There has been a recent surge of interest in applying shrink sleeves to aerosol cans. Shrink sleeve applications with cans are numerous and varied, including tamper evident bands, full-body shrink labeling or multipacking. One constant is the need to ensure safety since containers can be flammable due to the propellant gas used to release pressurized fluid in spray form.
Shrink sleeve labeling on aerosol cans can be applied in a number of ways. Some applications require tamper evident banding to keep an overcap in place through the point of purchase. This prevents in-store opening and test spraying of the cans. Often, a heat shrinkable band is used to secure the spray nozzle to the side of the can, as well as the overcap on the can, see system in the photo above. If a multi-pack is desired, the pack can be formed by applying sleeves over two, three or four cans with large billboard graphics that are oriented to face the consumer on the store shelves.
Since cans are under pressure and some propellants are flammable, extra precaution needs to be taken when shrink sleeving aerosol cans. This includes detecting can jams and activating a torque guard detent clutch in the machine product handling so that no can is punctured. It also includes tracking each can that enters the shrink tunnel. This can be done with Tunnel Jam Sensors that count each can as they enter and exit. If a can falls in the tunnel and there is a discrepancy in count, the operator is alerted and the steam valve turned off. It can also activate an optional Power Auto Lift Tunnel Stand that lifts the tunnel clear of the cans. This reduces the possibility of explosion in case of a fallen can or a conveyor stoppage. Another feature is a Rejection Unit that removes cans that aren’t compliant with required parameters.
On one recent system that PDC built, the product had a clear flexible hose that required securing. The cans arrived in free-floating fixtures, with the hose captured and oriented. After a band was applied, resting on the top of the fixture, a Walking Beam Band Positioner ensured that the sleeve was correctly positioned prior to shrinking.
It is important that the shrink tunnel holds a very precise temperature range to avoid overheating the can. To ensure a consistent temperature, a Tunnel Temperature Alarm can be used to prevent the machine from running if the tunnel is out of temperature range.
Sleeving aerosol cans entails a bit more care and consideration than other types of packaging. However, with the proper special equipment and sensing systems it can be done to insure operator safety and maximum uptime.