In the field of modern printing, ink is a key consumable, and its performance directly affects the quality and efficiency of printing. With its unique drying characteristics and comprehensive performance, medium fast-drying offset printing ink plays an important role in many printing scenarios, and is widely used in book printing, packaging printing and other industries, becoming an indispensable means of production for printing enterprises.
1. Drying principle of medium quick-drying offset printing inks
The drying process of medium fast-drying offset printing inks combines two mechanisms: oxidative polymerization drying and permeation drying. Oxidative polymerization drying is the oxidation polymerization reaction of the unsaturated double bonds of dry vegetable oils (such as linseed oil, tung oil, etc.) in the ink under the action of oxygen to form polymers, so that the ink can be transformed from a liquid state to a solid state and dry the conjunctiva. In this process, the drier plays a key role in accelerating oxidative polymerization, and by reducing the activation energy of the reaction, the drying reaction can be completed in a short time. Penetration drying is based on the porous structure of the paper, and some of the low molecular weight components in the ink (such as mineral oil and other solvents) penetrate into the paper under the action of printing pressure, so that the solid components such as pigments and resins are concentrated and aggregated on the surface of the paper, thereby accelerating the drying of the ink. In the actual drying process, the two drying methods cooperate with each other, oxidation and polymerization drying to form a solid ink film, giving the ink good wear resistance and gloss; Penetration drying quickly reduces the viscosity of the ink surface, prevents the back of the printed matter from being dirty, and ensures the continuity of printing production.
2. Composition of medium quick-drying offset printing inks
Medium fast-drying offset printing inks are mainly composed of pigments, connecting materials, fillers, additives and other components. Pigments give ink color, and its type and quality directly determine the hue, brightness and saturation of the ink. Common organic pigments such as azo pigments, phthalocyanine pigments, etc., have high tinting strength and bright color; Inorganic pigments, such as titanium dioxide and carbon black, play an important role in white and black inks. The binder is a key component of the ink, which plays the role of dispersing pigments, transmitting printing pressure, and drying and film formation. The binder of medium fast-drying offset printing inks usually uses a mixture of dry vegetable oil and synthetic resin, which provides good oxidative polymerization properties, and synthetic resins (such as rosin-modified phenolic resins, alkyd resins, etc.) improve the printability, gloss and hardness of the ink. Fillers such as barium sulfate, calcium carbonate, etc., are mainly used to adjust the color intensity of inks, reduce costs, and improve the fluidity and printing performance of inks. Although additives make up a small proportion of inks, they are critical to the optimization of ink properties. Drier accelerates ink drying, dispersant promotes uniform dispersion of pigment in the connecting material, anti-crusting agent prevents surface crusting of ink during storage, and defoamer eliminates air bubbles in ink to ensure the stability of printing quality.
3. Performance advantages
Moderate drying speed
Compared with quick-drying offset printing ink, medium fast-drying offset printing ink has a slightly slower drying speed, but it can achieve initial drying in a short time after printing, which meets the time interval requirements of multi-color overprinting and effectively reduces the phenomenon of rubbing on the back; Compared with slow offset printing inks, its drying speed has obvious advantages, which can improve printing production efficiency, especially for batch printing tasks. For example, in book printing, medium fast-drying offset printing ink can be quickly preliminarily dried after printing, which is convenient for subsequent binding, cutting and other processing processes to be carried out smoothly, and to avoid problems such as page adhesion and blurred handwriting caused by undried ink.
Good printability
Medium quick-drying offset printing ink has the right viscosity and fluidity, and can be smoothly transferred from the ink fountain to the printing plate and then to the surface of the paper during the printing process, ensuring that the ink is evenly distributed and the dots are clear and sharp. Its good transferability makes the color reproduction of the printed matter high and rich in layers, whether it is field printing or fine dot printing, it can present excellent printing results. In packaging printing, for packaging boxes with complex printing patterns and bright colors, medium fast-drying offset printing inks can accurately restore the color and details of the design draft, and enhance the visual appeal of product packaging.
Stable ink film performance
The dried ink film has good abrasion resistance, light resistance and chemical corrosion resistance. This makes the printed matter in the process of long-term storage and use, it can maintain bright colors, not easy to fade, the surface ink film is not easy to be scratched and damaged, and adapt to different environmental conditions. Taking outdoor advertising printing as an example, the advertising screen printed with medium fast-drying offset printing ink can maintain a clear and bright appearance for a long time in natural environments such as sunlight, wind and rain, and effectively transmit advertising information.
4. Application scenarios
Book printing
In the field of books, magazines and other book printing, medium fast-drying offset printing inks are widely used. Book printing usually has a large printing quantity, which requires the ink to have a certain drying speed to ensure production efficiency, and at the same time to ensure the printing quality, to ensure that the text is clear and the image is delicate. Medium quick-drying offset printing inks can meet these requirements, under the premise of ensuring the printing quality of text and images, fast drying, convenient for subsequent binding into books, and improve the production cycle of books and periodicals.
Packaging and printing
The packaging and printing of all kinds of commodities have high requirements for the performance of ink, which not only requires bright colors and exquisite printing, but also requires the ink to have good wear resistance and corrosion resistance to protect the packaging contents. Medium quick-drying offset printing inks perform well in packaging printing, whether it is paper packaging boxes, labels or plastic packaging, can achieve high-quality printing, and the dried ink film can effectively resist the influence of external environmental factors, ensuring the beauty and functionality of the packaging.
Commercial printing
Posters, brochures, business cards and other commercial prints also have strict requirements for the drying speed and printing effect of ink. Medium fast-drying offset printing ink can be quickly dried on the basis of ensuring bright printing colors and clear images, which can meet the requirements of commercial printing for delivery time, and its stable ink film performance can also ensure the quality of printed matter in the display and use process.
5. Precautions for use
Storage conditions
Medium quick-drying offset inks should be stored in a cool, dry, well-ventilated warehouse, away from direct sunlight and high temperature environments. High temperature will accelerate the oxidation and drying of the ink, resulting in crusting and deterioration of the ink, which will affect the use effect. At the same time, the humidity of the storage environment should also be controlled within a reasonable range, too high humidity may make the ink absorb water, resulting in emulsification during printing, affecting the printing quality.
Adjustment of printing equipment
Before using medium quick-drying offset printing ink, it is necessary to make appropriate adjustments to the printing equipment according to the characteristics of the ink. For example, adjust the ink supply of the ink fountain to ensure an even supply of ink; Adjust the printing pressure according to the viscosity of the ink to ensure that the ink can be smoothly transferred to the printing plate and paper; Reasonably set the drying device parameters of the printing machine, such as temperature, air volume, etc., to promote the drying of ink.
Matching with other consumables
Medium quick-drying offset printing ink needs to be matched with paper, dampening solution and other consumables during use. Choose the right paper to ensure that the absorbency and surface strength of the paper are compatible with the drying performance of the ink, so as to avoid problems such as transparency and powder loss. At the same time, it is necessary to ensure that the concentration and pH value of the dampening solution are within a reasonable range to prevent adverse reactions between the dampening solution and the ink, which will affect the printing quality.
6. Conclusion
Medium fast-drying offset printing inks occupy an important position in the printing industry due to their unique drying principle, reasonable composition and excellent performance advantages. With the continuous development of printing technology and the increasing diversification of market demand, medium fast-drying offset printing inks are also constantly innovating and improving to better meet the needs of printing enterprises for high-quality and high-efficiency printing, and make greater contributions to the development of the printing industry.
7. Recommendation of the same type of products
Ordinary Economical Offset Ink