Recently we’ve had some new and existing customers make a switch from one type of food packaging substrate (the material used to make a product) to another. Reasons for the switch are many and range from economic in nature to new applications such as microwave use, to environmental concerns. Whatever the reason, I strongly recommend thoroughly researching the substrate you would like to switch to before hand, as not all materials act and react the same way to external factors common to food service such as heat. Even if the geometry of the item in question is identical, say a 12 ounce bowl, the outcome during the application can be drastically different.
Using this 12 ounce bowl as an example, let’s assume a food service operator wants to switch from a foam laminated version to a clear PET version. Let’s further assume that hot soup is being served. The operator may have wanted to make this switch to be perceived as being “green” by using a material that is more easily recycled. Clear PET, sometimes referred to as APET, is generally #1 curb side recyclable and may even contain some post consumer recycled content. Two very highly coveted features for a good “green” story. Back to this example, there are a couple possible flaws with this particular switch away from a laminated foam part. First, an APET product would generally be more expensive than a foamed polystyrene item. Even if they have the exact same dimensions, the APET part would most likely weigh significantly more causing the price differential. An average 12 ounce laminated foam bowl might weigh in at 4 grams where a like APET bowl would be upwards of 10 grams. Even if the raw material cost was a bit less for APET at the time, its unlikely the delta would be enough to be on par cost wise with a foamed part.
Assuming our food service operator already knew the item would cost more and was prepared to absorb that extra cost, let’s move on to the next reason this might not be the best choice. APET is not a very good insulator. In other words, whatever the temperature of the soup is will be very close to the temperature of the outside of that bowl. APET, unlike foam will transfer heat fairly quickly. Given that the average temperature of soup at serving is around 145° F, that 12 ounce bowl will be far too hot to touch without burning your hands.
As you can see, a PET soup bowl might not be the best choice. Now for something like cold side salads sure, PET would be an excellent choice. In this instance however, if having an item that is perceived to be more environmentally friendly was the driving force behind a switch, I would have recommended our Harvest Fiber 12 ounce bowl. It has very good insulation properties, can handle hot foods, is compostable and is made from all natural, renewable resources.
Using that same example, let us assume our food service operator was considering polypropylene instead of APET. After all, polypro is a microwave safe material. He’ll still have the problem of a hot-to-the-touch bowl. Polypropylene is not a very good insulator either. Whatever that temperature the soup is will be very close to what the outside of the bowl will be. Another drawback of materials that are poor insulators is that hot food will cool quickly. So if the operator lets the soup cool enough to pick up the bowl without burning fingers, a consumer could be left with a cold bowl of soup in a fairly short period of time.
There are an infinite number of examples like this that span across all substrates and across all markets including food service, processors and retail. Polypro to PET, polystyrene to polypro, PET to a biobased …the list goes on and on. The absolute best way to make sure the switch you’d like to make will work for all aspects of your applications is to first check with your food service packaging professional. Whether that be your manufacturers rep, distributor rep or my personal favorite, the manufacturer themselves (me). A little research ahead of time can avoid an unhappy customer and bad experience in the end.