Key Technologies for PET Preform Injection Molding The chemical name of PET is polyethylene terephthalate, also known as polyester. At present, GF-PET is the most used by customers, mainly for bottle preforms. PET has better rheology in the molten state, and the pressure has a greater effect on viscosity than temperature. Therefore, We mostly adjust the injection pressure to change the fluidity of the melted PET material. 1. Processing of PET Material before Injection Molding Because PET macromolecules contain fat bases and have certain hydrophilicity, pellets are more sensitive to water at high temperatures. When the moisture content exceeds the limit, the molecular weight of PET decreases during processing, and the product becomes colored and brittle. Because of this, the materials must be dried before processing. The drying temperature is 150°C for more than 4 hours, generally 170°C for 3-4 hours. The air shot method can be used to check whether the material is completely dry. The proportion of recycled materials should generally not exceed 20%, and the recycled materials must be thoroughly dried. 2. How to Selection a Right
Read more →The PET preforms most used of PCO neck finish ( PCO = Plastic Closure Only ) are two types: PCO 1881 neck finish and PCO 1810 bottle neck finish. At the beginning of November 2006, the ISBT (International Society of Beverage Technologists) agreed on a new lightweight standard for 28mm preform neck finish called PCO 1881, which provides a weight saving of 1,3 g (26%) compared to current type bottle neck PCO 28 (3.74 g vs. 5.05 g) and of 2,5 g (40%) compared to BPF neck finish. In particular, it includes good venting capability due to sufficient thread length (650° thread travel, extendable to 680°) and adequate positioning of vertical slots across the threads; and efficient closure tamper-evident (TE) band functioning due to special TE bead profile. The SuperShorty PCO 1881 bottle neck is a 28-mm closure designed for a short-height PET preform neck finish. The biggest difference between PCO 1881 & PCO 1810 is the height of them. PCO 1881 is the with the height 17mm while PCO 1810 has 21mm. The neck finish PCO 1881 is about
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