Solution to stress cracking of PET polyester bottle

The packaging material is polyester, which undoubtedly plays an important role in beverage packaging. Among these packaging products, the packaging bottles of carbonated beverages (such as Coca-Cola and Pepsi) have the highest quality requirements. One of the indicators is the stress-cracking resistance of the bottle, which has great theoretical and application value for in-depth research.
The production of carbonated beverage polyester packaging bottles usually adopts a two-step method. The typical production equipment is a Canadian HUSKEY injection molding machine and a French SIDEL blow molding machine.

The first step is to make the preform: After the PET chips are dried at about 160°C for 5-6 hours, the preform is prepared by screw melt injection, the screw temperature is 285-290°C, the mold is cooled by cooling water, the water temperature is 8-10°C, and the cooling time is about 3.5s . After the preform is placed for 24 hours, the bottle can be blow-molded. Bottle blowing: The preform is heated to about 110°C, and then stretched and inflated to form a bottle. The mold is also cooled by cooling water, and the water temperature at the bottom is 11°C. Carbonated beverage polyester packaging bottles usually have several different capacities such as 500ml, 600ml, 1.25ml, 2L, etc. The shape of the bottom of the bottle is quite complex, usually petal-shaped, and its complex structure becomes the stress concentration point of the product and the location of cracking. They all happen here and become the key point of quality control.