Key factors affecting the transparency of medicinal polyester bottles

The medicinal polyester bottleis a transparent bottle, that is, a polyethylene terephthalate (PET) bottle, which is currently the most widely used plastic packaging material. 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 a light transmittance of 90%. The following factors affect the transparency of polyester bottles in the production process.

100ml amber and transparent PET bottles

First, the moisture content of the material, the raw materials must be fully dried before production. The drying temperature is generally 160 ° C for dry materials. If it is 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 directly using a continuous dryer. Otherwise, it must be placed in an incubator at 90~100 °C for heat preservation to avoid re-absorption after drying.

60ml amber PET medicinal polyester bottles

Second, the wall of the parison, the wall of the parison will directly affect the transparency of the bottle. The reason is that the size of the wall deposit directly affects the cooling process of the preform. When the mold temperature is low, the wall can be appropriately enlarged, and the wall thickness is reduced.

Third, the influence of the melt flow rate, the narrower the flow path at the bottom of the parison, the narrower the flow path, the flow speed of the melt through the spline will increase, which will promote the obvious position away from the scratch The crystallization phenomenon produces an opaque layer. When the gate size is increased or the runner size is increased, the size of the opaque layer will be reduced.

PET bottles manufacturer

Fourth, the viscosity of the melt will directly affect the melt viscosity of the resin at the same melting temperature. It is found that the higher the viscosity of the resin melt, the greater the flow resistance and the thicker the turbid layer. According to experience, the intrinsic viscosity of the resin is increased by 0.1. 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 gate portion of the mold to improve its fluidity.