InnoPET Blomax HR Series III: Hotfill

Hotfill is a suitable alternative to cold aseptic filling if temperature and sensitivity of the product during PET bottle filling as well as barrier requirements must be observed. The requirements for PET bottle filling with heat treated products are mainly dependent on the product, market requirements and shelf life.

The design elements and the process parameters must be selected carefully to optimize the cost-effectiveness of a machine.




Highest demands for hotfill processes.
Juices and teas are filled into prefabricated PET bottles at a temperature of approx. 92 °C. A high crystallinity is required to prevent moisture affecting the bottle quality during temporary storage. A bottle for hotfill no longer has a uniform, classical appearance. Even unusual bottle designs are possible and can hardly be distinguished from conventional PET bottles.

Viscous products require a wider bottle neck and a design that enables better absorption of the vacuum produced during cooling down from the bottling temperature (96°C). These properties can be included by means of special solutions in machine construction.

In order to pasteurize a bottle at 75° C for 30 minutes, the bottle must be totally stress relieved and geometrically designed to withstand the process.




InnoPET Blomax HR Series III mode of operation
The preform is heated to maximum temperature and blown in a hot blow mold. The material is aligned in the blow mold during the blow molding process. Due to the high blow mold temperatures, the material is stress relieved, alignment stress is neutralized and thermal crystallization is increased. PET material deformation at higher temperatures is reduced by the increase in thermal crystallization. The so-called glass temperature of the material rises and enables hot fill or pasteurization without significant bottle deformation.

The bottle is filled with cooling air prior to extraction to stabilize the bottle in the blow mold. This cools it sufficiently and prevents deformation during extraction.