PS and ABS(1)

1. PS (polystyrene)

1.PS performance

　　PS is an amorphous polymer with good fluidity and low water absorption (less than 00.2%). It is a transparent plastic that is easy to mold and process. Its products have a light transmittance of 88-92%, strong coloring power and high hardness. However, PS products are brittle, prone to internal stress cracking, poor heat resistance (60-80℃), non-toxic, and specific gravity around 1.04g/cm3 (slightly larger than water).

　　Molding shrinkage (its value is generally 0.004-0.007), the name of transparent PS only means the transparency of the resin, not the crystallinity. (Chemical and physical properties: Most commercial PSs are transparent, amorphous materials. PS has very good geometric stability, thermal stability, optical transmission properties, electrical insulation properties, and very small moisture absorption tendency. It It can resist water and diluted inorganic acids, but can be corroded by strong oxidizing acids such as concentrated sulfuric acid, and can swell and deform in some organic solvents.)

2. PS process characteristics

　　 PS melting point is 166 ℃, processing temperature is generally 185-215 ℃, melting temperature 180 ~ 280 ℃, for flame retardant materials, the upper limit is 250 ℃, decomposition temperature is about 290 ℃, so the processing temperature range is wide.

　　Mold temperature 40~50℃, injection pressure: 200~600bar, injection speed is recommended to use fast injection speed, runner and gate can use all conventional types of gate. Before processing PS material, unless it is stored improperly, it usually does not need to be dried. If drying is required, the recommended drying condition is 80C for 2~3 hours.

　　Because the PS specific heat is low, it can quickly condense and solidify some of the molds for heat dissipation, its cooling rate is faster than that of ordinary raw materials, and the mold opening time can be earlier. The plasticizing time and cooling time are shorter, and the molding cycle time will be reduced; the gloss of PS products is better as the mold temperature increases.

　　3. Typical application range

　　Packaging products (containers, covers, bottles), disposable medical supplies, toys, cups, knives, tape reels, windshield windows, and many foam products-egg boxes. Meat and poultry packaging trays, bottle labels and foamed PS cushioning materials, product packaging, household items (tableware, trays, etc.), electrical (transparent containers, light source diffusers, insulating films, etc.).