Characters of Polypropylene


In fact, there are many members of the large family of […]

In fact, there are many members of the large family of plastic packaging materials. PP is one of them, and it is widely used as a common packaging material in cosmetics and daily necessities. So what is special about PP that can be "reused"?

Material definition:



Polypropylene, referred to as PP, commonly known as 100% plastic, is easier to form. It is a thermoplastic resin obtained by polymerizing propylene. According to the position of the methyl group, it is classified into three types: isotactic polypropylene, atactic polypropylene, and syndiotactic polypropylene.

The density of the PP material is relatively small (0.91 g/cm^3), and in fact he is the least dense of the commonly used plastics. PP material has very good stress crack resistance and high bending fatigue life, which is why he is commonly known as “100 fold glue”. Good heat resistance. In fact, PP material is the best heat-resistant of the five general-purpose plastics (the five general-purpose plastics are: PE, PP, ABS, PVC, PS)

Main features:

PP is a translucent, semi-crystalline thermoplastic with high strength, good insulation, low water absorption, high heat profile temperature, low density and high crystallinity.

Disadvantages are low dimensional accuracy, insufficient rigidity, poor weather resistance, and easy to produce "copper damage". It has a post-shrinkage phenomenon, and it is easy to age, become brittle, and easily deformed after demolding.

Processing technology:

Injection molding, hot press molding, foam molding, and the like can be used.

Drying treatment: low water absorption, no need for drying treatment.

Melting temperature: 220-270 ° C (be careful not to exceed 275 ° C)

Mold temperature: 40-80 ° C (50 ° C recommended)

Injection pressure: 1500~1800bar

Injection speed: high speed injection

Material application:

It can be directly contacted with cosmetics and food, and is the main material for filling organic skin care products.