Chemical name: Polypropylene
English name: Polypropylene (referred to as PP)
Specific gravity: 0.9-0.91 g / cm 3
Mold shrinkage: 1.0-2.5%
Molding temperature: 160-220 ° C
Features: Low density, strength stiffness, hardness and heat resistance are better than low-pressure polyethylene, can be used at about 100 degrees. It has good electrical properties and high-frequency insulation is not affected by humidity, but it becomes brittle and not wear-resistant at low temperature. Easy to age. Suitable for making general mechanical parts, corrosion resistant parts and insulating parts.
Molding characteristics:
1. Crystallized material, low hygroscopicity, easy to melt fracture, long-term contact with hot metal is easy to decompose.
2. Good fluidity, but the shrinkage range and shrinkage value are large, and shrinkage, dent and deformation are easy to occur.
3. The cooling rate is fast, the pouring system and the cooling system should be slowly dissipated, and the molding temperature should be controlled. The material temperature is easy to orient at low temperature and high pressure. When the mold temperature is lower than 50 degrees, the plastic parts are not smooth, and it is easy to produce poor welding and flow marks. More than 90 degrees is prone to warping deformation.
4. The plastic wall thickness should be uniform to avoid lack of glue and sharp corners to prevent stress concentration.
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