Twenty Kinds of Plastics and Their Properties—(20) SA
20. SA styrene acrylonitrile copolymer
Typical application range:
electrical (socket shell, etc.), household goods (kitchen equipment, refrigerator device, TV stand, cassette boxes, etc.), the automotive industry (headlight box, mirror, dashboard etc.), household appliances (tableware, food, cosmetics packaging tool).
Injection molding process conditions:
Drying process: if the storage is not appropriate, SA has some hygroscopic properties. The proposed drying conditions are 80 °C and 2~4 hours.
Melting temperature: 200~270 °C. If the thick wall products are processed, the melting temperature below the lower limit can be used.
Mold temperature: 40~80 °C. For reinforced materials, the mold temperature should not exceed 60 °C. The cooling system must be well designed because the mold temperature will directly affect the appearance, shrinkage and bending of the products.
Injection pressure: 350~1300bar.
Injection speed: it is recommended to use high speed injection.
Runner and gate: all regular gates can be used. Gate size must be appropriate to avoid stripe, burn spot and gap.
Chemical and physical properties:
SA is a hard, transparent material. The styrene component makes the SA hard, transparent and easy to process; the acrylonitrile component makes SA with chemical stability and thermal stability. SA has a strong load bearing capacity, anti chemical reaction ability, thermal deformation characteristics and geometric stability. The addition of glass fiber additives in SA can increase the strength and thermal deformation ability and reduce the coefficient of thermal expansion. The softening temperature of the VEKA in SA is about 110 °C. The deflection temperature is about 100 °C under the load. The shrinkage rate of SA is about 0.3~0.7%.