Views: 65 Author: Site Editor Publish Time: 2019-08-30 Origin: Site
PET transparent plastic bottles are transparent packaging bottles and are the most widely used plastic packaging materials. It can be used for packaging of edible oils, condiments, alcohols, liquid detergents, pharmaceuticals, cosmetics and other chemical products. The PET material has good transparency and its light transmittance can reach 90%. In the production process, Ruida summarized the following factors affecting the transparency of PET plastic bottles.
1. The moisture content of the material. The raw materials must be thoroughly dried before production. The drying temperature is generally 160 °C. If it is stored in the air for a long time, it will gradually absorb moisture. Therefore, once the raw material is dried, it must be used immediately or directly using a continuous dryer. Otherwise, it must be placed in an incubator at 90~100 °C for heat preservation, so as to avoid moisture absorption after drying.
2, the wall of the preform in the wall of the preform will directly affect the transparency of the bottle. The reason is that the size of the wall directly affects the cooling process of the preform. If the mold temperature is low, the wall can be properly placed. Save more, and vice versa.
3, the influence of the melt flow speed, the narrower the flow path at the bottom of the parison, the narrower the flow path, the melt flow speed will increase, which will promote the obvious crystallization phenomenon in the part not far from the gate, resulting in An opaque layer. When the gate size is increased or the runner size is increased, the size of the opaque layer will be reduced.
4.The viscosity of the melt directly affects the melt viscosity of the resin at the same melting temperature. In production, it is found that the higher the viscosity of the resin melt, the greater the flow resistance and the thicker the emulsion layer. According to experience, the intrinsic viscosity of the resin is increased by 10 ° C for every 0.1 processing temperature. Therefore, depending on the viscosity of the resin, the viscosity is high, and the resin must increase its melting temperature and increase the temperature of the mold gate portion to improve its fluidity.