Coating technology: method for determination of the quality percentage of non-volatile matter in coating

Key tips: 1 Coating testing instruments and materials General laboratory equipment and the following coating equipment and materials: ① Analytical balance, accurate to 0.1mg Lacquer ware ③ The choice of lacquer receiver (round or plate) depends on the type of coating to be tested The disc is best used for low viscosity paints and paints diluted to spray viscosity The plate can be used for thixotropic paint or other paint that can be scraped with a paint scraper or color paint that can be applied by dip coating method ④ The diameter of the disc is about 60mm, the thickness is about 0.7mm, and there is a small hole 2-3mm from the edge ⑤ Plate, ruler Paint knowledge | precautions for wall paint color selection Recommended introduction: when painting the wall, the owner sometimes has difficulty in choosing what color of the wall paint to paint In fact, there is no ugly color in the wall paint, only the disharmonious color matching The use of wall color contains the knowledge of health Too strong color will stimulate people's perception, make people have a sense of fidgety, affect people's mental health Grasp the basic principles of wall color and paint a colorful space 1、 Wall paint color selection notice 1 Light color is generally used for the top surface Light colors make people feel light, dark colors make people feel heavy Usually, the treatment of rooms is from top to bottom, from shallow to deep For example, the ceiling and walls of rooms are white and Coating home news: 1 Coating testing instruments and materials general laboratory instruments and equipment and the following coating instruments and equipment and materials: ① analytical balance, accurate to 0.1mg ② The selection of lacquer receiver ③ depends on the type of coating to be tested The disc is best used for low viscosity paints and paints diluted to spray viscosity The plate can be used for thixotropic paint or other paint that can be scraped with a paint scraper or color paint that can be applied by dip coating method ④ The diameter of the disc is about 60mm, the thickness is about 0.7mm, and there is a small hole 2-3mm from the edge ⑤ The size of the plate is (75 ± 5) mm × (120 ± 5) mm There is a small hole 2 to 3 mm from the short side on the longitudinal axis of the plate The utility model relates to a plate with a tip, which can be used for coating construction by dip coating method ⑥ Desiccator, use dry material like silica gel ⑦ The air drying oven shall be able to maintain the specified or agreed temperature (see Appendix A) to ± 2 ℃ (for the maximum temperature of 150 ℃) or ± 3.5 ℃ (for the temperature above 150 ℃ and the maximum temperature of 200 ℃) ⑧ Small motor with voltage regulator: the motor speed is (200-4000) R / min, and it is better to install a drill chuck on the shaft of small motor ⑨ Metal Y-shaped parts: Y-shaped parts with two small hooks that can hang round pieces ⑩ Container: a round metal container or other container used to collect thrown material 2、 The key points of coating testing operation are parallel testing of samples in duplicate The sample can be dip coated, brush coated or applied on the round or plate with a scraper 1 Determination of the volume of the unpainted lacquer receiver (1) dry the lacquer receiver and the hook in the air drying oven If necessary, dry them at the recommended temperature for 10min, put them into the dryer for cooling, and weigh the mass of the lacquer receiver in the air Record this mass as M1 (2) Sufficient immersion liquid shall be added to the beaker to ensure that the liquid level is at least 10 mm higher than the top of the suspended lacquer receiver Mark the liquid level on the side of the beaker, and maintain the liquid level throughout the measurement process The liquid temperature should preferably be (23 ± 1) ℃ Hang the lacquer receiver in the liquid and weigh it again Record the mass as m2 Note: if water is used as the impregnating liquid, 1 to 2 drops of suitable wetting agent can be added to make the lacquer receiver wet rapidly and fully (3) Record the temperature of the liquid and determine the density of the liquid at that temperature The recording density is ρ 1 2 Application method (1) apply the required approximate amount of coating to the circular or plate to achieve the specified film thickness Note 1: the viscous coating can be diluted with a known amount of specified diluent with known density Note 2: the thixotropic coating can be stirred or applied with syringe before coating with film preparation device (2) Dip coating is the best construction method, but brush coating can also be used Attach the disc to a strong wire and immerse it all in the sample Then lift the disc out evenly, drip dry and remove any thick edges formed at the bottom of the disc This can be removed by scraping and pulling along the thick edge with a glass rod and rotating the glass rod at the same time If air bubbles form on the surface of the film, break it with the tip of a needle Immediately weigh the mass of the disc and record the mass as m3 For very thin coating products, the required thickness (30 μ m) of coating cannot be obtained through the above two dip coating operations, or for the pigment in coating products It is easy to separate from the resin, and the uneven distribution of pigment in the coating will be caused by scraping with a glass rod The operation of flattening can be adopted, i.e lifting the disc out of the sample at a constant speed, driping it and removing the air bubble on the disc with a needle tip, and then hanging it on the Y-shaped piece The Y-piece is clamped on the bit clamp of the small motor Turn on the motor and adjust the voltage to adjust the rotating speed until the disc is leveled (20-30) s When using the flattening operation, do not weigh the quality of the disc just after the wet paint is applied (3) The sample is applied to the plate as shown in Fig 2 by dip coating, or the sample is applied to the plate with a paint scraper or wire rod coater Immediately weigh the mass of the coated sheet and record the mass as m3 (4) The metal wire used to dry the lacquer receiver or other suitable devices to hang the painted lacquer receiver Do not use the hook at this time Allow the film to dry under the conditions specified in Appendix A (5) After drying, take the painted lacquer receiver off the device used for hanging when drying, put it together with the hook into the dryer for cooling, and then weigh the mass in the air Record the mass as M4 Note: this method is not suitable for coatings prepared at a concentration higher than the critical pigment volume concentration (6) The determination of the mass percentage of non-volatile matter in the paint is only used when the round piece is used for painting and the swing operation is adopted At this time, the determination shall be carried out according to the provisions of ISO 3251:1993 NVM NVM = (m4-m1) / (m3-m1) × 100, where: M1 - the mass of unpainted lacquered lacquered lacquered ware in air, unit: G; M2 - the apparent mass of unpainted lacquered lacquered ware immersed in immersion liquid, unit: G; m3 - the mass of wet lacquered lacquered lacquered ware, unit: G; M4 - mass of paint receiver in the air, unit: G; NVM - mass percentage of non-volatile matter; (7) repeat the test if the measured result exceeds the repeatability limit, carry out the third test, and take the arithmetic mean of all results 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,