Liquid Crystal Polyesters
A unique class of partially crystalline aromatic polyesters based on p-hydroxybenzoic acid and related monomers, liquid-crystal polymers are capable of forming regions of highly ordered structure while in the liquid phase. However, the degree of order is somewhat less than that of a regular solid crystal. Typically LCPs have a high mechanical strength at high temperatures, extreme chemical resistance, inherent flame retardancy, and good weatherability. Liquid-crystal polymers come in a variety of forms from sinterable high temperature to injection moldable compounds. LCP can be welded, though the lines created by welding are a weak point in the resulting product. LCP has a high Z-axis coefficient of thermal expansion.
“LCPs are exceptionally inert. They resist stress cracking in the presence of most chemicals at elevated temperatures, including aromatic or halogenated hydrocarbons, strong acids, bases, ketones, and other aggressive industrial substances. Hydrolytic stability in boiling water is excellent. Environments that deteriorate the polymers are high-temperature steam, concentrated sulfuric acid, and boiling caustic materials.”
Recent US Patents
9/7/2010
7,790,055
Wholly aromatic liquid crystal polyester composition and optical pickup lens holder using same
Murouchi and Nakayama of Nippon Oil has developed an aromatic liquid crystal polyester resin composition for injection molding, formed by melt-kneading 100 parts of the liquid crystal resin, and 5 to 20 parts glass fibers. This composition has excellent damping properties, and is suitable for a molding material of an optical pickup lens holder for short type pickups for use in high-speed DVD systems and playback pickups for use in Blu-ray systems. (RDC 11/29/2010)