By Cassandra Balentine
Certain rigid substrates are well suited for exterior signage applications. For this use case, factors like UV stability, moisture resistance, and recyclability are crucial for success.
Above: Plaskolite offers a series of rigid board solutions, including its VYCOM CELTEC Expanded PVC series.
Plastic Subsets
Acrylic, polycarbonate, polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and high density polyethylene (HDPE) are all plastic-based substrates used for exterior applications.
“Overall, plastic materials offer the best balance between strength, weight, and cost for outdoor use. Moisture-repellant characteristics allow plastic to withstand a wider variety of weather conditions better than paper products. Its lightweight characteristics, especially corrugated plastic, make it more cost efficient and easier to handle than metal or wood-based materials,” offers Karen M. Dicang, marketing director, Inteplast Group.
“Plastic substrates have been used for exterior signage for many, many years,” shares Scott Walton, national sales manager, sign and graphics, Plaskolite.
Walton explains features of popular plastic-based rigid materials. “Acrylic naturally allows UV rays to pass through. Polycarbonate sheet requires a UV cap layer to protect the sheet and what has been applied to second surface. PVC is an opaque printable, lightweight material that will not rot. HDPE has excellent resistance to the elements and graffiti, and some HDPE products contain multicolored layers that can be routed to create very low maintenance exterior signage that lasts the test of time.”
Acrylic, polycarbonate, PVC, and ABS can be cut, routed, and formed, have vinyl applied, digitally printed, or painted. HDPE can be cut, routed, and formed.“These attributes make these materials widely used when looking for rigid exterior weatherable substrates for a variety of signage applications,” adds Walton.
Rigid composite panels are also made with aluminum or vinyl faces over corrugated plastic or solid plastic, which provides strength, flatness, and durability for the outdoors, according to Garrett Thompson, VP sales and marketing, Laminators Incorporated. The company’s Alumalite and Omega-Bond products are most often used outdoors for exterior signage due to the plastic core.
Considerations
Print providers should consider several factors when searching for a rigid material, especially if it is meant for outdoor use.
As with any project, the first consideration is for the design-intent of the signage. “Which materials will suit the design best, are there three-dimensional effects—cut lettering, multiple layers, etc.—that require a thicker substrate, what fabrication and fastening techniques will be used?” asks Chuck Kunze, director, product management and marketing, 3A Composites USA.
Additionally, site-specific issues and mounting techniques can result in the need to consider the material’s rigidity and warp resistance; thermal expansion/contraction; screw and nail holding the change in properties in extreme cold—i.e. brittleness; temperature restrictions for any adhesives used); and overall durability—surface hardness, scratch and dent resistance, continues Kunze.
Rigid boards for exterior signage must offer durability against the elements—temperature, humidity, and direct sunlight—as well as retain the product properties such as rigidity and flatness, adds Kunze.
Alin Wang, oversea sales, Eastsign, notes features like fire resistance, high insulation, portability, non-toxic, UV stable, moisture resistant, and corrosion preventive are essential for exterior applications.
Thompson says “moisture resistance and UV stability are key factors. Other factors to consider include the strength and stability, and if the panel can meet wind load requirements.”
“The board needs to withstand a hot Summer day and a cold rainy night while ensuring that the customer’s content is well-presented on the sign,” adds Dicang.
Walton suggests asking where the sign is going. “Is the sign in a coastal region where it will be exposed to harsh elements, and will wind borne debris be an issue? If so, polycarbonate would be recommended as a see-through product. Impact modified acrylic could be used in these applications but would not have the impact resistance of a polycarbonate product.”
Consider the size of the cabinet or channel letter. “The rule of thumb is a channel letter that is 36 inches or less is good for acrylic. Anything greater than 36 inches should use polycarbonate or impact modified acrylic,” says Walton.
Is the sign clear, translucent, or opaque? “If the sign is going to be back- or edge-lit this would require a clear or translucent acrylic or polycarbonate substrate. If the sign is going to be opaque, this would require an ABS, PVC, or HDPE substrate,” adds Walton.
If the sign is to be printed, Walton says HDPE should not be selected due to the inherent adhesion properties. “However, this makes it an excellent choice where graffiti resistance is needed.”
Yara Linares, marketing manager, POLYVANTIS Sanford LLC, points out that many acrylic products require the use of primers or adhesion promoters to prevent ink from flaking or chipping during fabrication. In contrast, ACRYLITE digital print acrylic is engineered specifically for digital wide format printing. This acrylic ensures ink adhesion without the need for additional treatments, streamlining production processes.
Recyclability
As with any material these days, recyclability is a consideration.
Polycarbonate, acrylic, ABS, PVC, and HDPE are all recyclable products. “Plaskolite offers post-industrial recycled polycarbonate and acrylic, PVC, and HDPE sheet products currently. We also have post-consumer recycled content available in HDPE,” explains Walton.
Dicang says polypropylene (PP) is one of the most widely and commonly used plastics. Its production is vast and continues to expand every year, in large part, due to the demand. PP is fully recyclable, and promotes an element of sustainability throughout its customer base and in marketing materials. “Our materials’ durability and recyclability are complementary characteristics for customers who value quality and a circular economy.”
A product’s ability to be recycled is a consideration that has been growing in importance, whether it’s used for indoor or outdoor applications. “But especially in short-term outdoor applications, it becomes a balance of finding a product that can stand up to the elements of being outside but can also be recycled at end of use in order to avoid sending material to landfills after a short application life,” comments Kunze.
3A Composites’ SMART-X is a 100 percent polystyrene board that excels in exterior signage applications and is 100 percent recyclable in the existing commercial polystyrene foam recycling process, shares Kunze.
“Sometimes the best solution from an environmental impact perspective is to use the product that will have the longest life, such as DIBOND ACM,” adds Kunze.
Longevity
A lot depends on how long a sign needs to be in place.
“Longevity of the sign can depend on exposure to the elements, type of substrate used, is the graphic properly protected from UV, and how long do you need it to last,” shares Walton.
For long-term signage, Walton says UV protected plastic substrates like acrylic, polycarbonate, ABS, PVC, and HDPE can all be used. “Permanent signage—backlit or opaque—has a one to 20 year lifespan.”
“It is important to look for quality panels that offer a ten year warranty to ensure the panel and graphics don’t fade before the life of the sign,” explains Thompson.
For short-term graphics, like advertising graphics for 30 day plus promotions or announcements, Walton suggests PVC as an excellent option, even for outdoor use.
“If not protected, consider using a UV protected plastic sheet like acrylic or polycarbonate,” notes Walton.
Corrugated plastic material made of PP is ideal for short-term purposes with its lightweight and cost-efficient characteristics. “Our material is easy to handle, transport, and clean for occasions like short-term events and promotions. Notably, our material is ideal for political signs during election seasons,” says Dicang.
Application Based
Depending on a sign’s requirements, rigid materials are well suited for certain outdoor signage. As always, it is essential to consider long- versus short-term use, weather and climate considerations, and recyclability requirements when choosing an option.
Nov2024, Digital Output
