Liquid crystalline polymers (LCPs) are highly crystalline, inherently flame retardant, thermotropic (melt-orienting) thermoplastics. They are a unique class of thermoplastics that primarily contain benzene rings in the backbone with molecules that are stiff, rod like structures organized in large parallel arrays. Though LCPs are similar to semi-crystalline polymers, they have distinctive attributes. Conventional semi-crystalline polymers when melted have a random structure, which, as they cool, form highly ordered crystalline regions surrounded by an amorphous matrix. LCP molecules remain well ordered even in the melt and slide past each other easily under shear. The result is very low melt viscosity making it easy to fill extremely thin walls and to replicate intricate features. They exhibit little or no shrinkage in the flow direction and require very little time to set-up or solidify. For high precision, thin walled parts that may need to survive high heat exposure, many designers and processors specify liquid crystal polymers.

Vectra liquid crystal polymers (LCP) made by Ticona are highly crystalline, thermotropic (melt-orienting) thermoplastics that can deliver exceptionally precise and stable dimensions, high temperature performance, high stiffness and chemical resistance in very thin-walled applications. The polymer also provides a low coefficient of thermal expansion, uniformly in all three-axis directions. It can withstand surface mount soldering temperatures, including those needed with lead-free solder. These properties have led to the use of Vectra LCP in many electronic applications such as sockets, bobbins, switches, connectors, chip carriers and sensors. Many grades have outperformed ceramics, thermosets and other high temperature plastics, with negligible or no char formation.
Vectra LCP grade has replaced stainless steel in a range of medical applications. Several grades of Vectra LCP grades are compliant with USP Class VI guidelines and are resistant to gamma radiation, steam autoclaving and most chemical sterilization methods. Ticona MT grades comply with USP 23 Class VI for biocompatibility with skin, blood and tissue. Vectra LCP MT grades offer excellent strength, stiffness, creep resistance, dimensional stability and high flow in long, thin sections. They have excellent thermal and chemical resistance and withstand numerous sterilization cycles. They can replace metal in medical and dental equipment, provide for finely structured parts in drug delivery systems, and meet the needs of devices for minimally invasive surgery and other areas.

Dupont�s Zenite LCP promises more strength, toughness and precision for electronic connectors and other molded components. Tests demonstrate that connectors moulded from this grade provide superior resistance to damage during automated contact insertion and board assembly. The new resin also produces parts with lower warpage for better part alignment and increased soldering yields. In destructive testing of a back plane header, the new grade provided a 21% improvement in resistance to breakage, a 32% increase in deflection before fracture and a more ductile/less brittle fracture mode. The test used a press equipped with a tapered tool to force the connector's sidewalls apart. Break force and deflection of the walls at break were measured. Improvements in strength and toughness are also evident in standard property data for tensile strength, elongation, flexural modulus and flexural strength.
Moulded connector specimens made of Zenite 6130LX also showed a marked improvement in knit line strength. When contacts were inserted in test specimens made of an earlier generation LCP, tiny cracks developed at the knit lines. No cracks were discovered in parts molded from the new resin. Other tests reveal that parts made from the new resin show reduced warp. Toe-in of the test connector's side walls was 23% less than that of a part molded from the earlier generation LCP. Zenite 6130LX also delivers more resistance to soldering conditions. Its heat deflection temperature of 280�C is 15�C higher than that of the earlier generation LCP. Typical applications include a wide range of components for electrical/electronics, lighting, telecommunications, auto ignition and fuel handling, aerospace, fiber optics, motors, imaging devices, sensors, ovenware, fuel or gas barrier structures and more.

Solvay�s Xydar liquid crystal polymer is a glass fiber or mineral-filled resin that features excellent flow properties. It can be injection molded into thin-wall components and has outstanding strength at extreme temperatures to 572�F (300�C). Xydar resin is inherently flame retardant, transparent to microwave radiation, and resistant to virtually all chemicals. It key features include: 271�C HDT, inherently flame retardant, excellent flow, chemical resistance. Typical applications include coatings, composites, additives, electrical motor components, electronic applications such as LED's, SMT components