Author: Site Editor Publish Time: 2021-04-22 Origin: Site
(1) Film activation
Spread the water-coated transfer film flat on the water surface of the transfer water tank, with the graphic layer facing up, to keep the water in the water tank clean and basically in a neutral state, spray evenly on the graphic surface with an activator to make the graphic The layer is activated and is easily separated from the carrier film. The activator is an organic mixed solvent dominated by aromatic hydrocarbons, which can quickly dissolve and destroy the polyvinyl alcohol, but will not damage the graphic layer, leaving the graphic in a free state.
(2) Water coating transfer process
The items that need water transfer film are gradually approached to the water transfer film along its outline. The image and text layer will slowly transfer to the surface of the product under the action of water pressure, due to the inherent adhesion of the ink layer and the printing material or special coating And produce adhesion. During the transfer process, the lamination speed of the substrate and the water-coated film should be kept uniform to avoid wrinkles of the film and unsightly pictures and texts. In principle, you should ensure that the graphics and text are properly stretched and try to avoid overlaps, especially the joints. Too much overlap will give people a cluttered feeling. The more complex the product, the higher the requirements for operation.
Water temperature is an important parameter that affects the quality of the transfer. Too low water temperature may reduce the solubility of the substrate film; too high water temperature can easily cause damage to graphics and text, causing graphics and text to be deformed. The transfer water tank can adopt an automatic temperature control device to control the water temperature in a stable range. For large-scale workpieces with a relatively simple and uniform shape, special water transfer equipment can also be used instead of manual operations, such as cylindrical workpieces, which can be fixed on a rotating shaft and rotated on the surface of the film to transfer the image and text layer pp treatment agent.
The following steps should be carried out after transferring and covering the graphics and text:
Take the workpiece out of the sink, remove the remaining film, and then wash off the floating layer that is not fixed on the surface of the product with clean water. Note that the water pressure should not be too high, otherwise it will easily damage the transferred graphics.
Remove the moisture on the surface of the product to facilitate the thorough drying of the transfer ink layer; in order to increase the adhesion fastness, it can be dried with a hair dryer, or the product can be dried in a drying box. The drying temperature of plastic products should not be too high, about 50-60 ℃, too high temperature will easily deform the substrate; the drying temperature of metal, glass, ceramics and other materials can be appropriately increased.
③Spray protective paint
In order to enhance the resistance of the graphic layer to the environment, it is necessary to spray paint on the surface. Spray paint can use solvent-based varnish, which can be dried naturally or by heating after spraying; UV varnish can also be used and cured and dried by ultraviolet light. In contrast, UV curing is more suitable for environmental protection requirements.
Solvent-based varnishes need to be mixed with supporting hardeners. For example, the water transfer spray varnish sold by Mr. Han from a Qiming factory in Dongguan is a varnish with polyurethane resin as the binder, and 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 an oven. For different printing materials, spray varnishes are also divided into three types, namely varnish suitable for plastic materials, varnish suitable for flexible materials and varnish suitable for non-absorbent materials such as metal and glass.
2.Water mark transfer process
(1) Environmental factors
A clean substrate surface is a necessary condition for achieving high-quality transfer, which is the same for any printing process. Make sure that the substrate is completely exposed before transfer; in addition, a clean and tidy working environment is conducive to the transfer of the ink layer to adhere closely to the surface of the substrate, and dust floating in the air is most likely to affect the transfer effect.
(2) Water mark transfer paper activation
Water mark transfer paper is divided into peelable water mark transfer paper and dissolvable water mark transfer paper. The graphics and text of peelable water mark transfer paper can be separated from the substrate after activation to realize transfer; dissolvable water mark After the transfer paper is activated, the substrate is dissolved in water, and the image and text are in a free state to realize the transfer.
The activation of water-mark transfer paper is different from that of water-coated transfer film. It just immerses the transfer paper in water to separate the image and text from the base material without special solvents. As shown in the figure, the process is simpler.
The specific process is to first cut the graphic water transfer paper to be transferred to the required specifications, put it into a clean water tank, and soak for about 20 seconds to separate the mask from the substrate and prepare for the transfer.
The water mark transfer paper processing process is shown in the figure below. Take out the water transfer paper and gently close it to the surface of the substrate. Use a scraper to scrape the graphic surface to squeeze out the water. Keep the graphic flat on the specified position and dry naturally . For peelable watermark transfer paper, dry it naturally and then put it in an oven to improve the adhesion fastness of graphics and text. The drying temperature is about 100°C. Because there is a layer of protective varnish on the surface of the peelable water mark transfer paper, there is no need to spray protection. However, the soluble water mark transfer paper has no protective layer on the graphic surface. It needs to be sprayed with varnish after natural drying, and sprayed with UV varnish to be cured with a curing machine. When spraying varnish, you must pay attention to prevent dust from falling on the surface, otherwise the appearance of the product will be greatly affected. The control of the coating thickness is achieved by adjusting the viscosity of the varnish and the amount of spraying. Too much spray can easily cause the uniformity to decrease. For substrates with a large transfer area, screen printing is used for glazing to obtain a thicker coating, which is also a very effective protection measure.