Printing ink is a paste-like colloid composed of colorants, linking materials, fillers and other ingredients evenly mixed. As a kind of viscous fluid ink, due to its different varieties, its performance is also different, that is, there are thick and thin points, differences in viscous strength, fast drying and slow drying, and so on. Therefore, it is of great significance to correctly understand and understand the role of ink components in ink for accurately adjusting ink characteristics, satisfying the creativity of various printing conditions, and improving product printing quality.
1. The role of colorants in ink
Colorants include pigments and dyes. The colored materials used in printing inks are usually pigments, and some dyes are also useful, which are colored substances with extremely fine particles. Pigments are generally insoluble in water and in the linking material, and most of them are in a suspended state in the solution, while dyes are generally soluble in the linking material. Pigments have a great influence on the performance of inks. The relative density, transparency, heat resistance, light resistance and resistance to chemicals of inks are all related to pigments. The role of pigments in ink is obvious, its color determines the hue of the ink; its amount determines the concentration of the ink; its use gives the ink a certain consistency and other physical properties; its use affects to a certain extent The dryness of the ink is particularly prominent for inks that are mainly dry by oxidative polymerization. In addition, the durability of the ink in all aspects is also determined by the pigment. Therefore, due to the different types and uses of inks, the matching of pigments is also different. This requires that suitable inks should be selected according to product uses and process characteristics during printing. For example, bright light should be used for printing packaging products with high-speed multi-color printing machines. , Fast curing, wear-resistant ink to ensure printing quality.
2. The role of the linking material in the ink
Binder is a kind of fluid with certain viscosity and viscous, and its function is various. As a pigment carrier, it can mix and link solid particles such as powdered pigments, and make the cohesive pigments finally adhere to the printed matter. While affecting and determining the fixing speed, drying speed and drying type of the ink, the linking material can also give the ink a certain physical properties such as gloss, friction resistance, yellowing resistance and impact resistance, and to a large extent It determines the viscosity, viscosity, yield value and fluidity of the ink, so high-quality ink comes from high-quality binders. If the preparation of the linking material or the production process are not suitable, not only will the ink lack bright and glossy colors after printing, but it will also cause chain quality failures such as pasting, smearing, printing through, paper pulling, and ink failure, which will affect normal printing. present certain obstacles. Therefore, the binder is a factor that has a great influence on the quality of the ink.
3. The role of fillers in ink
The filler is a white solid substance that can be uniformly and well dispersed in the binder, and is in the form of a fine powder. When the fillers are mixed and ground in the binder and become slurry, some are transparent and some are opaque. Commonly used fillers are aluminum hydroxide, potassium sulfate, magnesium carbonate and calcium carbonate. In the ink, the filler can adjust the consistency, viscosity, viscosity, fluidity and yield value of the ink on the one hand, and can adjust the ink concentration on the other hand. That is to say, when the ink concentration is large and the hue is deep In some cases, the dilution effect can be achieved after adding fillers. Although the filler plays an auxiliary role in the ink, its performance has many requirements consistent with that of the pigment, and it also plays a role in affecting the dryness in the ink that is mainly dried by oxidative polymerization.
4. The role of additives in ink
For printing operators, the ink has good printability, and it can be put into use as soon as the can lid is opened, which is of course the most convenient and trouble-free. However, due to the difference in temperature and humidity in the printing environment, the characteristics of the printing material and the printing process conditions, such as the water content of the paper, the pH value of the printing machine, the speed of the printing machine, the overprinting method, etc., although there are various types of inks, each The ratio of pigments, binders and fillers used in inks is almost constant, and often cannot meet the printability requirements of various conditions. Therefore, from the perspective of improving printing efficiency and quality, according to the changing printing conditions, it is beneficial to properly add some additives to the selected ink to ensure normal printing.
(1), the role of varnish
Commonly used varnishes are No. 6 and No. 0. No. 6 varnish is used to increase the fluidity of the ink, improve the transferability of the ink, and reduce the concentration, viscosity and dryness of the ink. No. 0 oil has a relatively high viscosity. When the viscosity of the ink is insufficient and the ink color is blurred or even the ink is poorly distributed, an appropriate amount of No. 0 oil is loosened and added to the ink to increase the viscosity and adhesion of the ink.
(2), the role of adhesive
Detackifier is a kind of waxy paste mixture with loose and lubricated texture. Adding an appropriate amount of ink can reduce the viscosity of ink, reduce the problems of paper pulling and powder falling, and improve the uniformity of ink distribution.
(3), the role of anti-sticking agent
Overprinting is a common fault in the color printing process. After adding an appropriate amount of anti-sticking agent to the ink, it can prevent the backside from being dirty due to the wet ink layer in the stack of printed sheets, thereby ensuring product quality.
(4), the role of additives
It is a white transparent paste-like substance. After adding ink in an appropriate amount, it can eliminate the phenomenon of paper hair loss and powder loss, so as to prevent the occurrence of powder and paste problems on the layout and blankets.
(5), the role of desalination agent
The lightening agent is a kind of ointment-like transparent substance, which has good gloss and good printing performance. After adding colored ink, it can play a printing process effect of diluting the hue of the ink.
(6), the role of anti-friction agent
It is made of polyethylene wax and high boiling point kerosene. Adding 1%-5% anti-abrasion agent to the printing ink can improve the wear resistance of the printing ink layer and reduce the viscosity of the ink to reduce the occurrence of sticking. dirty chance.
(7), the role of anti-drying agent
After the anti-drying agent is added to the ink, it can inhibit the oxidation and polymerization of the ink, and slow down the drying speed of the ink conjunctiva. Spraying the anti-drying agent on the ink transfer carrier such as the ink roller can play a role in anti-drying, which brings convenience to stop and start printing in the middle of printing.
(8), the role of desiccant
There are two types of desiccants: white dry oil and red dry oil. Red dry oil is a desiccant mainly composed of cobalt naphthenate. It is a purple-red slurry liquid. It is suitable for adding to dark ink. The drying method is to dry the surface of the ink layer first, and the dosage is 1%. -2%. White dry oil is composed of metal salts of cobalt, manganese and lead, commonly known as mixed dry oil, which has the effect of drying the ink film inside and outside. Its dryness is not as strong as red dry oil, but the drying effect is better, and It is white and translucent, and it has no effect on the hue after adding light-colored ink.
(9), the role of varnish
In addition to being used for glazing, varnish is added to the toppan printing ink with an appropriate amount of varnish, which can not only increase the fluidity of the ink, but also facilitate the uniform distribution of ink, and can greatly improve the brightness of the printed ink film, making the ink layer It has a certain degree of wear resistance, light resistance and good effect of preventing fading. Due to the fast conjunctiva of bright oil, the drying speed of the printing ink layer is also accelerated after adding ink, so this situation should be fully considered when adjusting the ink.
In short, the composition and auxiliary materials of ink are the basis of ink and imprinting. Understanding and mastering this knowledge, understanding the performance and use of ink, and avoiding blindness in printing workmanship and product quality are of great importance. very important.
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