Twenty Kinds of Plastics and Their Properties —(1) ABS
1. ABS Acrylonitrile−Butadiene−Styrene Copolymer
Typical application range:
(the car dashboard, door tools, wheel cover, mirror box, refrigerator, etc.) high intensity tools (hair dryers, blenders, food processing machine, mower etc.), telephone housings, typewriter keyboard, vehicles such as golf carts and jet sled car entertainment etc.
Injection molding process conditions:
Drying process: the ABS material is hygroscopic and requires drying before processing. It is suggested that the drying condition is at least 2 hours at 80~90 °C. The temperature of the material should be less than 0.1%.
Melting temperature: 210~280 °C; suggested temperature: 245 °C.
Mold temperature: 25~70 degrees C. (the temperature of the mold will affect the smoothness of the plastic, and the lower temperature will lead to a lower degree of finish).
Injection pressure: 500 to 1000 bar.
Injection speed: middle and high speed.
Chemical and physical properties:
ABS is synthesized by three chemical monomers of acrylonitrile, butadiene and styrene. Each monomer has different characteristics: acrylonitrile has high strength, thermal stability and chemical stability; butadiene is tough and impact resistant; styrene is easy to process, high gloss and high strength.
In terms of morphology, ABS is a non crystalline material. The polymerization of the three middle monomers produces a three – phase copolymer of two phases, one is a continuous phase of styrene – acrylonitrile, and the other is a polybutadiene rubber dispersion phase. The characteristics of ABS depend mainly on the ratio of three monomers and the molecular structure in the two phases. This can be very flexible in product design, and thus produces hundreds of different quality ABS materials in the market.
These different quality materials provide different characteristics, such as the impact resistance from medium to high, from low to high to high degree of smoothness and high temperature distortion. The ABS materials have excellent machinability, appearance characteristics, low vermicular properties, excellent dimensional stability and high impact strength.