A method of determining the adhesion of the coating film

paint film adhesion refers to the degree of robustness of the paint film that binds to the surface of the coated objectAdhesion is one of the important indicators of the physical and mechanical properties of coatings, and through this inspection, it is possible to test the composition of coatings, especially whether the use of resin is reasonableIn addition to the adhesion of the paint film depends on the coating base selected, but also with the substrate surface pretreatment, construction methods and paint film maintenance has a very important relationship, for example, in wet, rusty, greased metal surface coating, adhesion is poormethods for determining adhesion are: lap method, row method, pull-out method, twisting method and the Dashes X method in ASTM, the national standard GB1720-89 (79) provides for the method of measuring the adhesion of paint film, while GB9286-88 provides for the use of the row method to determine adhesion, GB5210-85 provides for the use of the pull method to determine the method of coating adhesionOne of the simplest application is the lap method to determine the adhesion of the paint film, the site is the most commonly used is the row method(1), the dareto method to determine the adhesionthe adhesion method used in the adhesion measurement instrument is based on the extent of the paint film in the scratch range to assess, in order to gradeIs in accordance with the preparation of a good horse mouth iron plate fixed on the meter, in order to ensure that the diaphragm, as appropriate to add weight, according to the clockwise direction, to 80-100r/min uniform shake handle, to round roll scratches, the standard round length 7.5cm, take out the template, ratingThe following points need to be noted in the experiment:(a) the needle of the meter must be kept sharp, otherwise it is impossible to distinguish between 1, 2 levels, should be before the determination of the finger touch feeling is sharp, or after the determination of a number of test plates as appropriate(b) first try to cut a few laps, scratches should be just through the paint film, if not exposed to the bottom plate, add weight as appropriate, but do not add too much, so as not to increase resistance, wear the needle(c) rating can be 7 (the innermost layer) to start the assessment, can also be 1 level (outerring) rating, in order to check the integrity of the paint film of each department, such as a part of the grid has more than 705 intact, think that the part is intact, otherwise it is considered bad damagefor example, site 1 paint film intact, the best adhesion, as a level 1;the lowest level of adhesion according to the analogyUsually requires a better primer adhesion should reach 1 level, the adhesion of the paint can be about 2 levels