Views:238 Author:Site Editor Publish Time: 2020-04-14 Origin:Site
Luminous paint generally refers to paints with a pigment volume concentration of less than 33% and a gloss of more than 80%. It is mainly used as a topcoat and has good decorative properties. In our life, we often see this kind of paint, today we will briefly introduce the history of luminous paint.
Luminous paints are mainly composed of base materials, self-luminous materials, coating additives and solvents. In order to ensure that the luminous paint can obtain good luminous performance and luminous brightness, the base material is required to have colorless and transparent characteristics. Coating resins such as acrylic resin, amino resin, and polyurethane can be used. Coating additives and solvents are used to avoid damaging the light-emitting properties of self-luminous powder. Luminous coating additives must not contain heavy metals. The additives used are usually dispersants and anti-settling agents. A dispersant is used to improve the dispersion efficiency of the self-luminous powder, and a fine-grained self-luminous powder can be obtained. The function of the anti-settling agent is to improve the storage stability of the luminescent powder. Self-luminous materials are essentially fine powdery materials, including zinc sulfide-based, silicate-based, and alkaline-earth aluminate-based.
The history of self-luminous paint is almost related to the history of self-luminous materials, we will briefly introduce the history of self-luminous materials.
Self-luminous materials have a long history. In 1866, French chemist Cidot first produced ZnS: Cu self-luminous materials. In 1886, French chemist Bois Bourdrand discovered that the small amount of metal atoms doped in self-luminous materials played an important role. At the beginning of the 20th century, German physicist Leonard made a detailed study of self-luminous materials, and systematically studied the effects of active elements in sulfides such as Cu, Ag, Bi and Mn and the fluorescence decay curve, and obtained the central theory. In one word, it is believed that there are processes of excitation, storage of energy, and luminescence at the center. The more famous self-luminous materials are sulfide self-luminous materials, including CaS: BO which emits purple blue light, CaSrS: Si which emits cyan light, ZnS, Cu which emits green light, i2nCd5: Cu which emits yellow or orange yellow light. In 1946, Froelich discovered that the light-emitting material SrAl2O4: Eu2 + prepared by using aluminate as a matrix can emit colored light with a wavelength of 400--520nm after being illuminated by sunlight. In the 1960s and 1970s, SrAl2O4: Eu2 + materials research is mainly focused on the application of fluorescent lamp cathode ray tubes. Philips has done a lot of research in this area, mainly to improve the SrAl2O4: Eu2 + material, one is to prepare non-dose chemical SrAl2O4: Eu2 + materials, another is to add other materials based on the SrAl2O4: Eu2 + system. In 1968, Palilla discovered that the emission process of SrAl2O4: Eu2 + first experienced a rapid decay process, and then in the low luminous intensity range, there is also a long period of continuous light emission. This discovery makes the research of long afterglow photoluminescence materials enter a new stage. In the 1990s, research on the SrAl2O4: Eu2 + system mainly focused on adding a second activator besides Eu, such as Dy and Nd. Researchers hope to extend the afterglow time by introducing trace elements to form appropriate impurity energy levels. Sugimoto produced a new type of long-glow phosphorescent material with green self-luminous light -SrAl2O4: Eu, Dy3 +, and dissolved Dy 3+ as an auxiliary activator in the SrAl2O4: Eu2 + system. The results show that the self-luminous material has high brightness and long afterglow time, which can reach more than 12h. In 1999, American Weiyi Jia used Laser-Heated Pedestal Growth technology to prepare single crystals of SrAl2O4: Eu2 +, Dy3 + and CaAl2O4: Eu2 +, Dy3 +, which emit bright and long-lasting blue and violet light, respectively. In addition, in the same year, the Japanese T. Katsumata prepared a BaAl2O4: Eu2 +, Dy3 + single crystal using the Floating Zone method, which is mainly used for theoretical studies such as the mechanism of light emission.
At present, the most studied self-luminous materials are represented by SrAl2O4: Eu2 +, Dy3 +. The afterglow time is long, the brightness is high, the performance is stable, and it is non-toxic. However, this self-luminous material has a single light-emitting color and is poor in water resistance. In view of this shortcoming, silicate-based self-luminous materials have attracted people's attention because of their good chemical and thermal stability, many self-luminous colors, and abundant raw materials.
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