Ink is a colorant for printing. It is a kind of fluid material with certain viscosity, which is uniformly dispersed in the binder by pigment particles. 1. Composition of ink: ink is composed of pigment, connecting material, filler, additive, etc. (1) Pigment: pigment in ink plays a role in color, it has a direct impact on some characteristics of ink. Pigments are colored, black or white powders with high dispersion, which are insoluble in water and organic solvents. They can be divided into organic pigments and inorganic pigments according to their sources and chemical composition. ① Inorganic pigment is the oxide of non-ferrous metal, or some metal insoluble metal salt. Inorganic pigment can be divided into natural inorganic pigment and artificial inorganic pigment. Natural inorganic pigment is mineral pigment. ② Organic pigments are colored organic compounds, which can be divided into natural and synthetic ones. Nowadays, synthetic organic pigments are commonly used. There are many kinds of organic pigments with complete colors and better performance than inorganic pigments. Dyes are organic compounds, which are soluble in water and sometimes in organic solvents. Insoluble color precipitates, called lake pigments, can be prepared from certain dyes for printing inks. The requirements for pigments used in printing inks are quite high, especially for color, dispersion, light fastness, transparency, etc. the hue of color pigments should be close to spectral colors, and the saturation should be as large as possible. Magenta, cyan and yellow pigments used in three primary color inks must have high transparency. All pigments should not only be water resistant, but also be quickly and evenly combined with the binder to absorb pigment The oil capacity should not be too large. The pigment should have the properties of alkali resistance, acid resistance, alcohol resistance and potential resistance. (2) Binder is the main component of ink. It can disperse pigment, give ink proper adhesion, fluidity and transfer performance, and fix pigment on the surface of printed matter by film forming after printing. Connecting material is commonly known as inking oil. Binders can be made of various substances, such as various dry vegetable oils, which can be used to make ink binders. Mineral oils can also be used to make binders. Solvents and water, as well as various synthetic resins, can be used to make binders. The rheological property, viscosity, neutral, acid value, color, water resistance and printing performance of the ink mainly depend on the binder. For the same pigment, different binders can be used to make different types of inks; for the same binder, different pigments are used. The ink is still the same type, because it can not change the basic performance of the ink, so the quality of the ink, in addition to pigment related, mainly depends on the binder. (3) Filler: the filler is white, transparent, translucent or unsightly powdery material. It mainly plays the role of filling. Filling the pigment part, properly using some fillers can not only reduce the amount of pigment, reduce the cost, but also adjust the properties of the ink, such as thinness and fluidity, and improve the flexibility of formula design.(4) Additive: additive is in ink manufacturing, as well as in printing use, in order to improve the performance of the ink itself and some additional materials. When the ink prepared according to the basic composition can not meet the requirements in some aspects of characteristics, or can not meet the requirements of printing due to the change of conditions, a small amount of auxiliary materials must be added to solve the problem. There are many additional materials, such as: desiccant, anti desiccant, diluent, tackifier, plasticizer and so on. 2. Types of ink: there are many kinds of inks, which can be classified by various methods: (1) according to the printing methods, ① according to the format, there are printing inks for gravure, lithography, gravure, photogravure and screen plate; ② according to the printing methods, they are divided into offset printing, direct printing, etc. (2) According to the substrate material: paper, metal, plastic, cloth and other ink. (3) According to the drying form: ① according to the drying mechanism, it can be divided into infiltration drying type, oxidation polymerization type, volatile drying type, light hardening type, heat hardening type, cooling curing type and so on; (2) according to the printing material, it is divided into paper, metal, plastic, cloth and other inks. (3) According to the drying form, ① according to the drying mechanism, it can be divided into infiltration drying type, oxidation polymerization type, volatile drying type, light hardening type, heat hardening type, cooling curing type, etc.; ② according to the drying method, it can be divided into natural drying type, hot air drying type, infrared drying type, ultraviolet drying type, cooling drying type and so on. (4) According to the characteristics of the ink: ① according to the color, it can be divided into