Understanding the characteristics of PP material，PP production products are not shiny?

Sep 28, 2021

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PP is a semi-crystalline material, which is harder than PE and has a higher melting point. Since homopolymer PP is very brittle when the temperature is higher than 0°C, many commercial PP materials are random copolymers with 1 to 4% ethylene or clamp copolymers with higher ethylene content. Copolymer PP material has a lower thermal distortion temperature of 100°C, low transparency, low gloss, and low rigidity, but it has stronger impact strength. The strength of PP increases with the increase of ethylene content. The Vicat softening temperature of PP is 150°C. Due to the high crystallinity, the surface rigidity and scratch resistance of this material are very good.

PP plastic extrusion products are not shiny?

1. Due to the large particle size difference of raw materials, it is difficult to plasticize evenly and the luster is poor. Therefore, the raw materials need to be screened.

2. Too much recycled material or nozzle material is added in the raw material, which affects the uniform plasticization of the melt and has poor luster. Therefore, the amount of recycled material or nozzle material should be reduced.

3. Some raw materials will decompose and change color during temperature regulation, resulting in poor gloss. Therefore, raw materials with good temperature resistance should be selected.

4. The content of water or volatile matter in raw materials is too high, which volatilizes into gas when heated and condenses in the mold cavity and melt, resulting in poor gloss of plastic parts. For this, the raw materials shall be pre dried.

5. Some additives have poor dispersibility and poor luster of plastic parts. Therefore, additives with good flow performance should be used.

6. The raw materials are mixed with foreign matters, impurities or immiscible materials, which cannot be evenly mixed with their raw materials, resulting in poor gloss. For this, these impurities shall be strictly excluded in advance.