Postpress Technology 1000 Questions (4)

190. What is the mechanism of hot stamping aluminum?

The essence of electro-aluminum hot stamping is the use of hot-pressing to transfer the aluminum layer to the surface of the substrate. The specific mechanism of this process is: during the hot pressing, the hot melting silicone peeling layer and the adhesive are melted by heat, the adhesive force of the hot melt silicone resin is melted, and the aluminum layer is peeled from the base film. The thermal adhesive bonds the aluminum layer to the print under the effect of heat and pressure. At the moment of separation of the imprint lithography, the hot melt state of the adhesive is converted into cooling and solidification, so the anodized aluminum can be firmly transferred to the surface of the object to be heated.

191. What are the steps in the process of stamping anodized aluminum?

1 Determine the anodized aluminum and stamping equipment. 2 bronzing plate preparation. 3 installed version. 4 installation of anodized aluminum. 5 hot stamping.

192. How to determine the aluminum and stamping equipment?

Different hot stamping substrates have different requirements for anodized aluminum and hot stamping equipment. Because the aluminum foil has certain adaptability to the hot stamping substrate, such as hot stamping on white cardboard, ink layer, UV ink and composite film, the required aluminum material is slightly different. For example, due to the difference in the manufacturing processes of laser aluminum and ordinary aluminum, it is difficult to strip the laser aluminum in the hot stamping. The phenomenon is reflected in the fact that the hot stamping of the aluminum foil is not true, the peeling is not complete, and the hot stamping does not occur. Spots. Appropriate anodized aluminum should be selected based on the texture of the printed substrate (substrate). Selecting the right equipment for different hot stamping substrates is also important. For example, in the case of hot stamping on coated paper, since it is required that the time of thermal contact between the electrodeposited aluminum and the film is not too long, but it is necessary to ensure that the electrodeposited aluminum can be normally transferred, so in the case of using the same kind of anodized aluminum for the film. Only the flattened hot stamping method can do the job. Because the round stamping method is line contact, the entire paper stamping time is longer, but the contact time evenly distributed on each line is short, so as not to damage the film layer, and the temperature is even, and the hot stamping can be better displayed. Electrochemical aluminum bright effect. When hot stamping a large area of ​​anodized aluminum (such as field, through the lines), the round flat stamping hot stamping method is also better than the flat stamping hot stamping method. Because the flattened wire contact method is more easy to eliminate the aluminum stripping and the air completely eliminated, effectively solve the hot stamping in the flat stamping stamping often appear false and paste and difficult to control the smoothness of the paper feeding and other phenomena . Although the round press hot stamping machine has great difficulty in solving the hot stamping accuracy, the hot stamping speed is fast, and it is suitable for processing large-volume long-run games.

193. What is the version of the plate used for stamping anodized aluminum?

The printing plates used for hot stamping of aluminum are mostly copper relief plates, which are characterized by good heat transfer performance, pressure resistance, wear resistance and resistance to deformation. When the number of hot stamping is small, zinc relief can also be used. Copper-zinc plates require a thick plate of 1.5 mm or more. When making the plate, the corrosion is required to be slightly deeper, and the difference between the height of the graphic and the blank should be as large as possible. This can reduce the occurrence of contiguous and stencil printing during hot stamping, which is beneficial to guarantee the quality of hot stamping.

194. What are the steps in the process of photographing a metal relief printing plate?

The method of photographing the relief printing plate is that the negative plate film is transferred to a copper plate or a zinc plate coated with a photoresist, and the picture is formed by etching. The drying process of metal relief is:

Grinding plate → Coating photosensitive solution → Printing → Developing → Roasting plate → Retouching → Corrosion → Imposition → Inspection

195. What is the purpose of plate-based grinding with a metal relief printing?

The purpose is to use physical or chemical methods to remove oxide and oil on the surface of copper and zinc plates to improve their adsorption properties. The specific method is as follows.

1 zinc plate grinding method

A solution: aqueous nitric acid, concentration 80Be'

B liquid: aqueous hydrochloric acid, concentration is 110Be'

C fluid: (antioxidant): Potassium dichromate 50g

Water: 250ml

The plate base should be treated with liquid A before grinding, washed with water, treated with liquid B, washed with water, and finally placed in liquid C for several minutes.