yellow, red, blue, white, black, gold, silver, gold powder, fluorescent color, pearlescent color, etc.; ② according to the function, it can be divided into magnetic ink, anti forgery ink, edible ink, foaming ink, aromatic ink, recording ink, etc; ③ According to the resistance is divided into: light resistance, heat resistance, solvent resistance, abrasion resistance, alcohol resistance, drug resistance and other ink. (5) According to the ink composition, ① according to the raw materials, it can be divided into: dry oil type, resin oil type, organic solvent type, water-based type, paraffin type, glycol type, etc.; ② according to the form, it can be divided into colloidal, liquid and powdery ink. (6) According to the use: press ink, book ink, packaging ink, building materials ink, trademark ink, etc. 3. Characteristics of ink: ink is a paste with color and certain fluidity, which can be printed and dried on the substrate. Therefore, color, rheological properties and drying properties are the three most important characteristics of ink. (1) Viscosity: viscosity is a property that prevents the flow of fluid. It is a measure of the relative movement ability between molecules caused by the interaction of fluid molecules, that is, the resistance of fluid flow. The viscosity of the ink is related to the transfer of ink in the printing process, and is related to the nature and structure of the paper. If the viscosity of the ink is too large, the ink transfer is not easy to be uniform in the printing process, and the paper is roughened, which makes the page flowery; if the viscosity is too small, the ink is easy to emulsify and dirty, which affects the product quality. The viscosity of ink is related to the viscosity of binder, the amount of pigment and additive, the particle size of pigment and additive, and the dispersion of pigment and additive in binder. In the printing process, the requirement of ink viscosity is related to the printing speed of the printing machine, the softness of paper structure and the change of ambient temperature.(2) Yield value the minimum shear stress required to make a liquid flow is called yield value. If the yield value is too large, the flow performance is poor and it is not easy to open. If the yield value is too small, the printing dot is easy to halo and not clear. The yield value is related to the structure of the ink, and the yield value has a direct impact on the fluidity of the ink. It is an important test index for the quality of offset and gravure printing ink. (3) Thixotropic ink by the external force of stirring, it will be with the role of stirring from thick to thin, static, ink back to the original consistency of the phenomenon, called thixotropy. Due to the thixotropy of ink, when the ink is mechanically rotated on the ink roller, its fluidity increases and its ductility increases, making the ink easy to transfer. When the ink is transferred to the paper after printing, it will lose the effect of external force, and the ink will become thicker and not overflow to the surrounding area, forming a good imprint. But if the thixotropy of the ink is too large, the ink in the ink hopper is not easy to rotate, which affects the ink transfer of the ink roller. (4) Fluidity ink in its own gravity, like liquid flow performance, known as ink liquidity. The fluidity of ink is related to whether the ink can be poured out of the container, transported from the storage tank to the ink hopper of the printing machine, smoothly transferred from the ink hopper, well distributed on the printing machine, transferred to the layout, and transferred to the substrate, which also affects the printing effect. The fluidity of the ink is determined by the viscosity, yield value and thixotropy of the ink, and is also closely related to the temperature. (5) Ink length ink is stretched into a filament without breaking the program, called ink length. Ink with short ink is a good printing ink in offset printing and relief printing screen, because it will cause flying ink phenomenon. At the same time, the ink layer on the printed matter is uniform and thick. People often use the length of ink to measure the performance of ink. The ink length is related to the thixotropy, yield value and plastic viscosity of ink. (6) The drying of ink the ink adheres to the printed matter to form an imprint, which must change from liquid or paste to solid film, which is usually called ink drying. The drying of ink is completed by the connecting material in the ink from liquid or paste to solid. Various inks used in the binder and its ratio is different. Therefore, the drying process of the ink formed by different binders is also different. After the ink is transferred from the printing plate to the printing surface, a part of the binder in the ink permeates. At the same time, the solvent in the binder begins to volatilize, and some of the binders produce chemical and physical reactions, so that the imprinted ink layer on the substrate surface gradually increases its viscosity and hardness, and finally forms a solid film layer. Generally, relief printing