How to add decorative elements such as spot UV coating and hot stamping to a printed rectangular tins?

Decorative elements such as spot UV coating or hot stamping give custom rectangular tin cans a more “premium” look, leading consumers to pay an extra 10% to 15% for these designs. One high-end biscuit brand experienced a 23% increase in repeat purchases within six months after incorporating hot stamping into its rectangular tins. These decorative elements are not just icing on the cake; they transform printed rectangular tin cans into brand equity. Spot UV coating and hot stamping enhance the design, increase shelf visibility, and protect your brand image. This article will demonstrate how Tsing incorporates these decorative elements when printing rectangular tins, from surface treatment to quality control, ensuring that your custom tin cans stand out while meeting durability requirements.

Why are spot UV coating and hot stamping worthwhile?

Unlike full UV coating, which covers the entire tin can, spot UV coating targets specific areas, such as logos, text, or graphics, creating a contrast between a matte printed surface and a glossy finish. Meanwhile, hot stamping adds luxury and visual impact by applying metallic or colored foil. Whether used alone or in combination, they offer three main advantages:

Shelf Appeal: Spot UV coating and hot stamping stand out on busy retail shelves, crucial for brands using standard packaging. One coffee brand’s rectangular metal cans, featuring spot UV markings, were three times more eye-catching than standard packaging in in-store testing.

Durability: Spot UV coatings provide a protective layer against scratches, fingerprints, and moisture, extending the lifespan of printed rectangular tins, making them especially suitable for travel or storage.

Brand Recognition: Hot stamping or spot UV varnishing conveys a sense of quality, associating the product with “premium” or “craftsmanship.” One skincare brand found that customer perception of its products as “luxury” increased by 58% after using silver hot stamping on its rectangular tins.

Preparation for Printing Rectangular Tins

Spot UV coatings and hot stamping only achieve optimal results on properly pre-treated printed rectangular tins. Skipping these steps can lead to peeling, uneven coating, or wasted time. Here is Tsing’s process for preparing rectangular tin cans for decoration:

Ensuring Print Firmness: First, confirm that the base color printing is fully cured. Cured ink will adhere firmly to the can surface, preventing the design from peeling off. For rectangular metal cans, we recommend allowing the printed can to sit for 24 hours before applying spot UV or hot stamping.

Cleaning the Surface: Wipe the printed area with a lint-free cloth dampened with 70% isopropyl alcohol to remove dust, fingerprints, or oil stains. Even tiny debris can cause gaps in spot UV or hot stamping processes.

Eliminating Imperfections: Inspect the printed surface for stains, ink smudges, or dents. Use fine sandpaper to smooth out minor imperfections—uneven surfaces can cause uneven adhesion of the decorative design.

Testing Ink Compatibility: Not all inks are suitable for spot UV or hot stamping processes. For example, some water-based inks may react with the UV coating, causing bubbling. Tsing will test on a small area of ​​the tin can first to ensure compatibility, thus avoiding costly reprints due to ink compatibility issues.

Spot UV Coating Process for Rectangular Tin Cans

Spot UV coating is applied to specific areas of a rectangular tin after printing has been completed. Tsing typically uses a precision screen printing process to ensure a clear and uniform coating. First, a digital “mask” is designed to precisely outline the areas requiring targeted UV treatment, such as logos, borders, or text. The mask should be perfectly aligned with the printed design to avoid misalignment.

Then, technicians set up the screen printing machine and mount the mask onto the screen coated with UV-curable ink. They adjust the press pressure to ensure the ink adheres to the tinplate without smudging the base image. Next, they place the printed rectangular tin can in the screen printing machine and apply UV ink only to the masked areas. For rectangular metal tins, a conveyor system maintains the cans’ stability during the coating process.

After curing the UV ink, the tin can is immediately placed under a UV lamp for 10-15 seconds. This cures the ink, creating a hard, smooth coating that is scratch-resistant and moisture-proof. Finally, uniformity is checked, inspecting the coated area for gaps, bubbles, or uneven gloss. If necessary, recoat and cure the affected area.

Hot Foil Stamping: Techniques and Foil Selection

Hot foil stamping uses heat and pressure to transfer metallic or colored foil onto a rectangular tin with a printed design. It’s ideal for adding luxurious embellishments such as a gold logo or silver border. Here’s Tsing’s process flow:

Choosing the Right Foil: Select an aluminum foil that matches the material of your tin can (for rectangular metal tins, use foil with a strong adhesive backing). Standard options include Metallic foil, which is the choice that best showcases a high-end feel. Colored foil, for striking non-metallic embellishments. Holographic foil, for creating an eye-catching iridescent effect.

Making the Die: Create a metal die (custom-shaped to your design) to transfer the foil. Heat the die to 120–180°C to activate the adhesive.

Setting Up the Hot Foil Machine: Mount the die onto the machine, feed the foil roll between the die and the tin can, and adjust the pressure to ensure complete foil transfer.

Tin Can Imprinting: Place the rectangular tin can with the printed design under the mold, then lower the machine and apply heat and pressure for 1-2 seconds. The metallic foil will adhere to the printed surface, forming a clear metallic pattern.

Tear-Off Inspection: Remove excess foil and inspect for missing or stained areas. If necessary, minor imperfections can be repaired with a small handprint stamp.

Combining Spot UV and Hot Stamping for Better Results

To create truly eye-catching custom rectangular tin boxes, consider combining spot UV coating with hot stamping for a unique finish. This combination creates rich depth and contrast. For this industrial application, we first perform hot stamping and then apply spot UV. The hot stamping foil melts under a UV curing lamp, so applying a UV-cured coating after hot stamping protects the foil. Then, use spot UV to highlight the hot-stamped areas; for example, add a glossy spot UV border around a hot-stamped logo. This highlights both elements without creating a clashing effect.

During process compatibility testing, ensure that the spot UV ink does not react with the foil. Tsing first tests a sample can to check for peeling or discoloration after curing. Then, technicians slightly reduce the stamping temperature before UV coating to prevent the foil from becoming too brittle, ensuring it can withstand the UV curing process.

Spot UV coating and hot stamping enhance your packaging’s brand image.

Adding spot UV coating and hot stamping to printed rectangular tins is not just for aesthetics, but also to enhance brand recognition, increase perceived product value, and create packaging that customers are happy to keep and reuse. Through proper surface treatment, precise processes, and strict quality control, these decorative elements can transform ordinary rectangular metal cans into eye-catching premium packaging.