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Answers to Ink Tips

  • Company News | 2023-09-25

  1, composite ink in the printing no problem, but in the composite aluminium film when there is a white spot phenomenon, while the covering power is greatly reduced, how to deal with the above problems? Today, we introduce the content in detail.


  First, in the ink to increase the amount of colouring materials; second, the introduction of alcohol ether solvents or add levelling agent in the design of the formula; third, increase the amount of antistatic dispersant or low viscosity auxiliary resins; fourth, in the printing of the squeegee to move up a little bit or the printing pressure to appropriately increase some of the printing, but also can be transferred to the plate cavity of the deep printing plate, in order to improve the thickness of the ink film and to promote the wetting and levelling of the ink.

  2、Sheet printing ink in the printing does not ink, how to deal with?

  Ink attached to the substrate, the ink formula is not reasonable, such as several mixed solvents together when the surface is very easy to form oil beads, which means that the solvent is not soluble in each other, or not up to the solubility of the resin in the dissolving ink system. The second is the ink system in the ink thickening back to the thick or gelatinisation caused by the ink pile at the ends of the printing plate in serious cases, the transfer of ink on the transfer or transfer rate is insufficient.

  Before the production of ink, one is as far as possible in accordance with the "two-dimensional ink method" to design formulations; two is to minimise the amount of thickening thixotropic agent; three is to add solvent solvents in the printing; four is to avoid contact between the ink and water; five is to switch to a new ink.

  3、What is the ink colour chip toner made of?

  In short, it is made of resin and pigment by mixing, milling or filtering. The former are colour chips and the latter are colour powders. The producer can choose different pigments according to the printing application, especially the resin in the system of colour flake or colour powder.

  4、Gravure plastic ink, especially white ink, how to avoid yellowing and improve whiteness?

  According to different gravure plastic ink, should be used in different formula design, such as polyurethane ink or universal surface printing or universal printing white ink its method is different. Polyurethane gravure ink system often contains toluene or xylene, after printing the graphic ink film contact with oxygen in the air will be yellowed, especially the ink composition of the use of titanium dioxide titanium dioxide is more likely to turn yellow.

In order to avoid the above failures, one is to change the use of benzene-free polyurethane resin as the linker of the ink system; the second is to change from anatase to rutile. The easiest way is to add 0.01% - 0.03% of the whitening agent or 3% - 5% of the TS colouring material, which not only can greatly improve the whiteness, but also significantly reduce the cost of ink.

  5, PP woven bag flexo printing ink, especially black ink how to improve adhesion fastness?

  The ink system generally choose alcohol-soluble polyamide resin is mostly. In order to improve the adhesion of ink, one is the introduction of a pair of crosslinking agents in the ink system or wetting and dispersing agents or slow drying solvents; the second is the addition of aldehydes and ketones resins; the third is in the design of ink formulations, as far as possible, the surface tension of the ink and the design of the surface tension of the PP close to some of the best. As for the black ink in the proportion of resin can be a little larger or add TU-310, if in the printing, the appropriate increase in printing pressure is also feasible.

  6, white ink after exposure to the sun for 1 - 2 hours, first from white to yellow, and then the colour gradually faded, how to explain this problem and deal with it?

  White to yellow can refer to point 4 of this article. But by yellow gradually faded to colourless, mainly related to titanium dioxide. Because the titanium dioxide titanium dioxide itself acidic, plus some ink manufacturers do not ask the ink category, collectively adding a whitening agent, which not only accelerates the process of yellowing, but also due to the lack of proper use of the whitening agent instead of playing the role of oxidation, which led to the emergence of the above failure.

  In order to overcome this failure, the ink system in the introduction of anti-ultraviolet absorber or mica powder to prevent it, but also can be changed to rutile titanium dioxide in order to eliminate the problem.

7, how to improve the gloss of PP woven bag ink?

