Nanotechnology in paper
We are a big printing company in Shenzhen China . We offer all book publications, hardcover book printing, papercover book printing, hardcover notebook, sprial book printing, saddle stiching book printing, booklet printing,packaging box, calendars, all kinds of PVC, product brochures, notes, Children's book, stickers, all kinds of special paper color printing products, game cardand so on.
For more information please visit
http://www.joyful-printing.com. ENG only
http://www.joyful-printing.net
http://www.joyful-printing.org
email: info@joyful-printing.net
We know that paper is the most commonly used substrate in printing, and its quality is the best embodiment of print quality. Because the fibers of trees, bamboo, hemp and other fibers used in traditional paper are relatively thick, and the particles of paints (such as calcium carbonate, etc.) and fillers (such as kaolin) are large, there are some properties such as rubber and other ingredients that are not good. The reason is that there are some defects in the traditional paper. For example, plain paper has the disadvantages of being afraid of water and fear of moisture. Although offset printing paper and electrostatic copying paper have functions such as waterproofing and moisture proof, writing is inconvenient, and some special properties cannot be obtained. Realization and so on, thus affecting the quality of the printed crystal. In recent years, with the rapid development of nanomaterials science, nanotechnology has become more and more widely used in the paper industry, and new achievements have emerged. Related to pulp and paper is nanochemistry and nanomaterials, which promotes the development of the paper industry and improves the quality of printed matter.
According to the current state of the art and the practical application of paper, wood fiber can only be processed to the level of micron (100-1000 nm). Because the cell diameter of wood is relatively coarse, the nano-technology of wood can change the cell structure of wood and control the growth of cells. It is possible to change the characteristics of the wood. For most woods, when the fiber is processed to the micron level, the cells of the wood cells are completely broken, and the viscous liquid in the cell can easily flow out. After mechanical pulping, it is no longer necessary to chemically extract harmful liquids and separating fibers in the cell tube. If the wood is processed to the nanometer level, the original cell structure of the wood will be destroyed, the fibrous tissue structure will change, and the cellulose and semi-fibers will be changed. The lignin and lignin can be separated mechanically during processing, which can greatly increase the pulping rate and reduce the environmental pollution of the pulp and paper industry. In addition, from the general minimum specifications of the components of the papermaking furnish, in addition to the larger fiber width, the filler particles are generally in the range of 0.1-10 microns, and the remaining microfibers, non-fibrous fine materials, soluble polymers, etc. are all less than 1 - 2 microns, the whole is in a colloidal state, and the surface action and colloidal interaction between them are important, so the wet end chemistry of papermaking is also a kind of surface and colloidal chemistry. Since many components in the wet end of the papermaking are very small in structure, the introduction of nano-components with special effects can play the role of nanotechnology and improve the papermaking effect. For example, in the modern high-speed paper machine wet-end batching, when a new generation of anionic colloidal silica (ie ACS) and a cationic polymer are applied, silica nanoparticles having a particle size of 3-5 μm can be produced in the wet-end batching system. particle. The particles can flocculate the fine components in the ingredients around the fibers, thereby improving the structure of the slurry and reducing the loss of fine components, improving the operation of the paper machine and the uniformity of the paper, and reducing the amount of additives in the slurry. Significant effect.
In paper coatings, the application of nano-calcium carbonate to coated white paperboard coatings can effectively improve the performance of white paperboard. Nano-CaCO3 itself has the characteristics of high whiteness, large surface area, high surface activity, high strength and hardness. The addition of nano-calcium carbonate is beneficial to the improvement of several important performance indexes of the coating, such as IGT value, K&N ink absorption, smoothness and the like. However, the amount of nano calcium carbonate added is not proportional to the improvement in performance. In the paint with 5% nano-calcium carbonate coating, the viscosity is significantly higher than when it is not added when the pH and temperature are similar. However, nano-calcium carbonate has little effect on the whiteness of the coating. It seems to be contrary to the idea that the high whiteness of nano-CaCO3 can improve the whiteness.
