ABS Basic FAQ

The composition of acrylonitrile is 15-35%, and it contributes chemical resistance, thermal stability, hardness, and fatigue resistance. Butadiene provides toughness, impact strength, and low-temperature ductility, and the composition can be 5-35%. Styrene adds rigidity, processability, and gloss surface finish, and the composition can be 40-60%.

When ABS is subjected to this temperature range, its amorphous polymer starts to lose its rigid, glassy state to become rubbery, soft, and more flexible. The temperature range can vary for other ABS formulations. For example, the glass transition temperature of high-impact ABS is slightly lower at 95^oC to 110^oC (203oF to 230^oF) because of the higher butadiene content.

ABS offers good moisture and rain resistance, but when exposed to UV rays from the sun for a long time, it is prone to yellowing, degradation, and embrittlement. To prevent this, ABS needs UV stabilizers, specialized coatings, or carbon black. The surface degradation will usually not affect its structural strength.

The chemical structure of ABS, especially the presence of acrylonitrile, and its amorphous, non-polar nature makes it unreactive to diluted acids and alkalis. Acrylonitrile brings high chemical resistance and heat stability to the polymer. ABS has poor resistance to aromatic hydrocarbons, esters, and ketones.

It has a low shrinkage rate (generally 0.4% to 0.7%), which makes it suitable for complex shapes. To avoid molding defects like burning or voids, ABS must be dried to 0.1% moisture. For the best results and easy ejection, a draft angle of 1^o to 2^o is added on each side.

Sink marks can be prevented by maintaining uniform wall thickness (2.0mm to 3.5mm) and using an appropriate rib design. Splay or silver streaks are caused by overheating or moisture. Drying to 0.1% moisture and optimizing temperature can prevent this defect. Flow lines or burn marks can be controlled by optimizing injection speed and temperature.

Consumer electronics like computer keyboards, mice, remote controls, and so on are primarily crafted using ABS plastic. In the automotive industry, it is used for creating instrument and door panels. In the medical field, it is often used for manufacturing medical instrument housings like hearing aids.

ABS has low heat resistance and is not suitable for high-temperature applications because of its relatively low melting point (200—240^oC). When it burns, it produces significant smoke and potentially toxic fumes. It doesn’t resist strong acids, alkalis, or solvents like acetone. It is also susceptible to stress cracking and may not withstand repeated, high stress or heavy load applications.

ABS formulations allow engineers to optimize the material properties for different specialized environmental applications.  The different grades of ABS include: flame-retardant ABS, high-impact ABS, heat-resistant ABS, plating/electroplating grade ABS, UV-resistant ABS, and high-flow/medical grade ABS.

Manufacturers tailor the material for specific properties by adjusting the ratio of acrylonitrile, butadiene, and styrene. For example, higher butadiene content creates high-impact ABS, while higher acrylonitrile content increases the heat resistance of the resulting ABS.

Alternatively, ABS is categorized with the code #7 in specialized or international systems to separate them from other plastics. The coding system also facilitate identification for recycling, waste management, and to sort the material properties for industrial application.

The dominant modifications are ABS+ASA (improve weatherability, UV stability, and aging resistance for outdoor applications); ABS+PC (increase heat resistance, rigidity, and impact strength); ABS+PA (enhance chemical resistance, mechanical strength, and thermal stability); ABS+PVC (improve fire retardancy); ABS+PMMA (enhance transparency, gloss, and scratch resistance); and ABS+TPE (improves impact resistance and soft-touch properties).

Although all ABS grades are easy to process different grades like high-flow, high-impact, and heat-resistant, will require adjustments to the molding parameters. Temperature and drying times may need to be adjusted depending on the grade. The most common manufacturing processes for making products with ABS include injection molding, 3D printing, and CNC machining. Other techniques that can be used include blow molding, extrusion, and thermoforming.

Another way to identify ABS is to look for the ABS marking within the triangular recycling symbols. other tests to identify ABS include the burn test (it produces yellow flame with blue edges, thick black smoke, and has a distinctive cinnamon-like smell), density test (it will sink when placed in water because of its high density of between 1.05 and 1.18 g/cm³), and acetone test (it will dissolve or become sticky when placed in a container containing acetone).

The density of ABS is around 1.04 g/cm³, which is 10-15% lighter than PC, which has a density of around 1.20 g/cm³. The lower density of ABS makes it the primary choice in the automotive industries where lightweighting helps to improve the fuel efficiency of new electric vehicles (NEVs).

ASA and ABS share similar, high-strength mechanical properties. However, ABS has the tendency to degrade with prolonged exposure to UV from the sun, which limits its use for outdoor products. ASA offers better UV resistance, which makes it ideal for outdoor applications. Also, ASA is easier to print and less prone to warping.

ABS has superior rigidity, high impact resistance, and glossy finishes. PP is better when it comes to flexibility, chemical resistance, lightweight, durability, and cost-effectiveness. Also, PP is food-safe, which makes it ideal for producing food containers and flexible pipes. ABS is best for car interior components and electronic housings.

ABS is popular because of its high toughness, impact resistance, and rigidity. It remains durable under heat and mechanical stress. PS, on the other hand, is known for being rigid, brittle, and sometimes transparent or opaque. It is highly cost-effective and easy to process. The downside is that it cracks easily under stress, making it ideal for stationary or single-use items.

For underground, cold-weather, and high-impact applications, ABS is a better choice because of its strength and resilience. PVC is better for residential plumbing because if offer better sound-damping performance. PVC also offers better chemical resistance and lower cost. ABS is usually black, while PVC is typically white.

ABS is a thermoplastic polymer with good impact resistance.

South Korea accounts for nearly 46% of global exports, making the country the dominant net exporter. In 2024, the value of the country’s ABS export was $2.07 billion, driven by high demand from China. China also has a massive production capacity. In 2019, China accounted for 37% of global ABS production capacity. Other significant exporters of ABS resins are Taiwan and Malaysia.

China is both the leading importer and consumer of ABS plastic. The country imports heavily from South Korea to support its manufacturing sectors, particularly the automotive, electronics, and appliances sectors.

LG Chem is considered the largest producer of ABS in the world with a global market share of over 20%. They are also known for producing advanced ABS grades used in automotive, 3D printing, and appliances. Chi Mei focuses on high-performance polymers, including high-impact-resistant and high-heat-resistant ABS.