Low naphthenic liquid crystalline polymer composition for use in molded parts with a small dimensional tolerance

摘要

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.

主权项

1. A thermoplastic composition that comprises at least one thermotropic liquid crystalline polymer, wherein the total amount of repeating units in the thermotropic liquid crystalline polymer derived from naphthenic hydroxycarboxylic or naphthenic dicarboxylic acids is no more than 15 mol. %, the thermoplastic composition further comprising at least one hydroxy-functional compound and at least one aromatic dicarboxylic acid, wherein the weight ratio of hydroxy-functional compounds to aromatic dicarboxylic acids in the thermoplastic composition is from about 0.1 to about 30, and further wherein the thermoplastic composition has a melt viscosity of from about 0.5 to about 100 Pa-s, as determined in accordance with ISO Test No. 11443 at a shear rate of 1000 seconds−1 and temperature that is 15° C. above the melting temperature of the thermoplastic composition.