HOT-STAMP DECORATION
Basic Technique
- A die is heated.
- Foil is placed between the die and the substrate to be printed.
- Die presses against the foil, the heat and pressure releases the coloring layer from the polyester carrier and binds it to the end product.
The coating is transferred from the polyester carrier to the hot stamped substrate by a heated die. The dies transfer the foil by pressure and temperature to the substrate. Pressure and dwell time is adjustable. Stamping foils consist of coated layers on a carrier film. They are transferred by means of heat and pressure via a die onto the substrate. The die is usually made of metal or silicone rubber and contains the design that is to be impacted to the material being blocked. There are many variations in materials and decoration effects. All hot stamp operations employ basic procedures and require pressure and dwell time. The carrier film transfers the decorative coating to the surface. The brightness of hot stamping foils come from a layer of vacuum metalized aluminum. Pigment foils are precisely formulated blends of pigment particles, waxes, resin, solvents, water, coated onto polyester carrier film. Almost any material with exception of glass or metal can be marked with hot stamping foil. These layers are transferred during the hot stamping process:
Carrier 12my Standard 12 micron polyester. Carries the coatings and is used to protect the foil layers.
Can vary in thickness from 12 micron up to 50 micron.
Release 0,01 Releases the coloring layer from the polyester film with heat and pressure.
Most released are based on waxes, though resin release are also used for special applications. The inclusion of wax coat allows the user to apply the print at high speeds ensuring the lacquer separates from the carrier.
Lacquer 1my Resins & Dyes.
The lacquer coat gives the colour to the foil. Many different lacquers are used due to properties such as resistance etc. Most often this layer is transparent or translucent.
Metallization 0,01my
Purest aluminum, metallization by high vacuum. Generally composed to provide design and opacity desired in metallic foils. Gives the metallic effect.
Adhesive Coat 0,5-1my
Heat sensitive adhesive. Serves to bond the foil layers to the substrate. The printability characteristics of the foil are primarily determined in more or less adhesive implied in this coat.
Here are variables that can affect adhesion of hot stamping
Temperature, pressure, dwell time, adhesive, dyne level.
Overprinting
Foils are generally receptive to inks and coatings.
Shelf life / Storage
Most foils can be stored safely under normal conditions. Our foils are not recommended to be stored more than 12 months from the manufacturing date. Store away from direct sunlight and away from extreme heat, cold, moisture and pressure. To be placed in ventilated, shaded and cool places. Not to be placed near radiators. Horizontal storage if possible. Not to be stored more than 3 layers high. Storage temperature recommended 5C-25C . Humidity recommended 20%-70%. Avoid pollution such as smoke or dust. Not to be stored in plastic bags as it can cause condensation.
Cores
Master and slit rolls on 25mm paper or plastic cores, 76mm paper cores, 17mm cores is also available. Jumbo rolls on 76mm alt. 153mm cores.
Widths
Our standard master/jumbo rolls are available in 610-695mm widths depending on grade. Custom slit rolls in various sizes.
Roll Lengths
Our master rolls length 122m, 305m, 610m. Jumbo rolls 3050m or 6100m. Custom slit rolls in various lengths.
Equipment and processing
Vertical stamping machine. Up and down strokes. Flat details.
Cylinder machine. Round/flat detail. Flat dies.
Roll-on stamping machine. Round detail. Applies foil with a rolling action.
Rotary stamping machine. A press where the die is round.
Clamshell machine. Heidelberg, Kluge.
The two basic hot stamp processes include rotary and up and down, vertical flat printing. The rotary best suited for large surface areas. There are three basic principles involved in the use of foils. Temperature, pressure, dwell time.
Dies
Metal or silicone rubber dies.
Temperature
Optimum stamping temperature will vary depending on substrate, design and machine conditions.
We recommend a stamping temperature of about:
Graphics: 90-130C at the die face for optimal results.
Plastics: 120-160C at the die face for optimal results. Metal die.
If a silicone rubber die is used the temperature has to be higher, approximately 180-280C. When you set the line speed, dwell time, design and change of material it is important to adjusting the temperature. Please note that there might be a fluctuation from the set of the temperature controller and the temperature on the die. Plus or minus 5-10C degrees.
Dwell time
0,4-0,5 seconds. The length of time the heated die is allowed to remain in contact with the substrate being stamped. A fast dwell time is desirable.
Pressure
The depth of the stamp below the surface of the part. The pressure vary depending on the substrate, design and die to be used.
Recyclability & biodegradability
There is no problem to recycling hot stamping or polyester film.