Coating technology: scratch test of paints and varnishes

Key tips: 1 Coating experiment instrument: Scratch tester, the paint film scratch tester is mainly composed of a horizontally sliding test board (1), a constant speed motor (2), and a scratch needle (3) The constant speed motor drives the test bench to slide under the needle tip at the speed of 30mm / S ~ 40mm / s, and the needle is perpendicular to the coating The scriber is fixed in the collet, and there is a support with added weight directly above the collet The support rod shall be able to bear at least 2kg of mass, and the maximum load that the instrument can bear shall be marked on the coating instrument Indicator to indicate coating according to electrical contact between scriber and metal substrate Shenyang steel structure fireproof coating construction expert punde Building Fire Engineering Co., Ltd Recommended introduction: since its establishment, Shenyang punde Construction Fire Engineering Co., Ltd has cultivated a group of professional construction teams with excellent equipment, rich experience and serious responsibility with advanced and scientific management methods and strict engineering quality assurance and after-sales service system It has undertaken a number of fire system installation projects, which has been praised by customers Every idea and special requirement of you will be fully considered by us and fully realized in the construction technology, which will become the cornerstone of our successful long-term development We are looking forward to your invitation, to provide you with quality services and high-quality technical support! All construction coatings have passed ISO9001 Paint Home News: 1 Paint experiment instrument: scratch instrument, the paint film scratch instrument mainly consists of a horizontally sliding test board (1), a constant speed motor (2), and a scratch needle (3) The constant speed motor drives the test bench to slide under the needle tip at the speed of 30mm / S ~ 40mm / s, and the needle is perpendicular to the coating The scriber is fixed in the collet, and there is a support with added weight directly above the collet The support rod shall be able to bear at least 2kg of mass, and the maximum load that the instrument can bear shall be marked on the coating instrument Indicator, according to the electric contact between the scriber and the metal substrate to show whether the coating is scratched The stroke needle has a hard hemispherical needle with a diameter of 1mm The hemispherical needle shall be firmly fixed to the stroke needle, and the exposed part shall contain any pollutant Fig 1 Schematic diagram of scratch tester 1-Test bench 2-constant speed motor 3-scribe pin 4-stop rod 5-balance weight 6-electrical connection of indicator 2 Sample representative samples of coating products (or each product in composite coating system) 3 The test plate shall be polished tinplate, steel plate or hard aluminum plate passivated with acid The test plate can be cut into proper size after the coating is dried Dry (or bake) each painted test plate under the specified conditions and place it for the specified time Before the test, the test plate shall be adjusted for at least 16h at the temperature of (23 ± 2) ℃ and the relative humidity of (50 ± 5)% and tested 4 Test steps: (1) test conditions: unless otherwise specified, the test shall be carried out at the temperature of (23 ± 2) ℃ and relative humidity of (50 ± 5)%; the test shall be carried out on the test bench without vibration (2) For the measurement step of single specified load ① check the needle with a 30 times magnifying glass to ensure that the hard needle of the needle is smooth, hemispherical and free of pollutants ② Fix the scriber in the collet so that it can be perpendicular to the coating during the test With the help of adjustable weight to balance the arm of the needle holder, check whether the indicator can work normally by making the needle contact with the test bench ③ Paint the test plate upward and clamp it on the test plate platform of the instrument The long side of the test plate shall be parallel to the scratch direction ④ Place the weight on the bracket above the scriber to obtain the specified load ⑤ Start the scratch tester, scratch it on the scratch, and observe the indicator during the test to determine whether there is electric contact between the scratch needle and the test plate ⑥ Remove the test plate, check whether the coating is scratched through, or use the appropriate magnification to observe, but the magnification shall be indicated ⑦ Conduct three tests on each of the two test plates If six scratches do not penetrate the coating under the specified load, the record result is "pass", otherwise, the record result is "fail" (3) To determine the minimum load of the scratch through coating, carry out the test on different parts of the test plate according to the steps specified in ① ~ ⑥ of the previous step, first use a small load and then gradually increase the load until the coating is scratched through, and record the minimum load of the scratch through coating Repeat the determination on the other two test plates, and record the minimum results on the three test plates 5 For the "pass / fail" test, the repeatability deviation of the result is usually ± 10% of the load 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,