ink is mainly osmotic drying, offset printing ink is mainly oxidative conjunctival drying, gravure printing ink is mainly volatile drying because of its strong solvent as binder. Characteristics of various inks (1) letterpress ink: letterpress ink includes: printing ink, rotary printing ink, color ink, plastic ink, water-based ink and newspaper ink. Lead printing ink is mainly used for printing books and periodicals, and also for book printing ink. When printing books and periodicals on the platform machine, the ink is a permeable dry ink with a certain degree of blackness, which has a smaller viscosity and lower yield value, so as to adapt to the printing machine with less uniform ink rollers. Books and periodicals paper structure is rough, but they have better oil absorption performance, so the use of permeable dry ink. Lead printing color ink is commonly used in copper plate color printing, some called copper plate ink. When printing, it is carried out by flat press, so the pressure is relatively large and flat, and the printing dot is mainly used. Therefore, it is required that the ink transfer performance is good. The ink film in the dot should be uniform and consistent, the ink fixation should be fast, and the ink film should not be spread after embossing, so that the dot on the printed matter has a good contrast, and the imprint is consistent and plump. This kind of ink should have a lower yield value, have a certain fluidity and viscoelasticity. Once the ink is imprinted on the paper, it should be able to fix and dry immediately. Therefore, the binder of the ink to the oxidation of conjunctiva and solvent part of the penetration of fixed drying, not only drying fast, but also ink transfer. Letterpress rotary printing ink is also known as news rotary ink. To adapt to high-speed printing, news rotary ink should have good fluidity and low viscosity. Generally, he said that the faster the printing speed is, the better the fluidity and viscosity of the ink are required. News rotary ink is a typical infiltration drying ink, which almost completely depends on the absorption of paper fiber and the connecting material. Letterpress rotary printing ink is suitable for the use of books and periodicals rotary machines with printing speed between the platform machine and the news rotary machine. In order to adapt to high-speed printing of high-quality paper, infiltration drying type or oxidation conjunctiva drying type can not meet the requirements. It is easy to produce poor dryness, poor adhesion, powdering, rubbing and so on. In order to overcome these disadvantages, thermosetting ink is used, that is, in printing, the solution in the ink will escape after baking at 200 ~ 250 ℃, so that the ink can be fixed on the printed matter.(2) Offset ink: lithographic ink includes various offset printing inks, offset iron printing ink, lithographic photosensitive iron printing ink, collotype ink, offset thermosetting ink, etc. One of the characteristics of offset printing ink is that the color coloring power of the ink is high. Because offset printing is indirect printing, the ink imprint printed on the printed matter is very thin. Only a strong coloring force can meet the requirements. As the printing speed is faster and faster, the ink should have good fluidity and good dryness. According to the characteristics of offset printing, ink should have good water resistance, so the water resistance of pigment in ink is very high. Lake pigments are mostly soluble in water, resulting in floating dirt. Such as hydrophilic emulsion, the ink transfer will be poor, dry decline, resin type binder than oil type binder water resistance is stronger. (3) Gravure ink: gravure ink includes all kinds of photographic gravure ink, engraving gravure ink, Gravure plastic film ink, etc. Photographic gravure ink is a typical volatile dry ink. Its viscosity is the lowest among all kinds of inks. It has good fluidity and low surface tension. It is easy to fully fill in the concave holes of the printing plate. The ink has strong adhesion. After the paper is embossed, the ink can be transferred from the concave hole to the surface of the printing brush as much as possible. The ink can be dried quickly and thoroughly on the printed matter. Engraving gravure ink is characterized by thick but not sticky, loose and short, with appropriate thixotropy. The ink should be easy to fill in the ink hole of gravure, and it is easy to wipe off the blank part of the plane when erasing the plate. The ink in the printing part should also be easy to transfer to the printed matter. After the oil ink is printed on the printed matter, the dot line of the picture and text should not be spread out and enlarged, but should be dried quickly. Engraving gravure ink pigment performance to ink based, can not use transparent pigments. Engraving intaglio is widely used in the printing of securities, so it requires high performance of pigments, such as light resistance, water resistance, heat resistance, oil resistance, etc. In order to prevent forgery, some special additives are often added to the