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2022-10-16
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Research and development and innovative technology of nano water-based inks in China

introduction

nanotechnology is a term with extremely rich meanings. Its basic meaning is to understand and transform nature in the nano scale space, and to create new substances by directly manipulating and arranging the motion laws and characteristics of atoms and molecules. This means that people can produce extremely pure materials, a variety of new products, and can greatly improve the efficiency of the machine. Nanotechnology refers to a comprehensive technical system for the preparation, research and application of substances at the nano scale. Its ultimate purpose is to manipulate and control atoms and molecules to prepare artificial functional materials. The broad scope of nanotechnology can include nano material technology, nano processing technology, nano measurement technology, nano application technology and so on. Among them, nano material technology focuses on material production (ultra-fine powder, coating, etc.) and performance testing technology (chemical composition, microstructure, surface morphology, physical, chemical, electrical, magnetic, thermal, optical and other properties). Nano processing technology includes precision processing technology (energy beam processing, etc.) and scanning probe technology [1]

a famous scientist in China pointed out that "among the three 'leading' disciplines representing the future development trend of science and technology, information science, bioengineering and nanoscience, nanoscience is the discipline with the smallest gap between China and developed countries, and it is also the discipline that China is most likely to maintain synchronous development with developed countries". At the turn of the century, a summary entitled "decisive battle in the nano era - a world competition in the field of high-tech" by Xinhua News Agency on August 29, 2000 made nano technology quickly recognized by the society

nanotechnology will become the leading technology for scientific development in the next 20 to 30 years. The most important field of nanotechnology application is the manufacture of new functional materials with specific physical and chemical properties. The most typical application is to make nanocomposite particles from two different materials. As early as 1995, the European Union published a report that predicted that in the next 20 years, the development of nanotechnology will become the second largest manufacturing industry in the world after chip manufacturing. The application of nanotechnology in the future is far beyond the computer industry. According to historical experience and the latest scientific and technological development, many scientists all over the world believe that nanotechnology is heralding the dawn of the industrial revolution, and its impact will be the same as the information revolution triggered by microelectronics in the late 20th century

The development of nanoscience and technology is of great significance. First of all, it will change the traditional production mode of mankind, improve social productivity unprecedentedly, and may fundamentally solve many serious problems faced by mankind at present, such as environmental pollution, ecological balance destruction, raw materials and energy consumption. At the same time, nanotechnology can develop the potential information and structural potential of substances, and increase the capacity of storing and processing information per unit volume of substances by more than a million times

the technological innovation of this century is largely supported by clarifying more microscopic phenomena and developing operational technology accordingly. However, this traditional technology development will encounter limits in many fields. If there is no new discovery that is fundamentally different from the tradition, we cannot climb a new level. Nanotechnology is a unique structural technology to discover this effect and artificial. It is precisely by fully mastering and utilizing advanced modern science and technology that people make the prediction and research of nanotechnology possible

as we all know, ordinary ink is a complex polymer composition, which has specific viscosity and excellent printability. The main ingredients are pigments (dyes), polymer binders, solvents and a small amount of additives. When inking, people put the above components in a certain proportion into special equipment, and after full dispersion, a uniform printing ink with a certain viscosity and thixotropy is prepared

the composition and manufacturing method of nano ink are no different from ordinary ink. If there is any difference, it is only the "pigment" particles used in the two inks, which are very different in particle size. The pigment particle size of ordinary ink is micron( μ m) And the "pigment" particle size of nano ink is nano. The difference between the two is about 1000 times. It is understandable that the introduction of nano "pigments" with specific properties will bring modest changes to some links of its ink manufacturing process

although both nano ink and ordinary ink are used for product printing, the former mainly focuses on the application of special functions, while the latter is often used for the printing of monochrome or color printing materials

recently, although nano ink just emerged last week, it has initially shown excellent performance and great attraction in the fields of processing and installation of electronic components, decoration and decoration of high-end products, sterilization and detection in medicine, and anti-counterfeiting printing of special products [2]

1. The characteristics of nano water-based ink and the improvement of nano powder on ink

1959 physicist and Nobel laureate Chad? After richardfeynman first proposed the idea of nanotechnology, nanotechnology has gradually been valued and widely used in various fields. In 1994, Xmx, a Massachusetts company in the United States, successfully obtained a patent for nano-sized uniform particle raw materials used in the manufacture of inks. Because nano metal particles can absorb all light waves and make themselves appear black, they can also scatter light. Therefore, using these characteristics, nano metal particles can be added to black ink to produce nano ink to improve its purity and density. Semiconductor nanoparticles exhibit certain characteristics of light absorption due to the significant quantum size effect and surface effect

