Hot stamping process of Shenzhen Buke Printing Company

Hot stamping process of Shenzhen Buke Printing Company

The method of hot stamping metal foil or pigment foil onto printed materials or other substrates with the help of certain pressure and temperature is called foil stamping processing, commonly known as hot stamping.

1. Principle and characteristics of hot stamping

(1) The principle of hot stamping. Hot stamping is the process of using the principle of hot pressing to melt the hot-melt silicone resin in the isolation layer, reducing its adhesive strength. The aluminum layer and base film are peeled off, and the thermosensitive adhesive is adhered to the hot stamping material. Due to the rapid cooling and solidification of the adhesive, the aluminum layer with pigment is firmly hot stamped on the surface of the substrate. Therefore, hot stamping must be completed with four conditions: temperature, pressure, color foil, and hot stamping plate. Electroplated aluminum hot stamping foil is generally composed of 5 layers of different materials, from the back to the front, which are the base film layer (also known as the film base layer), isolation layer (also known as the release layer), protective layer (also known as the color layer, dyeing layer), aluminum layer, and adhesive layer.

(2) Characteristics of hot stamping

① Chemical stability and the ability to maintain a unique metallic luster.

② Rich in colors, including gold, silver red, blue, green, orange, etc.

③ Simple process

④ The pattern is beautiful and clear, with eye-catching colors and strong visual impact, which can serve as the finishing touch.

⑤ Wear resistant and protect printed materials.

⑥ Widely applicable, such as paper, leather, plastic, silk fabrics, and organic glass. Simply put, the process involves applying a certain temperature and pressure to the color foil to instantly attach the pattern and text of the printed product to the surface. The proportion of hot stamping on cigarette labels printed now is very high. Especially when the trademark adopts hot stamping technology, it has strong impact.

(3) The function of hot stamping. Hot stamping products have unique effects that cannot be compared to ink and other printing methods, and are increasingly being used by Shenzhen Buche Printing Company for three main purposes:

① The surface finishing effect enhances the added value of the product, and the combination of hot stamping and embossing technology highlights the quality level of the product.

② Endow the product with high anti-counterfeiting performance, adopt holographic positioning hot stamping trademark logo to prevent counterfeiting and protect the brand.

③ Hot stamping can demonstrate the personalization, safety, and environmental friendliness of product packaging. Therefore, many products now use hot stamping for their packaging

2. Classification of hot stamping equipment

Hot stamping equipment can be divided into three types according to the stamping method: flat press, round press, and round press. Flat press is more commonly used, and Shenzhen Buche Printing Company divides it into three types according to the degree of automation: manual, semi-automatic, and fully automatic. According to the different types of whole machine models, hot stamping machines are also divided into vertical and horizontal types.

3. Determination of hot stamping process parameters

The hot stamping process parameters mainly include: hot stamping temperature, hot stamping pressure, and hot stamping speed.

(1) Temperature. If the temperature is too low, the insulation layer and adhesive layer of the aluminum foil will not melt sufficiently, which will cause incomplete or weak hot stamping, resulting in incomplete and blurred marks. If the temperature is too high, the hot-melt film layer will melt beyond the range and produce a paste; It can also oxidize and polymerize the synthetic resin and dye in the aluminum dyeing layer, causing foaming or cloud like appearance of the aluminum imprint; Causing oxidation on the surface of the electroplated aluminum layer and the dyed layer, resulting in the loss of metallic luster and reduced brightness of the hot stamping product.

(2) Pressure. There are three forces involved in the entire hot stamping process: the peeling force generated when the aluminum foil is peeled off from the base film layer, the adhesive force between the aluminum foil and the substrate, and the fixing force on the surface of the substrate (such as the ink layer of printed materials and white paper). During the hot stamping process, the pressure should ensure that the aluminum foil can adhere to the substrate and cut the hot stamping area of the aluminum foil. Therefore, the hot stamping pressure should be higher than that of general printing. If the hot stamping pressure is too low, it will not be able to adhere the aluminum foil to the substrate. At the same time, the edge area of the hot stamping cannot be fully cut, resulting in the inability to print or the imprint of the hot stamping area becoming blurred. Excessive pressure can cause compression deformation of the liner and substrate, resulting in paste or thicker imprints.

(3) Hot stamping speed. The hot stamping speed determines the contact time between the aluminum foil and the substrate, and the contact time is directly proportional to the hot stamping fastness under certain conditions. The hot stamping speed is slightly slower, which can make the electroplated aluminum adhere firmly to the substrate, which is beneficial for hot stamping; When the machine speed increases and the hot stamping speed is too fast, the hot melt film and peeling layer of the electrolytic aluminum may not melt or melt sufficiently in an instant, resulting in hot stamping failure or imprint smudging. Therefore, the hot stamping speed must be adapted to the pressure and temperature, as both too fast and too slow have drawbacks.

4. Development of hot stamping technology

With the progress of society, the development of the times, and the improvement of aesthetic standards, people's requirements for printed products are becoming increasingly high. In order to beautify the packaging, not only should there be smooth and colorful printing colors, but also a higher level of metallic luster and a three-dimensional sense are needed to display its magnificence and nobility. If metal ink is used for printing, not only is the printing effect poor, but the cost is also high. Ink that comes into contact with air for a long time is prone to oxidation, causing the color to darken. Therefore, using the method of "hot stamping+concave convex" to process the patterns or text that need to be highlighted in the design composition can not only make the product color last forever, beautiful and generous, but also play a finishing touch, simple and economical, achieving multiple benefits at once. In this regard, the domestic technological level is close to the international advanced level. The most advanced holographic hot stamping technology is rapidly developing today, and its unique beauty will occupy a large share of the hot stamping process. In terms of equipment, hot stamping machines both domestically and internationally are developing towards high speed, high precision, high stability, high intelligence, and online capabilities. At present, the development of flat pressing equipment for hot stamping in China is relatively mature, and circular pressing and hot stamping equipment is the current development direction in order to improve production efficiency.

   Hot stamping process of Shenzhen Buke Printing Company