The use of ink to answer questions

1. The compound ink has no problem in printing, but there is a white point phenomenon in the composite aluminized film, and the hiding power is also greatly reduced. How to deal with the above problem?

First, increase the amount of the colorant in the ink; secondly, introduce the alcohol ether solvent or add the leveling agent when formulating the design; third, add an appropriate amount of antistatic dispersant or auxiliary resin with low viscosity; Fourth, in the printing when the blade is moved up a bit or the printing pressure is increased appropriately, and the printing plate of the deep hole can also be replaced to increase the thickness of the ink film and promote the wet leveling of the ink.

2. When the printing ink is not inked during printing, how to deal with it?

The ink is not adhered to the substrate, indicating that the formula design of the ink is unreasonable. For example, when several mixed solvents are used together, the surface can easily form oil beads. This indicates that the solvent does not have mutual solubility, or the resin in the dissolving ink system is not reached. Solubility. The second is that the thickening of the ink in the ink system is caused by thickening or gelation of the ink. In severe cases, the ink piles at both ends of the plate, and the ink is not transferred or the transfer rate is insufficient.

Before ink production, the first is to design the formula in accordance with the "two-dimensional ink making method"; second, to minimize the amount of thickening thixotropic agent; third, to add a solvent for assisting dissolution during printing; fourth, to avoid contact between ink and water; The fifth is the exchange of new ink.

3, ink color toner is made of what?

In short, resin plus pigments are mixed, milled or filtered. The former is a color film, and the latter is a toner. Producers can choose different pigments for printing applications, especially resins in color chips or toner systems.
4, gravure plastic ink, especially white ink, how to avoid yellowing and increase whiteness?

According to different gravure plastic inks, different formulas should be used, such as polyurethane ink or universal surface printing or universal ink printing. The method used is different. Polyurethane gravure ink systems often contain toluene or xylene. After printing, the graphic ink film contacts the oxygen in the air and yellowish. In particular, the ink composition using anatase titanium dioxide is more yellow.

In order to avoid the above failures, one is to use urethane resin containing no benzene as the binder for the ink system; the other is to change from anatase to rutile. The easiest way is to add 0.01% to 0.03% of brightener or 3% to 5% of TS colorant, which can not only greatly improve the whiteness, but also can significantly reduce the ink cost.
5, PP woven bag flexo ink, especially black ink how to improve the attachment fastness?

The ink system is generally dominated by alcohol-soluble polyamide resins. In order to improve the ink adhesion, one is to introduce an even cross-linking agent or a wetting dispersant or a slow-drying solvent in the ink system; the other is to add a aldehyde-ketone resin; and thirdly, to adjust the surface tension of the ink and the surface of the PP as far as possible during the ink formulation design. Tension design is close to some as well. As for the proportion of resin in the black ink can be larger or add TU-310. If printing, appropriate increase in printing pressure is also feasible.
6, white ink after exposure 1 to 2 hours, the first change from white to yellow, and then gradually faded color, how to explain and deal with this problem?

The yellowing of white can be seen in point 4 of this article. However, fading from the yellow to colorless, mainly related to titanium dioxide. Because anatase titanium dioxide itself is acidic, plus some ink manufacturers do not ask the ink category, all adding brighteners, which not only accelerate the process of yellowing, but also because of the use of non-optimized brighteners have played an oxidant Effect, which led to the emergence of the above failures.
In order to overcome this failure, the introduction of anti-ultraviolet absorbers or mica powder in the ink system can also be changed to rutile titanium dioxide for future success.
7. How to increase the gloss of PP woven bag ink?

The first proposal is to increase the resin content, the second is to add leveling additives, the third is to add the boiling point in the ink system at 150 °C ~ 245 °C solvent 3% to 5%, the fourth is to add polyketone or 3% -5% of Darma resin, The fifth is to extend the grinding time of the ink or add about 3% of erucic amide as a flexible filming aid for the ink, so as to promote the increase of gloss through the diffusion and flow of macromolecules. The proper crystallinity of the ink improves the cohesion and adhesion of the printing ink.
8. When the thermoplastic PU resin is used, the glossiness of the blue-black and black ink produced is reduced, and the coloring power is deteriorated. What causes this is, and how is it handled?

In the PU resin ink system, the above phenomenon is often caused by the failure of a single solvent to fully achieve the solubility of the PU resin. When we add a cosolvent solvent or a coupling dispersant, its solubility is close, the transparency is good, and the coloration of the ink is improved. Of course, there is also a poor pigment dispersion, or a short polishing time, and the thick ink is the cause of the above phenomenon. This not only reduces the gloss of the ink film, but also the ink is not as bright as the coloring power. For this reason, it is recommended to extend the grinding time. Addition of solvent for dissolution (for example, toluene solvent can be mainly added with butanone, isopropyl alcohol can be mainly added with n-butanol) or slow-drying solvent can improve the luster of printing ink film. degree.
9, CPP resin plus toluene solvent ink, the ink stored for some time, CPP tends to precipitate on the surface, if the winter is obvious, this is why?
CPP resin plus toluene solvent solution, the reason for the above failure after ink production is that the solubility between CPP resin and toluene is approximately
10% difference. Since the CPP and toluene are dissolved under certain temperature conditions or under certain shear conditions, due to the difference in solubility,
CPP (precipitation) instability is a common occurrence. The level of CPP added to the chlorine content will also cause the above problems. For this reason, it is recommended to add some butanone or ethyl ester as the auxiliary solvent is often very effective. The addition of alcohol ether ester solvent can not only improve the water resistance of CPP, but also enable CPP and toluene to be mutually soluble, thereby reducing the solvent residue in the printing ink graphic ink film.
10, how to reduce the ink material cost?
(1) Reducing the resin content, or reducing the resin with high price and low supplemental price is an auxiliary resin.
(2) Increase the thickening thixotropic agent and reduce the proportion of resin and pigment.

(3) When designing ink formulations, ink formulations with similar solubility of resin and solvent, similar hydrogen bond strength, similar surface tension, and similar volatilization velocity should be considered. Generally, the dilution solvent is increased by 30% to 50% without affecting the ink quality. And ink formulations. For example, the principle of inorganic binder: acid, alkali, similar structure, ionic radius ratio and compatible number.

Because the binder in the ink is a liquid dispersion medium, it is a carrier for pigments and fillers, it has a certain viscosity and fluidity, film formation, can effectively disperse pigments and fillers, giving the ink flow ability, Printing ability and film forming ability.
11. The ink on the printing plate is not clean, how to solve it?

The reason that the ink is not clean is that the content of the resin in the ink system is too high, especially caused by the long oil of the oil (or the length of the ink pulled out), and also caused by the static electricity of the ink. There is also ink that is too soft (ink film) or the plate is not smooth. In a word, ink does not "stand up" and requires "standing without stickiness."

The usual processing method is: the printing speed should be fast, select the ink with short oil, or increase the proportion of antistatic agent, or use a harder ink, the system resin has a high softening point. At the time of printing, a diluting agent or diluent containing a filler is added to reduce the filament of the ink (the thermoplastic resin may be formulated with a thermosetting resin, and the single type may be added with a curing agent). Add wax or other thickeners to remedy the problem by letting the ink “stand up” or replacing plates.
12. The ink's scratch resistance is poor. After the wax powder is raised to 5%, it will not work. It will not work if the amount of nitrocellulose is increased. What is the reason and what should be done?

The main reason why the ink film is not scratch resistant after printing is: the ink film is too soft or