Mold Chilling Unit for PET:PET preform neck crystallization system

PET preform makes progress to get the heat resistant by crystallization of neck finish

Heat resistant more than 70 deg C is ensured by neck finish crystallization of PET preform


PET Preform Neck Crystallizer

Necessity of Crystallization of PET Preform Neck Finish

Generally, The PET resin begins softening in the temperature of 70 degC or higher temperature. This softening temperature is so called TG (grass transition temperature) of PET. Supposing that when PET bottle leaving in more than 70 degC atmosphere, the bottle neck will start softening and almost the dimensions will shrink also the deformation of the neck finish will be occur at the same time.

Specially the demand in the beverage market such as fruit juice, oolong tea, coffee drinks and lactic acid drinks are expanding in recent years. However, almost the beverage are filled into the PET bottle at the high temperature of more than 85 degC, just after that, the PET bottle capped on the filling line conveyor then, handstand the bottle to sterilize the inside of neck finish with the high temperature content liquid for some time.

Therefore, the neck finish of PET bottle must be withstanding the condition of the high temperature atmosphere. Normally the state of PET preform neck finish is amorphous because of it molded by injection molding and that's why it does not have heat resistant at more than 70 degC. In other words, this neck finish will have shrinkage of the dimensions and the shape deformation in the hot filling, and it bring about the fatal defect for PET bottle such as micro leakage.

But, PET has the characteristic to become heat resistance when it crystallized. The density of amorphous PET is 1.365 g/cm3, but forget the heat resistant, it becomes the higher density when making progress the crystallization from 1.365 to 1.380 (crystallinity index 25 % to 39 %).

Our equipment system, which was developed in this time, the crystallization of the neck finish of PET preform makes progress to get the heat resistant.

System Features

  • 1. At the lading and take out station of the preforms can be operate continuously. Besides we designed the new mechanism which the devices does not any inflict damage of the preforms such as scratch on the surface.
  • 2. The heater unit (lamp unit) was designed by our own unique technology,save consumption electricity (more than 30% saved in comparison with other crystallizer) and it has an excellent efficiency reflector.
  • 3. The system can be cope with flexible layout for the existence preform production line.
  • 4. For obtain to more accurate boundary between crystallized and non crystallized section,the water cooling chamber (heat insulation) was designed by our own ideas.
  • 5. Rotation core is composed of supporting part of preform and heat insulation part. And to improve the crystallization quality such as dimensions, contour of neck,crystallinity and position of crystallization boundary, all our technology is focused on this device.
  • 6. Heater unit and cooling chambers are easy to put on and take off due to they are modular designed.
  • 7. SCR controlled heater intensity and the life of heater is improved.
  • 8. The whole operation and set up the conditions for the crystallizer is able to control under a touch panel with alarm, therefore setting of optimized crystallizing condition and process operation is very simple and quick.
  • 9. The system is designed for minimized floor space utilization.