Polymer paint for a car. Car painting with polymer powder paint. Work technology Our experience and guarantees
Powder coating of cars - is the latest technology for applying polymer coatings and paints and varnishes to the surface of cars, including the body, wheels and fenders. Powder coating is a special method of applying polymer coatings, thanks to which not only excellent decorative qualities are achieved, but also increased protective properties. This technology is environmentally friendly, waste-free and allows obtaining high quality polymer coatings.
Painting is carried out using high-polymer powders that are applied to the surface of car parts intended for painting. The whole process is carried out in powder spraying chambers. In these chambers, an electrostatic field is formed, under the influence of which particles of polymer powder paint are deposited on the surface of the product.
After that, the parts of the car are heated in special ovens for polymerization. The melting point of the polymer is 160-200 ° C. The part is kept in the oven for some time and then cools down. This forms a thin and durable polymer layer on the surface. This painting technology can be used for glass or metal products, since these materials can withstand the specified temperature.
To date, about 15% of all painted products have been powder coated. And this figure is constantly increasing. This technology is widely used not only in the automotive industry. Today powder coating cars -far from the only area where this staining method is used. The powder painting method today is used to paint products of various types and purposes - office and garden furniture, roofing materials and metal tiles, instrument panels, furniture fittings, shelves, refrigerators, sports equipment and much more.
Powder paint is a special powder, finely ground polymer. Its particles are about 10-100 microns in size.
As a method of painting, powder painting has many advantages. The main advantage is that this technology does not need to perform additional operations, such as dilution, dissolving, tinting, adjusting the viscosity or coating with an additional layer. Powder coating is carried out with one thinnest layer of polymer coating.
Thus, powder coating is a cost-effective technology that can save not only on materials, but also on time and manpower. Additional cost-effectiveness is provided by the recuperation system used in the spray booths. Those polymer particles that do not fall on the surface to be painted are again returned to the painting cycle. Thus, when powder painting cars and other products, it is possible to reduce the loss of dye to 1-2%. To be convinced of the profitability of powder painting, compare this figure with the traditional method of painting, where losses can reach 50-60%. The advantage of powder coating is obvious.
How is powder coating of cars carried out?
Powder coating of cars Is a technology that uses special equipment - polymerization ovens and spraying chambers. Also, the complex of equipment includes a system for transporting products that are painted. Transportation is required in order to easily move the product between painting stages. This is especially important for car parts that are large in weight and size.
Before starting powder painting, the surfaces of car parts should be prepared. It is necessary to degrease it, clean it from rust and oxides, and then cover it with a layer of phosphate or chromate, which will ensure better adhesion of the powder polymer to the surface. When carrying out preparation in painting, special equipment is also needed, which is included in the complete line for powder painting of cars.
To date, powder painting of parts in the production and assembly of cars has taken a strong leading position in comparison with other painting methods, as well as polymer coatings. This technology can be used to coat the body, fenders, wheels, reflectors, bumpers, plastic parts inside the cabin and many other structural elements.
Of all possible ways painting metal products, body parts of cars and motorcycles, powder painting is one of the most technologically complex, but at the same time economical. Economical in terms of material consumption and losses during the painting process. A certain dilemma arises regarding cost savings, on the one hand, not cheap equipment, on the other hand, savings on raw materials and materials. Such savings will be relevant for workshops professionally engaged in powder painting; for an ordinary person, such savings are questionable.
What is car powder coating?
The method of painting with powder materials is called electrostatic or polymerization, as you like. The technology itself appeared quite a long time ago, but it was applied in the auto and motorcycle industry literally a dozen years ago. Powder paint is applied to car frames, wheels, some body parts, elements of the engine compartment and suspension, frames and engines of motorcycles, wings and gearbox housings, in general, everything that is exposed to negative environmental influences and temperature extremes. The services of powder coating of rims, motorcycle frames and vintage cars for restoration have been especially popular lately.For high-quality coating, the technology of working with powder paints should be observed, otherwise the desired effect will not be achieved. This is the catch of working with such material - compliance with all conditions. Unlike standard paints and varnishes, the powder requires a special chamber for application and polymerization (sintering).
