Why Mylar Bags Feel Metallic but Are Not Solid Metal

The first time you hold a Mylar bag, it may be a surprise to you. They feel very strong, a little rigid and some of them even feel cold to the touch. The metallic feel of the Mylar bag is usually what leads people to think that Mylar bags are made completely of metal.

The truth is that a Mylar bag is made of a number of layers of materials, which were developed to protect what's inside of the Mylar bag, not to simulate being made of metal. The outer layer is typically made of a plastic film, which is specifically developed to be strong enough to print on and yet flexible enough to allow for bending without sacrificing strength.

There are generally two layers which cause the reflective inside of the Mylar bag, and thus the majority of confusion. The reflective and shiny surface of the Mylar bag is due to either a layer of aluminum foil or a layer of a metalloplastic film put on it before the manufacture of the Mylar bag was completed. These layers help to prevent light, oxygen and moisture from getting in and maintain their original condition for as long as possible.

The reason for the multi-layered construction of the Mylar bags is the reason they are found in many industries today, whether it is food storage, nutritional supplements or retail packaging. Most of the layers work together to preserve the foods and extend their shelf life, without adding excess weight to the Mylar bags.

Some Mylar bags have an all-aluminum foil layer and other Mylar bags will be made with a vapor deposited metal films. The reason behind which one is used is due to the amount of barrier protection the product inside requires, and how long the producer expects the product to remain undamaged on the shelf.

Since there are so many options available when it comes to materials to use in Mylar bags, not all Mylar bags will be the same. There are clear pouches, partially metalloized bags and full foil bags, all of which have different uses, depending on the product to be placed inside the bag.

Further information on how aluminum is used in the manufacturing of Mylar bags is available in the blog post titled; Are Mylar Bags Made of Aluminum?