ink. (4) Porous printing ink: including screen printing ink, screen plastic ink, oil type transcription ink, water-based copy ink, etc. Because the imprint of silk screen printing is thick by applying ink and pressure with rubber scraper, the flow characteristics of screen printing ink should be thick, loose, short and non sticky, and the pigment content in the ink can be correspondingly less, so as to facilitate the ink to pass through the screen smoothly. Screen printing ink in the oxidation drying ink, printed on the printed matter, the faster the drying, the better, volatile dry ink is to use heating process, in order to facilitate solvent volatilization. Printing ink generally liquidity is not too big, viscosity is relatively small, mainly depends on infiltration drying. (5) Special function ink: microcapsule ink, the material with special function is sealed in the capsule, the ink is made with appropriate connecting material, and the printing is carried out in a way that does not damage the capsule, so that the printed matter has special properties. For example, liquid crystal ink changes the color of liquid crystal according to the difference of temperature and pressure, which is used to indicate the number of thermometer and calculator; perfume ink is made of perfume, and the capsule is destroyed, it will emit fragrance; the foaming ink uses foaming agent, which is heated and foamed after printing, and is used for printing Braille and other printed materials. Gold silver ink with metal powder instead of pigment. In the past is in the wipe gold, wipe silver ink attached gold powder, silver powder. For gold and silver printing, the ink mixing oil is mixed with gold powder or silver powder before printing. There are also mixed inks. Copper powder is used for gold powder and aluminum powder is used for silver powder, which are all made of flake and give metallic luster. Fluorescent ink is a kind of ink that uses fluorescent pigment. It brings bright and strong color effect, so it is often used in advertising, packaging materials, advertising, exhibits and other eye-catching printed products. Fluorescent pigment dissolves fluorescent dye in synthetic resin, with coarse particles and weak light resistance. Once irradiated by ultraviolet lamp, it can get more brilliant effect. Magnetic ink is an ink made of magnetic iron oxide powder. It is used to read the characters of magnetic ink, control the magnetic properties of magnetic powder, read by magnetic beam from special literature and font to be printed, and mainly used to print magnetic tape on credit card. Security ink (anti forgery ink) is a kind of ink for printing various securities. It must have all kinds of excellent properties of light resistance, heat resistance, water resistance and oil resistance. Gravure printing ink is one of them. In order to prevent forgery and tampering, it must be matched with compounds that can see special reactions. It can also be used as a safety ink for ink disappearing, fading, discoloring or coloring. Conductive ink is an ink made of gold, silver, copper or conductive carbon black. The dry ink layer has conductivity and is used for printing circuits, electrodes, etc. Gold powder, silver powder and copper powder have their own electrical conductivity, but the price of gold and silver is too high, copper is easy to oxidize, carbon black is easy to be different due to the different properties of raw materials, graphite crystal has the best conductivity, which is a commonly used one at present.Copy ink, subpoena copy ink, with hot melt heating melt for printing. Carbon free copy is colorless due to pressure and color, unnecessary copy part of the use of desensitization ink, reduce the contact of copying and lose the copy effect, the use of chemical functional materials to prevent color. There are many other functional inks, such as monitoring inks that change color under the action of gases, temperature indicating inks that change color due to temperature changes, color developing inks that change from colorless to colored under the action of light, edible inks printed on food, fire inks printed on the friction part of firewood boxes, etc.
Dongguan Beite packaging materials Co., Ltd. - located in Dongguan City, the world's manufacturing city, is a subsidiary of Beite packaging (China) Co., Ltd., with a plant area of 6000 square meters. It is a flexible packaging enterprise integrating R & D, production and sales. It has a complete set of domestic advanced production equipment, a scientific and humanized management system and a group of experienced technical personnel For backing, to provide customers with quality products and first-class service.
The company produces composite bags, roll film, fruit bags, aluminum foil bags, suction mouth bags, self-supporting bags, zipper bags, anti-static bags, special-shaped bags, etc., which are suitable for the internal and external packaging of food, daily chemicals, electronics, toys, medicine, cosmetics, industrial products and other industries.
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