Stages of applying powder paint
The first and most time consuming step is surface preparation. Depending on the state of the part to be painted and the complexity of its relief, we use sandblasting or ordinary sandpaper. The surface must be thoroughly cleaned to ensure the smoothest and most even layer of future paint, as well as for the durability of the coating. The cleaning process includes surface degreasing and phosphating.Phosphating is necessary to protect the metal from corrosion and improve adhesion (adhesion). Instead of mechanically sandblasting the surface, chemical cleaning can be carried out using solutions based on hydrochloric, phosphoric, nitric or sulfuric acid. Chemical cleaning (etching) is more efficient than mechanical cleaning and is easy to use.
After thorough cleaning of the surface, the product must be rinsed and dried. After complete drying, the product must be primed with a special powder primer. It is better to use epoxy primers, this will improve the adhesion and anti-corrosion properties of the material. The soil has dried up and go to the next stage - painting.
At this stage, all the most interesting happens and it requires special equipment: a powder paint sprayer, a spray booth and a dryer. It is best not to spare money for a sprayer and buy a high-quality one, the quality of the coating will depend on it. But with a camera, you can save money, but not in the sense of buying Chinese consumer goods, but making it yourself. More on this in the next article. So, we have a professional spray (spray gun), painting booth, polymerization oven.
Unlike a conventional spray gun, a powder spray gun sprays a charged powder (electrostatic) onto an oppositely charged product. IN spray booth the powder is held onto the surface of the part to be painted by static attraction. Then we send the painted object to the polymerization oven - this will be the final stage of painting. In the polymerization chamber, the paint is sintered, a protective layer is formed, which acquires the necessary elasticity, aesthetics and strength characteristics. In fact, the polymerization process is a kind of drying under the influence of a temperature of 200-220 degrees. Next, the part must be completely cooled and can be polished. Furnaces can be equipped with any heat source (electricity, gas and even oil products), the main thing is that the optimum temperature can be controlled and maintained.
This method of staining has a number of clear advantages and disadvantages that will help you determine the need for choosing this process to restore or protect the surface of a car or motorcycle.
Powder coating benefits
- Application in one layer (from one pass the coating thickness reaches 35 microns, which significantly saves time);
- Anti-corrosion, impact-resistant properties, as well as resistance to temperature extremes;
- Profitability (paint loss during the passage is 1-2%, standard paints - 40-50%);
- There is no need to use hardeners and solvents, which significantly saves money and greatly improves fire safety;
- The ability to obtain an unusual texture (matte, semi-matte, leather-like, etc.);
- Drying of the surface in 30 minutes;
- Durability (manufacturers give a guarantee of at least 20 years).
Disadvantages of powder coating
- You can apply paint only with the help of professional (and expensive equipment for an hour);
- The declared thickness of 35 microns is the minimum, which limits work with parts that require thinner layers;
- It is not possible to tint the paint yourself, but this drawback is easily compensated for by a large number of shades and textures.
Powder paints are fundamentally different from other paints and varnishes - they are not a liquid substance, but fine suspended particles, held on the surface to be treated due to the difference in electrical potentials.
Powder coating is the fastest and cheapest
The technology of powder painting of metal products became widespread in the 50s of the last century, closer to zero this method was refined to the ideal, after which it began to be used for painting cars.
This article presents the painting technology. You will learn what are the advantages of powder painting, what equipment is needed for its implementation and how the coating process takes place.
Powder coating: advantages
Powder paints for metal consist of three types of fine particles:
- grains of polyester resin), which melt when heated and form a continuous film surface on a metal part;
- A binder component that connects polymer particles to each other;
- Colored pigment that gives the powder paint the desired shade.
Powder coating of metal products is widespread in the factory painting of cars, because in comparison with the use of classic paints and varnishes (acrylic, alkyd and melamine alkyd enamels), this technology has significant advantages:
- Powder coating provides a reference quality of the treated surface in terms of visual appeal - a knowledgeable person will accurately identify a powder-painted car among enamelled cars;
- The coating, which has undergone the polymerization process, is distinguished by wear resistance, resistance to mechanical damage and weathering. Powder coating does not change the influence of ultraviolet solar radiation;
- Powder coating technology does not require the use of expensive colorist services to select the shade of the composition (such materials do not mix with each other). On sale are compositions with a matte and glossy effect, metallic and mother-of-pearl paints;
- Powder coating of metal products is an environmentally friendly technology. Unlike enamels, which require dilution with chemically aggressive solvents, which form toxic fumes during application, the material does not have harmful effects on the body of the painter;
- Due to the absence of solvents and their explosive vapors, the application of a polymer coating is not associated with an increased risk of fire hazard;
- Metal painting with powder is performed much faster than applying enamel compositions, since this material does not require separate layers of paint that are forced to dry out - the powder is sprayed in one layer and polymerized in 20-30 minutes (the full set of coating strength occurs within 24 hours).