  It is suggested that one is to improve the resin content, the second is to add levelling additives, the third is to add the boiling point in the ink system at 150 ℃ - 245 ℃ solvent 3% - 5%, the fourth is to add a polyketone or Damar resin 3% - 5%. Five is to extend the grinding time of the ink or add about 3% of the erucic acid amide as the ink's flexible film-forming additives, prompted by the diffusion of macromolecules, flow to achieve the improvement of gloss. Appropriate crystallinity of the ink can improve the cohesion and adhesion of the printing ink.

  8, the use of thermoplastic PU resin, the production of blue-black and black ink gloss drop, colouring power deterioration, which is caused by what reason, and how to deal with it?

  In the PU resin ink system, often due to a single solvent can not fully reach the solubility of PU resin caused by the above phenomenon. When we add co-solvent or coupling dispersant, its solubility is close, the transparency is good, and the colouring of the ink is improved. Of course, there is a pigment dispersion is bad or grinding time is too short, the ink is coarse are the causes of the above phenomenon. This not only makes the ink film gloss decreased, and the ink is neither bright colouring power and poor. To this end, it is recommended to extend the grinding time, supplemented by solvent (such as toluene solvent-based can be added to butanone, isopropanol-based can be added to n-butanol) or slow drying solvents can improve the gloss of the ink film of the printed graphic.

  9, CPP resin and toluene solvent made of ink, ink stored for a period of time, CPP tends to precipitate to the surface, if in the winter is the official obvious, this is why?

  CPP resin plus toluene solvent solution, the production of ink after the occurrence of the above failure is due to the solubility of CPP resin and toluene has a solubility of about

  There is a difference of about 10% between the solubility of CPP resin and toluene. Since the difference in solubility between CPP and toluene is dissolved under certain temperature conditions or under certain shear force conditions despite the fact that

  CPP (precipitation) instability is common. The level of chlorine content of the added CPP also causes the above problem. For this reason, it is often effective to suggest the addition of some butanone or ethyl ester as a co-solvent. Adding alcohol ether ester solvent can not only improve the water resistance of CPP, but also make CPP and toluene to achieve mutual solubility, to achieve a reduction in the printing ink graphic ink film in the solvent residue.

  10、How to reduce the material cost of ink?

  (1) Reduce the resin content, or reduce the high price and supplement the low price of resin as auxiliary resin.

  (2) Increase the thickening thixotropic agent, reduce the proportion of resin and pigment.

  (3) The design of ink formulations should focus on the solubility of the resin and solvent solubility, hydrogen bonding force is similar, surface tension is similar, similar volatility ink formulations, generally increase 30% -50% of the dilution of the solvent without affecting the quality of the ink and ink formulations. For example, the principle of inorganic linker: acid, alkali, similar structure, ionic radius ratio and the number of matching is similar.

  Because the linker in the ink is a liquid phase dispersion medium, is the carrier of pigment and filler, it has a certain viscosity and mobility, film-forming, can effectively disperse the pigment and filler, gives the ink flow ability, printing ability and film-forming ability.

  11、How to solve the problem that the ink on the printing plate cannot be scraped clean?

  Ink scraping is not clean because: the ink system in the resin content is too high, especially the oil (or the ink pulled out of the filament length) long resin caused by the ink static electricity. There are also ink too soft (ink film) or printing plate is not smooth. In a word, the ink "can not stand up", the requirements of "standing and not sticky".

  The usual treatment is: fast printing speed should choose a short oil ink, or increase the proportion of antistatic agent, or choose a little hard ink, the system resin softening point is high. In the printing, adding a filler containing diluent or thinner to reduce the ink filament (thermoplastic resin can be matched with a little bit of thermosetting resin, a single type can be added to the curing agent). Add wax or other thickeners to make the ink "stand up" or replace the printing plate and other methods of remedies.

  12, the poor scratch resistance of the ink, wax powder to 5% after the increase is not working, improve the nitrocellulose dosage is not working, what is the reason? How to deal with?

  This may be due to the ink itself is not dry enough, the ink itself after drying the hardness to reach a relatively high level before you can also add a layer of varnish on the original ink but this varnish (fog oil), not enough to the hardness of the requirements of a relatively high level.

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