(1) The concept of ink The ink is a homogeneous mixture of colored bodies (such as pigments, dyes, etc.), binders, filling (filled) materials, and additives; it can be printed and dried on the printed body; A colored, paste-like adhesive with a certain degree of fluidity.
Therefore, color (hue), body bone (thinning, rheological properties such as fluidity), and drying performance are the three most important properties of the ink.
Many of them are of different physical properties, some are very thick and sticky, and others are quite rare. Some use vegetable oil as a binder; others use resins and solvents or water as a binder. These are based on the printing object, that is, the substrate, the printing method, the type of printing plate, and the drying method.
The ink should have a vivid color, good printability, and a suitable drying speed. In addition, it should also have certain application indicators of solvent resistance, acid, alkali, water, light and heat.
As printing, paper, and other requirements increase, the technical requirements for inks have also increased. Modern high-speed multi-color printers and various color rotary presses require the ink to be dried at a speed of several seconds or even faster. Glass and gold, silver, and coated paper require bright ink. Printed plastic film requires good bonding with the plastic film; or ink that adheres to the plastic film as much as possible. India special prints require the use of photosensitive inks and so on.
The ink is mainly used in the printing industry. Pigments and binders are the two main types of inks that make up the ink.
When a printing operator selects an ink, the color is generally regarded as the first requirement. The color (hue) of the ink is one of the most intuitive indicators. In fact, it is a major indicator of the quality of the printed product. Therefore, the pros and cons of pigments play a decisive role in the quality of inks.
Pigments are solid powdered substances that are insoluble in water, or in oil or binders, and have a certain color. It is not only the main solid component in the ink, but also the part of the color body that is visible on any object. The quality of the ink is determined to a large extent, such as the color (hue), thinness, and the like. It has great influence on viscosity, physical and chemical properties, printing performance and so on. Therefore, the pigments are required to have vivid colors, high concentration, good dispersibility, and other related properties required by the ink.
In fact, perfect colors that are perfect are not existent and can only be met with relative or partial satisfaction.
The binder is an adhesive fluid. As its name implies, it plays a linking role. In the ink industry, powdery pigments and other substances are mixed and mixed, so that after grinding and dispersing, it is possible to form paste adhesives with a certain degree of fluidity.
The binder is a fluid component in the ink. The fluidity (viscosity), viscosity (viscosity), dryness, and printing performance of the ink all depend on the binder. Therefore, the link material is the basis for the quality of the ink.
Most vegetable oils can be used to make ink binders. Some animal oils and mineral oils are also used in ink binders. Solvents and water are no exception.
The emergence of various resins in recent decades has expanded the sources and types of binders.
The filling material is a white, transparent, translucent or transparent powdery material and is also a solid component in the ink. Mainly from the filling effect. In the ink is filled with pigment. Appropriate use of some fillers can not only reduce the amount of pigment, reduce costs, but also adjust the properties of the ink, such as thin, fluidity. It also increases the flexibility of recipe design.
Additives. It is not difficult to understand that the additive is an additional part of the ink except for the main composition. They may be an additional part of the pigment, an additional part of the binder, and may also be an additional part of the finished ink, depending on the characteristics and requirements of the product.
Of course, many additional materials are printing (auxiliary) additives.
At present, there are as many as 5,000 kinds of raw materials used to make ink in the world.
(B) Classification of ink
The problem of ink classification is not strict and unclear in our reality. Therefore, it is very difficult to divide them into very scientific ones.
The problem of ink classification in a broad sense should be classified according to the type of printing, namely, letterpress ink, lithographic ink, gravure ink, and filtered ink. However, such classification is too principled to express all realities. In recent years, due to the ever-increasing variety of inks, new designs have appeared continuously. There are limitations only because of the type.
In addition to classification by type, there are generally classified by dry type. Examples include oxidatively drying inks, osmotic drying inks, volatile drying inks, and freeze drying inks.
There are also classified by product use. Such as book inks, printing inks, glass inks, plastic inks and so on. Also classified by product characteristics. Such as security ink, bright ink, photosensitive ink, transparent ink, electrostatic ink and so on. He also often hears the name of alcohol (soluble) ink and water (soluble) ink, which is a way to reflect their characteristics.
The conditions for classification in the dry form are also relative, for example, the volatile dry ink has both gravure and letterpress and the like.
Therefore, when we discuss the classification of inks, we should first establish a concept based on the type of classification, and then link each other by methods such as drying form, product use, and product property classification, so that we can establish a complete and systematic Classification concept