About ABS performance and processing characteristics

ABS is synthesized from three chemical monomers of acrylonitrile, butadiene and styrene. (Each monomer has different characteristics: acrylonitrile has high strength, thermal stability and chemical stability; butadiene has toughness and impact resistance; styrene has easy processing, high finish and high strength.

Polymerization of the three monomers resulted in a two-phase terpolymer, one being a continuous phase of styrene-acrylonitrile and the other being a dispersed phase of polybutadiene rubber. From the morphological point of view, ABS is an amorphous material with high mechanical strength and good comprehensive properties of “hard, tough, steel”. It is an amorphous polymer. ABS is a general-purpose engineering plastic. It is widely used and widely used. It is also called “universal plastic” (MBS is called transparent ABS). ABS is hygroscopic and has a specific gravity of 1.05g/cm3. The water is slightly heavy), the shrinkage rate is low (0.60%), the size is stable, and it is easy to shape and process.

The properties of ABS are mainly determined by the ratio of the three monomers and the molecular structure in the two phases. This allows for great flexibility in product design and results in hundreds of different quality ABS materials on the market. These different quality materials offer different properties such as medium to high impact resistance, low to high finish and high temperature distortion. ABS materials have superior processability, appearance characteristics, low creep and excellent dimensional stability and high impact strength.

ABS is a light yellow granular or bead opaque resin, non-toxic, odorless, low water absorption, and has good comprehensive physical and mechanical properties, such as excellent electrical properties, wear resistance, dimensional stability, chemical resistance and surface gloss. And easy to shape. Disadvantages are weather resistance, poor heat resistance, and flammability.

2. ABS process characteristics

2.1 ABS has a large hygroscopicity and moisture sensitivity. It must be fully dried and preheated (for a minimum of 2 hours at 80-90C) before the molding process, and the moisture content should be controlled below 0.03%.

2.2 The melt viscosity of ABS resin is less sensitive to temperature (unlike other amorphous resins). Although the injection temperature of ABS is slightly higher than PS, it does not have a loose temperature range like PS. It is not possible to use a blind heating method to remove the viscosity. It is possible to increase the fluidity by increasing the screw speed or injection pressure. Generally, the processing temperature is preferably 190-235 °C.

2.3 ABS has a medium melt viscosity, which is higher than PS, HIPS and AS. It requires a higher injection pressure (500~1000 bar) of beer.

2.4 ABS material is better at medium and high speed injection speed beer. (Unless the shape is complex, thin-walled parts require a higher injection speed), the product nozzle is prone to gas crevices.

2.5 ABS molding temperature is higher, and its mold temperature is generally adjusted at 25-70 °C. When producing larger products, the temperature of the fixed mold (front mold) is generally about 5 °C higher than the dynamic mold (rear mold). (The mold temperature will affect the smoothness of the plastic part, and the lower temperature will result in a lower finish)

2.6 ABS should not stay in the high temperature barrel for too long (should be less than 30 minutes), otherwise it will easily decompose and yellow.

3. Typical application range:

Cars (dashboards, tool hatches, wheel covers, mirror boxes, etc.), refrigerators, high-strength tools (hair dryers, blenders, food processors, lawn mowers, etc.), telephone housings, typewriter keyboards Recreational vehicles such as golf carts and jet skis.