Plastic Injection Molding with LCP - Rebling Plastics
Properties of Liquid Crystal Polymer
LCPs are partially crystalline aromatic polyesters that are based on p-hydroxybenzoic acid and other similar monomers, giving LCPs the ability to form regions that contain highly ordered structure while in liquid state. This contrasts with the more chaotic molecular chain orientation that conventional polymers exhibit in solid and liquid phases. Because of this quality, they can perform very well in environments such as high heat, electrical, and chemical resistance and act as suitable replacements for ceramic, metals, other plastics and composites. The three most common types of LCPs are copolyimide, polyester-amide and PET copolyester.
Liquid Crystal Polymers are very inert and are capable of resisting stress cracking when confronted with chemicals at high temperatures. The tensile strength of LCPs is 12,000-32,000 psi with temperature resistances of 430°-500° F. The polymers are capable of being deteriorated by high-temperature steam, sulfuric acid (concentrated) and caustic materials at their boiling points. LCPs are also anisotropic, meaning that the strength of the material is not the same in every direction. They also have excellent chemical resistance.
The various properties of LCPs make them useful in several applications that require either high strength or heat resistance such as for projects that require withstanding high loads, electrical parts, mechanical parts, engine components, parts for cookware and ovens, and food containers. The low dielectric constants of the polymer make LCP great for electronics with microwave frequency. LCPs are also utilized for ignition system components for cars, pump components, and car safety belt sensors.
Liquid Crystal Polymer Injection Molding Design
Rebling design engineers have extensive experience with LCPs, including designing very thin-walled parts for high performance applications. The anisotropic nature of LCPs means that design engineers need to pay close attention to the gating locations on the mold for the desired resin flow. Like other crystalline materials, mold temperature is critical to maximizing the properties of LCP. The one downside to using LCP is its very high cost per pound. When LCP is cost prohibitive, Rebling engineers can help offer alternative materials with similar properties for high demand applications.