Definition and composition of the hottest high glo

2022-08-17
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Definition and composition of high brightness offset printing ink

the gloss of printed matter is the essence of printed matter, and it is also an important aspect to measure the appearance quality of printed matter. It can not only increase the brightness of printed matter colors, make the picture bright and textured, but also improve the beauty of printed matter and enhance the three-dimensional sense of printed matter

in the case of limited ink conditions, post press processing methods are often used to improve the gloss of printed matter, such as film coating, plastic coating, printing cover varnish, etc., but this is only limited to improving the gloss of the cover, and increasing the printing cost. In order to comprehensively improve the gloss and color of printing materials, we must improve the gloss of printing materials themselves. Improving the gloss of ink has become an important part of ink production

high gloss ink is a kind of high gloss ink that can improve the brightness of printed matter. Its gloss is higher than that of general offset ink, and its saturation is also high. The album printed with high gloss ink has fine images, rich layers and good texture, and overcomes the feeling of floating color of printed matter

I have done some targeted experiments on high gloss ink, hoping to put forward some meaningful suggestions and references for the application of high gloss ink in practice through the analysis of the basic composition and printability of the ink

I. definition of high brightness offset printing ink

the gloss of offset printing ink refers to the ability of the ink on the surface of the print to concentrate and reflect light in the same direction under the irradiation of light after it is dried through the oxidized conjunctiva. It reflects the brightness of the ink on the surface of the substrate after drying

then, what is high gloss ink? In the national standard of the people's Republic of China - ink terminology, "high gloss offset ink" is "offset ink with high gloss imprinted". According to the industrial standard of the people's Republic of China - offset gloss ink, offset gloss ink is a colloidal body made of synthetic resin, dry vegetable oil, high boiling point alkane oil, high-quality pigments and additives. The gloss index of offset four-color bright ink is shown in Table 1

high gloss ink also belongs to the category of offset bright ink, but its gloss is higher than that of bright ink. According to the experimental data, the gloss of high gloss ink should be more than 60%, and the gloss on the substrate should be more than 35%

the high gloss ink AGH (hereinafter referred to as "DIC high gloss") produced by Shenzhen sun (DIC) ink company and the famous German brand BASF high gloss ink (hereinafter referred to as "BASF") are excellent high gloss offset printing inks at present. The ordinary bright quick drying ink (hereinafter referred to as "DIC") produced by Shenzhen sun ink company is also a high-grade offset printing ink in the ordinary bright quick drying ink, which has a very good reputation in the printing industry. This paper intends to compare and analyze the above products in order to explore the practical application of high gloss ink

the data mentioned in this paper are all completed through experiments and tests at 25 ℃ and 60% humidity

II. Composition of high gloss offset printing inks

high gloss offset printing inks, like general offset printing inks, are also composed of binders, pigments, fillers and additives

1. Binder

binder is a viscous fluid. Its function is to mix and connect powdered pigments and other substances, so that after grinding and dispersing, it can form a slurry adhesive with a certain fluidity. Binder is the fluid component of ink

the quality of the binder directly affects the performance of the ink. Because pigments are generally solid powders, and binders are liquids with a certain viscosity, pigments rely on its wetting and adhesion to complete the transfer in the printing press. On the printed matter, the binder also plays the role of protecting the ink film, and presents the necessary gloss

binders largely determine the viscosity, viscosity, dryness and flow properties of inks. In order to get high-quality inks, we must use high-quality binders. If the binder is not prepared properly or there are problems in the production process, not only can we not get the printing materials with bright colors and excellent gloss, but also it will take several years to produce a series of faults, such as no inking, pasting, rubbing, penetrating the back, pulling the paper wool, not drying, and even make the printing unable to proceed smoothly. Therefore, binder is an important component of ink

high gloss ink requires fast drying speed, good film formation on the substrate, and the ink film has ideal specular reflection effect and high gloss. Because the gloss of ink is mainly determined by the binder, the binder of high gloss ink is particularly important, which directly affects the gloss of high gloss ink. The binder of high gloss ink is composed of the following components

1) resin

resin is a kind of amorphous substance. Generally speaking, resins are organic compounds with relatively large molecular weight and complex structure compared with the warming of the international market. Its form includes both hard and brittle solids and viscous liquids. Different solid resins can be dissolved in different organic solvents and oils, and then become resin solution. When the solvent evaporates from the resin solution, the concentration of the resin solution gradually increases, and the solution becomes more and more viscous. Finally, the resin molecules are closely combined to form a solidified gel, which can form a transparent film layer, which is also the reason why the ink can form a film on the printed matter

as a resin of high gloss ink, in addition to making the offset ink meet the requirements of printability in the printing process, such as rheology, it must also have good mutual solubility with oils, solvents or other resins in the binder. At the same time, it must also make the printed matter have high gloss, strong adhesion and certain hardness on the surface of the substrate, and good film-forming performance

resins can be divided into natural resins and synthetic resins. Due to the problems of natural resin, which will affect the quality stability of ink, synthetic resin soon replaced natural resin

synthetic resin usually refers to polymer compounds synthesized by chemical plants or laboratories without molding, such as polyethylene resin, polyvinyl chloride resin, polypropylene resin, polyacrylate resin, phenolic resin, polyester resin, polyamide resin, etc

synthetic resins are different from natural resins and their simple processed products. There are two main differences: first, the molecules of synthetic resins are prepared through complex artificial synthesis; Second, the molecular weight of synthetic resin is very large, even as large as tens of thousands or even millions. Although their molecular weight is large, their composition is not complex. They are macromolecules connected by thousands of small molecules of the same or different species through chemical polymerization, so macromolecular compounds are also called polymers or polymers

functional compounding of various materials commonly used in the ink industry has gradually become an important technical means to improve the performance of automotive non-metallic parts. The resin is also different from ordinary polymer compounds. As the ink industry is developed on the basis of vegetable oil as binder, the oil solubility of synthetic resins used must be considered first. Therefore, rosin modified phenolic resin, vegetable oil modified alkyd resin and other products are mostly used to treat this kind of resin

phenolic resin is the product of condensation of phenol and aldehyde under the action of catalyst. Due to different raw materials, types of catalysts and reaction conditions, a series of resins with different properties can be obtained. Modified phenolic resin is mainly used in ink. These resins have good oil solubility. The ink prepared with rosin resin has the advantages of fast fixation, high gloss and strong water resistance. The modified phenolic resins used more in ink include rosin modified bisphenol propane resin, rosin modified p-tert-butyl phenolic resin and rosin modified other alkyl phenolic resins

the resin used in high gloss ink is mainly rosin modified phenolic resin. Its production process is complex. Different refining temperatures, that is, different ranges of heating and cooling, and different measures taken in the middle of the process, the structure and molecular weight of the resin obtained are different, which will directly affect the gloss, drying performance, water resistance, viscosity, rheology and printing performance of the ink. On this point, it is precisely the technical key to the manufacturing of high brightness ink binder. (to be continued)

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