LCP

LCP is a new type of polymer with outstanding properties. LCP is a wide range of materials:

a. Lyotropic liquid crystal: need to be processed in solution;

b. Thermotropic liquid crystal: it can be processed in the molten state.

Second, the characteristics and applications of LCP

a. LCP has self-reinforcement: it has the characteristics of unusually regular fibrous structure, so the non-reinforced liquid crystal plastic can reach or even exceed tens of percent of the glass used for ordinary engineering plastics.

The level of mechanical strength and modulus after glass fiber reinforcement. If it is reinforced with glass fiber, carbon fiber, etc., it is far more than other engineering plastics.

b. The liquid crystal polymer also has excellent thermal stability, heat resistance and chemical resistance. For the creep characteristics of most plastics, the liquid crystal material can be ignored, and it is resistant

Both wear and anti-friction properties are excellent.

c. LCP has good weather resistance and radiation resistance, and has excellent flame retardancy. It can extinguish the flame and no longer continue to burn. Its combustion rating reaches UL94V-0 level.

d. LCP has excellent electrical insulation properties. Its dielectric strength is higher than that of general engineering plastics, and its arc resistance is good. In the continuous use temperature of 200-300℃, its electrical performance will not be affected

. The intermittent use temperature can reach about 316℃.

e. LCP has outstanding corrosion resistance. LCP products will not be corroded in the presence of 90% acid concentration and 50% alkali concentration. For industrial solvents, fuel oil, and detergents

And hot water, will not be dissolved after contact, and will not cause stress cracking.

2. Application

a. Electrical and electronic is the main market of LCP: The surface assembly and welding technology of electrical and electronic has high requirements for the dimensional stability and heat resistance of the material (it can withstand the surface assembly technology

Gas phase welding and infrared welding used in );

b. LCP: printed circuit boards, satellite electronic components, jet engine parts, auto mechanical parts, medical aspects;

c. LCP adds high filler or alloy (PSF/PBT/PA): as integrated circuit packaging material;

Instead of epoxy resin as the encapsulation material of the coil frame, as the sheath of optical fiber cable joints and high-strength components; instead of ceramic as the filling material in the separation tower for chemical industry;

Instead of glass fiber reinforced polysulfone and other plastics (panels on the exterior of aerospace vehicles, braking systems on the exterior of automobiles).

Three, LCP injection molding process

Since the modified performance and usage levels are very different, and the processing technology is also very variable, the following ranges

should be adjusted accordingly:

1. Drying: 140℃～140～150℃ /5-7Hr

2. Injection temperature: 260～300～410℃

3. Mold temperature: 100～100～240℃

Fourth, the main production company

①Du Pont

②Eastman

③Solvay

④Ticona

⑤Mitsubishi Engineering Plastics Company

⑥Sumitomo

⑦Polyplastics (a joint venture between Ticona and Dasai Luo Chemical Company)

⑧Toray

In addition, there are Ueno Fine Chemicals Company and Unitika Company.

Five, other understanding

Thermotropic LCP has a structure of wholly aromatic polyester and copolyester. It also has a densely arranged linear polymer chain structure, and the formed product has good unidirectional mechanical properties.

Good high temperature performance (heat distortion temperature is 121～355℃), good radiation resistance, hydrolysis resistance, weather resistance, chemical resistance, inherent flame retardancy, low smoke generation,

High dimensional stability, low moisture absorption, very low linear expansion coefficient, high impact strength and rigidity (Compared with the same weight, the strength of LCP is greater than steel, but the rigidity is only 15% of steel)

. LCP is resistant to chemicals such as acids, solvents and hydrocarbons, and has good barrier properties.

Liquid crystal aromatic polyester is oriented in the macromolecular chain in the liquid crystal state, it has an unusually regular fibrous structure, special performance, high product strength, no less than metal and

ceramics. Tensile strength and flexural modulus can exceed a variety of thermoplastics developed in 10 years. Different monomers are used, and the performance, processability and price of the liquid crystal polyester obtained are also different.

different. The choice of filler and the amount of filler also affect its performance.