Principle Of Hot Filling Of Pet Preforms » Discussions

Principle Of Hot Filling Of Pet Preforms

• preform nicole

  

  Leader
   

  April 27, 2019

  The production principle of PET hot-filled bottles is: PET beverage bottles (usually injection molded into [u]Pet Preforms[/u]) → After heating, pet preforms are longitudinally stretched → transversely stretched → blown bottled. The final molding in this production process uses mechanical cold setting, so when the PET bottle is used in the temperature of the PET glass transition temperature of 78 ° C), the molecular chain will be slack and the bottle will be seriously contracted. The bottle is only suitable for cold-filled beverages.
  In the process of stretching and shaping of the above process, the hot-filled bottle is always at a relatively high temperature (about 140 °C), and the PET molecular chain is shaped by high temperature in a relaxed state. Finally, the bottle body produces a large number of neat and dense crystals, crystallizing. The degree can reach 30% to 45%, which makes the bottle have higher heat resistance and becomes a practical hot-fill bottle.
  
  One blowing method. That is, the bottle is only subjected to a blow molding process from the pet preform to the molding process by heating the mold to 100 to 180 °C. When the pet preform is stretched and blown into the shape of the [u]Pet Preform Mould[/u], the heat setting crystallization process will last for a few seconds to more than 10 seconds. This method is characterized by simple equipment, low cost, and replacement of spare parts. After that, ordinary PET bottles can be produced; the floor space is small; since the bottles are directly heated on the mold, the heat energy consumption is small. The disadvantage is that the heating treatment temperature is lower than that of the secondary blowing method, the degree of crystallization is slightly lower, the heat resistance is also slightly worse, and the heat resistance temperature is 85 ° C to 90 ° C; the bottle is subjected to heating treatment and cooling, etc., and the production is increased. The time of the cycle.
  Secondary blowing method.
  The secondary blowing method is to blow the pet preform to a larger volume (about twice the capacity of the bottle), then heat it to about 200 ° C, then let it shrink, and then blow it into the final bottle shape, twice. The characteristics of blowing are: the advantage is that the temperature of the heating treatment is higher, the ratio of crystallization is correspondingly increased, and the heat resistance can reach 90 ° C to 95 ° C; since the heating treatment process can be carried out independently, it can achieve higher Productivity. The disadvantage is that the machine is bulky and complicated, and the price is high; the floor space is large; the energy consumption is high.

  The production principle of PET hot-filled bottles is: PET beverage bottles (usually injection molded into [url=https://www.pet-preform.com/][u]Pet Preforms[/u][/url]) → After heating, pet preforms are longitudinally stretched → transversely stretched → blown bottled. The final molding in this production process uses mechanical cold setting, so when the PET bottle is used in the temperature of the PET glass transition temperature of 78 ° C), the molecular chain will be slack and the bottle will be seriously contracted. The bottle is only suitable for cold-filled beverages. In the process of stretching and shaping of the above process, the hot-filled bottle is always at a relatively high temperature (about 140 °C), and the PET molecular chain is shaped by high temperature in a relaxed state. Finally, the bottle body produces a large number of neat and dense crystals, crystallizing. The degree can reach 30% to 45%, which makes the bottle have higher heat resistance and becomes a practical hot-fill bottle. One blowing method. That is, the bottle is only subjected to a blow molding process from the pet preform to the molding process by heating the mold to 100 to 180 °C. When the pet preform is stretched and blown into the shape of the [url=https://www.pet-preform.com/][u]Pet Preform Mould[/u][/url], the heat setting crystallization process will last for a few seconds to more than 10 seconds. This method is characterized by simple equipment, low cost, and replacement of spare parts. After that, ordinary PET bottles can be produced; the floor space is small; since the bottles are directly heated on the mold, the heat energy consumption is small. The disadvantage is that the heating treatment temperature is lower than that of the secondary blowing method, the degree of crystallization is slightly lower, the heat resistance is also slightly worse, and the heat resistance temperature is 85 ° C to 90 ° C; the bottle is subjected to heating treatment and cooling, etc., and the production is increased. The time of the cycle. Secondary blowing method. The secondary blowing method is to blow the pet preform to a larger volume (about twice the capacity of the bottle), then heat it to about 200 ° C, then let it shrink, and then blow it into the final bottle shape, twice. The characteristics of blowing are: the advantage is that the temperature of the heating treatment is higher, the ratio of crystallization is correspondingly increased, and the heat resistance can reach 90 ° C to 95 ° C; since the heating treatment process can be carried out independently, it can achieve higher Productivity. The disadvantage is that the machine is bulky and complicated, and the price is high; the floor space is large; the energy consumption is high.