Basic method of powder coating construction
1, corner coverage: before spraying, add about 0.5-1.0% of the total amount of the formula in the coating, such as polyethylene wax, polyvinyl butanal and other rheological agents, or add block agent of silica for improvement.The inner and outer surfaces of the edges and corners of the coated workpiece are coated with powder during spraying, and solidified into a film, which can be as even as the plane position, without the phenomenon of shrinking edge and fat edge.Otherwise there will be uneven phenomenon.
2, powder ball: powder ball phenomenon refers to the coating adsorbed on the workpiece solidified after the formation of tumors.The main reason is the coating powder agglomeration, or uneven atomization, there is a case that some types of powder such as metal powder adsorption to the nozzle.The solution is to add loose fine powder alumina Al2O3, silica SiO2, and add some such as dry powder fluidity agent 445, anti-adhesion agent 780 and other powder flow of organic anti-adhesion.So as to avoid the appearance of powder.
3, convex particle concave point shrinkage hole: sometimes, by spraying powder coating after the object surface has concave and convex particle phenomenon.Generally speaking, the raised particles are mostly due to the presence of nonfusible inorganic materials in the raw materials, or the gelatinized organic matter produced during extrusion.Concave shrinkage cavity and resin type, or the outside of the oil.A variety of different organisms are incompatible with each other or not wetting, it is easy to appear less than 1 mm diameter and a large number of small shrinkage cavity.It is different from the characteristic of pinhole, which is small and more irregular, and the small shrinkage hole is round and regular.The main cause of shrinkage cavity defects, leveling agent failure and external oil pollution.
4, pigment cover: when doing color is more trouble, black and white red color highlights flow smooth or difficult to do.
A. Make black powder with good coloring power of carbon black. Add 0.5-1% of pigment.
B. The amount of thin coated titanium dioxide in white powder should be 25%. For indoor use, some lithopone can be added to improve the cover.Adjust white to use group green and permanent violet commonly.Always purple.The addition of powdered wax can improve dispersion and cover, as well as eliminate stomata and shrinkage cavity.
C, some of the red powder pigment oil absorption will be bad adhesion, at this time to improve the proportion of resin.Red base, 2 to 3 percent red pigment, 5 percent titanium dioxide, sometimes about 3 percent yellow pigment to brighten.Although the variety of powder coating did not resemble solvent coating so various, but the polymer resin that can be used as powder coating also is a lot, the construction of some coating and traditional method are not quite same, requirement also is same, come to see powder coating construction requirement next below.
(1) in order to give full play to the characteristics of powder coating and extend the service life of the coating film, the surface of the coated object shall be treated strictly before surface treatment.
(2) during spraying, the coating should be completely grounded to increase the spraying efficiency of powder coating.
(3) for the coated object with larger surface defects, the conductive putty should be scraped to ensure the smoothness and smoothness of the coating film.
(4) after spraying, the object shall be heated and cured. The curing conditions shall be subject to the technical specifications of the powder product, but the curing temperature and time shall be fully guaranteed to avoid quality accidents caused by insufficient curing.
(5) check immediately after powder spraying.
(6) the recycled powder shall be mixed with the new powder in a certain proportion after screening and removing sundries.
(7) the powder supply barrel, powder spraying room and recovery system should avoid the pollution of other powders of different colors. Therefore, it is necessary to purge and clean the powder every time the color is changed.Notes for powder coating construction
1, due to the state of powder coating is 100% solid powder, not only need to spray the environment protection, also need workers to do their own protective measures, wear protective clothing, avoid skin contact with paint for a long time, if the skin accidentally stained on powder coating, need to wash with soap and water, not with other organic solvent to clean.
2, powder coating construction for spraying environment requirements are very high, generally need to be in a good ventilation environment for the construction, this is because powder coating is the use of powder spraying equipment powder coating to the surface of the object.In addition, the spraying conditions also need to maintain a certain temperature, generally under 35 degrees Celsius can be used, in addition to these, also need to maintain the construction environment without open fire, no direct sunlight.
3 is powder, powder coating, so also need to keep the paint when spraying powder has not been set, the phenomenon such as clouds, it is need to pay attention to check before spraying, ensure the paint stored in a cool, dry environment, storage area can not have water, oil and other organic solvents, so as not to mix powder coatings and the solutions.
4, powder coating in spraying equipment spraying will be under the action of static electricity, forming a layer of coating on spraying items, and achieve spraying effect, so the electrostatic effect is very important, which also needs to maintain the spraying equipment completely grounding, eliminate static electricity, avoid the impact of static electricity on spraying equipment.In addition, construction personnel also need to pay attention to the use of electricity standards, safe construction.
Contact Person: Mr. Don