Coating technology: Determination of the freshness of coating film

Core tip: the freshness of the coating film is used to describe the clarity of the object on the surface of the coating film The freshness is related to the smoothness, fullness and luster of the coating film, which is a comprehensive index to characterize the decorative properties of the coating film From the micro state analysis, the relationship is shown in Table 1 Table 1 a large number of test data of film freshness and surface state show that although glossiness is the factor of freshness, their dependence is not large It is not difficult to ensure the high gloss of the car finish used now, however, its freshness is not necessarily high In contrast, smoothness and freshness 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 Paint Home News: the freshness of paint film is used to describe the clarity of the objects on the surface of the paint film The freshness is related to the smoothness, fullness and luster of the coating film, which is a comprehensive index to characterize the decorative properties of the coating film From the micro state analysis, the relationship is shown in Table 1 Table 1 a large number of test data of film freshness and surface state show that although glossiness is the factor of freshness, their dependence is not large It is not difficult to ensure the high gloss of the car finish used now, however, its freshness is not necessarily high In contrast, smoothness and freshness are closely related To improve the freshness of the film, we should focus on improving the smoothness of the film There are many kinds of instruments and methods to evaluate the freshness of the film, and the following kinds have been used in China (1) The structure principle and standard digital board of PGD coating measuring instrument are shown in Figure 1 The standard digital board is illuminated by the light source, and the light reflected by the standard digital board is reflected to the paint test board through two reflectors, and then the reflection light of the paint test board is reflected to the eye mirror by another two reflectors The observer observes the clarity of the image sequence on the standard digital board through the eye mirror, and records the PGD value corresponding to the sequence that can be read clearly (also useful for DOI Value representation) Before each measurement, the voltage shall be adjusted to the specified range When calibrating the instrument with a standard reflecting lens, the vision of the observer must be able to clearly read out the sequence corresponding to the DOI value of 1.0 before using the instrument During the measurement, the flat surface of the test plate shall completely block the measurement window of the instrument Fig 1 Schematic diagram of PGD instrument (2) image braiding method is to use the so-called ring with notch ("Landolt ring") image on the tested coating surface, and then evaluate the image clarity, which is a comprehensive reflection of the specular gloss, freshness and fog that affect the surface vision The coating apparatus is shown in Figure 2A A 15W fluorescent lamp is installed in the light source box, with a piece of ground glass at the bottom to ensure uniform illumination of the whole surface The ground glass is printed with a transparent film with a notch ring on the test drawing (Fig 2b) When calibrating the instrument, place the black glass plate as the standard under the instrument, and the observer's position is at the 30 ° reflection angle, that is to say, the front edge of the light source box is exactly flush with the mark line in the middle of the test diagram, and adjust the observation distance until the picture with DOI = 100 can be clearly seen, and observe the test plate at this angle and distance, Find out the image of the smallest ring with notch that can see the ring opening clearly, and record the value of its side, that is, DOI value If you hesitate between two columns of images, you can use the middle value of the corresponding two values This method is only suitable for flat surfaces with a specular gloss of more than 40% (20 ° angle) or surfaces with a radius of curvature of more than 1 m Fig 2 structure diagram of image resolution instrument paint house is devoted to news and information of coating, diatom mud, paint coating, coating process, fire retardant coating and coating, diatom mud, paint coating, coating process, decoration knowledge and decoration effect diagram of fire retardant coating,