What is second surface printing and how to use it in your project?

Labels and product identification components come in many different shapes and sizes. Fortunately, the market is full of options that meet even the strictest demands of applications realized for industries such as military, defense, or healthcare. 

Some of the most popular options among our clients are graphic overlays and second surface printed labels. In this article, we take a closer look at the latter to show you what second surface labels are, what they’re made of, and where they find the best applications.

What is a second surface printed label? 

Second surface printing is reversed printing on the back of a clear substrate. With the right choice of materials, this type of printing offers excellent protection for graphics from abrasion, but also oils, greases, chemicals, and solvents.

The second level of protection can be achieved by using a hard-coated material that prevents scratching of the top surface. 

At Melrose Nameplates, we have many years of experience in providing second surface printed labels to customers who required labels of outstanding durability and quality. We use the most innovative and durable materials to create components that perfectly match even the strictest requirements.

Materials used in second surface printing

When creating a second surface label for your application, you can choose from several materials.

Polyester is a more appreciated overlay material for applications where the overlay will flex during used – for example, in membrane switches. In such usage, polycarbonate might fatigue and crack. 

However, when fatigue is not an issue and, it’s possible to create polycarbonate with a wide range of features and properties, making it an ideal material for many different applications. Let’s take a closer look at these materials to understand their characteristic traits, advantages, and drawbacks.

Polycarbonate 

When considering polycarbonate material for your label, take into account factors such as scratch resistance, outdoor use or indoor use, texture, fire rating, and thickness. 

Texture

When it comes to texture, textured polycarbonate is often part of an overlay expected to be used indoors or as part of the equipment. Viewable transparent windows aren’t required for any type of displays like LCD. The available textures range from fine matte to coarse velvets, depending on the desired visual effects of the graphic overlay. The Lexan brand made by General Electric sets the industry standard for polycarbonate film textures today. 

Scratch resistance

Polycarbonate is a relatively soft material. If it’s not treated with a hard coating material, it might easily scratch. However, scratches aren’t instantly viewable when they occur on textured polycarbonate films. However, if the application requires a completely clean window, hard-coated polycarbonate material is a good choice. Such hard coatings are available with a wide range of gloss levels, depending on your application\s demand for glare attenuation. 

Outdoor or indoor use

Polycarbonate formulated for UV resistance is a must-have for your application if the overlay is going to be used indoors. Exposure to UV light might result in a yellowing of the polycarbonate if it’s not outdoor rated, so make sure that you pick the right type of polycarbonate for your project. 

Fire ratings

Polycarbonate labels have wide coverage of fire ratings.

Final note: In keypad applications, polycarbonate will crack and fatigue after approximately 1000 key cycles.

Polyester

Polyester is an excellent overlay material for membrane switches because of its resistance to cracking fatigue with use. The leading supplier of polyester for such applications is Autotype. Polyester comes in scratch-resistant, textured, and outdoors-ready options. 

Excellent fatigue resistance

The primary benefit of polyester is its superior fatigue resistance. It promises excellent quality for up to 1 million cycles. 

Chemical resistance

Another important feature is resistance to chemicals and solvents. Polyester is a bit more resistant to chemicals than polycarbonate. 

Textures

When it comes to textures, polyester offers a narrower range of options than polycarbonate. 

Fire ratings

The fire ratings for polyester materials are either very limited or nonexistent. This is due to the thin gauge of polyester material. However, in many applications, fire ratings aren’t necessary and polyester is still a good choice.

Scratch resistance

If your application might generate scratches, you can be confident when choosing polyester labels. Thanks to hard coating, they work very well in clear window applications. 

Final note: All in all, polyester comes with several limitations in comparison to polycarbonate, especially in the range of thickness, fire ratings, and textures. 

Conclusion

We hope that our guide to second surface printed labels helps you to choose the best option for your application. 

If you have any questions, please reach out to our consultants, who are ready to assist you in any inquiry and help you choose the best materials for your project.