Classification of Characteristics of PP Granulators

Classification of Characteristics of PP Granulators

Polypropylene, English name: Polypropylene, Japanese name: ポリププレンン Molecular formula: C3H6nCAS Registration No.: 9003-07-0 Abbreviation: PP is a thermoplastic resin made from propylene polymerization. According to the methyl arrangement position, it is divided into three types: isotactic polypropylene, atacticPolyPropylene, and syndiostaticPolyPropylene.

PP is a semi crystalline material that is harder and has a higher melting point than PE. Due to the brittleness of homopolymer type PP at temperatures above 0C, many commercial PP materials are random copolymers with 1-4% ethylene added or block copolymers with higher ethylene content. Copolymer type PP materials have lower thermal deformation temperature (100 ℃), low transparency, low glossiness, and low rigidity, but have stronger impact strength. The impact strength of PP increases with the increase of ethylene content. The Vicat softening temperature of PP is 150C. Due to its high crystallinity, this material has excellent surface stiffness and scratch resistance. PP does not have environmental stress cracking issues. Usually, PP is modified by adding glass fiber, metal additives, or thermoplastic rubber. The flow rate of PP has an MFR range of 1-40. PP materials with low MFR have good impact resistance but low ductility strength. For materials with the same MFR, the strength of the copolymer type is higher than that of the homopolymer type. Due to crystallization, the shrinkage rate of PP is quite high, generally ranging from 1.8 to 2.5%. And the directional uniformity of shrinkage rate is much better than materials such as PE-HD. Adding 30% glass additive can reduce the shrinkage rate to 0.7%. Both homopolymer and copolymer PP materials have excellent resistance to moisture absorption, acid and alkali corrosion, and solubility. However, it has no resistance to Aromatic hydrocarbon (such as benzene) solvents, chlorinated hydrocarbon (carbon tetrachloride) solvents, etc. PP also does not have antioxidant properties at high temperatures like PE.