35 results about "Fluoran" patented technology

The present invention relates to a unique dual color security paper authentication system. The authenticating system comprises the combination of a security paper together with a coordinated applicator. The paper contains a starch, an iodide salt and an acidic developer resin. The applicator of the system comprises two authenticating solutions. The first authenticating solution comprises one or more of a sulfonamide and a copper salt dispersed in a solvent. The second authenticating solution comprises one or more of a leuco and fluoran dye precursor dispersed in a solvent. On applying the authenticating solutions to authentic security paper, a first color of a starch iodine is expressed and a second color of a leuco or fluoran dye is expressed.

The invention belongs to the technical field of material science, and in particular relates to a method for preparing high-sensitivity temperature-sensitive reversible discoloration microcapsules. The present invention designs and synthesizes a series of novel fluorane dyes, which can realize the color changing performance without a color developer, and compound it with a phase change material according to a certain ratio to prepare a series of two-component reversible temperature-sensitive color-changing dyes, and then adopt Two-component reversible thermochromic microcapsules with good color performance and color change response were prepared by solvent evaporation method. The two-component reversible thermochromic microcapsules of the present invention can effectively improve the color hysteresis of the traditional three-component thermochromic capsules.

The invention provides a method for synthesizing fluorane type black thermal-pressure sensitive color formers. The method, which takes benzophenone acid and 4-methoxy-2-methyl diphenyl amine as raw materials, comprises the following steps: adding benzophenone acid, 4-methoxy-2-methyl diphenyl amine and a catalyst into an organic solvent for reaction, and filtering the reaction liquid to obtain filtrate after the reaction is ended; adding water into the filtrate and regulating the pH of the filtrate to be greater than 10, and then heating and refluxing to remove a water phase and to obtain an organic phase; cooling and crystallizing the organic phase, and filtering to obtain the fluorane type color formers. The color formers prepared by the method comprise aryls which replace the alkyls in a conventional black color former, so that a conjugated system in the color former molecules is further increased, and the photon absorbing intensity of the color formers is increased. An efficient and recoverable a solid-acid catalyst is adopted, so that consumption of acid and alkalis in the preparation process is reduced, the discharge amount of waste acid and waste water is greatly reduced, the production cost is saved, and the color formers are more environmentally friendly.

The invention relates to the field of thermosensitive dyes, in particular to a preparation method of 3,6-diethoxyfluorane yellow thermosensitive dye. The method comprises: (1) adding fluorescein and a solvent into a reaction container, stirring and dissolving at room temperature for 1 to 2 hours; (2) adding sodium hydroxide and reacting for 1 to 2 hours, and then adding sodium carbonate; wherein, sodium carbonate, The molar ratio between sodium hydroxide and fluorescein is 2:2:1~4:2:1; (3) Heating to 40~90°C, adding dibromoethane dropwise in 2~4 hours, dibromoethane The molar ratio to fluorescein is 3:1~5:1, after the dropwise addition, react at this temperature for 6~16 hours; (4) Add water to cool down to room temperature, stir, disperse and precipitate for 8~10 hours, filter, dry, Obtain a crude product; (5) The crude product is recrystallized with a mixed solvent composed of ethyl acetate and dimethyl carbonate to obtain 3,6-diethoxyfluorane yellow thermosensitive dye. The method of the invention has simple process, is suitable for large-scale industrial production, and is widely used in the production of medical CT films.

The invention relates to a synthesis method and a catalyst for fluorane compounds. The synthesis method comprises the step that under the action of the catalyst, a compound with a structure I and a compound with a structure II are subjected to refluxing in methylbenzene, and a product is obtained; the catalyst comprises components of oxidation graphite, aluminum oxide and transition metal oxide. The catalyst is prepared through steps as follows: aluminum oxide is added to deionized water and stirred for 1 h at the temperature of 80 DEG C, oxidation graphite and transition metal oxide are subjected to ultrasonic dispersion in another part of deionized water, a dispersion liquid is added to an aluminum oxide system and continues to be stirred for 3h, centrifugal separation is performed, solids are dried and ground into powder, the powder is placed in a muffle furnace, roasted for 5 h by slowly raising the temperature to 300 DEG C from the room temperature and cooled to the room temperature, and solid powder is obtained. With the adoption of the synthesis method and catalyst for the fluorane compounds, concentrated sulfuric acid is prevented from being used, produced tar is effectively reduced, the yield is increased, the reaction process is simplified, and large-scale production of products is facilitated.

The invention describes a thermally-responsive record material substantially free of aromatic isocyanate. The record material comprises a support having provided thereon a heat-sensitive composition comprising a substantially colorless dye precursor comprising a fluoran; and a developer material selected from the group consisting of 4,4′-diaminodiphenylsulfone and 3,3′-diaminodiphenylsulfone, which upon being heated react with said dye precursor to develop color, and including a binder material. Optionally, a modifier compound is included in the heat-sensitive composition. The modifier compound can be selected from the group consisting of a fatty acid amide, preferably a saturated fatty acid amide such as an alkyl amide, a bis methylene alkyl amide, or a bis ethylene alkyl amide, or any of 1,2-diphenoxy ethane, dimethyl diphenoxy ethane, and dimethyl phthalate.