with the continuous improvement of printing quality requirements, customers' requirements for printing products should not only be of good quality, but also meet the special needs of environmental protection, anti-counterfeiting and so on, so they also put forward higher requirements for inks. The fineness and purity of ink have a great impact on the quality of printed matter. To print high-quality products, we must have ink with high fineness and purity as a guarantee. The fineness of ink is directly related to the properties of pigments and fillers and the size of particles. The fineness of ink refers to the size of pigment (including fillers) particles in ink and the uniform self production and assembly degree of pigments and fillers distributed in binder. It not only reflects the quality of printing products, but also affects the print resistance of printing plates

nanotechnology is a new science and technology. At present, its main research object is nano materials. Now nano materials have penetrated into all fields, as well as the printing industry. When nanotechnology is combined with printing ink, it can create ink with small particles (particles less than 100nm) and high fineness. The finer the ink particles, the larger the contact surface between the pigment particles and the binder, the better and more stable the printing performance, and the clearer and fuller the dots, which is called "nano ink"

because the color of nano ink is relatively saturated and gorgeous, the four primary color ink made of nano ink has a higher color gamut than the traditional four primary color ink in printing overlay. In addition, nano ink still has the advantages of water resistance, wear resistance and good penetration. In fact, the local fracture of metal wire does not mean the ultimate failure of all components. It can be said that it not only retains the advantages of traditional ink, but also combines the advantages of nanotechnology [3, 10]

1.1 characteristics and characteristics of nano water-based ink

1.1.1 composition of nano water-based ink [4, 5]

nano water-based ink is a uniform paste adhesive composed of colored bodies, connecting materials, physical pigments, additives and other substances, which can be printed and dried on the printed object. The main agent of nano water-based ink is composed of pigment as dispersed phase and binder as continuous phase. Pigments give ink color, and binders provide ink with the necessary transfer properties. The composition of nano water-based ink is shown in Figure 1

1.1.1.1 connecting material

connecting material is the fluid part of nano ink, which can make the coloring material, namely the pigment, fine and evenly dispersed on the dispersion equipment; It is firmly attached to the substrate, and makes the ink have the necessary gloss, drying performance and printing transfer performance. Nano ink connectors are generally named according to their solubility

1.1.1.2 pigments

pigments in nano ink provide color and various durability for ink, and also have a great impact on the rheological properties (fluidity, viscosity, etc.) of ink

1.1.1.3 additives

additives (auxiliary agents) are some materials added to improve the performance of nano ink in the manufacturing and printing of nano ink. When the ink prepared according to the basic composition still cannot meet the requirements of printing use in some characteristics, or cannot meet the requirements of printing use due to changes in conditions, a small amount of auxiliary materials must be added. There are many kinds of additives for nano ink, mainly including the following: coupling agent, neutralizer, solvent (co solvent), thickener, anti sedimentation agent, mildew inhibitor, wetting agent, dispersant, defoamer, etc

1.1.2 drying mechanism of nano water-based ink [6, 8, 11]

1.1.2.1 drying of water diluted binder

the drying principle of water diluted binder is as follows: the reason why water diluted binder can dissolve in water is that these polymer resins contain a COOH (carboxyl), an OH (hydroxyl), an NH2 (amino), a c-nh2 and a C-1, which are hydrophilic

after a certain process, the polymer resin is made into organic amine salts, which can be completely dissolved in water. Therefore, the reaction of carboxyl and amino groups can now be used to form a viscous liquid soluble in water. For example:

rc00h + nh2ch2ch2oh → rconhch2ch20h + H20

in water, the above product will form: rco-n + hch2ch20h, which has good hydrophilicity. Due to the large evaporation latent heat of water, the drying speed of ink will be slowed down. At the same time, due to the unstable decomposition reaction of amine salt when exposed to heat, it is mainly volatile drying, and also reactive solidification drying. Once dried, the ink film will become water insoluble. The drying process is as follows:

1.1.2.2 drying process of water dispersed binder

moisture. The drying process of type a lotion binder can be described by a three-stage drying model: ① water volatilizes from the surface of the wet film, the overall volume of the ink film shrinks, and the dispersed polymer particles gradually concentrate; ② Polymer particles begin to contact each other; ③ The particles agglomerate and form a dry ink film. As shown in Figure 2

1.1.3 characteristics and characteristics of nano water-based ink

after chemical modification on the surface of nano semiconductor particles, the medium around the particles can strongly affect their optical properties, which shows that the absorption spectrum has a red shift or blue shift. Experiments show that the light absorption edge of CdS nanoparticles has obvious injection molding +rim solvent-free blue shift, and the absorption edge of TiO2 nanoparticles has a large red shift. If they are added to yellow and cyan inks respectively to make nano inks, their purity can be improved. Printing color prints with nano inks with specific nano particles will enrich the layers and greatly increase the ability of image detail expression. In terms of pigments, it will bring a great change to the ink manufacturing industry. It no longer depends on chemical pigments, but selects nano particles of appropriate volume to present different colors. Because when some substances are at the nanometer level, the particle size is different and the color is different, or different substances have different colors, such as TiO2 and SiO2

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