There are several development directions for enhancing the dispersion of nanoparticles in the liquid phase: 1 selecting a suitable solvent or solution to increase the wetting heat of the powder, so that the wetting spontaneously performs 2 design efficient dispersing machinery to make the effective volume and Increased energy efficiency I3 selects a suitable dispersant to make the manufactured primary particles very stable and prevent re-flocculation. In addition, the addition of nano-silicon-based oxides to the coating can achieve the purpose of shielding ultraviolet rays and greatly improve the anti-aging properties of the coating. Nano-silica oxide (Slox) is an amorphous white powder (referred to as a soft agglomerate), which is a non-toxic, odorless, non-polluting inorganic non-metallic material. Due to the small size effect of nano-SiOx, it causes a drenching effect, forming a dense "nano coating film" at the interface of the coating, which greatly improves the scrub resistance of the coating and the self-cleaning property of the coating film surface. It also produces good affinity with the coating system to improve the suspension stability and rheology of the coating. At present, the use of nanotechnology in the paper industry has begun to enter into practical production, which will overcome some of the defects of ordinary paper and improve the special properties of paper. For example, Henan Silver Pigeon and Huazhong Normal University Nanotechnology Research Institute have adopted the most advanced nanotechnology in the world to prepare nanostructured layers on plain paper and successfully developed new waterproof nanopaper. In addition to maintaining the original writing and copying functions of the paper, the nano paper has the special properties of super hydrophobicity and moisture resistance which are not possessed by plain paper, improved printing surface strength and reduced expansion ratio.
In addition, in the rapid development of science and technology, people will have higher requirements on paper performance and quality. In addition to conventional printing and writing paper, the demand for paper with special functions is also increasing. Nanomaterials, as a special additive for the manufacture of special papers, are attracting more and more attention. At present, in the papermaking industry, nanomaterials are mainly used for the development of functional papers such as water, antibacterial, antistatic, anti-aging and flavoring, flame retardant, discoloration, etc., and some products have been available.
1. Nano-paper with antibacterial function
Many organic antibacterial agents have the disadvantages of poor heat resistance, volatility, easy decomposition and harmful substances, and poor safety performance. To this end, people actively develop research and development of inorganic antibacterial agents, and the use of ultra-fine technology to produce sub-micron and nano-scale inorganic antibacterial agents, can well solve the shortcomings of organic antibacterial agents. By mixing the nano-inorganic antibacterial agent into the papermaking slurry and the surface sizing solution, the paper can be antibacterial industrialized, such as physical antibacterial composite fiber non-woven fabric, medical food wrapping paper, and high-grade household paper.
2. There is antistatic. Wear-resistant nano paper
In the diversified industrial product packaging, especially high-precision instrumentation, stainless steel materials with high finish requirements and packaging materials for various alloy materials, not only the packaging paper is required to be waterproof, oil-proof and rust-proof, but also required. It has the characteristics of high strength, abrasion resistance, antistatic and anti-aging, and it is difficult for ordinary paper to have these characteristics at the same time. However, if 0.1%-0.3% of nanometer titanium dioxide, chromium oxide, zinc oxide, ferric oxide, tin dioxide, etc. are mixed into the papermaking pulp, the special paper can have Excellent wear resistance, water resistance, corrosion resistance, etc., and it also produces good electrostatic shielding performance, greatly reducing its electrostatic effect, which can greatly improve the safety factor of packaging products.
