Third, the application of fluorescent ink
1. Fast dry fluorescent ink
Fast-drying fluorescent ink is an ink produced by adding a fluorescent pigment to a fast-drying connecting material. The ink has good brightness and flexibility and is suitable for outdoor poster printing. Most of them are dried by evaporation. When the fluorescent ink is to be printed on a non-white surface, the surface should first be coated with a white base. Fast-drying fluorescent inks can be printed on uncoated cloth labels, pigments, and nylon surfaces. A test should be done when it is not known whether the ink is bonded to the printed surface.
The life of fluorescent ink printing products is determined by the ink, not by the product itself. If the quick-drying ink can prevent direct sunlight, the life of the printed product can be greatly improved. In the absence of light, fluorescent ink printing products can be preserved and maintain their original appearance. Approximately 30 S is required for the natural drying of a quick-drying ink, and the use of mechanical drying can shorten the time to 30 s to 2 min.
A better ventilation environment is the conditions required for printing and drying. The drying process must be completed as quickly as possible to prevent blemishes from appearing during printing. A single-edged squeegee can print about 25 to 38 μm of ink layer thickness. After printing, the screen can be cleaned with ink thinner, toluene, xylene, or the manufacturer's recommended solvent. Indoor products can be printed with 80 to 140 mesh screens; outdoor products can be printed with 80 to 110 mesh screens.
2. Solvent type fluorescent ink
If the solvent-based fluorescent ink can be printed better, the brightness can be maintained for the same time as the fast-drying ink, and the outdoor print can be maintained for 3 to 6 months. It takes 1-4 hours for the ink to dry by oxidative polymerization, which is mainly related to the printing substrate, ink layer thickness and workshop conditions. The drying of the ink can also be accelerated by gas heating, infrared rays, and spray drying agents. It is also possible to dry using a common ink drying method. Solvent-based fluorescent inks can be printed with most screen printing and can be printed on paper, wood, glass, metal, decals, and other surfaces with a white base coating. The ink can be printed with 80 to 160 mesh screens. Solvent-based fluorescent inks can be diluted with mineral spirits or the manufacturer's recommended solvent. The printing of letters should be in bold type with some contrast. Do not overprint the varnish on the ink. It will reduce the fluorescence effect. Solvent inks should not be mixed with fast drying fluorescent inks. The use of solvent-based fluorescent inks can be used for wide-format advertising printing. It is also necessary to rinse off the stickers with water.
3. Daylight type fluorescent screen printing ink
Daylight-type fluorescent screen printing ink was put into use in 1948, and it left a deep impression with its neon-like effect, dramatic colors, attractive attraction and artistic expression. Since the gloss, stability, weather resistance and uniform ink film layer of the fluorescent ink make it possible to obtain the best performance in the field of screen printing, screen printing becomes an ideal printing method for the fluorescent ink. The particle size of fluorescent ink pigments is coarser than traditional pigment particles and was first used for rough screen printing. However, in recent years, more and more fluorescent inks that can be used for fine screen printing continue to emerge. Fluorescent inks are mainly used in printing window displays, decals, bumper guards, industrial insurance equipment, body advertising, letterhead, posters (posters), 24 inch posters, notebooks, signal flags, magazine covers, invitations, cloth labels, etc. Due to the great difference between the fluorescent ink and the common ink color -ZIN, the fluorescent ink plays an important role in screen printing outdoor and indoor advertising.
The daylight fluorescent color is best used in dark environments and contrasting colors, especially on white surfaces. For best impact, fluorescent colors should not be used alone. It can be used to highlight some special effects; it can also be set off with 50% gray or the opposite color. Half-tone printing with fluorescent ink is not practical unless the halftone black ink is printed on a surface that has been coated with a solid fluorescent ink. When using fluorescent ink to print text, the space between the letters must be wide enough to facilitate reading. The fluorescent ink should be leveled after printing because the uneven ink film absorbs light, and light and fluorescent ink should be prevented from acting as much as possible.
4. Luminous ink
Luminescent fluorescent inks are best used in screen printing. Luminous ink is made of long-lasting rare earth luminescent materials and made by high-tech means. When it absorbs sunlight for 10-30 minutes during the day, it will continue to emit light for more than 10 hours, so it will continue to glow in the middle of the night, especially when the car is driving in the dark. It shines brightly and eye-catching. It acts as a neon sign, and neon lights need power to shine. While Luminous Ink requires no electricity, saves energy, and is recycled endlessly, also known as solar "neon" advertising.
Luminous ink is non-toxic, harmless, non-radioactive, and has a lifetime of more than 10 years. Luminous fluorescent inks can print the patterns and text you need through screen printing. Design the screen to expose the luminescent layer, do not cover it all, otherwise it will reduce the luminescent effect. In addition, try to be consistent with the design document sent by the customer. If the font in the ad is red, then a 1.5 cm x 3 cm wide luminous ink printed on the outside of the red font, or a blue bottom dew-white font The luminous ink printed in the font is better. The printing of the luminous type fluorescent ink is similar to the printing of the daylight type fluorescent ink, and it cannot be mixed with ordinary ink because ordinary light affects the light emitting effect of the fluorescent ink under the night light.
Fourth, the characteristics of fluorescent ink printing process
Fluorescent inks are suitable for printing on paper and vinyl films. There are two types of paper-based fluorescent inks: oxidative drying and volatilization-drying. The fluorescent film for vinyl films is a volatile drying type. Due to different formulations, resulting in different fluorescent pigment particle sizes, the appropriate type of printing varies with the size of the fluorescent pigment particles. In general, fluorescent inks are generally suitable for screen printing, gravure printing and flexographic printing. The standard size of daylight fluorescent pigments is generally 3.5μm, which can be used for screen printing. The medium size particle size is used for gravure printing and textile screen printing. The ultrafine particle size is mainly used for offset printing, printing and Flexible flexographic printing, where the particles can be as small as 0.25 to 0.5 μm. However, daylight-type fluorescent inks are not suitable for color development when they are used for embossing and offset printing, so they are mostly screen printed. The rheological properties of most fluorescent inks exhibit plastic flow and low viscosity. These characteristics determine that the printing process is different from the printing process of ordinary inks.
Fluorescent inks have three colors, red, green, and blue. The wavelengths of the transmitted light of red and green inks are different from the wavelengths of ultraviolet fluorescence, so the generated fluorescent colors are obvious. When the blue ink is printed on a light or white background, it can be obtained when the ink layer reaches a certain thickness. Better fluorescence effect. Therefore, when there is no special color requirement, red and green fluorescent inks should be used. When screen printing, pay attention to the following points: Fluorescent inks are suitable for screens up to 200 mesh; When printing inks are printed at 50 to 60 g/m2, the hair color and light resistance are ideal; Fluorescent ink printing The life of the product is determined by the ink rather than the product itself; if the quick-drying ink can prevent direct sunlight, the life of the printed product can be greatly improved; the fluorescent ink printing product can be stored without light. And maintain the original appearance; solvent inks do not mix with fast-drying fluorescent inks.
Ma Jintao Screen Printing-2006 No.5
Jinzhou City Hejin Clothing CO.,Ltd , https://www.hejin-cloth.com