First, a brief history of ink and development trends
China was the first country to use ink. As early as the Western Han Dynasty (200 BC), people began to use ink. Such ink can be used to write information on bamboo rafts. Some of its functions can be compared with contemporary inks.
In the 15th century, Gutenberg in Germany invented the movable printing of lead alloy, and the ink has been improved. Lamp black was used as a pigment, and linseed oil was used as a connecting material, and it was evenly mixed by hand to make the ink at that time. In the middle of the 19th century, ink manufacturers were able to produce various pigments with different hue, lightness and unsaturation according to the requirements of users. Ink production has entered a new stage of development.
The formation of China's modern ink industry began with the printing of banknotes in the paper store in Beijing before printing. At that time, the raw materials for ink production were all imported. Before the liberation, only domestic ink production workshops, small-scale ink manufacturing plants, weak technical forces, backward production equipment, can only produce some of the lower ink, poor quality, fewer varieties, the situation is stagnant.
After the liberation, especially since the reform and opening up, China's printing industry has developed rapidly. There are more than 160 ink production companies in China with an annual output of more than 10 million tons, accounting for 5% of the world's annual ink consumption. At present, there are more than 30 Chinese-foreign joint ventures and cooperative enterprises, and the output accounts for more than 50% of the total output of the country. The main problems in the ink industry are the small scale of production, single products, excess product of low-grade products, lack of high-grade products and special products, and the production of raw materials (such as pigments, resins, solvents, etc.) cannot be synchronized with the development of ink in terms of quality and quantity. Nano-scale calcium carbonate for inks has all depended on the ultra-fine calcium carbonate for the “OT†type ink produced in Japan. In the 1980s, Beijing Building Material Factory and Zijiang Nitrogen Fertilizer Plant began to produce ultra-fine calcium carbonate products for inks instead of “OTâ€. "Calcium, but so far, very few high-grade inks still need to be imported from Japan's Shiraishi Kogyo Co., Ltd.'s "OT" calcium. Therefore, the research and development of ink-specific nano-scale calcium carbonate, especially in terms of transparency, coloring power, dispersibility, glossiness and other indicators, needs to be improved.
Nano-scale calcium carbonate is a filler for printing inks, with good stability, high gloss, does not affect the drying performance of printing inks, strong adaptability and so on. Calcium carbonate products are widely used in various sectors of the national economy. With the continued development of science, the production of fine calcium carbonate will increase accordingly. The application of nano-scale calcium carbonate can effectively improve the quality of products such as ink, medicine, food and daily chemicals, and its importance. Sex will be increasingly understood by people.
Second, nano ink and mechanism of action
The application of nano-materials to the ink system will bring a huge boost to the ink industry. In 1994, the XMX Corporation of Massachusetts, USA, had successfully obtained a patent for the production of nano-sized homogeneous particulate raw materials for inks. Then, XMX prepared to design a commercial production system, using this patent, select the appropriate volume of nano-particle raw materials to get a variety of ink pigments. According to another report, the nanoscale transparent iron oxide series pigments that have been rated as national key new products by the Ministry of Science and Technology in recent years have been successfully developed. It will have an important impact on the upgrading of traditional pigments, mainly used in nano-ink, nano-water coating materials. The typical needle particle size of this material is 45 nanometers in long axis and 6 to 7 nanometers in minor axis. It has good dispersion, crystallinity and weatherability, high brightness and strong coloring. Its successful development has great significance for the replacement of traditional pigments in our country. It can be used especially for the production of nano inks, which can greatly improve the quality of inks.
Today, with the help of high technology, various components (inks, pigments, fillers, etc.) in ink can be made into nano-scale raw materials, so that they can achieve better flow and lubricity due to their high degree of fineness and good lubrication. The dispersion and suspension are stable and the amount of pigment is small, but the hiding power is high, the gloss is good, the resin particle size is fine, the film formation is continuous, uniform and smooth, the film layer is thin, so that the printed image is clear; if used in UV ink, it may lead to faster Curing speed, at the same time due to the fine and uniform dispersion of the filler to eliminate the shrinkage wrinkles of the ink film; In the ink of glass ceramics, if the inorganic raw material is composed of nano-scale fine color. Because some substances are in the nanometer scale, the different particle sizes are different, or different materials have different colors. For example, Ti02 and Si02 are white in the nanoparticles, Cr203 is green, and Fe203 is brown. In addition, inorganic nanomaterials such as nano-AI203 have good fluidity, and if added to the ink, the abrasion resistance of the ink film can be greatly improved. Nano-scale carbon ink is conductive, has a good shielding effect on static electricity, to prevent electric signals from being disturbed by external static electricity. If it is added to ink, it can be made into conductive ink, such as large-capacity integrated circuits, modern contact panel switches, etc. . In addition, in the conductive ink, such as the Ag made of nano-level instead of micron Ag, you can save 50% of the Ag powder, the conductive ink can be directly printed on the ceramic and metal, the ink film is thin and uniform smooth, very good performance it is good. If the Cu, Ni material made of 0.1 ~ 1 μm ultrafine particles, it can replace palladium and silver and other precious metals conductive. In addition, some nanopowder particles themselves have luminescent groups and may emit light themselves. These new nano-luminescent materials can emit light in darkness for more than 12 to 24 hours after a few minutes of illumination, and their luminous intensity and maintaining time are more than 30 times that of traditional fluorescent materials, and the materials themselves are non-toxic, harmless, and non-toxic. Contains any radioactive element, it has excellent stability and weatherability, and can be used for unlimited cycles. The printed matter printed with the ink added with such nanoparticles does not require the irradiation of an external light source, and can be recognized by the human eye only by its own light emission, and can be used for anti-counterfeiting printing to achieve a good first-line anti-counterfeiting effect. The printed matter for outdoor large-scale advertising printing or night-time reading does not need external light sources. It not only saves energy, but also greatly facilitates users. Also, since nanoparticles have good surface wettability, they are adsorbed on the surface of the pigment particles in the ink, which can greatly improve the ink's lipophilicity and wettability, and can ensure the stability of the entire ink dispersion system. Nano-particle nano inks have greatly improved printability. It is believed that with the further development of nanomaterial technology, there will be more nanomaterials with different characteristics that will be recognized and used by people. Applying these nanomaterials to the manufacture of inks for confidential document printing, various security printing, and printing of various handicrafts can achieve exceptionally good results.
