Rotating offset ink performance

Rotating offset ink consists of four parts: connecting material, pigment, filler and additive.
1. In the
industry, the connecting material is a liquid with a certain viscosity, and its quality directly affects the performance of the ink. Since pigments are generally solid powders, they need to rely on the wetting of the connecting material to be studied by the grinding machine, and also rely on the viscous effect of the connecting material to achieve the transfer of

. In print, the connecting material also acts as a protective ink film and substrate, and presents the necessary gloss. To a large extent, the connection material determines the viscosity, viscosity, dryness and fluidity of the ink. For high-quality inks, high-quality connecting materials must be used.
At present, several large-scale rotating offset ink production plant production of the main selection of resins are petroleum resin, modified petroleum resin, pine modified phenolic petroleum resin and nitric acid resin, etc. ;
the proportion of connecting materials in rotating offset inks is large, at 60%-70%, and will vary with the production process, ambient temperature and printing models. If the fabric preparation is not suitable or the production process is not appropriate, not only can not print a bright color, good gloss newspaper, but will cause printing ink, the edge of the picture sticky, the back of the newspaper dirty, through printing, paper wool and a series of printing failures.
2. Pigments
pigments are another important component of ink, the proportion of ink is 15%-20%, and its proportion directly affects the color saturation of ink and ink cost.
Ink in the printing is the final performance of the color presented by the pigment, pigment in the ink can be summarized as follows: show the color of the ink and ink color concentration; Ink pigments must have a high coloring force, chemical stability and light resistance, but also in the connecting materials have a better dispersion capacity, particles to be fine.
rotation offset printing ink due to its specific transfer process, the ink layer is relatively thin, so the color saturation of pigments is required to be high, the color phase to be pure. At present, the domestic large-scale ink factory pigments are carefully designed to meet its concentration, gloss, printing performance and other requirements.
In actual production, because carbon black has low price, good covering power, strong coloring, light resistance, heat resistance, high moisture resistance and good chemical stability and other advantages, most manufacturers choose carbon black as the main pigment of black ink. Because organic pigments are bright in color, stable in performance and affordable, ink mills mainly use organic pigments in the production of color inks. Such as the use of pinion ink is aloin nitrogen pigment, yellow ink mainly uses bi-aloin aniline yellow pigment, blue ink mainly uses indistin pigment.
3. Filler
filler in offset ink is a white solid powder that can be evenly dispersed in the connecting material, the main effect is to increase the solid content of the ink. At present, the filling materials used in rotating offset inks are mainly ultra-fine calcium carbonate (CaCO3), bentonite and gas-phase silicon dioxide (SiO2).
the role of fillers in ink is: to regulate the consistency and ink, such as viscosity, flow, density and concentration;
4. Additives
As the name implies, is in ink manufacturing and printing, in order to improve or highlight a certain characteristics of ink materials used in inks, inks used in a variety of additives, rotating offset printing inks are commonly used additives mainly thinners, adhesives, dryers, surfactants, ink balance agents and so on.
(1) thinner, its role is two, one is to make the ink thinner, increase the fluidity of the ink; At present, most of the domestic newspaper printing presses use the under-ink way to ink printing, but in the past two years, some newspaper printing plants have purchased the ink-out mode of newspaper printing press, this ink-out mode of ink performance requirements are higher, one of the outstanding points is to require good ink mobility, sometimes need thinner adjustment flow. In addition, in the printing process due to poor paper quality, resulting in paper hair, paste and other issues, add a small amount of thinner, can reduce the viscosity of the ink.
(2) de-adhesive, also known as de-adhesive, the use of adhesive is to reduce the viscosity of the ink, without affecting the body bone of the ink. Rotating offset printing machine used newsprint if its paper fiber combination is poor, poor surface strength, poor ink absorption of the paper, water resistance is not enough, or the printing workshop temperature is too low, as well as the ink itself is too viscous, printing will cause paper wool or picture part of the ink pile and other phenomena, in this case, the appropriate use of adhesive can effectively reduce such failures. The amount of de-adhesive is generally 3% - 5% of the ink, when used according to the actual printing situation as required to add.
(3) drying agent, also known as desiccant, is a very important additive in ink. It is the catalyst for the oxide polymerization conjunctivum of dry vegetable oil, and the drying method combined with osmosis drying depends on its catalytic drying. Ink is mainly osmotic dry ink, so in the production of rotating offset ink should be used as little as possible or do not use detergent, otherwise ink and air contact time is slightly longer, the surface of the ink will appear oxide conjunctivation (ink epithelial phenomenon), affecting the use of ink.
(4) surfactants, also known as dispersants. The surfactant wets the surface of the pigment, shortens the grinding time when the ink is manufactured, facilitates the dispersion of the pigment, and sometimes significantly reduces the suction of the pigment. When manufacturing high concentrations of ink, the yield value of the ink can also be reduced and the concentration and precipitation of pigment particles in the ink can be prevented. The amount of surfactant added is generally 1% - 3% of pigment dosage, surfactant selection to reduce the surface pressure of the connecting material, thereby increasing the wetting capacity of pigments as well. Excessive use may result in pigments gathering in chunks, which is not conducive to grinding.
(5) ink balancer, also known as anti-emulsifying agent, dosage is generally less than 1%. Ink film between the ink rollers are cut and constantly in contact with the moisturizer, under normal circumstances, the moisturizer to enter the ink, if the water intake is appropriate, the ink flow, viscosity and other performance is not significantly damaged, printing is not affected, that is, printing can achieve the ideal state of ink balance. When the ink balance performance is not good, there may be two kinds of situations, one is the ink hydrophobic is too strong, the layout part of the text to accept the wetting fluid because of water beads or water vapor attachment and reprimand ink, and finally lead to white spots in the newspaper, thin lines, intermittent or fine dot disappear; Strong sex, so that the moisturizer into the ink too much, ink shorter, poor transmission, slow drying, because the ink bucket constantly supply new ink and it is difficult to achieve ink balance in a short period of time, so the ink performance of the printing press will change with ink addition, shutdown, scraping, paper change and other operations, resulting in instability of newspaper printing quality.
in short, the amount of additives in ink is not large, but can significantly improve or change the performance of certain aspects of ink, without too much impact on the overall performance of ink. Therefore, ink additives have become an indispensable part of ink production and use.
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