What is Hot Foil Stamping?

14/05/2024   Views
Hot foil stamping is a finishing method used to give texts and patterns an eye-catching appearance. The foil can have a glossy or matt finish with a coloured, metallic or holographic appearance. The size of the area that can be covered varies from very small details, such as letters, to large, solid areas.

The Hot Foil Stamping Operation:
The foil is carried on a heat-resistant film. During the operation the paperboard and the foil are kept parallel. A heated matrix, which is fitted to the stamping plate or cylinder, relieves the foil from the carrier and makes it adhere to the paperboard.
Since the carrier film reacts with the foil due to the pressure and heat of the stamping process, the composition of the paperboard surface is essential to provide good runnability and satisfactory bonding of the foil. The paperboard surface must be very smooth and free from impurities and spray powder.
The size of the area which can be hot foil stamped varies from small, such as lettering, to large areas. If the foil covers a relief pattern, hot foil stamping is performed at the same time as embossing to minimise the risk of misregister between the relief and the foil.

The following factors are essential for good hot foil stamping:
• Foil type
• Time of pressure (seconds)
• Pressure (bar)
• Temperature (°C).

Key paperboard features when performing hot foil stamping:
• Smoothness
• Surface structure
• Adhesion
• Surface strength
• Flatness and dimensional stability at the specified moisture content

For the best visual appearance of the foil, it is important to have a clean and very smooth paperboard surface with a minimum of interfering surface irregularities, since these are strongly accentuated when foiled.

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