Introduction to the hottest liquid crystal ink

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Introduction to liquid crystal ink (Part 2)

III. printing of liquid crystal ink

liquid crystal ink printing refers to printing with ink mixed with liquid crystal, so that the printed product has reversible or irreversible reaction. The key of liquid crystal printing technology is to display bright colored liquid crystals at different temperatures, and to form a series in the color gamut value. The production of liquid crystal microcapsules is also the key. Microcapsules are required to be small and uniform, the capsule wall is transparent and thin, mixed with ink, and solvent resistance is required to be stable, reliable, and long life; Ensure that the liquid crystal microcapsules are not crushed during the printing process; The surface is covered with protective film, etc

1. Plate making

(1) generally, nylon or polyester can be selected. If the ink load is large, stainless steel wire version can be used

(2) the number of wire mesh should be 100 ~ 175 mesh, which should be selected according to the requirements of ink microcapsule diameter and ink layer thickness. Because the silk liquid crystal microcapsule ink is water-soluble, (1) principle, so when making plates, we should use the mechanical grinding equipment with strong water resistance, which is widely used at present is the pre grinding photosensitive glue

2. When printing with liquid crystal ink, pay attention to the following points:

(1) when printing, pay attention to that the printing plate should be filled with enough ink at one time, the ink should be evenly fed, and it is best not to replenish the ink halfway to prevent foaming

(2) because the microcapsule ink is easy to block the plate, when blocking and foaming are found in printing, it is necessary to stop the machine immediately when measuring and recording the change of signal voltage, and thoroughly clean it with alcohol water

(3) the printing pressure should be moderate. Low pressure, insufficient ink on the substrate, will affect the color effect; Excessive pressure will cause the liquid crystal capsule to rupture

(4) in order to make the hair color of the printing part obvious, the printing bottom can reach 0.001 ⑴ 000mm/min color should be black or dark. The background color can be printed with water-soluble ink or organic solvent ink. After printing, it must be fully dried, and the ink film must not remain organic solvents, otherwise it will react with the liquid crystal and affect the color effect

(5) in the printing process, pay attention to the smooth and bright ink layer, and the thickness of the ink layer should be controlled within 15 ~ 35 μ m。 Uneven or too thin ink layer will reduce the ink color effect. Measures should be taken to thicken the ink layer during the printing process, such as using a scraper with soft hardness, a smaller scraper angle, a larger distance, and improving the ink viscosity

(6) printing color sequence arrangement. Black (or dark) ink can be used to print the background color, and then LCD ink can be used to print the required pattern; You can also print the base with liquid crystal ink first, and then print the required negative pattern with water-soluble black (or dark color) ink to cover it

3. Post press treatment

(1) the best drying method for printed matter is natural drying, or hot air drying at about 40 ℃

(2) do not press hard when stacking printed matter. Try not to stack and overlap too much after drying, and do not apply too much local pressure during cutting, so as to prevent the liquid crystal microcapsules from being crushed

(3) when using liquid crystal ink, the color change temperature range and the durability of liquid crystal should be determined according to the purpose of use

in order to improve the wear resistance, temperature resistance, gas insulation and maintain its gloss of the ink layer surface, the surface can be coated with gloss paint or pasted with protective film

source: fine chemicals in the 21st century

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