Effect of Pressure on the Properties of Polypropylene Products in Injection Moulding

Changing feature of cavity pressure with injecting pressure and holding up pres-sure,and the effect in crystallinity and rnechanical properties of PP injecting products,were stud-ied.The results showed that the injecting pressture and holding up pressure on the effect of properties of PP are related.With multistage holding up pressure system,the smooth transitive pres-sure gradient favoured crystallinity and properties of PP.