PET process conditions and physical and chemical properties

 PET(polyethylene terephthalate)

Drying treatment: Due to the strong hygroscopicity of PET, it must be dried before injection molding. The recommended drying condition is 120~165°C, 4h. Requires humidity less than 0.02%

Melting temperature: 265~280°C for non-glass fiber filled varieties; 275~290°C for glass fiber filled varieties

Mold temperature: 80~120℃ Injection pressure: 30~130MPa

Injection speed: Higher injection speeds can be used without causing embrittlement

Runners and Gates: All conventional types of gates can be used. The gate size should be 50%~100% of the thickness of the plastic part.

The glass transition temperature of PET is around 165°C, and the crystallization temperature ranges from 120 to 220°C

PET has strong hygroscopicity at high temperature. Glass fiber reinforced PET material is also very easy to bend and deform at high temperature. The degree of crystallinity of the material can be increased by adding a crystallization enhancer. Transparent articles processed with PET have gloss and high heat distortion temperature. Special additives such as mica can be added to PET to minimize bending deformation. Using lower mold temperature to form non-filled PET material, transparent products can be obtained.

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