Water transfer printing is quite popular these days. This printing method offers an easier way to update the look of practically just about anything - from boats to trucks to mugs to hunting equipment. Before, heat transfer printing was the method of choice but these days, more and more people are getting interested in water transfer printing.
Water transfer printing is a kind of printing which uses water pressure to carry on the macromolecule hydrolysis of the transfer paper/plastic film with color pattern. As the image carrier, the printing film appears to be a great progress in printing technology - there are a lot of products that are difficult to direct printing, but with this carrier, people can use mature printing technology to print the first graphic on the carrier, then the image will be transferred to the substrate.
The whole process can be divided into 9 steps.
1) Film printing: print different patterns on polymer films.
2) Spray primer: many materials must be coated with an adhesion agent, such as metals, ceramics, etc. To transfer different patterns, different primers must be used, e.g. brown, coffee, earthy yellow, etc. for wood grain, while white usually for stone grain.
3) Film stretching: let the film lie flat on the water surface and leave it to stretch flat.
4) Activation: activate the pattern of the transfer film with a special solvent (activator) into an ink state.
5) Transfer printing: use water pressure to print the activated pattern on the object.
6) Washing: rinse off the floating layer which is not attached to the surface of the product. Remember that the water pressure should not be too high, otherwise it is easy to destroy the graphic.
7) Drying: remove the moisture from the surface of the product, in order to dry the ink layer thoroughly. Hair dryer can also be used to increase the adhesion fastness; or you can put the product in the drying box. The drying temperature for plastic products should not be too high (the ideal temperature is between 50 to 60 degree ), for if the temperature is too high, substrate will be easily deformed. The drying temperature for metal, glass, ceramics and other materials can be appropriately improved.
8) Spraying top coat: in order to enhance the environmental resistance of graphics and text, spray transparent protective paint on the surface. The paint can be solvent light oil (spray after natural drying or heating drying); or UV light oil, which is used for ultraviolet curing drying. Generally, UV curing is more adaptive to environmental protection requirements.
9) Drying: dry the surface again after spraying the top coat.
Water transfer printing can be divided into water mark transfer and cubic transfer - the former mainly accomplishes the transfer of text and patterns, while the latter tends to complete the transfer on the entire surface of the product. Cubic transfer uses a water-based film that dissolves easily in water to carry the text. Due to the excellent tension of the water-based film, it is easy to wrap around the surface of the product to form a graphic layer, giving the surface a very different appearance as if it were painted. Cubic transfer allows for the overlay of colored patterns on any shape of workpiece, providing manufacturers with a solution to the problem of printing three-dimensional products. Different patterns, such as leather, wood, jade and lucite patterns, can be added to the cured cubic surface. The usual false spots found in general panel printing can be avoided as well. The surface of the product does not have to come into contact with the printing film during the printing process, thus avoiding damage to the surface and its integrity.
With the improvement of packaging and decoration requirements, the use of water transfer printing is more and more extensive. The principle of indirect printing and perfect printing is effective to solve the problem of surface decoration of many products, mainly used for various types of ceramics, glass, paper, etc.