"Dry" method of applying paint is more popular among car owners. Among the disadvantages of this technology, we highlight the fact that the powder coating of metal products is unrealizable in garage conditions, since the powder hardens at elevated temperatures (150-200 degrees), which can only be achieved in a special polymerization chamber.
The downside is the impossibility of mixing compositions that differ in color with each other (as a result, you will not get a uniform color) - you will have to choose the shade of the material among the paints on the market.
Powder coating principle
Powder coating of metal is carried out using the electrostatic method. The essence of this technology consists in spraying a negatively charged powder onto the grounded surface of the car - due to the potential difference, fine polymer particles are held on the metal body.
Powder coating equipment that imparts electrostatic properties to the material used consists of four mechanisms:
- Feeder - a sealed unit for storing the powder used in the work;
- Compressor - pumps compressed air into the feeder under pressure;
- Ejector - a pump that delivers powder to the atomizer;
- A spray gun is a gun by means of which the material is applied to the painted surface.
Electrostatic painting consists in the following - a working amount of powder is poured into the feeder and the compressor begins to pump compressed air into a sealed tank, which brings the material to a "boiling" (suspended) state. Then the ejector transports the mixture into a spray bottle equipped with a corona electrode - a source high voltage, when passing through the zone of which the particles acquire a negative electric charge.
Powder painting can also be carried out using the tribostatic spraying method, in which suspended particles receive an electric charge not under the influence of a voltage source, but due to friction with a fluoroplastic coating inside the sprayer. This method is economical financially, however, it differs in 2 times less productivity.
You can also paint your car at home Metal powder painting is carried out in a special one, consisting of two separate rooms:
- Powder coating booth, where the composition is applied to the surface of the car. This unit is equipped with a recuperative ventilation system - air containing particles of powder that has got into it during coloring is sucked in by an exhaust compressor and passed through a pulse filter. In the filtration process, polymer particles are removed and fed back to the feeder for subsequent use, which ensures zero waste of materials during operation;
- Polymerization chamber is a room in which the applied coating cures at a constantly maintained temperature of 150-200 degrees. Based on they are classified into convective and thermo-radiation: in convective, the temperature rise occurs due to the movement of air masses heated by a heat generator (running on gas or diesel fuel), in thermo-radiation chambers, point heating of the painted surface is carried out by infrared heating elements.
The powder paint polymerization chamber provides heating of the powder to a temperature at which it melts and forms a viscous coating that penetrates into microcracks on the surface of the car. Upon further heating, the material hardens and obtains maximum adhesion to the metal body.
Powder coating: technology
Powder painting of vehicle elements (body parts are previously dismantled, since heating the entire vehicle in the polymerization chamber to a temperature of 200 degrees is unacceptable) is performed in the following sequence:
- Stage number 1 - preparation of the body or part
Initially, the existing deformations and irregularities are eliminated on the body using the straightening method, then the treated places are putty with polymer or fiberglass putty. The composition is diluted according to the manufacturer's instructions and applied to the surface of the body with a soft rubber spatula... After the putty has hardened (to speed up the process, the applied composition is heated with an infrared heating element or a building hair dryer), it is matted with fine-grained sandpaper.
The old paint-and-lacquer coating of the part is sanded with P600 sandpaper to obtain a rough surface. Grouting is carried out "wet" - with moistening, which helps to reduce the amount of dust emitted. The filled areas are protected from moisture penetration by pasting with oilcloth.
- Stage number 2 - priming
The sanded parts are degreased with a solvent and covered with 2-3 coats of primer. Powder paint for metal requires the use of special primers containing iron phosphates in the composition, due to which the adhesion of the coating to the metal surface increases.
This process is called "phosphating" - the primer is applied with a standard spray gun at a supply pressure of 2-2.5 MPa from a distance of 20-25 cm from the body surface. The pause recommended by the manufacturer for the drying of the composition is maintained between the application of layers.
