Analysis on the cause of ink deposition

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Analysis: causes of ink oil precipitation

stratification, precipitation and precipitation phenomenon: it is almost similar to the acidification situation, but it is not the stratification, precipitation and precipitation caused by the absorption of water in the ink system. Most of them are caused by one or several resins in the ink system are not completely miscible during mixing, or one of them is not dissolved at all (such as turbidity). Packaging printing ink in the printing process, using a single solvent or using the wrong solvent can also lead to floating color, light color and inconsistent ink film gloss

cause: ① the ink has expired; ② It is the precipitation caused by the formation of large flocculating groups of pigments; ③ Is the ink itself is relatively thick, high concentration and low viscosity viscous and poor plastic fluid; ④ Is in addition to storage stratification, precipitation, the ink system in the binder is unstable; ⑤ It is to add bad diluent or inking oil during packaging and printing

method: ① add phenyl ether or propyl ether produced by Shanghai Jinshan Chemical Plant; ② For the problem of ink layering, for example, when polyamide and nitrocellulose are mixed, the cotton solution is usually added first, and then the polyamide solution is added when stirring to eliminate it immediately; ③ If several resins are used for mixing, it is better to use 3%~5% ethylene glycol phenyl ether or propylene glycol benzene ether to make the polymer miscible; ④ Replace the diluting solvent (there will be no delamination, turbidity and whitening after diluting with the ink); ⑤ Add tm-27 coupling agent, bentonite or white carbon black produced by Tianyang chemical plant; ⑥ The problem of ink separation (the surface looks like a layer of resin liquid) is generally caused by the solvent and resin. 1. Oil supply: the hydraulic oil uses 40 × tightening oil or 32 × 46 hydraulic oil to supply the oil hole. The solubility of the resin on the right side of the instrument and equipment is unbalanced. If the elongation is converted into the tensile value, first, calculate the solubility of the solvent and resin and try to reach an agreement. Generally, it is better to be greater than 0.75 and not less than 0.75; The second is to add expansive soil, but silica is usually added to the printing compound ink to prevent pigment precipitation; ⑦ Ink sedimentation, such as ⑥, can also lead to sedimentation of automobile wheels as a product with high safety requirements. Once this fault occurs, the resin should be increased and the amount of pigments and fillers should be reduced; Add wax soil; Prolong the grinding time/i.e. the finer the ink, the better; And add tm-27 coupling agent (which can increase the concentration and improve the adhesion when there is sound); ⑧ Put a stirring stick in the ink fountain; ⑨ Then disperse and filter the ink; ⑩ Replace with new ink; (11) add universal solvent to make several resins in the ink system miscible; (12) use high viscosity ink; ⒀ select pigments with light specific gravity or use anti flocculant; (14) add real solvent with strong solubility

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