Powder coating production process requirements and precautions

Update:12-10-2019
Summary:

Powder coating is a new solvent-free 100% solid powder […]

Powder coating is a new solvent-free 100% solid powder coating. Powder coating manufacturers, it has two major categories: thermoplastic powder coatings and thermosetting powder coatings. The coating is prepared by mixing special resin, pigment filler, curing agent and other auxiliary agents in a certain ratio, and then through hot extrusion and sieving and sieving. They are stable at room temperature, electrostatically sprayed or fluidized bed dip coated, heated and baked to melt and solidify to form a flat and bright permanent coating film for decorative and anti-corrosion purposes. Features: 1. The product is non-toxic, free of solvents and volatile and toxic substances. Therefore, there is no pollution, no fire, no “three wastes” and other pollution problems, which fully meet the requirements of the National Environmental Protection Law. 2. The utilization rate of raw materials is high, and the oversprayed powder can be recycled and utilized, and the utilization rate is over 99%. 3. After pre-treatment of the coated object, one-time construction, without the need of primer, can obtain a coating film with sufficient thickness, easy to realize automatic operation, high production efficiency and low cost. 4, the coating is dense, adhesion, impact strength and toughness are good, corner coverage is high, with excellent chemical corrosion resistance and electrical insulation properties. 5, powder coating storage, transportation is safe and convenient.

Powder coating construction process and requirements: The so-called powder electrostatic spraying is the principle of using high-voltage electrostatic corona electric field. A high-voltage negative electrode is connected to the metal guide of the spray gun head, and the workpiece is grounded to form a positive pole, so that a strong electrostatic electric field is formed between the spray gun and the workpiece. When the powdered paint is sent from the powder supply tank to the guide rod of the spray gun through the powdery tube as the compressed air of the carrier gas, a dense negative charge is generated in the vicinity of the guide rod due to the corona discharge generated by the high voltage negative electrode. The powder is negatively charged and enters an electrostatic field with a high electric field strength. Under the dual action of electrostatic force and carrier gas, the powder uniformly flies to the surface of the grounded workpiece to form a thick and uniform powder layer, which is then heated and solidified into Durable coating. Pre-treatment of the coating construction process - drying to remove water - spraying - inspection - baking - inspection - finished product.

General powder spraying construction requirements (1) In order to fully exert the special properties of the powder coating and prolong the service life of the coating film, the surface of the broken coating material is first strictly subjected to surface pretreatment (2) when spraying, the coated object must be completely grounded to increase Spraying efficiency of powder coating. (3) For coated objects with large surface defects, the conductive particles should be scraped to ensure the smoothness and smoothness of the coating film. (4) After spraying, the object needs to be heat-cured. The curing conditions are based on the technical specifications of the powder product. The curing temperature and time must be fully guaranteed to avoid quality accidents caused by insufficient curing. (5) Check immediately after dusting. If defects are found, they should be treated in time. If defects are found after curing, the range is small and only partial and does not affect. The surface of the coated object is decorated. It can be repaired with the same color powder and diluted with acetone. If the range is large. If the surface quality is affected, sanding with sandpaper, spraying once or removing the coating with a paint remover, and then re-spraying. (6) The recovered powder shall be mixed with the new powder at a certain ratio after screening to remove the impurities. (7) The powder supply bucket, dusting room and recycling system should avoid the contamination of other different color powders, and must be purged every time the color change.

Art-type powder coating construction requirements: art-type powder, with beautiful features, strong three-dimensional effect, good decorative effect, etc., but the construction process requirements are strict. (1) The input air pressure during dusting should not be too large, generally it is better to control 0.5-1.5kg/cm2. Too much air pressure can cause poor pattern sharpness or some pitting. The electrostatic voltage should not be too high, generally controlled at around 60-70Kv. If the voltage is too high, the powder attached to the surface of the workpiece will rebound and pitting. Defects such as poor leveling. (2) Spraying powder should pay attention to ensure the thickness of the coating film. Generally, it can be controlled between 70-100μm to facilitate the formation of obvious patterns and large patterns. If the coating film is thin, the pattern is not obvious, and the pattern is small, and at the same time Defects such as pitting and dew bottoming (3) must be baked at the specified temperature and time when curing. If the temperature is too low, the powder will not be patterned, and the mechanical properties will be greatly reduced due to incomplete curing. In addition, due to the particularity of the art pattern powder production process, after the recycled powder is sprayed, the pattern will become smaller or less obvious. It is generally recommended that the recycled powder of the art type powder should not be used, and it must be tested after use.

Although the construction requirements are stricter from the above, as long as the above factors are well grasped in the painting process, the desired satisfactory effect will be achieved. Storage and access of powder coatings 1. Keep away from fire and avoid direct sunlight. Place in a well ventilated place with a temperature below 35 °C. 2. Avoid storage in places subject to water, organic solvents, oil and other materials. 3. Do not expose the powder coating to the air after use. It should be covered or tightened at any time to avoid the inclusion of debris. 4, to avoid long-term skin contact, the powder attached to the skin should be washed with soapy water, do not use solvents. Safety in painting construction site l. Equipment used for painting operations must be grounded to eliminate static electricity. 2. Avoid the phenomenon of endless discharge of the coating machine. 3. In the spray chamber, the concentration of floating dust should be controlled below the safe concentration to avoid the danger of dust explosion.

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