1.LCP is short for Link Control Protocol(Link Control Protocol), which is a subset of the PPP protocol. In PPP communication, the sender and the receiver send LCP packets to determine the necessary information for data transmission. The LCP checks the identity of the linked device and decides whether to accept or reject it. Determines the number of packet bytes that can be received in a transmission; Check whether their configurations match. If they do not match, disconnect the link. Data can only be networked if the LCP packet link is available
2. Overview of liquid crystal polymer (LCP)
Liquid Crystal polymer is a new type of high-performance engineering plastic developed in the early 1980s, named Liquid Crystal Polyester for short LCP. The main polymerization method is melt polycondensation, and the whole aromatic LCP is supplemented by solid phase polycondensation to produce high molecular weight products. Non-aromatic LCP products are often prepared by one-step or two-step melt polymerization. In recent years, the technology of producing high molecular weight LCP by continuous melting has been developed.
Liquid crystal aromatic polyester in the liquid crystal state due to its macromolecular chain orientation, it has an unusually regular fibrous structure, special performance, product strength is very high, no less than metal and ceramics. The tensile strength and bending modulus can exceed the various thermoplastic engineering plastics developed in the past 10 years. Mechanical properties, dimensional stability, optical properties, electrical properties, chemical resistance, flame retardant, good processability, good heat resistance, low coefficient of thermal expansion. The properties, processability and prices of liquid crystal polyesters are also different with different monomers. The different fillers selected and the different amount of fillers added also affect its performance.
Properties and applications of liquid crystal polymer (LCP)
I. Characteristics
Liquid crystal polymer resin is generally beige, but also has a white opaque solid powder. The density is 1.4 ~ 1.7g\/cm3. Liquid crystal polymer has high strength, high modulus mechanical properties, due to its structural characteristics and enhanced, so the unreinforced liquid crystal plastic can reach or even exceed the level of mechanical strength and modulus of ordinary engineering plastics reinforced with dozens of percent glass fiber; If reinforced with glass fiber, carbon fiber, etc., it is far more than other engineering plastics.
Liquid crystal polymer also has excellent thermal stability, heat resistance and chemical resistance, the creep shortcomings of most plastics, liquid crystal materials can be ignored, and wear resistance, wear reduction are excellent.
LCP weather resistance, radiation resistance is good, with excellent flame retardant, can extinguish the flame and no longer continue to burn. Its combustion rating reaches the UL94V-0 level. LCP is one of the best special plastics for fire safety.
LCP has excellent electrical insulation properties. The dielectric strength is higher than that of general engineering plastics, and the arc resistance is good. As an electrical application component, its electrical performance is not affected when the continuous use temperature is 200 ~ 300℃. The intermittent use temperature can reach about 316℃.
LCP has outstanding corrosion resistance, LCP products will not be corroded in the presence of 90% acid and 50% alkali concentration, for industrial solvents, fuel oils, detergents and hot water, will not be dissolved after contact, and will not cause stress cracking.
LCP has been used in microwave oven containers and can withstand high and low temperatures. LCP can also make printed circuit boards, satellite electronic parts, jet engine parts: for electronic and electrical and automotive mechanical parts or components; It can also be used for medical purposes.
LCP can be added with high filler as integrated circuit packaging material to replace epoxy resin as coil skeleton packaging material, to replace epoxy resin as coil skeleton packaging material; For fiber optic cable connector head cover and high strength components; Instead of ceramic for chemical separation tower filling materials, etc.
LCP can also be blended with polysulfone, PBT, polyamide and other plastics to make alloy, high mechanical strength after molding, to replace glass fiber reinforced polysulfone and other plastics, which can improve the mechanical strength, but also improve the use of strength and chemical stability. The LCP is currently being studied for use in the external panels of space vehicles and the external braking systems of automobiles.
Liquid crystal polymer (LCP) forming process
The molding temperature of LCP is high, because of its different varieties, the melting temperature is in the range of 300 ~ 425℃. LCP melt has low viscosity and good fluidity, which is similar to olefin plastics. LCP has a very small coefficient of linear expansion and good dimensional stability. The reference of forming processing conditions is: forming temperature 300 ~ 390℃; Mold temperature 100 ~ 260℃; The molding pressure is 7 ~ 100Mpa, the compression ratio is 2.5 ~ 4, and the molding shrinkage is 0.1 ~ 0.6.