PP granules Plastics Raw Material hp550p injection molding grade food grade high flow high impact polypropylene

Polypropylene is a thermoplastic resin made by polymerization of propylene. According to the methyl arrangement position, it can be divided into isotactic polypropylene, atactic polypropylene and syndiotactic polypropylene.

If methyl groups are arranged on the same side of the molecular main chain, it is called isotactic polypropylene. If methyl groups are arranged disorderly on both sides of the molecular main chain, it is called random polypropylene. When methyl groups are arranged alternately on both sides of the molecular main chain, it is called syndiotactic polypropylene. In general industrial polypropylene resin, the content of isotactic structure is about 95%, and the rest are random or syndiotactic polypropylene. Industrial products are mainly composed of isotactic substances. Polypropylene also includes copolymers of propylene and a small amount of ethylene. It is usually a translucent colorless solid, odorless and non-toxic. Due to the regular structure and high crystallization, the melting point can be as high as 167 ℃. It is heat-resistant and corrosion-resistant, and the products can be sterilized by steam. Low density, yes. Light general purpose plastic. The disadvantage is poor low-temperature impact resistance and easy aging, but it can be overcome by modification.

Copolymer PP material has lower thermal deformation temperature (100 ℃), low transparency, low gloss and low rigidity, but has stronger impact strength. The impact strength of PP increases with the increase of ethylene content. The Vicat softening temperature of PP is 150 ℃. This material has good scratch resistance and high surface stiffness. PP has no environmental stress cracking problem.

The melt mass flow rate (MFR) of PP is usually 1 ~ 100. PP material with low MFR has better impact resistance, but lower tensile strength. For the same MFR materials, the impact strength of copolymerization type is higher than that of homopolymerization type. Due to crystallization, the shrinkage of PP is quite high, generally 1.6 ~ 2.0%.