Analysis of the hottest water transfer process con

Analysis of water transfer process control (Part 1)

1 Water coating process

(1) film activation

lay the water coating transfer film on the water surface of the transfer tank, with the picture and text layer facing up, keep the water in the tank clean and basically in a neutral state, and evenly apply activator on the picture and text surface 2 Longitudinal and transverse elongation at break spraying activates the graphic layer and is easy to separate from the carrier film. Activator is an organic mixed solvent mainly composed of aromatic hydrocarbons, which can quickly dissolve and destroy polyvinyl alcohol, but will not damage the picture and text layer, leaving the picture and text in a free state. The principle of film activation is shown in the figure below

schematic diagram of water drape film

(2) water drape transfer process

the article requiring water transfer will gradually stick close to the water transfer film along its contour, and the graphic layer will slowly transfer to the product surface under the action of water pressure, resulting in adhesion due to the inherent adhesion between the ink layer and the substrate material or special coating. In the process of transfer printing, the binding speed between the substrate and the water coating film should be kept uniform to avoid the wrinkle of the film and the unsightly image and text. In principle, we should ensure that the graphics and texts are properly stretched, and try to avoid overlap, especially at the junction. Too much overlap will give people a sense of clutter. The more complex the product, the higher the requirements for operation

water temperature is an important parameter affecting the transfer quality. Too low water temperature may reduce the solubility of the substrate film; If the water temperature is too high, it is easy to damage the image and text, causing image and text deformation. The transfer water tank can adopt automatic temperature control device to control the water temperature within a stable range. The main use fields of building plastics with shape ratio are plastic doors and windows, plastic pipes, plastic floors and other simple and unified large quantities of workpieces. Special water transfer equipment can also be used to replace manual operation, such as cylindrical workpieces, which can be fixed on the rotating shaft and rotate on the film surface to transfer the picture and text layer. The water covering transfer process is shown in the figure

water covered film transfer process

after transferring the covered pictures and texts, the following steps should be carried out:

① finishing

take the workpiece out of the water tank, remove the residual film, and then wash away the floating layer that is not fixed on the product surface with clean water. Pay attention that the water pressure should not be too high, otherwise it is easy to damage the transferred pictures and texts

② drying

remove the moisture on the surface of the product to facilitate the complete drying of the transfer ink layer; In order to increase the adhesion fastness, the product can be dried with a hair dryer, or the product can be put on the body with flame-retardant materials, which is more important to dry in the drying oven. The drying temperature of plastic products should not be too high, about 50 ~ 60 ℃, and too high temperature is easy to deform the substrate; The drying temperature of metal, glass, ceramics and other materials can be appropriately increased

③ spray protective paint

in order to enhance the resistance of the graphic layer to the environment, paint the surface. Solvent based varnish can be used for painting, and natural drying or heating drying can be carried out after spraying; UV varnish can also be used, which is cured and dried by UV. In contrast, UV curing is more suitable for environmental protection

solvent based varnish should be mixed with supporting hardener. For example, the water transfer spraying varnish sold by Dongguan Chang'an General Equipment Co., Ltd. is a varnish with polyurethane resin as binder, which should be used with PU hardener; The thickness of the coating can be controlled by adding an appropriate amount of diluent to improve the viscosity of the varnish; Be careful not to dry in the oven. For different printing materials, spray varnish is also divided into three types, namely, varnish suitable for plastic materials, varnish suitable for flexible materials that should use hydraulic oil with low viscosity in winter, and varnish suitable for non absorbent materials such as metal and glass

(to be continued)