After the final drying of the primer, its surface is matted with fine-grained emery paper (P400 - P600), rinsed and dried at room temperature.
- Stage 3 - powder coating
The powder application technology is selected based on the shape of the part to be painted - for painting surfaces with a complex configuration (discs, shock absorbers, body kits), it is rational to use the tribostatic method, which allows for more accurate spraying, when processing flat elements (hood, wings) - electrostatic feed.
When implementing the electrostatic method, a voltage of 30-100 kV is applied from the generator to the corona electrode of the spray gun.
The compressed air used to supply the powder should have a moisture content of 1.3 g / m3 and a dew point of up to 7 degrees, since suspended polymer particles have hygroscopic properties - they absorb the vapor contained in the air, which leads to poor adhesion of the material to the metal surface. For the preparation of compressed air, special drying installations of the OSV-30 type are used, where air is driven through a layer of filtering sorbent.
Painting is performed by applying 3-4 thin layers of powder in overlapping stripes. The layers are applied sequentially, without intermediate pauses. A thickened coating is sprayed onto the rounded ends and corner parts of the parts.
- Stage 4 - polymerization
VIEW VIDEO INSTRUCTIONS
After painting, the part is moved to the polymerization chamber, where it is kept at a temperature of 160-200 degrees for 15-25 minutes. In the process of melting the powder, it is required to maintain a constant temperature; drops above 5 degrees are not allowed.
After heating to the melting temperature, the polymer particles become viscous and, displacing the air contained in the coating, form a monolithic film, which solidifies upon further heating. After a specified time has elapsed, the part is cooled (without a sharp temperature drop). The full set of strength of the powder coating occurs 24 hours after polymerization.
Warning: Use of undefined constant videoembedder_options - assumed "videoembedder_options" (this will throw an Error in a future version of PHP) in / home / d / dana21j3 / site / public_html / wp-content / plugins / video-embedder / video-embedder .php on line 608
Powder coating of cars - new technology painting, allowing to obtain a high-quality polymer coating with a minimum amount of losses and a high degree of safety. The indisputable advantages of this method over traditional painting lead to its increasingly frequent use not only in the automotive industry, but also in other areas of the industry.
Powder paint is based on the use of high-polymer powders consisting of polymer granules ranging in size from 10 to 100 microns.
What elements are included in powder paint?
In addition to the polymer that forms a film on the surface of the car, the following components are included in the powder paint:
- color-determining pigment;
- hardener;
- filler that strengthens the film;
- additives that regulate flow and create structure.
A prerequisite for the implementation of powder painting of cars is the availability of a vehicle equipped with special equipment. Of the usual equipment, the chamber should have air supply and filtration systems. Specialized equipment includes spray guns, a powder recovery system, and a polymerization oven.
Powder coating technology is based on the ability of magnetized powder granules to attach to the elements of the car body. In this case, the powder is pre-magnetized and then sprayed in a thin layer onto the surface of the part. After that, the part is placed in a polymerization oven, where it is kept at a temperature of 160 - 200 degrees for 10 - 20 minutes. Under these conditions, the powder melts and forms a continuous paint layer.
Depending on the polymer used, paints are divided into thermoplastic and thermosetting. Thermoplastic paints fuse when heated without chemical transformation and form relatively fragile coatings. For powder painting of cars, mainly thermosetting paints are used, in which, when heated, not only the fusion of polymer particles occurs, but also a chemical reaction between them. The result is a strong film that is resistant to physical and chemical damage.
The most important advantage of powder painting is the ability to reuse paint particles that have been sprayed but did not get onto the car part.
Powder particles go through the stages of filtration, preparation and then again fed for application to the part. This method allows you to significantly save paint, reducing losses to 1 - 2 percent versus 50 - 60 percent when painting with liquid enamels.
Powder painting, like painting with liquid paints, requires thorough preliminary processing of the car body. The preparation process includes the following stages:
- Removing rust and oxides from metal parts of the car.
- Degreasing of all parts and surfaces.
- Coating the degreased surface with a layer of phosphate or chromate to increase the adhesion of the powder to the surface.
Advantages and disadvantages of powder coating
In the case of well-conducted preparatory work, as well as compliance with powder coating technology, it is possible to obtain a very reliable paint coating.
