The raw material for cosmetics packaging is mostly plastic. In order to show the metal texture of the packaging itself or improve the grade, it is also often used to obtain consumers' recognition of texture and taste through hot-stamp. It is commonly used for hot-stamping on the edge or LOGO, which is common in cosmetics, skin care and other product packaging. With the development of hot-stamp, various customized patterns or special textures of hot-stamp also came into being.

 

 

Introduction to hot-stamping process

 

The basic hot-stamping process is to heat the anodized aluminum under the pressure. When the anodized aluminum is pressed by the hot stamping plate or the substrate, the hot-melt silicone resin layer on the anodized aluminum been melted. At this time, the viscosity of the hot melt silicone resin becomes smaller, while the viscosity of the special thermosensitive adhesive increases, so the aluminum layer and the anodized base film peel off and transfer to the substrate at the same time. As the pressure is removed, the adhesive cools and solidifies rapidly, so the aluminum layer is firmly attached to the substrate, a hot stamping process has completed.

Hot stamping has two main functions: first, surface decoration, which can improve the added value of the product. The combination of gold stamping and other processing methods such as concave convex process can show a strong decorative effect of the product; The second is to endow the product with high anti-counterfeiting performance, such as the use of holographic positioning hot stamping trademark logo.

 

Features of hot stamping

As a widely used secondary process, hot stamping also has its unique characteristics:

 

1. Little impact on the environment and low energy consumption (high conversion rate of electric energy to thermal energy and less mechanical energy loss);

 

2. Low requirements on the site and flexible operation, and can be connected with molding, printing and assembly according to needs;

 

3. With high customization freedom, you can customize the appearance effects (such as gold foil or transfer film with special effects) according to different customer needs;

 

4. Most of the stamping operations are mechanical operations, which can relatively easily realize efficient automated integrated workstations.

（Automatic hot stamping machine）

 

Material Needs of Hot-Stamping Process

 

Hot-Stamping Mold

 

Hot-stamping mold includes zinc mild, steel mold, copper etching mold, silica gel mold and plastic mold

 

The requirements of the hot-stamping mold is to be able to resist high temperature, high pressure and deformation. As the hardness of zinc is far lower than other materials, products with high hardness and large output do not choose this material. The advantage of zinc hot-stamping mold is easy to produce and cheap. Copper hot-stamping mold can resist high temperature and high pressure, but it is not easy to etch, especially in corners. Due to different materials, the heat exchange rate is also different. The most popular materials are silica gel and aluminum. The heat resistance temperature of silica gel is between 250 ℃ and 350 ℃ (the temperature between the bronzing plate and the parts is usually kept between 80 ℃ and 180 ℃)

 

 

Silica gel hot-stamping mold

Etching hot-stamping mold

Copper hot-stamping mold

 

Copper engraving hot-stamping mold

 

Silica gel hot-stamping mold：

It is used for lines decoration of product.

The recommended range of processing temperature for silica gel plate is 250 ℃ - 300 ℃ (silica gel is easy to harden and shorten service life if it exceeds 350 ℃, and it is usually appropriate to set it at about 250 ℃).

 

Etching hot-stamping mold：

Used for special patterns, characters, lines, patterns and other hot decoration.

 

Copper hot-stamping mold

For products requiring obvious concavity and convexity for hot finishing, the range of copper plate processing temperature is 100 ℃ - 200 ℃.

 

Copper engraving hot-stamping mold：

Used for hot decoration of products with curved or irregular surfaces.

 

(2) Hot stamping foil (anodized aluminum foil)

The hot stamping process is based on the principle of hot press transfer. For example, hot anodizing transfers the aluminum layer in the anodized aluminum to the substrate surface to form a special metal effect. Electrochemical aluminum foil is usually composed of multi-layer materials, and the base material is usually PE, followed by separation coating, color coating, metal coating (aluminum plating) and glue coating.

 

1. The appropriate hot stamping foil must be selected according to the different materials of the hot objects. During hot stamping, it is necessary to master the three-way cooperation of temperature, pressure and hot stamping speed (or time), and make differences according to different hot stamping materials and areas.

 

2. The speed and direction of the turning knife shall be mastered when cutting the hot foil.

 

3. The anodized hot stamping foil shall be made of paper, ink (especially black ink) and composite glue with appropriate properties. The hot stamping parts must be kept dry to avoid oxidation or damage to the hot stamping layer.

 

4. The general package is 64cm × One 120m roll, one box for every 10 rolls; Large rolls with a width of 64cm and a length of 120m or 360m or other special specifications (1.5m wide, 1000m or 3000m long) can be customized.

 

5. Store in a cool and ventilated place.

 

Note: If the color of the gold foil is silver, generally the gold foil has only four layers (the anodized layer itself is silver). The thickness of most recommended gold foils is 0.012mm and 0.016mm. If there are other three-dimensional effects, there will be 5-6 layers, and the extra layer is the effect layer.

 

Common gold foil colors are: gold, silver, black, red, etc.

Example of foil color

 

There are some differences between the transfer film and the anodized aluminum foil. The special transfer film sometimes requires special treatment or hot stamping conditions, which shall be adjusted according to the actual situation.