Polymer paint for the car. Car painting with polymer powder paint. Work technology Our experience and guarantees

Powder coating 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...

Powder coating of cars- this 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 enhanced protective properties are imparted. This technology is environmentally friendly, waste-free and allows to obtain high quality polymer coatings.

Painting is carried out using high-polymer powders, which are applied to the surface of car parts intended for painting. The whole process is carried out in powder coating chambers. In these chambers, an electrostatic field is formed, under the influence of which particles of polymer powder paint settle on the surface of the product.

After that, parts of the car are heated in special polymerization ovens. The melting point of the polymer is 160-200 °C. For some time, the part is kept in the oven, and then cools down. In this case, a thin and durable polymer layer is formed on the surface. This painting technology can be used for glass or metal products, as 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 coating method today paints the products of the most different types and purposes - office and garden furniture, roofing materials and metal tiles, instrument panels, furniture fittings, racks, refrigerators, sports equipment and much more.

Powder paint is a special powder, finely ground polymer. Its particles have a size of about 10-100 microns.

As a painting method, powder coating has many advantages. The main advantage is that this technology does not need to perform additional operations, such as dilution, dissolution, tinting, viscosity adjustment or coating with an additional layer. Powder coating is performed with one very thin layer of polymer coating.

Thus, powder coating is a cost-effective technology that saves not only on materials, but also on time and human resources. Additional efficiency is provided by the recuperation system, which is used in the spraying chambers. Those polymer particles that do not fall on the painted surface again fall into the painting cycle. Thus, when powder coating cars and other products, it is possible to reduce dye losses to 1-2%. To see how profitable powder coating is, compare it with the traditional method of painting, where losses can reach 50-60%. The advantage of powder coating is obvious.

How is car powder coating done?

Powder coating of cars- This is a technology in which special equipment is used - 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 carry out the movement of the product between the stages of painting. This is especially important for large parts of the car in terms of weight and size.

Before you start 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 cars.

To date, powder coating of parts in the production and assembly of automobiles has taken a strong leading position compared to other painting methods, as well as polymer coatings. Using this technology, it is possible to coat the body, fenders, wheels, reflectors, bumpers, plastic parts inside the cabin and many other structural elements.

Of all possible ways painting of metal products, body parts of cars and motorcycles, powder coating is one of the most technologically complex, but at the same time economical. Economical in terms of material consumption and its losses during the dyeing 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 coating; for an ordinary layman, such savings are doubtful.

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 they began to use it in the auto and motorcycle industry literally a dozen years ago. Powder paint covers car frames, wheels, some body parts, engine compartment and suspension elements, motorcycle frames and engines, fenders and gearbox housings, in general, everything that is exposed to the negative effects of the environment and temperature extremes. Especially popular in recent years are powder coating services for wheel rims, frames of motorcycles and retro cars for restoration.

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 paintwork materials, the powder requires a special chamber for application and polymerization (sintering).

Stages of powder coating application

The first and most time-consuming step is surface preparation. Depending on the condition 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 strength of the coating. The cleaning process includes surface degreasing and phosphating.

Phosphating is necessary to protect the metal from corrosion and improve adhesion (sticking). Instead of mechanical sandblasting of the surface, chemical cleaning can be carried out using solutions based on hydrochloric, phosphoric, nitric or sulfuric acid. Chemical cleaning (etching) is more productive than mechanical cleaning and is easy to use.

After thorough cleaning of the surface, the product must be washed 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 adhesive and anti-corrosion properties of the material. The primer has dried up and we proceed to the next stage - painting.

At this stage, all the fun 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 purchase a quality one, the quality of the coating will depend on this. But with a camera, you can save money, but not in terms of buying Chinese consumer goods, but making it yourself. More on this in the next article. So, we have a professional sprayer (spray gun), spray booth, polymerization oven.

Unlike a conventional spray gun, a powder sprayer sprays a charged powder (electrostatic) onto the product with the opposite charge. IN spray booth the powder is held on the surface of the part to be painted by static attraction. Next, the painted object is sent 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 with any source of heat (electricity, gas and even oil products), the main thing is that the optimum temperature can be controlled and maintained.

This method of painting has a number of distinct advantages and disadvantages that will help you determine whether you should choose this process to restore or protect the surface of a car or motorcycle.

Advantages of powder coating

• Application in one layer (with 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 (loss of paint 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 possibility of obtaining an unusual texture (matte, semi-matte, under the skin, etc.);
• Drying of the surface in 30 minutes;
• Durability (manufacturers give a guarantee of at least 20 years).

But there are no ideal materials and powder paint is no exception to the rule.

Disadvantages of Powder Coating

• You can apply paint only with the help of professional (and sometimes expensive equipment);
• The declared thickness of 35 microns is the minimum, which limits the work with parts that require thinner layers;
• It is not possible to tint the paint yourself, but this disadvantage is easily compensated by a large number of shades and textures.