- Powder painting of cars can significantly reduce painting time due to the fact that the paint is applied in just one layer. The thickness of this layer can be adjusted within wide limits from 35 to 250 microns. Thanks to the application of one uniform layer, the likelihood of formation is excluded;
- The painted surface is capable of withstanding impacts and temperature changes from -50 to + 130 ° C. Powder coating has a lower porosity compared to conventional paints, therefore it has a greater anti-corrosion resistance;
- Powder paint manufacturers give a coating guarantee for up to 20 years;
- Currently, powder paint is used not only for painting metal parts of a car, but also for plastic and glass products. It is used in painting car rims, bumpers, headlight reflectors, mirrors, and plastic parts inside the car. With the help of powder paint, you can get not only a smooth color, but also a matte, semi-matte color, leather-like coating and other effects;
- Powder coating of cars eliminates the need for solvents and hardeners. The paints are marketed ready for use. This eliminates the process of selecting the degree of paint dilution. In addition, powder paint does not dry out during long-term storage;
- The absence of flammable solvents in the composition of powder paint almost completely eliminates the possibility of a fire. The process of painting a car with powder paint is environmentally friendly.
Powder painting of cars also has disadvantages. Among them are the following:
- Powder painting can be done only in a specially equipped room using sophisticated and expensive equipment. This condition does not allow small and medium-sized companies to use the above painting method;
- Powder paint cannot be colored independently. Although this disadvantage compensates for the huge number of colors and shades offered by various manufacturers of car care products;
- Difficulties are possible when applying paint on non-heat-resistant surfaces;
- The minimum paint thickness is limited to 35 µm.
The significant prevalence of the advantages of powder painting of cars over the disadvantages contributes to the rapid growth of the popularity of this technology. The number of powder paint manufacturers, as well as companies offering powder coating methods, is constantly increasing. Production technologies are constantly being improved, which allows to achieve the highest quality of car painting.
The current operating conditions of cars are such that the paintwork on the body can withstand only a few years. After that, the processes of corrosion and irreversible destruction begin. This is due to the difficult ecological situation and the use of aggressive, from a chemical point of view, road reagents. Therefore, a complete painting of a car 4-5 years after the purchase is quite common.
Unfortunately, prices for full body paint are so high that some car owners prefer to sell a not quite old car and buy a new one to replace it, fresh from the salon.
A compromise option does not always help out - painting individual parts of the body. Despite the abundance of proposals, it is very difficult to find a car service in which body work is performed with high quality, namely, car painting.
The real salvation in this regard is powder coating technology, which has been gaining momentum and popularity over the past few years. Its main advantage over conventional paint application is the several times lower material consumption. At the same time, a very small percentage of powder pigment goes to waste. With traditional technology, losses can reach more than 50% of the used volume of paints and varnishes.
The essence of powder coating technology is as follows:
- the surface of the part to be painted is prepared in the traditional way - it is thoroughly washed, protected, sanded and degreased;
- in a special chamber, a pre-prepared powder coloring pigment is sprayed, while it has an opposite electrical potential compared to the part itself;
- under the influence of the forces of electrostatic attraction, the coloring powder is deposited in a uniform layer and adheres to the surface of the part;
- the part or the whole structure is sent for melting and subsequent polymerization of the powder pigment into a special oven chamber, where the temperature is maintained at 160-200 degrees Celsius;
- in the process of cooling, the paint slowly cools down and firmly "sticks" to the painted surface.
The efficiency of the process is achieved by the fact that unused powder is filtered out and goes to the painting of other parts. It is also noteworthy that the pigment layer is "magnetized" to the painted surface in an extremely even and uniform manner. In the traditional method, a lot depends on the "human factor" - the skill of a specialist. The powder method allows you to get excellent results in almost 100% of cases.
Powder coating technology is relatively new, so it is quite difficult to find a car service that is ready to completely paint a car body in this way. And nevertheless, there are already enough proposals for painting single parts and body parts. For example, powder coating is actively used in the process of restoration of wheel disks - the hubs after the pigment has cooled down look like new.
Powder coating you can expose all surfaces that, without negative consequences, are heated to a temperature of 200 degrees Celsius. And this can be not only body parts, but also some types of plastic, elements of a car body kit, as well as a trunk, a trailer and much more.
