UV Flatbed Printer Coating Selection
One of the biggest highlights of UV flatbed printing is its ability to print on a variety of substrates. Unlike traditional methods, UV flatbed printing can achieve high-quality prints on materials such as glass, ceramics, metals, acrylics, and wood, which were previously difficult to print on. However, UV ink has poor adhesion on surfaces like glass, ceramics, metals, acrylics, and some smooth woods, which can lead to peeling. Therefore, using a coating for UV ink adhesion is a crucial process in UV flatbed printing.
Flowing Property
Flowing property is a common performance indicator in coatings, referring to the ability of the coating, when applied by brushing or spraying onto a surface, to automatically level out and form a smooth, even surface, eliminating brush marks and spray mist particles. A UV flatbed printer coating with poor flowing properties can affect the decorative effect of the printed products. More importantly, if brush marks on the coating surface do not self-level, the uneven surface may cause friction with the printhead, resulting in significant damage. A high-quality coating should have a well-formulated composition that allows it to level quickly after brushing or spraying.
Weather Resistance
For UV printed products, especially outdoor signage, billboards, and prints, it is essential that the products maintain a glossy appearance and resist fading over time. Specifically, this requires UV flatbed printer coatings to have UV resistance. Some coatings on the market may yellow under long-term exposure to sunlight, making them unsuitable for outdoor use. Even for indoor UV prints, coatings with weather resistance are typically required to ensure long-lasting product quality.
Adhesion
There are various methods to test adhesion, such as the cross-hatch test. For high-quality printed products, tests can be conducted to see whether the printed image comes off after being submerged in water or boiled. Adhesion is a key factor in determining the quality of UV flatbed printer coatings. A high-quality coating should pass the cross-hatch test and remain intact even after water immersion or boiling.
Convenience
Currently, UV flatbed printer coatings on the market come in two-component and multi-component products. Single-component UV flatbed printer coatings, which do not require mixing, have significant advantages over multi-component products in terms of ease of use.
Safety
Solvent-based UV flatbed printer coatings not only have a strong odor but also pose safety hazards if stored improperly, making them inconvenient to transport. Given the high investment in UV flatbed printers, it is best to choose a safer, water-based UV flatbed printer coating. If solvent-based coatings must be used, it is recommended to store them separately from the UV flatbed printer to avoid safety risks.
Film Formation Properties
As high-value decorative products, UV prints typically require high aesthetic standards. This means that the coating on UV flatbed prints should form a colorless, transparent film. Some two-component coatings based on epoxy resins on the market may yellow during film formation, negatively impacting the decorative effect.