Coating classification: reversible color changing building coating

Core tip: Introduction: Reversible color changing architectural coating is a functional coating made of thermochromic materials, also known as temperature indicating coating Its basic characteristic is that when the coating can reach a certain temperature, the color of the coating changes, and when the temperature decreases, the original color will be restored This kind of coating is used to decorate the interior walls of entertainment places, hotels, hotels, restaurants, meeting rooms and family rooms, with its unique decorative function Discoloration principle: The color change of reversible color changing coating is due to the use of reversible color changing pigment which can change color at a certain temperature Color changing pigment at a certain temperature Which is the price of Dajin diatom mud Recommended brief introduction: which is the price of Dajin diatom mud? How to buy genuine diatom mud? Guangdong diatom mud agent suggests placing a basin of cold water in the air conditioning room, so that the diatom mud wall can breathe effectively The feature of the breathing wall is obvious When the indoor air is dry, the diatom mud wall will release the absorbed water quickly Put it out to help regulate the indoor dry humidity It is suggested to place a basin of cold water in the air conditioning room, so that the wall of diatom mud can breathe effectively The feature of the wall that can breathe is obvious When the indoor air is relatively dry, the wall of diatom mud will absorb the water Introduction: reversible color changing building coating is a functional coating made of thermochromic materials, also known as temperature indicating coating Its basic characteristics are that when the coating can reach a certain temperature, the color of the coating changes, and when the temperature decreases, the original color will be restored This kind of coating is used to decorate the interior walls of entertainment places, hotels, hotels, restaurants, meeting rooms and family rooms, with its unique decorative function Principle of color change: the color change of reversible color change coating is due to the use of reversible color change pigment which can change color at a certain temperature The discoloration of the pigment at a certain temperature is attributed to the coating When the reversible color changing coating film is heated to a certain temperature, the color of the pigment may change due to the physical and chemical changes of the pigment in the coating, such as the lattice transformation, the gain and loss of crystal water, the change of the geometry of the coordination body, the change of pH value, the gain and loss of electrons, the change of liquid crystal polymer system, etc When the temperature decreases, the pigment can return to its original color For inorganic reversible thermochromic pigments, the mechanism of color change is mainly crystal transformation, the gain and loss of crystal water and the change of geometry of coordination body ① Crystal transformation many inorganic pigments have crystal structure Under certain temperature, crystal transformation may occur in their crystal lattice, because the same substance has different colors in different crystal forms, which leads to color change of pigments When the temperature changes (decreases), the crystal form changes back and the color changes accordingly For example, mercury iodide (HgI2) has a square crystal structure at room temperature, which is red When it is heated to 137 ℃, it changes into a square crystal structure, which is cyan After cooling to room temperature, the crystal form changes into square and red again As shown in Figure 1: ② when the lost crystal water containing crystal water is heated to a certain temperature, the lost crystal water will cause the change of color; when the material is cooled, it will absorb water from the environment and contain crystal water again, and the changed color will change again The process is illustrated in Figure 2 The reversible color change pigment can be obtained by using the color change caused by the gain and loss of crystal water For example, when the pink cobalt oxide · hexamethylenetetramine is heated to a certain temperature (35 ℃), it loses crystal water and changes its color After cooling, it can absorb water from the air and combine with crystal water to restore its original color The equation of the reaction is as follows: the essence of the color change of this kind of pigment is the decomposition reaction of the compound losing the coordination body When there are enough coordination bodies in the environment, the reverse reaction can be carried out, but the color recovery needs a long time and a high air humidity This kind of pigment is also called semi reversible color change material with memory function CoCl2 · 2c6h12n4 · 10h2o color changing pigment is prepared by reacting Urotropine (hexamethylenetetramine) and CoCl2 · 6H2O in a certain proportion in solution, filtering and drying ③ The change of pH value some substances are mixed with higher fatty acids, when heated to a certain temperature, the dissociated carboxylic acid protons in the acid are activated, and the color changes obviously when interacting with another substance After cooling, the proton recovery of carboxylic acid causes the color to recover The reversible color changing pigment can be obtained by using the principle that the pH value changes with the temperature For example, the color of stearic acid and bromophenol blue changed from yellow to blue at 55 ℃, and the color recovered when cooled to room temperature Composition: ① the color changing mechanism of reversible color changing pigment is that reversible color changing pigment is used in the paint, and reversible color changing pigment gives the film reversible color changing function There are many kinds of pigments that change color due to heating When used for reversible color changing paint, one is to have a fixed and obvious color at room temperature, which is sensitive to heat, and can change color quickly when reaching a predetermined temperature; the other is to change color in a wide temperature range, and change color obviously; the third is to have stable physical and chemical properties of pigments, which will not be affected by external light and humidity Wait and change color The reversible color changing pigment is mainly composed of iodide, complex or complex salt of Ag, Hg and Cu and the compounds formed by cobalt salt, nickel salt and hexamethylenetetramine, etc., as shown in the following table: ② the base material for reversible color changing paint has certain influence on the temperature indicating effect of pigment besides film forming effect, so it should be selected according to the comprehensive performance of paint For example, fuchsin is evenly dispersed in shellac resin, with bright color However, it does not show color in epoxy modified silicone resin The amount of base material also has some influence on the discoloration For the same base material, when the amount of base material is large, the discoloration temperature of the coating film is high, which is because the pigment particles are isolated from each other when the amount of base material is large, which reduces its physical or chemical properties and increases the discoloration temperature ③ The selection of solvent should not only be based on the selection principle of normal coating, but also consider the influence on the film leveling, so as to obtain a film with good leveling ④ Pigments, fillers, pigments and fillers are auxiliary materials in reversible color changing fillers, but proper selection can make the color of the film bright and stable, even tone, and adjust the color changing temperature of the color changing pigments Pigments and fillers should be white pigments and fillers with strong heat resistance, such as zinc oxide, alumina, calcium oxide, antimony oxide, titanium dioxide, silicon dioxide, zirconia, magnesium oxide, barium sulfate, magnesium carbonate, calcium carbonate, barium sulfate, barium metaborate, kaolin, talcum powder, etc In addition, the variety of pigments and fillers can also affect the color changing performance of reversible color changing paint The reason is that under a certain temperature, some active elements can play a catalytic or inhibitory role on the color changing paint Therefore, when different pigments or fillers are added, the discoloration temperature will increase or decrease Formula examples: ① as a functional paint, reversible color changing paint for temperature warning still needs to have basic paint components, such as base material, pigment, dispersion medium and paint additives For example, the formula of a reversible color changing paint used for temperature warning is as follows, the color changing temperature of the formula paint is 50 ℃, which is reversible single color changing from yellow to orange; for example, the formula of a reversible color changing paint used for temperature warning is as follows, the color changing temperature of the formula paint is 40-50 ℃, which is reversible single color changing from yellow to green ② The formulation of the water sensitive color changing coating is as follows: the preparation method of the water sensitive color changing coating is as follows: 120 parts of ammonium molybdate, 96 parts of oxalic acid, an appropriate amount of 1-amino-2-phenol-4-sulfonic acid, 720 parts of sulphurous acid and 12 parts of hydrochloric acid solution are mixed to obtain the precipitate The precipitate is dissolved in 144 parts rosin, 16 parts oxalic acid and 400 parts methanol, then 80 parts titanium dioxide are added, and the water-sensitive discoloration coating is stirred evenly Home of coatings is specialized in coatings, diatom mud, paint coating, coating technology, fire retardant coating news and coating, diatom mud, paint coating, coating technology, fire retardant coating decoration knowledge and decoration renderings,