Printing of the hottest liquid crystal ink 0

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Printing of liquid crystal ink

according to practice, the printing method of liquid crystal ink can be plate printing or gravure printing, but plate printing is better, the odor score ≤ 3, and the formaldehyde content ≤ 10mg/kg. Liquid crystal ink printing is a printing method in which the ink mixed with liquid crystal makes the printed matter have reversible reaction or irreversible reaction. The key of liquid crystal printing technology is that liquid crystal can display bright colors at different temperatures, and it should be in series in color temperature range. The manufacturing technology of liquid crystal microcapsules is also the key. Microcapsules should be small and uniform, and the capsule wall should be transparent and thin. It is required that the ink mixed should be solvent resistant, stable, reliable and long life; During the printing process, it is also necessary to ensure that the liquid crystal microcapsules are not crushed, and the surface is covered with a protective film

when printing, the liquid crystal is sealed in the microcapsule and mixed with a certain amount of ink for printing. Liquid crystal encapsulation has the following advantages: it can prevent the pollution of liquid crystal itself; It can play a protective role, extend the service life of imitating the stress condition when the cab is overturned, and facilitate long-term storage; Improve printability. The amount of liquid crystal added into the ink is 40% of the total amount of ink, and the diameter of the capsule is 10 ~ 30 μ m。

1. plate making

nylon or polyester can be used for general silk plate. If the ink load on the printing plate is relatively large, the stainless steel wire version can be used. According to the requirements of the diameter of the ink microcapsule and the thickness of the ink layer, the number of wire mesh is selected, 100-175 mesh is appropriate. Because liquid crystal microcapsule ink is water-soluble, photosensitive adhesive with strong water resistance should be used in plate making

2. Printing

pay attention to the following points when printing with liquid crystal ink

(1) when printing, it should be noted that the printing plate should be filled with enough ink at one time, and the ink should be given evenly. 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 blistering are found in the printing, stop the machine immediately and clean it thoroughly with alcohol water

(3) the printing pressure should be moderate. When the pressure is small, the amount of ink on the substrate is insufficient, affecting the hair color 12 The effect of using standard database to manage experimental data; When the pressure is too high, it will cause the liquid crystal capsule to rupture, so that the hair color effect is not ideal

(4) the printing background color should be black or dark to improve the hair color effect. The background color can be water-soluble ink or organic solvent ink. Printing methods include printing, offset printing and gravure printing. When using organic solvent ink, it must be fully dried after printing, otherwise the residual organic solvent will react with liquid crystal and affect the chromogenic effect

(5) pay attention to keep the ink layer smooth and bright during the printing process, and the thickness of the ink layer should be controlled to 15-35 μ m. This can greatly improve the hair color effect. Uneven or too thin ink layer will reduce the ink effect. Some measures should be taken to thicken the ink layer in the printing process, such as using a soft scraper, a slightly smaller scraper angle, a slightly higher distance, and improving the viscosity of the ink

(6) printing color sequence arrangement. You can use black (or dark) ink to print the background color first, and then use liquid crystal ink to print the desired pattern; You can also use liquid crystal ink to print the background color first, and then use water-soluble black (or dark color) ink to print the required negative pattern

(1) when drying printed matter, it is best to use natural drying, or hot air drying at about 40 ℃. Do not accelerate and heat it for high-temperature rapid drying

(2) do not press the printed matter heavily when stacking, and try not to stack and overlap too much after drying. 7: hydraulic cylinder and control valve: the hydraulic cylinder is specially customized, and it is not suitable to add too much local pressure, so as to prevent the liquid crystal microcapsule from being crushed

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

reprinted from: China washing and dyeing industry information center

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