Nanoparticles can also be used instead of chemical pigments to make printing inks. This production system uses uniform nanoparticle printing inks. The resulting ink is brightly colored with pure hue and is non-toxic and tasteless. The application prospects of nano inks in offset printing, gravure printing and flexo printing to produce color cartons and cartons are very broad.
Third, the ink production of nano-scale calcium carbonate and product quality
The composition of the ink can be divided into three parts: the liquid component is called the binder; the solid component is the pigment (pigment or dye) and various additives. Nano-scale calcium carbonate is a filler in body pigments and pigments in the ink industry (carbon ink, titanium dioxide, lithopone, chrome yellow, iron blue, iron oxide blue, metallic pigments, aluminum hydroxide, colloidal calcium carbonate , organic pigments and dyes, reducing pigments, quinacridone, dioxacin, tetraoxaisoindolinone). Colloidal calcium carbonate is nano-sized calcium carbonate and its average particle size is between 0.02 and 0.1 μm. The colloidal calcium carbonate used in the ink was first precipitated with calcium hydroxide and calcium carbonate, and was surface-modified to prepare calcium carbonate having good transparency and gloss. It has good printing adaptability in ink manufacturing, that is, after it is grinded with a certain proportion of varnish, it has good fluidity, luster, transparency and no gray character. Limestone carbonization is currently used to produce nano-calcium, and its production process and product quality must be adapted to the requirements of ink production.
(1) Carbonization Process Flow and Process Parameters Cao Yunchang proposed the ultra-fine calcium carbonate process for the production of ink using the intermittent bubbling carbonization process based on grinding high-grade ink packing 206# small-scale test and middle-scale test, as shown in Figure 1. The process conditions are shown in Table 1. A certain amount of chelating agent and dispersant are added to a certain concentration of purified lime milk, and CO2 gas is introduced in a certain temperature range until the reaction reaches the end point. The reaction mechanism is shown in the figure.
The types of chelating agents used are aliphatic (polycarboxyl) carboxylates, oxycarboxylic acids, thiocarboxylates, aromatic sulfonic acids, amino acids, etc.; dispersants are mainly aluminum salts, sodium salts, zinc Salt, iron salt, magnesium salt and so on.
(2) Product Quality and Influencing Factors High-grade ink filler 206# is an ultra-fine calcium carbonate. Its property index is very different from that of ordinary PCC, and it is also different from fine calcium carbonate. See Table 2 for details.
The fineness and purity of the ink are very important for the quality of the printed matter. To print high-quality products, we must have fine-grained, high-purity inks as guarantees. Therefore, a correct understanding of the relationship between ink fineness, purity and print quality, deepening understanding of nano inks, and development of higher quality nano inks are of great significance to the printing industry.
Product 206# After the ink manufacturer's testing and appraisal, the measured data was analyzed and arranged, and the factors affecting the quality of 206# product were obtained. See Table 3 below.
Fourth, the amount of nano-calcium carbonate in the ink
The production of ink can be roughly divided into preparation, batching, stirring, rolling, inspection and canning. This stage of preparatory work is to pre-process various raw materials into the factory in accordance with the requirements of the manufacture of ink, to ensure that the raw materials meet the requirements of the production of ink; the ingredients are prepared according to the formula of the ink to mix various raw materials in proportion, this is the manufacture of ink The key is that the stirring is to disperse the pigment particles in the liquid connection material, and it takes a certain amount of energy to break the solid material and disperse it in the liquid connection material; after stirring, the mixture is subjected to rolling grinding, according to the different thick inks, respectively. The use of three-roller or ball mill for grinding, the purpose is to make the pigment fully dispersed into the connecting material, and to achieve a certain degree of fineness of the pigment particles, the tested hue, fineness, fluidity, viscosity, dryness and other properties in line with the design Requirements, can be barreled to complete the ink production process.
It can be known from the ink production process that the pigment is a solid, and the better the dispersion, the smaller the average particle size, the easier it is to disperse uniformly in the binder, and the better the ink quality, otherwise the ink quality is poor. As a constitutional pigment in the ink, calcium carbonate, if it reaches the nano level, and the surface is modified, it has good compatibility with the binder, which will play a role in the production of the ink and improve the quality of the ink. Nano-scale active calcium carbonate is required as a filler in ink manufacturing. Different types of ink require different amounts of calcium carbonate. The following are examples.
V. Conclusion
In the packaging and printing industry, nanoparticles play an increasingly important role. Nano inks are compatible with all aspects of performance. Many of the products (especially food) packaging and printing have high requirements for sterilization, preservation, etc., while the traditional ink and packaging materials are a blank in this regard.
Reprinted from: China Ink Web
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