Hot Stamping Technology--Types of Hot Stamping Materials (1)

Type of hot stamping material

There are many types of hot stamping materials, such as metal foils, powder sheets, anodized aluminum, colored foils, etc., and their performance varies.

1. Electrochemical aluminum foil.

Electrochemical aluminum foil is a stamping material made by vacuum evaporation of a layer of metal foil on a thin film substrate. Electrochemical aluminum foil can replace metal foil as a decorative material, with gold and silver as the majority. It is characterized by beautiful appearance, bright color, glittering eye-catching, easy to use, etc. It is suitable for hot stamping on paper, plastic, leather, coated fabric, organic glass, plastic and other materials. It is the most commonly used material for modern hot stamping.

Electrochemical aluminum foil was transmitted from Japan and the United Kingdom to China in the mid-1960s. In the second year after its introduction (1965), Shanghai, Beijing, Fujian and other places were put into production. Since then, dozens of manufacturers across the country have successively produced such anodized aluminum materials. For more than 30 years, electro-aluminum foil has become a familiar material for framed stamping.

(1) The composition of the electrochemical foil. Electrochemical aluminum foil is coated on a polyester film of 12, 16, 18, 20 μm thick, 500-1500 mm wide (16 μm thick, 500 mm wide film in China). The layer was finally finished by rewinding the finished product. Domestic galvanized aluminum foil is generally 4-5 layers.

The first layer of galvanized aluminum foil is a base film layer. In China, a 16 μm thick biaxially stretched polyester film (12 μm thick for foreign use) is used. The main function is to support the enamel coating on the top layer, which is convenient for continuous hot processing. India. Electrochemical aluminum foil base film layer, in the hot stamping process can not be due to stamping temperature and deformation, should have strong, tensile, high temperature and other properties.

The second layer of electro-aluminum foil is a release layer, which is generally coated with a silicone resin or the like. The main function is to enable the pigment, aluminum, and adhesive layers to quickly separate from the polyester film after hot stamping (heating and pressure application) and be transferred and bonded on the surface of the object to be stamped. Detachment layer should have better shedding performance, otherwise it will make the hot stamping picture unclear, and revealing the bottom, affecting the product quality of hot stamping.

Some galvanized aluminum foil products do not come off the layer, and use the color layer adhesive material with less adhesion to the base film, so that the color layer can react color and play a role in detachment. This is a four-layer structure of electro-aluminum foil.

The second layer of the galvanized aluminum foil is a colored layer, and the main component is a synthetic resin and a dye that are suitable for film formation, heat resistance, and transparency. Commonly used resins are polyurethanes, nitrocellulose, melamine formaldehyde resins, modified rosin resins, and the like. During the production, the resin and dye are dissolved in the organic solvent ink, then coated and dried. The main role of the color layer is two, one is to display the color; the other is to protect the aluminum plated image stamped on the surface of the cover or other items is not oxidized. Electrochemical aluminum foil has a variety of colors such as golden, orange, gray, red, blue, and green. The color of the color layer is imparted with luster by the aluminum plating layer, and the color has a certain change, such as yellow after being plated with aluminum, and gray after being plated with silver. The application of the color layer is delicate without any small particles, so as to avoid trachoma, uniform coating.
The fourth layer of galvanized aluminum foil is an aluminized layer. The color coated film is placed in a vacuum chamber of a vacuum continuous aluminizing machine. Under a certain degree of vacuum, the aluminum wire is melted and continuously evaporated to the color layer of the film through resistance heating to form an aluminum plating layer. The main function of the aluminized layer is to reflect light, change the color of the color layer, and make it appear metallic.

The fifth layer of anodized aluminum is an adhesive layer. The adhesive layer is generally a fusible thermoplastic resin, such as methyl methacrylate (ethyl ester, butyl ester) and acrylic acid copolymer, and other resins such as Cuban gum, shellac, and rosin may be used depending on the material to be stamped. Wait. The resin is dissolved in an organic solvent or formulated into a water emulsion, coated on an aluminum layer by a coater, and dried to form an adhesive layer. The main role of the adhesive layer is to bind the hot stamping material to the hot object.

One of the main reasons for the phenomenon of unsatisfactory hot stamping is that the adhesive layer is different. The main reason for the phenomenon of non-performing hot stamping is that the adhesive layer is different. The object of hot stamping is different, and the type of electrified aluminum foil used should be different from that of the other types. The electroformed foils of various types have different adhesive layers. Therefore, it is advisable to choose the electrified aluminum foil according to the actual situation of the object to be ironed.

(2) The production process of galvanized aluminum foil. Electrochemical aluminum foil production process, in the base film dye coating, vacuum aluminum plating, adhesive layer, inspection and packaging of the four major processes, the process shown in Figure 2-7. The production of electro-aluminum foil vacuum aluminum plating is the main link, and the quality of the aluminum plating directly affects the appearance quality of the electro-aluminum foil. Vacuum aluminum plating is continuously completed on the vacuum coating machine through vacuum, aluminum plating and inspection.

The vacuum device is connected with the aluminized device sealed street. The main work is to remove the air in the aluminum plating device to a certain degree of vacuum to ensure that the vaporized aluminum can be evenly sprayed onto the base film color layer. The aluminizing device consists of four parts: an evaporation crucible, an aluminum sending device, a film feeding device, and a film collecting device. These devices are installed in the sealed vacuum aluminum plating room. The vacuum plating room is equipped with high-temperature resistant, high-pressure resistant glass window. From the appearance, you can see the working conditions in the vacuum plating room to prepare for the problem and deal with it in time.

There are three evaporation sources in the vacuum chamber, and each evaporation source consists of a set of positive and negative electrodes and a graphite crucible. The graphite crucible is fixed on the electric plate, and the resistance of the high-temperature ink crucible is high after the electric current is applied), so that the high-purity aluminum bar sent from the aluminum sending device rapidly melts into a liquid at a high temperature of 1400-1500° C. and then evaporates into gas. After the aluminum and vaporized aluminum encounters a low-temperature polyester film coated with a pigment layer, they condense on the surface of the color layer to form a uniform and bright aluminum layer. If the temperature of the crucible is further increased, the aluminum gasification is faster and the speed of the film feeding machine is slowed down, then a thicker aluminum plating layer can be obtained, and on the contrary, a thinner aluminum plating layer is obtained.

After the vacuum aluminum plating device is processed, the adhesive layer, drying, rewinding, inspection, etc. can be processed to complete the entire process of electrochemical aluminum foil production.