What Is Electrostatic Powder Coating?

Powder coating is a solid powdery synthetic resin coating composed of solid resin and pigment, filler and auxiliary. Unlike ordinary solvent-based coatings and water-based coatings, its dispersion medium is not solvent and water, but air. It has the characteristics of no solvent pollution, 100% film formation and low energy consumption. There are two main types of powder coatings: thermoplastic and thermosetting. The coating film appearance (gloss and leveling) of the thermoplastic powder coating is poor, and the adhesion to the metal is also poor, so it is rarely used in the field of automotive coatings. Generally, thermosetting powder coatings are used for automotive coatings. Thermosetting powder coatings are The thermosetting synthetic resin is used as a film-forming substance. During the drying process, the resin is melted, and then chemically cross-linked to solidify into a flat and hard coating film. The appearance and various mechanical properties and corrosion resistance of the paint film formed by this coating can meet the requirements of automotive finishing. ^[1]

Powder coating

Powder coatings are based on solid resins and

Powder coatings are completely different from ordinary coatings in that they exist as fine powders. Because no solvent is used, it is called powder coating. The main features of powder coatings are: harmless, high efficiency, resource saving and environmental protection.

It has two broad categories:

Although there are not as many types of powder coatings as solvent-based coatings, there are many polymer resins that can be used as powder coatings. It can be divided into two types: thermoset and thermoplastic. ^[2]

1. This product is non-toxic, contains no solvents and does not contain volatile and toxic substances, so there is no pollution, no fire, no "three wastes" and other pollution problems, which fully meet the requirements of national environmental protection laws.

2,

The biggest growth areas of the powder coatings market in China are: the shipbuilding industry and the pipeline industry. The problem is that impact resistance and hygroscopicity need to be improved and improved. Researchers have focused their efforts on modification with various base materials. The domestically produced pipeline anticorrosive epoxy powder coatings still have a certain gap compared with foreign high-quality products in terms of storage stability and coating workability.

Due to advances in foreign automotive powder coating technology, automotive glazing, coatings for wood and plastics are the most dynamic potential markets. The automotive industry will be its largest consumer. The powder coating coating market in Greece, Turkey and Eastern Europe has a good growth momentum. The Asia-Pacific region has greater market potential and has been considered the fastest growing region in the world.

The coating is made of special resin, pigments, fillers, curing agents and other auxiliaries, mixed in a certain ratio, and then prepared by processes such as hot extrusion and crushing and sieving. They are stable in storage at room temperature. They can be electrostatically sprayed, friction sprayed (thermoset method) or fluidized bed dip-coated (thermoplastic method), then heated, baked, melted and solidified to form a flat and bright permanent coating film for decoration. And anti-corrosion purpose.

Electrostatic spraying (for details, refer to the coating process of powder coatings)

Surface treatment of coated objects electrostatic powder coating melt leveling or cross-linking solidification cooling products

(1) To make full use of and extend the characteristics of powder coating

1. Keep away from fire and avoid direct sunlight. It should be placed in a well-ventilated place with a temperature below 35 ° C.

2.Avoid storage in water,

I. Appearance identification method :
1. The hand feel is silky smooth, fluffy, floating. The hand feels rough, heavy, and feels heavy. Holding a hand of powder in the hand, the smoother and looser the powder, the better the quality, on the contrary, the rough powder feels heavy and the quality is rough. Poor. It is not easy to spray, there are many secondary powder drops, and waste is large.
2. The larger the volume, the less the filler in the powder coating, the higher the cost. The better the powder quality. The smaller the volume, the higher the filler in the powder coating, the lower the cost. The worse the quality of the powder. The same carton, see The powder of that house is large, which is a good powder, and the volume of that house is small, which is a poor powder. It is not easy to spray, the second powder fall, the waste is large, the spray area is small, and the use cost is high.
3. The powder with good storage time can be stored for a long time, and the powder leveling and other effects are unchanged. The poor powder cannot be stored for a long time, and the poor powder will have poor leveling and other effects after 3 months. Normal powder is in The shelf life is 12 months at room temperature. The quality of the low-end raw materials is unstable and easy to deteriorate. The powder is produced using poor raw materials. The sprayed surface will accelerate powdering and aging after half a year. It will affect the customer s reputation. In addition, the powder is not easy to store and is given to customers Causes a large waste of powder and a lot of fees

