Polypropylene (PP) is a semi-crystalline thermoplastic. It has a high impact resistance, strong mechanical properties and is resistant to many organic solvents and acids and bases. It has a wide range of applications in industry and is one of the most common polymer materials.
Mainly used in the production of various long and short polypropylene fibres, for the production of polypropylene woven bags, bagging, injection moulded products, etc. Used in the production of electrical appliances, telecommunications, lighting, lighting equipment and fire retardant parts for televisions
Usually, PP is modified by adding glass fibres, metal additives or thermoplastic rubber. the flow rate MFR of PP ranges from 1 to 40. low MFR PP materials have better impact resistance but lower ductility. For the same MFR, the copolymer type has higher strength than the homopolymer type. Due to crystallisation, the shrinkage of PP is quite high, typically 1.8 to 2.5%. And the directional uniformity of shrinkage is much better than for materials such as PE-HD. The addition of a 30% glass additive can reduce shrinkage to 0.7%. Both homopolymer and copolymer types of PP material have excellent resistance to moisture absorption, acid and alkali corrosion, and solubility. However, it is not resistant to aromatic hydrocarbon (e.g. benzene) solvents, chlorinated hydrocarbon (carbon tetrachloride) solvents, etc.