Author: Site Editor Publish Time: 2021-04-26 Origin: Site
The characteristics of water transfer printing include many aspects, mainly including structural characteristics, material characteristics, and operating characteristics. Structural features. Water transfer structure is also called water transfer paper or water transfer film structure. The structure of water transfer printing is shown in Figure 1. The structure is generally composed of 4 layers, that is, transfer bottom paper (or film), whose function is to support water-soluble materials and facilitate printing; therefore, water immersion treatment should be carried out within the specified time. Then, without damaging the materials and graphics, the watermark of the transfer bottom paper is peeled off or pulled away. The watermark is mainly used in food packaging and food labeling (label). The focus is on the control of force and time parameters. Water transfer paper or water transfer film products are generally printed into special water transfer products first, and they are easy to peel off under the action of water. The third layer of printing ink features, all information materials to be transferred should have sufficient adhesion to the second layer. The key material for water transfer printing is water-soluble material, that is, water-soluble plastic film. Its basic ingredient is polyvinyl alcohol, which has good safety ingredients and prevents migration and penetration.
Research experiments have shown that the products of dissolving water-soluble plastic films are hydrogen atoms, oxygen atoms and carbon atoms, which have no side effects on the environment and the human body. Food surface decoration. Especially for food labels (labels), the water transfer is completed after being soaked in water and peeled off and pressure is applied. Take the four-layer material in Figure 1 as an example for analysis. The characteristics of the first layer of transfer paper (or film) must have a certain strength and resistance, so that the water-soluble material adheres to it, and it is convenient to print graphics and text on the water-soluble material. The characteristics of the second layer of water-soluble material. This material is a carrier for printed graphics and requires effective combination with the first layer. The current practice is to use adhesives to stick printed plastic labels and paper labels on the surface of the food. Above, this method can inevitably lead to food safety problems as the time and temperature increase because the adhesive and ink may migrate and penetrate into the food. Water transfer printing has good safety for food labels (labels). Analyzing the principles and characteristics of water transfer printing, water transfer printing applied to food has the following advantages. Material characteristics refer to the performance characteristics of the water transfer structure of each layer. The second layer is water-soluble material, used as printing material (graphic carrier) and water-soluble peeling and bonding products; the third layer is ink (printing ink), printed graphics and text. The fourth layer is cover oil, its function is to protect the printed graphics from damage and improve reflectivity, producing a three-dimensional effect. Water transfer printing is sometimes made into a five-layer or six-layer structure. The five-layer structure adds a protective film to the surface of the cover oil. The six-layer structure is a combination of water-soluble materials, water-soluble glue and plastic film.