How to avoid case and carton pop-opens with the right frozen food packaging equipment
Frozen food packaging manufacturers want the same results as other case and carton sealing applications: a quality seal that stays in place. However, realizing a successful end-of-line packaging process in frozen food manufacturing presents unique application challenges.
The packaging challenges in the frozen food industry are different from those in other food industries. The packages must protect the frozen contents from vapor, odor, moisture, pests, air, and/or light in a harsh environment.
Three steps to reliable frozen food packaging
The processes associated with frozen food packaging create a production environment that is constantly changing. In order to support an optimized manufacturing process in frozen food applications, it is important to understand the following aspects:
- The challenges of adhesives in different environments
- The importance of a consistent adhesive temperature
- How aggresive adhesives increase char
Challenges of adhesives and environments
Certain frozen food packaging applications create specific challenges related to the particular circumstance. Products manufactured with a blast freezer demand very precise control of adhesive temperature to maintain the adhesive properties and deliver a quality seal.
For example, frozen waffles are typically bagged and placed into the carton in a cold room, then hot melt adhesive at 177 °C (350 °F) is applied to the carton flaps before it goes into the blast freezer. This transition represents a drastic temperature change – from a 5 °C (41 °F) environment to a -40 °C (-40 °F) environment in a very short period of time.
Consistent adhesive temperature
To deliver a quality case and carton seal, it is critical to control the adhesive temperature. Inconsistencies with adhesive temperature lead to ineffective hot melt applications. Adhesives with temperature fluctuations may hold initially and remain intact leaving the plant, but may fail after product cartons sit for 24 or 48 hours at -18 °C (0 °F).
There are two common causes of inconsistent adhesive temperature:
- Maintaining a consistent adhesive temperature with tank-based hot melt systems typically requires line operators to constantly adjust temperature settings.
- Adhesive temperature swings are also common if operators let tank-based melters run low and then fill them with unmelted adhesive. Without the proper time to recover (upwards of 45 minutes), adhesive temperature may drop to 177 °C (350 °F) or lower – making the bond susceptible to failure.
More aggressive adhesives increase char
To overcome frozen food packaging issues, adhesive manufacturers have developed materials that are formulated to withstand temperature as cold as -40 °C (-40 °F). This is appealing to frozen food manufacturers as more aggressive adhesives provide an added insurance policy to prevent pop-opens.
Unfortunately, increased char is a reality with some of these formulations. In general, the more aggressive the adhesive, the more quickly it degrades under temperature. Manufacturers may also choose to make the glue hotter and tackier while also applying more adhesive than typically necessary. However, this is not a viable solution as it increases adhesive consumption, increases the likelihood of charring and nozzle plugs, and ultimately compromises the quality and consistency of the resulting seal.
New technology delivers consistency and reliability
Frozen food manufacturers can achieve consistent case and carton sealing by using true Tank-FreeTM hot melt systems that include revolutionary melting chambers instead of inefficient heated tanks.
The new technology in these systems:
- Provides real melt-on-demand capability
- Maintains consistent adhesive temperature
- Maximizes adhesive stability and performance
Even if a more aggressive adhesive material is required, operators don’t have to worry about adjusting system settings to maintain temperature or avoid glue degradation. This technology melts adhesive on a “first in, first out” basis – so it melts only the glue that is needed, when it is needed. These benefits help frozen food manufacturers optimize adhesive performance.