Several key factors affecting the transparency of PET bottles

PET bottles are packaging bottles with good transparency and are currently the most widely used plastic packaging materials. It can be applied to the packaging of edible oil, condiments, alcohol, liquid detergent, medicine, cosmetics and other chemical products. PET material has good transparency, and its light transmittance can reach 90%. The following points affect the transparency of polyester bottles during the production process of polyester bottle manufacturers:

1. The moisture content of the material: The material must be fully dried before production. The general drying temperature is 160°C, for dried materials. If stored in the air for a long time, it will not absorb moisture. Therefore, once the raw material is dried, it must be used immediately or a continuous dryer must be used directly, otherwise it must be kept in an incubator at 90~100℃ for standby use, so as not to absorb moisture again after drying.

2. The wall storage of the preform:  The wall storage of the preform will directly affect the transparency of the bottle. The reason is that the size of the wall storage directly affects the cooling process of the preform. When the mold temperature is low, the wall can be properly adjusted. If the deposit is larger, on the contrary, the wall thickness will be reduced.

3. The influence of melt flow rate: When the burner at the bottom of the parison becomes narrower and narrower, the melt flow rate will increase, which will promote the obvious crystallization phenomenon not far from the gate. An opacifying layer. When the gate size is increased or the runner size is increased, the size of the opacified layer will be reduced.

4. The viscosity of the melt will directly affect the melt viscosity of the resin at the same melting temperature. It was found in production that the higher the viscosity of the resin melt, the greater the flow resistance and the thicker the opacified layer. According to empirical estimation, the intrinsic viscosity of the resin increases by 10°C every time the processing temperature increases by 0.1. Therefore, according to different resin viscosity, the viscosity is higher, the resin must increase its melting temperature and increase the temperature of the gate part of the mold to improve its fluidity.