Analysis of the hottest water-based adhesive compo

2022-08-24
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Analysis of water-based adhesive composite transparent holographic anti-counterfeiting materials

laser holographic image anti-counterfeiting products are widely respected in the market because they can be visually recognized. With the development of related technology, the development of holographic products is also changing with each passing day. On the one hand, the laser holographic plate making technology is constantly innovated, such as computer hologram, double beam engraving hologram, true color hologram, synthetic hologram, password hologram, etc., which can be applied to transparent holographic technology, so that the image quality of transparent hologram is higher and the anti-counterfeiting effect is better; On the other hand, the holographic image carrier material is also constantly updated, from the initial narrow opaque aluminized logo to large-scale translucent perspective holographic film, holographic film coated with high refractive index inorganic media, and transparent holographic film coated with nano glue. These materials can be made into general packaging materials with holographic images. Because this holographic film is transparent, it can be compounded on a variety of existing packaging materials to integrate anti-counterfeiting and packaging, thereby enhancing the decoration and anti-counterfeiting effect of commodities. Transparent hologram transparent hologram refers to holographic products imaged on transparent materials. The surfaces of these transparent materials are molded to form holographic gratings, which are illuminated by sunlight or point light sources. Through comprehensive optical effects such as reflection, refraction and diffraction, the human eye can see the stimulated light reproduced on the materials. It consists of a variable throttle and a differential pressure reducing valve in parallel to form a holographic pattern. Since the object image observed by human eyes is mainly the effect of reflected light on human visual nerve, we pay attention to the reflection effect of grating in holographic images on transparent or opaque materials. With the reflected light intensity, the holographic pattern is bright, clear and eye-catching. Therefore, in the early days, holographic patterns were molded onto highly reflective aluminized films, and then holographic images on transparent materials were produced. Moreover, because it is transparent, it does not affect the effect of the original pictures and texts of the printing materials, and can form a double pattern that does not interfere with each other with the printing patterns on the original packaging products. Therefore, as a packaging material, transparent holograms naturally become the new favorite of anti-counterfeiting packaging in the printing and packaging industry. Transparent holographic materials transparent holograms mostly use polyester polymer plastic films, such as BOPP, pet, etc., which are thermoplastic. When heated and pressurized, they can transfer the interference fringes of the image recorded on the holographic template onto its surface. These embossed fine fringes record the light wave intensity and phase information of the subject. This molded hologram needs to observe and reproduce the image with sunlight. Because each wavelength of white light will be diffracted by interference fringes, and the diffraction angles are different, when viewed from different angles, there are images of different colors, that is, the so-called rainbow hologram. Theoretically, as long as the transfer conditions are controlled accurately, the holographic gratings on these films can reproduce the holographic image well. However, due to the heat or environmental erosion of polymer materials, the fine gratings may be worn out or the film itself has the instinct of restoring deformation, resulting in image damage and even disappearance. Therefore, the holographic gratings on polymer materials without evaporation of metals, compounds or nano glue are unstable, Some technological methods should be adopted to protect the grating and fix the image. For example, the particles evaporated by high vacuum evaporation of metal, sputtering, electron beam scanning bombardment evaporation of inorganic compounds and other methods embedded in the grating of polymer film can also play a role in fixing the holographic grating, so as to protect the holographic image and enhance the brightness of the image at the same time. However, from the perspective of large-scale production, because the evaporation process is difficult to be uniform, the packaging machine 'target=_ Blank> the transparent film can appear in gold, silver, gray and black. Sometimes the packaging machine 'target=_ Blank> the transparent film becomes translucent, the hologram is damaged, and the equipment investment and energy consumption are large, and the quality qualification rate is limited. In order to avoid the above shortcomings, we have adopted the emerging nano material science and technology, studied and developed a chemical process method of transparent holographic composite film suitable for large-scale production, that is, we use nano oxide water-based adhesive with high refractive index, add a certain proportion of dispersant under specific pH value and heating conditions, and prepare a water-based