There is a unique type of plastic formulated for just about any purpose you can think of, and laboratories develop new ones every day. Calling them all “plastics” may be a convenient short-hand, but the word plastic doesn’t communicate much about UV-resistance, impact strength, clarity, weight, dyne levels, compatibility with other materials, fabrication methods, decoration options—and any number of other properties materials need to be suitable for a sign project. Plastics used in sign making include vinyls, urethanes, polyesters, polystyrenes, polyethylenes, acrylics and polycarbonates—to name just a very few. Here we will take a look at two similar but not interchangeable plastics that are often used in sign making: acrylics and polycarbonates.
- Both acrylics and polycarbonates are thermoplastic polymers, which means they can be re-heated and re-shaped, as opposed to thermosetting polymers, which cure to a hard material and remain so even as new heat is applied. Being thermoplastic, both are suitable materials for thermoforming processes. Acrylics generally soften at lower temperatures than polycarbonates.
- Both polycarbonates and acrylics transmit light efficiently and are used to make specialty lenses, including polycarbonate eyeglass lenses and acrylic contact lenses. These optical properties also make them both excellent materials for backlit sign faces and lenses for LED lamps.
- Physically, the density of PMMA is just under 1,200 kg/m3; the density of PC is just over 1,200 kg/m3. Essentially, this means either material is about half as heavy as an equally sized piece of glass. Acrylics and polycarbonates will scratch easier than glass but, to an acceptable level, can be buffed out.
- Compared to glass, acrylic is much more impact resistant, but not nearly as much so as polycarbonate. Polycarbonates are stronger than acrylics but also more expensive.
- Polycarbonates and acrylics can be fabricated economically and efficiently for various signage applications, using mills, saws, drills, thermal forming equipment, CNC routers, engravers and laser engravers.
- Polycarbonates and acrylics are available in a range of sizes and thicknesses, making them suitable not only for sign faces but also individual cut letters and other graphic and architectural elements.
- Extruded acrylics and polycarbonates in the 3/16” thickness range are most suitable for vacuum-formed sign faces and are sometimes pre-decorated.
These characteristics are in no way intended to be a comprehensive summation of the properties of either material. But understanding each a little better can help you decide which material might be best suited for your next sign application.
For more information on this topic from Eddie Wieber, click HERE.