Flame Treatment Process

Understanding flame treatment for label adhesion

There is a plethora of packaging design options out there for branding your product -- from screen printing to in-mold labeling to the classic adhesive label. Proper labeling showcases your product's attributes, drives brand awareness and makes your product stand out on store shelves. Conversely, labels that fall off or don't adhere properly to the container can leave consumers with a bad impression. Surface treatments can address these adhesion issues. One popular treatment to ensure your container is primed for labeling is Flame Treatment.

What is flame treatment?

Flame treatment is an important step in a plastic container's manufacturing process if its intended for an application with a label. Polyolefin plastics, such as high-density polyethylene (HDPE) , low-density polyethylene (LDPE) and polypropylene (PP), are commonly used in plastic packaging applications; however, these plastics have low surface energy when produced, making it difficult for inks, paints, glues and other labeling mediums to adhere to their surfaces. If the surface isn't treated properly, your label will not stick.

Flame Treatment

Flame treatment is a surface treatment process used to chemically modify a plastic container's surface for better label adhesion. This process uses specially designed equipment to create a controlled blend of natural gas and air that produces a flame. This oxidizing flame is then exposed to the container surface for 0.2 to 0.3 seconds. As the container is exposed to this flame:

  • Dirt, dust, fibers, oils and other contaminants that can also affect adhesion are removed.
  • The plastic's surface is activated by breaking the molecular chains and adding polar functional groups.

On a microscopic level, this process creates a "rougher" finish that provides a clean, high energy surface ideal for accepting inks, paints, coatings or bonds. Flame treatment will help your label stick to the container surface.

What are the benefits of the flame treatment process?

Aside from better surface adhesion, flame treatment offers several additional advantages including:

  • This surface treatment offers uniform treatment of the container's surface allowing inks, coatings and adhesive labels to bond with the container surface without any gaps.
  • Flame treatment does not scorch, char, distort or otherwise damage the plastic container.
  • Flame treatment requires less costly equipment than other methods, such as corona, plasma activation and chemical surface treatment.
  • Oxidizing flame involved in this process can be created with readily available butane, propane, methane (natural gas) or coal gas so no special chemicals are needed.
  • The flame treatment process helps form a long-lasting, durable bond between the label and the container surface once the label has been applied.

How long does flame treatment last?

The length of time the flame treatment will last can vary depending on the type of plastic. Ideally, labeling should take place shortly after treatment.

Looking for flame-treated plastic containers?

Many of our bottles, jars and jugs are shipped already flame treated! In addition, we offer label design and application. Contact us for more information about flame-treated containers or discover our complete plastic container selection below: