Third, the use of UV curing ink 1. Mixed use of ink The light and solid inks can be mixed with each other, but they must not be mixed with ordinary inks. When changing the type of ink, they should be washed before printing. 2. Ink wash Washing solvent application Special light-curable ink products. 3. Auxiliary materials Adjunct materials are viscosity reducers, driers, and hardeners. The viscosity reducing agent is used to reduce the viscosity of the ink, and the addition amount is preferably within 5%, more than this amount will reduce the hardening of the ink; the drying agent is used to increase the curing speed of the photocurable ink, and the addition amount should be within 2%; The maximum amount of agent is 10%, beyond which no effect will be achieved. The auxiliary agent is special for photocurable inks and must not use general auxiliary agents. Fourth, UV curing ink inspection method 1. Test methods such as color, tinctorial strength, fineness, fluidity, and viscosity are the same as those for lithographic inks. 2. The test method for impact strength is the same as that for printing ink. 3. There are two ways to test adhesion: 1 The circled method is the same as that for printing ink. 2 Use a metal tip (needle tip) to mark the ink film with a “׆shape, then use cellophane tape on the nicks and pull to check if the ink film will be pulled away from the metal substrate. If all the nicked ink film is basically pulled off, the adhesion is poor; if a small amount of ink film is pulled out, rated as possible; if only a few ink films are pulled out, it can be rated as good; if the ink film It did not fall off at all and can be rated as excellent. 4. Photo-solid speed test method: 1 No stickiness This is a condition where there is no stickiness or ink transfer when the ink film is touched or the film is brought into contact with other surfaces. On a very rough substrate, this curing can be achieved with minimal ultraviolet light irradiation depending on the absorbency of the substrate; on a less rough or impermeable substrate, the dry surface ink film may cover the semi-fixed ink On the membrane, it may become dirty when pressurized. 2 thumb turbulence without stickiness This applies a downward pressure of about 5 kg, and the thumb is rotated on the ink film. After the test, the ink film does not break and passes through. 3 No scratch cure This is hard to nail the ink film. If this rigorous test is passed, the ink film does not break and the ink cures completely. Fifth, UV curing ink packaging and transportation and storage 1. Currently, most UV-curable inks are packaged in 1kg or 2kg tin containers. However, according to some information, plastic containers are better packaged because it is not an oxygen-permeable layer that allows air to pass through, and the presence of oxygen in the air inhibits the curing of photo-curable resins and slows the drying of the surface. 2. Transport storage. 1 It is necessary to cover and cover the rain during transportation, and it is strictly forbidden to throw and throw in the process of loading and unloading; 2 The product shall not be stored in the open air, the warehouse shall be dry and ventilated, the temperature shall be kept below 25 °C to prevent from dampness and away from the fire source; 3 The storage period of the product is 6 Month, the storage temperature of the ink is preferably 18-23 °C. Sixth, screen printing UV curing ink Since the ink contains no solvent, the viscosity of the ink does not change during the printing process, and printing defects such as "plugging holes" do not occur. Even fine mesh screens can be printed with precision and stability, making it possible to overprint four-color screens. UV curing screen ink formulations are: Pigments 5 % Urethane Acrylate 30% Epoxy acrylate 10% Thinner 30% Photoinitiator 10% Additives 15% The UV ink has a viscosity of 5000 cps/25[deg.] C. and a curing speed of 15 m/min, and adheres well to PVC. UV-curing inks have a broad application prospect in screen printing because the range of printable using UV technology is very wide, such as paper printing, plastic printing, tape measure printing, printed circuit board, chrome printing, electronic parts printing, metal surface printing , aluminum foil surface printing and so on. Also includes a variety of special packaging printing inks that can produce special effects for decoration, such as: UV matte ink, UV ice ink, UV foam ink, UV wrinkle ink, UV embossed ink, UV gem ink, UV varnish Etc.; widely used in high-end, exquisite chic tobacco, wine, cosmetics, health products, food, medicine and other packaging and printing, in line with environmental requirements. However, from a production point of view, currently there are not many manufacturers that can actually mass-produce UV-curable inks in the country. In particular, high-grade UV-curable inks are scarce. Many high-end users use imported inks for high-grade printing jobs. Therefore, The production of UV-curing inks in China can only belong to the initial stage.
Source: Screen Printing Industry Author: Zhou Zhen
UV curing screen printing ink (below)