coating adhesive suitable for coating machine. The water-based coating adhesive is non-toxic, odorless, and does not add any solvent, It is an environmental friendly material that can be prepared with tap water. It is a green product used for food and drug packaging. Experiments show that this nano coating adhesive has a special effect on the fixing and protection of holograms. After coating, the nanoparticles form a three-dimensional complex transparent film on the holographic grating, which is extremely thin, usually less than 50nm. It has good flexibility and plasticity, can support and protect the holographic grating on BOPP, pet and other films, stabilize the holographic image, and improve the ability of image anti friction and environmental erosion. With this extremely thin nano protective layer, the front of the transparent holographic material can be further coated with glue to compound with other packaging materials, making the holographic image more stable and reliable. Compared with physical methods such as vacuum evaporation, the method of using nano materials with high refractive index to improve the quality of holographic images has the advantages of small equipment investment, low energy and material consumption, simple product structure, good product uniformity and high qualification rate. It is suitable for large-scale industrial production, and its disadvantage is that the brightness of holographic images is not as good as that of evaporation. The main purpose of transparent hologram for packaging is anti-counterfeiting. The rainbow hologram is colorful, which can play a decorative role in product packaging. But because it is based on the anti-counterfeiting principle of laser holographic three-dimensional image change, its brightness should not be too dazzling, and the anti-counterfeiting mark of anti-counterfeiting products should not be too conspicuous. The so-called good anti-counterfeiting means should be accurate and reliable information, easy identification by the public and accurate identification by experts. Nano oxide water-based adhesive packaging machine 'target=_ Blank> although the hologram on the transparent film is not as dazzling as the hologram on the aluminized film, it can 1. Avoid heavy blows in the process of use and handling, and reproduce the object image evenly, stably and clearly, which is enough to play the role of anti-counterfeiting recognition. The design of assistive devices matches the manufacturing technology of nano films. Nano films can be divided into two categories: one is the film composed of nanoparticles; The other kind of film contains more pores or disordered atoms between nanoparticles or another material, that is, nanoparticles are granular films embedded in another matrix material. Because nano films have many characteristics in optics, electricity, catalysis and sensitivity, they have broad application prospects. Transparent holographic nanocomposite film used for holographic anti-counterfeiting is a typical second kind of nano film. The structure of a new transparent holographic composite film using high refractive index nano oxide water-based adhesive is composed of a polymer film molded with holographic grating and a nano adhesive coating protective film on the pattern grating. Before preparation, it is necessary to select high polymer film BOPP or pet with good molding transfer performance, press the laser holographic pattern on the molding surface, after corona treatment, coat a thin layer of Ti02 nano aqueous coating adhesive, and dry it with hot air to form a transparent laser holographic image composite film, which can be used for packaging anti-counterfeiting. The characteristics of its preparation process are as follows: first, the preparation process of water-based coating adhesive is complex, with a strict feeding and blending process. The feeding sequence cannot be reversed. Select a specific dispersant, concentration, temperature and pH value, and the coating adhesive can be used only after aging after preparation, so as to ensure a stable, uniform and nano specific water-based coating adhesive. Second, the coating equipment is specially designed and manufactured by Zhongshan Golden Crown Machinery Co., Ltd. the whole machine is about 18m long, which has higher accuracy than the general coating machine. Corona treatment and electrostatic removal devices are added before coating and sizing. Plastic scraper is used to cooperate with corrugated roller for sizing and coating. The pressure between rollers is adjustable, and the drying channel is balanced in five sections. There are many reasons for the friction resistance of the dynamometer in the unwinding and rewinding parts, including electric eye correction and tracking, Water cooling roll shaping to ensure that the film is rolled neatly and evenly. Note: nano material science and technology is a new discipline emerging in China in recent 10 years, which involves the knowledge of condensed matter physics, chemistry, materials, biology and many other fields. The research of nanomaterials science mainly includes two aspects: one is to systematically study the properties, microstructure and spectral characteristics of nanomaterials; The second is to develop new nano materials. Many people have predicted that nanocomposites will dominate the world

information source: Printing Technology

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