P.S. As for the price range, focusing on the average cost of painting rims, it is 800 - 2000 r, depending on the size of the rim. In principle, not a big price to upgrade or restore appearance surface, cheaper only spray can.

Powder paints are fundamentally different from other paints and varnishes - they are not a liquid substance, but finely suspended particles held on the treated surface due to the difference in electrical potentials.
Powder coating is the fastest and cheapest

The technology of powder coating of metal products became widespread in the 50s of the last century, closer to zero, this method was finalized to the ideal, after which it began to be used for painting cars.

This article presents the painting technology. You will learn about the benefits of powder painting, what equipment is needed for its implementation and how the coating process works.

Powder Coating Benefits

Powder paints for metal consist of fine particles of three types:

1. grains of polyester resin), which, when heated, melt and form a continuous film surface on a metal part;
2. A binder component that connects polymer particles to each other;
3. A colored pigment that gives powder paint the desired shade.

Powder coating of metal products is widely used 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-coated car among enameled cars;
• The coating, which has passed the polymerization process, is wear-resistant, resistant to mechanical damage and atmospheric influences. Powder coating is not affected by ultraviolet solar radiation;
• Powder coating technology does not require the use of expensive services of colorists 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 that require dilution with chemically aggressive solvents that 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 fumes, the application of a polymer coating is not associated with an increased risk of fire hazard;
• Painting metal with powder is much faster than applying enamel compositions, since this material does not require forced simple drying of individual layers of paint - the powder is sprayed in one layer and polymerized in 20-30 minutes (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 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 from 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.

The principle of powder coating

Powder coating of metal is carried out by electrostatic method. The essence of this technology is to spray a negatively charged powder on the grounded surface of the car - due to the potential difference, fine polymer particles are held on the metal body.

Powder coating equipment, which gives the material used electrostatic properties, consists of four mechanisms:

1. Feeder - a sealed unit for storing the powder used in the work;
2. Compressor - pumps compressed air under pressure into the feeder;
3. Ejector - a pump that feeds the powder into the spray gun;
4. A spray gun is a gun by means of which the material is applied to the surface to be painted.

Electrostatic painting is as follows - a working amount of powder is poured into the feeder and the compressor starts to pump compressed air into the sealed tank, which brings the material to a "boiling" (suspended) state. Then the ejector transports the mixture into a spray gun equipped with a corona electrode - a source high voltage, passing through which the particles acquire a negative electric charge.

Powder coating can also be carried out using the tribostatic spraying method, in which suspended particles receive an electrical charge not under the influence of a voltage source, but due to friction with a fluoroplastic coating inside the spray gun. This method is economical in financial terms, but differs in 2 times less productivity.

You can paint your car at home

Metal powder painting is carried out in a special one, consisting of two separate rooms:

1. Powder coating chamber, 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 entered it during painting is sucked in by an exhaust compressor and passed through an impulse filter. During the filtration process, polymer particles are removed and fed back to the feeder for subsequent use, which ensures zero waste of materials during operation;
2. The polymerization chamber is a room in which the applied coating is cured at a constantly maintained temperature of 150-200 degrees. Proceeding from, they are classified into convective and thermoradiation: in convective, the temperature rises due to the movement of air masses heated by a heat generator (running on gas or diesel fuel), in thermoradiation chambers, the painted surface is spot-heated by infrared heating elements.

The powder paint polymerization chamber ensures that the powder is heated to a temperature at which it melts and forms a viscous coating that penetrates into microcracks on the car surface. With further heating, the material hardens and gets maximum adhesion to the metal body.

Powder coating: technology

Painting powder paint car elements (body parts are pre-dismantled, since heating of 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 parts

Initially, existing deformations and irregularities are eliminated on the body by straightening, then the treated areas are puttied 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 paintwork of the part is sanded with P600 sandpaper to obtain a rough surface. Grouting is carried out "wet" - with moisture, which helps to reduce the amount of dust emitted. The puttied areas are protected from moisture by pasting with oilcloth.

• Stage number 2 - priming

Sanded parts are degreased with a solvent and covered with 2-3 layers of primer. Powder paint for metal requires the use of special primers containing iron phosphates, which increase the adhesion of the coating to the metal surface.

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 surface of the body. Between the application of layers, the pause recommended by the manufacturer for drying the composition is maintained.

After the final drying of the primer, its surface is matted with fine-grained sandpaper (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 being 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, fenders) - 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 must have a humidity within 1.3 g/m3 and a dew point of up to 7 degrees, since the suspended polymer particles have hygroscopic properties - they absorb the vapor contained in the air, which leads to a deterioration in the adhesion of the material to the metal surface. For the preparation of compressed air, special installations for drying of the OSV-30 type are used, where the air is driven through a layer of filtering sorbent.

Coloring is carried out by applying 3-4 thin layers of powder in overlapping stripes. Layers are applied sequentially, without intermediate pauses. A thicker coating is sprayed onto the rounded ends and corners of the parts.

