What is the raw material of liquid crystal polymer LCP?

Liquid crystal polymer is an intermediate state between liquid and crystal. LCP has low viscosity and high orientation at the phase interval temperature of its liquid crystal state. Therefore, LCP materials have a series of excellent properties, such as high strength, high modulus, outstanding heat resistance, minimum linear expansion coefficient, excellent flame retardancy, electrical insulation, chemical corrosion resistance, weather resistance, microwave permeability and excellent formability. According to the formation conditions of liquid crystals, they can be divided into thermotropic liquid crystals and lyotropic liquid crystals. The liquid crystal state of lyotropic liquid crystal polymer is formed in solution, and the liquid crystal state of thermotropic liquid crystal polymer is formed in melt or above the glass transition temperature. Lyotropic liquid crystals can be spun into fibers or films by solvent method, and thermotropic liquid crystals can be injected and extruded. Thermotropic liquid crystals are widely used, and most of the thermotropic liquid crystals that have been industrially produced are aromatic polyester LCP.

Since Kevlar, the first LCP product of 1965, came out in DuPont, its superior performance has attracted people's attention. So far, the fibers made of Kevlar have been widely used in various fields, such as airplanes and bulletproof vests. But Kevlar is lyotropic liquid crystal polymer. Almost at the same time, many scientists studied thermotropic liquid crystal polymers, which blossomed in 1970s and 1980s, and many thermotropic liquid crystal polymer products came out, most of which were aromatic polyester liquid crystal polymers.

Economy J, Cottis S and others [2] of American Emery Company studied the polymerization of p-hydroxybenzoic acid (HBA), hydroquinone (HQ) and phthalic acid (terephthalic acid or isophthalic acid, TPA) in different proportions to obtain LCP, and applied for patents in 1970 and 65438+.

1977 Gordon, Calundann et al. [3] studied the melt polymerization of p-hydroxybenzoic acid (HBA) and 2,6 acid (HNA) to obtain LCP, and its structure is shown in Figure 3. Hearst-Celanese made further research on this basis, and put it into production in 1985, forming a series of Vectra products.

1976 Jackson ·WJ Jr and KuhfnsHF of Hysmans-Kodak Company [4] reacted p-hydroxybenzoic acid (HBA) with molten PET to obtain LCP with HBA/PET composition of 60/40, and Iman-Kodak Company began to produce LCP containing X-in190.

In 1993, Eastman company studied [5] thermotropic liquid crystalline polyester polymerized with p-hydroxybenzoic acid (HBA), 2,6-naphthalenedicarboxylic acid (NDA) and hydroquinone (HQ). The LCP material synthesized by this method reduces the raw material cost and improves the process of liquid crystal polyester.

In 2003, Eastman Company transferred LCP department to DuPont Company, and Titan brand products were merged into Zenite series. 8 ^+ C. t9 b% n% S！ {15m

Dupont originally produced HX brand LCP material, and HX series was polymerized with p-hydroxybenzoic acid (HBA), hydroquinone (HQ) and isophthalic acid (TPA) as monomers. Later, Zenite series LCP materials were introduced. Zenite series is polymerized with p-hydroxybenzoic acid (HBA), hydroquinone (HQ), isophthalic acid (TPA), biphenol (BP) and 2,6-naphthalenedicarboxylic acid (NDA) as monomers [6]. Compared with HX series, Zenite series has better processability and thermal stability, and became Titan brand in 2003.

K-brand LCP material produced by Bayer Company is polymerized by p-hydroxybenzoic acid (HBA), hydroquinone (HQ), terephthalic acid (TPA), isophthalic acid (IPA) and biphenol (BP).

Ultrax brand LCP material produced by BASF Company is polymerized from p-hydroxybenzoic acid (HBA), hydroquinone (HQ), terephthalic acid (TPA) and isophthalic acid (IPA) [8].

Granmont Company's granular brand LCP material is polymerized from terephthalic acid (TPA), phenylhydroquinone (PhHQ) and styryl hydroquinone (StHQ) [9], and it is also one of the few aromatic polyester LCP materials without p-hydroxybenzoic acid monomer in commercial products.