The methyl group is called isotactic polypropylene on the same side of the main chain of the molecule, if the methyl group is randomly ordered to be called random polypropylene on either side of the main chain of the molecule. Individual properties of polypropylene resin, the isotactic structure content of about 95%, the rest of the random or syndiotactic polypropylene. The property product is an important component. Polypropylene is also a copolymer of propylene and a small amount of ethylene. Usually colorless translucent solid, odorless non-toxic. Due to the high degree of crystallization and regular structure, the melting point can be as high as 167 DEG C. Heat resistance, corrosion resistance, the product can be used steam disinfection is its outstanding benefits. Density is small, is the lightest general plastic. Weaknesses problem is the poor low-temperature impact resistant, easy to aging, but can be overcome by modified respectively. Copolymer PP material has a lower thermal deformation temperature (100 DEG C), low transparency, low gloss, low rigidity, but has a stronger impact strength, the impact strength of PP increases with the increase of ethylene content. PP VEKA softening temperature of 150 degrees C. Due to the high crystallinity, the stiffness and scratch resistance of this kind of material are very good. PP does not exist the problem of stress cracking. PP melt mass activity velocity (MFR) usually in 1~100. The low MFR PP material has better impact resistance but lower ductility. For the materials with different MFR, the impact strength of the copolymer is higher than that of the homopolymer. Due to crystallization, PP shortening rate is very high, usually 1.6~2.0%.