Preparation And Application Of Photochromic And Temperature Thermochromic Material In Anticounterfeit Paper

In recent years, the progressive development of anti-counterfeit technology and exploitation of new materials supplies the anti-counterfeit paper field in China paper industry with a bran-new developmental opportunity. Chemical anti-counterfeit is one of the most fundamental technologies and occupies a quite important position in anti-counterfeit field. Therefore, it is very important to study the synthesis of new anti-counterfeit materials.The synthesis and application of reversible thermochromic materials were studied in the first part of this paper. Considering the fact of the current carbonless paper and facsimile paper are the applications of irreversible thermochromic microcapsule technology in paper industry, and they are one-off materials, and it is never reported that the technology of reversible thermochromic microcapsule has been applied in native paper industry. So, using the tetradecanol, hexadecanol and octadecanol as corresponding solvents, with letlacton compound of 3-diethylamino-7,8-phenyl-fluoran as procrypsis dye, H₁₅H₁₆O₂ as color agent, these reversible thermochromic materials which can turn color when temperature range at respectively 36.0～39.5℃, 44.5～46.5℃, 51.0～53.5℃were prepared. A number of trials showed that the optimal ratios of procrypsis dye, color agent and solvent are 1:4:30(tetradecanol), 1:3:40(hexadecanol), 1:2:20(octadecanol). And by infrared spectrum technology, their chromic mechanisms of this kind of reversible thermochromic materials were analyzed. In order to strengthen the resisting capability of aging of these materials the phase disengagement and interphase polymerization were adopted to synthesize the low temperature (<100 ℃) reversible thermochromic microcapsule. By repeating experiments, the preparation technological conditions of microcapsule were determined considering their respective optimal compositions of the core and shell of microcapsule, and other factors. And some properties of reversible thermochromic materials and microcapsules were studied including the resisting capabilities of fatigue and oxidation, the stability to chemical ambiences such as acid, alkali and solvents, etc.Presently, in home and abroad, reversible thermochromic materials are mostly used in ink and paint. However, in this paper, they were firstly applied in the system of pulp and coating paper, and the anti-counterfeit mechanism of this kind of paper and the retention mechanism of reversible thermochromic materials were investigated systematically, the strength properties of anti-counterfeit paper andprinting properties of anti-counterfeit coating paper were tested. The low temperature reversible thermochromic microcapsule was successfully applied to prepare the thermochromic anti-counterfeit paper for the first time, which supplies a native gap of the low temperature reversible thermochromic anti-counterfeit paper.In the second part, rare earth polymer complex photochromic materials were synthesized and applied. Rare earth polymer complex photochromic is the interdisciplinary of inorganic, organic and biological, and has important research significance in theory and application value in practice. Presently, applications of photochromic materials in paper are limited to process banknote and bond paper. In this paper, the synthesis factors of rare earth polymer complex were studied, including the option of ligand, the optimal ratio of ligand and rare earth, the stability of ligand and so on. The anti-counterfeit properties of anti-counterfeit paper by fluorescent spectrum were studied, consequently extending the application of rare earth polymer complex photochromic materials in anti-counterfeit paper field.Presently, in the world, rare earth polymer complex thermochromic materials are commonly used in ink and paint. But, in our experiments, they were firstly applied in the system of pulp and coating paper, the anti-counterfeit mechanism of this kind of paper and the retention mechanism of rare earth polymer complex thermochromic materials were investigated systematically, the strength properties of anti-counterfeit paper were tested, the resisting capability of aging, the anti-counterfeit and printing properties of anti-counterfeit coating paper. The development of this kind of anti-counterfeit paper supplies a native gap of the photochromic anti-counterfeit paper, and supplies reliably theoretical reference to develop comprehensive anti-counterfeit paper, and has definite guiding significance to practical production.