SAN processing conditions

SAN processing conditions

Generic Class

SAN (Styrene Acrylonitrile)

Typical Applications

Electrical (receptacles, mixer bowls, housings, etc. for kitchen appliances, refrigerator fittings, chassis for television sets, cassette boxes, etc.), automotive (head lamp bodies, reflectors, glove compartments, instrument panel covers, etc.), household appliances (tableware, cutlery, beakers, etc.), cosmetic packs, etc.

Injection Molding processing Conditions

Drying

Under improper storage conditions, SAN absorbs moisture; it is recommended that it be dried at 80 C (176 F) for 2-4 hours prior to molding. 

Melt Temperature 

200 - 270 C (392 - 518 F); 230 - 260 C (446 - 500 F) for most applications; lower end of the range is used for molding thick wall components 

Mold Temperature

40 - 80 C (104 - 176 F); SAN solidifies rapidly at higher temperatures; for reinforced grades, the mold temperatures should not be less than 60 C (140F).
The cooling system must be well designed because the mold temperature affects the parts appearance and shrinkage and warpage.

Material Injection Pressure

35 - 130 MPa

Injection Speed

High speeds are recommended

Gates

All conventional gate types may be used. The gates must be of proper size which aid in processing and do not cause streaks, burn marks, or voids.

Chemical and Physical Properties

SAN copolymers are produced by the polymerization reaction of styrene and acrylonitrile. They are strong, transparent materials. The styrene component imparts clarity, stiffness, and processibility and the acrylonitrile component imparts chemical and thermal resistance.

They have excellent load bearing capacity, rigidity, good resistance to chemicals, heat deformation, and cyclic temperature loads, and dimensional stability. The properties are dependent on the acrylonitrile content and commercial grades offer different acrylonitrile molecular masses. The addition of glass fibers enhances rigidity and resistance to heat deformation, and decreases the coefficient of linear thermal expansion.

The Vicat softening point is approximately 110 C (230 F) and the deflection temperature under load is approximately 100 C (212 F).

Shrinkage ranges from 0.003 - 0.007 mm/mm (0.3 - 0.7%).


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