Coroplast is a brand name that has become the common term for corrugated plastic sheeting used extensively in the signage industry. This material is recognized for its distinctive internal structure, which provides a rigid yet remarkably light substrate for graphic display. Understanding this material requires examining its physical composition, the diverse range of applications it serves, and the practical considerations for maximizing its lifespan. Coroplast dominates the market for temporary and semi-permanent signage needs.
Understanding the Material and Structure
Coroplast is chemically composed of polypropylene (PP), a resilient thermoplastic polymer. The material is manufactured through an extrusion process, pressing the plastic into sheets that resemble corrugated cardboard, earning it the nickname “plastic cardboard.” This unique structure includes two smooth outer walls separated by parallel internal ribs, known as flutes or air channels.
These flutes are fundamental to the material’s performance, providing a high strength-to-weight ratio while reducing the amount of raw material needed. The hollow channels allow for the simple insertion of accessories, such as H-stakes, which are thin metal wire frames used for ground installation. While various thicknesses exist, the 4-millimeter sheet is the industry standard for yard and temporary signs, balancing rigidity with cost efficiency. The direction of the flutes dictates the bending strength and the proper orientation for mounting hardware.
Key Advantages of Using Coroplast
The economic accessibility of Coroplast makes it a preferred choice for high-volume signage projects where material costs are a major factor. Polypropylene is inexpensive to produce, and the corrugated structure minimizes material usage while retaining stiffness. This low unit cost allows businesses and organizations to deploy large quantities of signage without committing significant budget resources.
The material’s plastic composition grants it exceptional resistance to environmental degradation, making it ideal for outdoor use. Unlike paper-based substrates, Coroplast is completely waterproof and will not swell, warp, or decompose when exposed to rain, snow, or humidity. The material is also immune to rust or corrosion, ensuring the sign remains structurally intact even in coastal or high-moisture environments.
Coroplast sheets are remarkably light, simplifying handling, shipping, and installation logistics. A standard 4mm sign is easily carried and mounted by a single person without specialized equipment, reducing labor time and transportation expenses. This lightweight nature does not compromise its toughness, as the material is highly resistant to tearing, cracking, or impact damage under typical outdoor conditions.
Common Applications for Coroplast Signs
Real Estate Signage
The ease of installation and removal makes Coroplast the default choice for the real estate sector, particularly for “For Sale” and open house displays. Agents frequently use these signs to provide quick, directional instructions near properties or to promote services directly on lawns. The material’s ability to withstand repeated use and exposure to various weather cycles ensures that the messaging remains clear throughout the listing period.
Event and Directional Signage
Large gatherings, such as fairs, festivals, and sporting events, rely heavily on Coroplast for temporary instructions and wayfinding. These signs efficiently direct pedestrian and vehicle traffic to parking areas, restrooms, or registration booths. Construction sites also use them for safety warnings and temporary detours due to their high visibility and resistance to site conditions.
Political Campaign Signs
Political organizations utilize this material for high-volume, short-term deployment, making it the standard medium for yard signs during election cycles. The low production cost allows candidates to saturate residential areas with their names and messages quickly. These signs are designed to be highly visible from a distance but are intended for removal once the campaign concludes.
Temporary Retail Promotions
Retail environments leverage Coroplast for both indoor and outdoor point-of-purchase (POP) displays and short-term sales announcements. Inside stores, the material is used for hanging or easel-backed displays due to its flat surface and light weight. Outside, it is employed for sidewalk or window promotions, offering a cost-effective way to advertise seasonal sales or new products.
Design and Printing Methods
Transforming a digital design into a physical Coroplast sign utilizes specialized printing processes tailored to the material’s surface. The two most common methods are differentiated by volume and graphic complexity.
Screen printing is reserved for large production runs requiring simple graphics and a limited color palette. This method involves pushing ink through a fine mesh screen onto the plastic substrate, depositing a thick, durable layer of color. Screen-printed signs benefit from vibrant, consistent color reproduction and exceptional longevity, as the inks bond strongly with the polypropylene.
For jobs involving complex images, gradients, or full-color photographic quality, digital printing is the preferred technique. Digital flatbed printers apply UV-cured inks directly to the Coroplast surface. This allows for small-batch production and highly detailed graphics without the high setup costs of screens. Regardless of the method, pre-press preparation is necessary, including ensuring the design files are high-resolution to prevent pixelation on the final product.
Designers must also consider the orientation of the flutes, particularly if the sign requires specialized shaping or cutting. Cutting across the flutes can reduce the sign’s structural integrity, necessitating careful placement of the design elements relative to the material’s internal channels for maximum stability.
Considerations for Longevity and Placement
While Coroplast is resistant to moisture, its primary long-term vulnerability is degradation from ultraviolet (UV) radiation exposure. Prolonged, direct sunlight can cause the polypropylene material to become brittle and the printed inks to fade, diminishing the sign’s visual impact. To counteract this, manufacturers often incorporate UV-resistant additives into the plastic and utilize specialized UV-cured inks or protective liquid laminates during printing.
Proper installation is equally important for maximizing the sign’s lifespan and effectiveness, particularly when ground-mounted. The most common method involves sliding an H-stake into the vertical flutes of the sign’s bottom edge before pressing the stake into the soil. Ensuring the flutes are oriented vertically is non-negotiable for ground mounting, as horizontal flutes would allow the sign to sag immediately under its own weight.
When the signs are not in use, proper storage methods help maintain their integrity for future deployment. Stacking the signs flat and storing them in a cool, dry environment prevents warping and surface abrasion. Avoiding prolonged exposure to extreme heat, such as inside a vehicle on a summer day, helps preserve the plastic’s structure and prevent premature material breakdown.