Graphic Overlay Material Selection: Polyester vs. Polycarbonate

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By Rachel Wienckoski | Dec 02, 2020
Polyester and polycarbonate are both popular overlay materials

Have you ever walked up to an ATM or gas pump and noticed the cracking, fading numbers on the keypad? It is a prime example of why the material selection is vital for graphic overlays. At GMN, the two most common materials used for graphic overlays are polyester and polycarbonate. Depending on the application, there are advantages and disadvantages to both materials.

When evaluating overlay materials, one of the most important factors to consider is durability. Polyester and polycarbonate are both extremely durable materials, but polyester is generally known as the more durable option. Polyester has a longer actuation life (over 1 million actuations vs. 200,000 actuations), meaning that it can endure more switch actuations before the overlay starts to crack or deform. As a result, polyester is a better choice for membrane switches and overlay designs that include embossed buttons. Polycarbonate has a broader thickness range and increasing the thickness of an overlay can help make it more durable. However, polycarbonate is best suited for applications with minimal flex requirements because continual flexing can cause stress fractures over time.

Polyester is also resistant to abrasion and significantly more resistant to acids and chemicals, making it an ideal substrate for the medical, industrial, and appliance industries. While polyester is flammable, polycarbonate is flame retardant, making polycarbonate perfect for industries in which safety is of high importance, such as the aerospace industry. Alternatively, a hard coating can be added to significantly improve the durability of both materials.

While polyester has an edge in terms of durability, polycarbonate has some cosmetic advantages over polyester. Polycarbonate offers a broader range of textures and finishes, which can be attractive when the design is the most crucial factor. It also has very high clarity and color brilliance. If an overlay is being used purely for appearances and won’t be exposed to frequent use, polycarbonate may be the most appropriate substrate choice.

In terms of production, polycarbonate tends to process easier than polyester. It’s easy to print effectively on polycarbonate of all thicknesses. Polycarbonate is also easier to die-cut and emboss, which can help to reduce manufacturing costs. While polyester is slightly more expensive than polycarbonate, the cost difference between the two materials is minimal.

Ultimately, the choice between the two materials will depend on the overlay’s design requirements and environmental conditions. To see how polyester and polycarbonate compare, visit our graphic overlays page or watch the video below.