Identification method of spray area :
The resin content of normal powder in the spray area should be about 55-65%, the resin is about 20 yuan / KG, and the filling material is about 2 yuan. Some bad powder factories use resin content below 45% to fill it up. Adding fillers to reduce costs and reduce spraying area. Contrast method: two sprays of the same product of the same type, depending on which one has more powder spraying products, which one has less spraying products, and the one with less spraying products is worse, the use cost High. For the manufacturer, the spraying area is small, and the cost is high. It is calculated based on 6 squares per kilogram of powder spraying, and each square is less, which is equivalent to the manufacturer paying 3-6 yuan more per kilogram of powder. It is recommended that the manufacturer use Use genuine powder and carefully calculate your actual cost of use

Three. Sprayer job identification method :
Powder loading rate, powder with good working efficiency is easy to spray, spraying 1-3 guns can cover the substrate, less secondary recycling powder, high work efficiency. Poor powder is not easy to powder, spraying 3-5 guns Can cover the substrate, more secondary recycling powder, low work efficiency. Operators can be sprayed on the powder rate, the amount of powder is not much identification. The same time output less product, more secondary recycling powder, increase work Staff burden and low work efficiency.

4. Baking identification method:
Does the smoke produce a good powder without a large amount of smoke during the baking process? Poor powder has a large amount of smoke during the baking process. A good powder raw material does not generate a large amount of smoke, and some manufacturers charge the raw material Good material. The amount of powder will increase, the square number will not be sprayed out, increasing the cost of use, and the same amount of powder will produce less products.

V. Appearance and gloss identification of the finished product after baking:
After baking, the powder products with good appearance are delicate, full, transparent, and have a strong three-dimensional appearance. Poor powder products have a dim, dull appearance, and the surface is foggy, impervious, and have a poor three-dimensional appearance. Observe the two plates facing each other. Poor appearance, affect customer reputation, affect product appearance. Good gloss powder has good gloss and can maintain relative gloss for a long time. Poor powder gloss has good effect when just baked out, and it will start to shine after a few months. The powder made of materials with poor gloss appearance can not maintain long-term gloss stability, and there is a haze, chalking, peeling, etc.

Six. Adhesion and aging identification method:
The powder with good adhesion and aging has strong adhesion, strong toughness, and can be kept for several years without powdering and aging. Poor powder has poor adhesion and is very brittle. It will begin to age and powder after 3 months to half a year after spraying. Contrast test the adhesion and bending, and observe the product for aging and chalking after several months. Poor adhesion and aging, the product is easy to aging, chalking, rusting, shortening the service life of the product and affecting customer reputation

Seven. High temperature identification method :
High temperature, adjust the temperature to 220-230 degrees, and keep the powder for 10-15 minutes. The temperature and weather resistance are better. After baking at high temperature, the color becomes smaller and the gloss is not changed. Poor powder, temperature and weather resistance Poor, serious discoloration and matte gloss after baking at high temperature. This method is particularly effective for detecting light-colored powder outdoors. Poor powder, poor resin, titanium dioxide, poor pigment and filler, poor temperature and weather resistance. Low cost, good charge.
Environmental protection identification method :
SGS environmental protection testing good powder materials are produced by large factories, environmental protection is guaranteed. Poor materials and adding recycled powder, there is no way to ensure that environmental protection does not exceed the standard for a long time. Environmental protection SGS testing for environmental protection exceeding the standard causes large economic losses to some export companies.

Nine. Analysis of the status of powder coatings :
Powder coatings are processing consumable products. The investment threshold is relatively low and the market is fiercely competitive. This has also caused the powder coatings market to be chaotic, cut corners and cut materials, and pursue short-term benefits, which has caused a relatively large impact on some genuine companies. The paint is a powdery substance, which is difficult to identify, and causes large economic losses to some powder companies. The actual product usage was 3 tons. The price of the material was increased through the use of material leave, which increased to 4-5 tons. Instead, it increases the cost of powder companies.Most powder companies only care about the price of the powder and do not care about the actual cost of use, which causes large losses to the company.

1. Keep away from fire and avoid direct sunlight. It should be placed in a well-ventilated place with a temperature below 35 ° C.

2. Avoid storing in places susceptible to contamination by water, organic solvents, oil and other materials.

3. Do not expose the powder coating to the air after use. Cover it or close the bag tightly at any time to avoid the inclusion of debris.

4. Avoid prolonged contact with the skin. Rinse the powder that adheres to the skin with soap and water. Do not use solvents. Safety of painting construction sites

5. The equipment used for painting work must be well grounded to eliminate static electricity.

6.Avoid endless discharge of coating machine

7. In the spraying room, the concentration of floating dust should be controlled below the safe concentration as much as possible to avoid the danger of dust explosion and fire.