to achieve a certain molecular weight. | 02-28-2013 |
20130062558 | Cast Molded Parts Formed from a Liquid Crystalline Polymer - A molded part having a predetermined shape is provided. The molded part may be formed by casting a liquid crystalline polymer composition into a mold cavity at a relatively low shear rate. Due to the use of a relatively low shear rate, the polymer composition does not generally undergo extensive shear orientation, which can allow the resulting part to be further processed using standard finishing techniques. The ability to use relatively low shear rates during casting is achieved in the present invention through the use of an aromatic amide oligomer. More particularly, the present inventors have discovered that the aromatic amide oligomer can serve as a flow aid by altering intermolecular polymer chain interactions, thereby lowering the overall viscosity of the polymer matrix to “ultralow” levels without having a significant impact on the mechanical properties. | 03-14-2013 |
20130085253 | Solid-Stage Polymerization System for a Liquid Crystalline Polymer - 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. | 04-04-2013 |
20130157033 | Nucleating System for Polyarylene Sulfide Compositions - A nucleating system for a thermoplastic composition that contains a polyarylene sulfide is provided. The nucleating system includes a combination of an inorganic crystalline compound and an aromatic amide oligomer. The present inventors have discovered that the combination of these different types of nucleating agents result in excellent crystallization properties (e.g., rate of crystallization). Due to the improved crystallization rate, the thermoplastic composition can be molded at lower temperatures to still achieve the same degree of crystallization. In addition to minimizing the energy requirements of the molding operating, the use of lower temperatures can also decrease the production of “flash” normally associated with high temperature molding operations. The composition may also possess good viscosity properties that allow it to be readily molded into parts of a variety of different shapes and sizes. | 06-20-2013 |
20140242385 | Liquid Crystalline Polymer Fibers - A fiber formed from a polymer composition that comprises a liquid crystalline polymer and an aromatic amide oligomer is provided. The present inventors have discovered that the oligomer can act as a flow aid for the polymer, which can provide a variety of different benefits. For example, the use of the oligomer during polymerization can lower the melt viscosity of the polymer as it is formed. This enables the formation of high molecular weight polymers that do not solidify within the reactor vessel. The formation of high molecular weight polymers during melt polymerization can, in turn, provide a variety of benefits, such as allowing for higher molecular weight polymers to be formed through additional processing (e.g., solid state polymerization) than conventionally possible, as well as enhancing the melt strength of the polymer composition and thereby aiding in the fiber formation process. | 08-28-2014 |
20140288221 | Aromatic Amide Compound - An aromatic amide compound having the following general formula (I) is provided: | 09-25-2014 |