Performance and application of the hottest anti fa

2022-08-26
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Performance and application of anti-counterfeiting paper

a typical example of anti-counterfeiting paper is banknotes. The paper used in banknotes and other securities is different from general printing paper, which generally adopts tough, smooth, crisp and wear-resistant special paper for banknote printing. This kind of paper is durable, lint free, folding resistant and non breaking. Its paper-making raw materials are mainly long fiber cotton and hemp. Some countries have also added their own unique products to pulp, and their formulas are confidential

in recent years, in order to prolong the service life of banknotes, some countries have developed and applied plastics instead of paper carriers for banknote printing. Generally, the paper shows fluorescence under UV irradiation, so the banknote printing paper and some securities or bills are made of special paper without Yingguang to prevent counterfeiting. For example, the paper bases of banknotes, passports and some tickets in various countries are not fluorescent, which makes it easier to show fluorescent pictures and texts with additional secret marks

1) watermark paper: paper with embossed, perspective, touchable images, bar codes, etc. made by using the mold mechanism. In the process of papermaking, the watermark graphic printing plate designed in advance is installed on the silk, or it is pressed by the printing roller. Due to the different height of pictures and texts, the pulp forms the corresponding density with different thickness. After the paper is finished, due to the different density of the pulp at the image and text, its transmittance is different. Therefore, when observing the light transmission, the original designed image and text can be displayed. These images and text are called watermarks. It is reported that a new transparent watermark developed abroad can only be displayed and recognized from a certain angle, and cannot be copied with a scanner

2) chemical watermark paper: watermark paper made by printing chemical substances on paper

3) ultra thin paper: anti counterfeiting paper with different colors on the surface, which can be used to prevent erasing numbers or signatures, also known as low-strength paper

4) anti counterfeiting inserts: small discs, particles, fibers, ribbons, holograms, translucent strips with words, etc. with anti-counterfeiting effect are added or coated in the paper

there are two kinds of fibers mixed into pulp: colored fibers and colorless fluorescent fibers. The former can be seen on paper with the naked eye; The latter and color dots must be visible under ultraviolet radiation. Their colors include red, blue, orange, etc. their shapes can be coarse or fine, long or short, depending on the design. Some fibers are scattered on the paper before it is formed. The positions of fibers and colored dots in the paper are generally randomly distributed, so their density and embedding are different. There are also fixed positions, such as the US dollar printed before 1928. The red and blue fibers are only distributed in a narrow and long area in the middle of the ticket. Medical high molecular materials have gradually become the most widely used and used material field

in recent years, small round pieces of metal foil and plastic have also been mixed into pulp for anti-counterfeiting. There is also a kind of flat polyester filament encryption paper abroad, which is printed with words on the polyester filament. These words can only be seen when observing the light in a certain direction. They cannot be copied with a copier, and have good anti-counterfeiting performance. Some banknotes are sandwiched with a metal foil invisible to the naked eye, which will make a sound when the coding disc is rotated by an electromechanical machine, that is, when the special recognizer is checked. In the process of papermaking, embedding special metal wires or polyester plastic wires of different colors, microfilming lines, fluorescent lines, etc. in a specific position of the paper is called a safety line. When observing the light, it can be seen that there is a complete or intermittent line buried in the paper base. The shape of the line can be straight line, wavy, sawtooth, etc. Some safety lines are exposed to the face of the ticket at intervals. When copying with a color copier, the exposed metal line will become a black discontinuous dotted line. Some safety lines also have micro printed words, which can be seen with a magnifying glass, and some can also be seen with the naked eye. Some safety lines with microfilms are flat polyester lines, which are transparent and visible, but cannot be copied

in recent years, a thermal safety line has been introduced, which is pink and opaque at room temperature. When the finger is used to heat the local part, as long as it reaches 37 ℃ of the body temperature, the local part will show the micro printed text. There is also a kind of safety line whose color changes due to different viewing angles. Laser holographic safety wire can not only change color, but also change image. A metal or magnetic safety wire, which can send a specific signal or sound when checked with the corresponding controller

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