Whitening phenomenon of printing ink film

1 point whitening. The main reason is that the ink feeding system causes poor mutual solubility of wax surfactants, and the second reason is that the printing process is not reconstituted after the ink crust is transferred to the graphic.

Treatment method: Aromatic hydrocarbons or ester solvents should be added to promote re-dissolution. Or install a stirrer in the ink Fountain (such as using plastic pipe, cover it with unprinted plastic film on the outside, and then turn the two heads tightly in the ink head to randomly stir the ink), or add resistance when the ink is made Oxygen treatment.

2-point white point. The main cause is the static electricity of the ink or the static electricity of the substrate. Or due to the dilution of solvent generated static electricity (due to different solvents have different resistance). Usually occurs when the temperature is high or the printing speed is high. Secondly, when the film is tight, it is loosened or loosened before it is tight, and the static electricity is often caused by high humidity.

Treatment method: In the ink can increase the amount of antistatic agent (excess will affect the composite fastness), select the solvent resistance of the solvent dilution ink, adjust the release, take the ground wire (general depth of 700 ~ 1500 mm) to deal with it.

3 Cracked Albino. One of the main reasons is that the ink transfer performance is poor, and the second is that the plate pattern is too shallow and it is very easy to volatilize the solvent in the ink system too quickly.

Roughness of the general imprinting results in poor film formation, especially when the ink system or the ink fountain thinner is added to inhale moisture and whitening occurs, mostly in an environment where the humidity of the summer workshop is too high.

Treatment method: Replace the ink with good transferability or replace the deeper plate, and add the slow-drying solvent to it.

4 Bleaching of the whole block. One of the main reasons is that when the continuous printing time is too long, the operator repeatedly adds a single solvent when it is found that the viscosity of the ink becomes sticky or thickens, thereby breaking the balance of volatilization of the mixed solvent in the original ink system, resulting in printing ink. The ink layer is rough and white when forming a film. The second is that the operator has added the mixed solvent even if it is added in excess, but the amount of the synthetic resin contained in the ink is relatively reduced, and the above whitening phenomenon may also occur. Treatment methods: First, add 3% to 7% of slow-drying solvents, especially the real solvents that can increase the resistance of the ink to the invasion of water molecules; the second is to use a special diluent containing resin; the third is to add 5 to the ink. % ~ 15% of the oil varnish to overcome the whitening caused by the lack of resin content, the fourth is installed in the workshop can regulate the temperature and humidity of the central air conditioner or eliminate it with a moisture absorber.