3. Dyeing nano paper
Colorants used for paper coloring can be divided into two major categories of dyes and pigments. Pigments for dyeing are mostly natural inorganic pigments, and some are organically synthesized. The pigment is insoluble in water, has no affinity with the fiber, and the dyeing performance is not as good as that of the dye, but the pigment has strong light resistance and strong resistance to chemicals such as acid and alkali. Although the dye is easy to color, it is easily hydrolyzed, has a large loss in the wet end, is highly polluting, has poor color fastness to paper, and is not resistant to chemicals such as acid and alkali. If nano-scale pigments are used, the color fastness of colored paper can be solved. Recent studies have found that the addition of nano-titanium dioxide, chrome yellow, iron oxide red and other powders to chemical fibers can shield the excessive irradiation of ultraviolet light. Using computer simulation design, it is found that when the particle size of titanium dioxide particles is 50-120 lm, the ultraviolet absorbing effect is the best. The shielding powder particles of this particle size range can be added into the fiber to make light-resistant matt high-white paper. And bright colored paper, and can achieve anti-ultraviolet effect.
4. Inorganic fiber nano paper
The paper industry mainly uses plant fiber as raw material, and now also uses inorganic compounds to produce special paper. Since these inorganic materials are processed to have excellent dimensional stability, heat resistance, chemical resistance, flame retardancy and electrical insulation, these properties are unmatched by plant fibers. The representative inorganic fiber-glass fiber, because it can not withstand the beating, lacks the bonding between the glass fibers, and the copied sheet is very fragile, but if the diameter of the glass filament is controlled below 100 nm, then it can be solved. The phenomenon that paper fiber is difficult to form due to small expansion and contraction of glass filaments is advantageous for interlacing fibers.
5. Color flavored nano paper
With the development of science and technology, people's living standards have been continuously improved, and the quality requirements for paper have become higher and higher. Nowadays, a series of papers such as offset printing papers and writing papers of various fragrance types and various colors have been developed and produced. This scented paper is not only soft and delicate, but also has a subtle fragrance. The application of nanotechnology to the development of flavored paper will greatly improve the quality and printability of the flavored paper, and the image of the printed high-grade printed crystal will be more delicate and realistic. The use of color fragrant paper for printed books, primary and secondary school textbooks, exercise books, notebooks and various children's books, etc., people will not be glaring because of the high whiteness of the paper when reading, thus reducing the fatigue of long reading It has a certain effect on protecting vision and preventing myopia. Therefore, this kind of flavored paper has been well received by users since its launch.
6. Nano flame retardant paper
It is the paper that can stop the burning of fire. For it, no matter how much firepower, it will not cause burning. It is the nemesis of any kind of fire. It can only burn, and often the clothes of the people who deal with the fire often, to prevent the clothes from burning. It has a flame retardant effect. In addition, the flame retardant paper is applied to the dry type transformer, which is safe, non-toxic and carbon-resistant, but does not catch fire. After the paper is used, it can be used as waste paper, and no harmful substances are released in natural degradation. Flame-retardant paper can be generally used for fireworks, fireworks, colored cannons, Christmas toys, tourist cookers, and the like. It is an ideal green product in today's holiday products. It has even been suggested that the use of this paper to make firefighters has a special effect. Development and research of high-performance specialty paper products such as color-changing paper and energy storage paper. In addition, due to its excellent chemical activity, nano-materials have broad application prospects in papermaking chemical crystals and wastewater treatment. In addition to its application on paper, nanotechnology currently has many uses in the packaging and printing industry, such as nano-adhesives and sealants in packaging and printing, nano-magnetic materials, nano-substrate packaging materials, nano-catalysts and water purifying agents. , nano luminescent materials and anti-counterfeiting printing and so on. In short, nanotechnology, as a high-tech research and development in recent years, will be applied in the printing field as well as other fields, and will continue to develop in depth and breadth.
Although nanomaterials and nanocomposites have good performance and wide applications in the papermaking field, the research and development of nanomaterials is still not mature, and there are still some problems that need to be further solved, such as crushing, agglomeration, dispersion technology, etc. Not ideal enough, need to be further improved, for the performance testing of nano-products, product standards have yet to be further improved. However, it can be predicted that as the production cost of nanoparticles decreases and the variety of functional nanoparticles increases, nanotechnology will play a greater role in the printing field and the paper industry, bringing unlimited vitality and vitality to the printing and related industries.