• Stage number 4 - polymerization

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After dyeing, 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 of more than 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 hardens upon further heating. After the set time has elapsed, the part cools down (without a sudden temperature drop). Full curing of the powder coating occurs 24 hours after polymerization.

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Powder coating of cars - new technology painting, which allows to obtain a high-quality polymer coating with a minimum amount of losses and a high degree of safety. The undeniable advantages of this method over traditional painting lead to its more and more frequent use not only in the automotive industry, but also in other industries.

Powder paint is based on the use of high-polymer powders, consisting of polymer granules ranging in size from 10 to 100 microns.

What are the ingredients in powder coating?

In addition to the polymer that forms a film on the surface of the car, the composition of the powder paint includes the following components:

• color-determining pigment;
• hardener;
• filler that strengthens the film;
• additives that regulate spreading and create structure.

A prerequisite for the implementation of powder coating of cars is the availability of special equipment. Of the usual equipment in the chamber, there should be air supply and filtration systems. Specialized equipment includes spray guns, a powder recovery system, and a curing oven.

Powder coating technology is based on the ability of magnetized powder granules to attach to car body elements. 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 such conditions, the powder melts and forms a continuous layer of paint.

Depending on the polymer used, paints are divided into thermoplastic and thermoset. Thermoplastic paints fuse when heated without chemical transformation and form relatively fragile coatings. For powder coating of cars, thermosetting paints are mainly used, in which, when heated, not only the fusion of polymer particles occurs, but also a chemical reaction between them. As a result, a strong, resistant to physical and chemical damage film is formed.

The most important advantage of powder coating is the ability to reuse paint particles that were sprayed but did not get on the car part.

The powder particles go through the stages of filtration, preparation and then again fed to be applied 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 preliminary careful processing of the car body. The preparation process includes the following stages:

• Cleaning rust and oxides on 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 adherence to powder coating technology, it is possible to obtain a very reliable paint coating.

• Powder coating of cars allows you to significantly reduce the time of painting due to the fact that the paint is applied in just one layer. The thickness of this layer can be adjusted over a wide range from 35 to 250 µm. Due to the application of one uniform layer, the likelihood of formation is eliminated;

• The painted surface is able to withstand impacts and temperature fluctuations from -50 to +130ºС. Powder coating has less porosity compared to conventional paints, therefore it has greater anti-corrosion resistance;

• Manufacturers of powder paints give a guarantee for coating 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, as well as plastic parts inside the car. With the help of powder paint, you can get not only a smooth color, but also matte, semi-gloss color, skin-like coating and other effects;

• When using powder coating of cars, the need for the use of solvents and hardeners disappears. Paints are sold ready for use. This allows you to get rid of the process of selecting the degree of dilution of the paint. 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 coating of cars also has disadvantages. Among them are the following:

• Powder coating can only be done in a specially equipped room using complex and expensive equipment. This condition does not allow the use of the above painting method by small and medium-sized companies;

• Powder paint cannot be tinted by yourself. Although this disadvantage compensates for the huge number of colors and shades offered by various manufacturers of auto cosmetics;

• Difficulties are possible when applying paint to non-heat-resistant surfaces;

• The minimum paint layer thickness is limited to 35 µm.

The significant predominance of the advantages of powder painting cars over the disadvantages contributes to the rapid growth in the popularity of this technology. The number of manufacturers of powder paint, as well as companies offering powder coating method is constantly increasing. Production technologies are constantly being improved, which makes it possible 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. The reason for this is the difficult environmental situation and the use of aggressive, from a chemical point of view, road reagents. Therefore, the complete painting of the car 4-5 years after the purchase is quite common.

Unfortunately, the prices for a full body painting are so high that some car owners prefer to sell a car that is not yet quite old and buy a new one, fresh from the salon, to replace it.

A compromise option does not always help out - painting individual parts of the body. Despite the abundance of offers, it is very difficult to find a car service where body work is carried out with high quality, namely, car painting.

The real salvation in this regard is the technology of powder coating, which is gaining momentum and popularity in the last few years. Its main advantage over conventional paint application is the reduced consumption of materials by several times. In this case, a very small percentage of the 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 intended for painting is prepared in the traditional way - it is thoroughly washed, protected, polished and degreased;
- a pre-prepared powder coloring pigment is sprayed in a special chamber, while it has the opposite electrical potential compared to the part itself;
- under the influence of electrostatic attraction forces, the coloring powder is deposited in a uniform layer and sticks to the surface of the part;
– a part or the entire structure is sent for melting and subsequent polymerization of the powder pigment in 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 tightly "sticks" to the painted surface.

The cost-effectiveness of the process is achieved by the fact that the unused powder is filtered out and used for painting other parts. It is also noteworthy that the pigment layer is "magnetized" to the painted surface in an exceptionally even and uniform manner. In the traditional method, a lot depends on the "human factor" - the skill of the specialist. The powder method allows you to get excellent results in almost 100% of cases.

Powder coating technology is relatively new, so finding a car service that is ready to completely paint a car body in this way is quite difficult. Nevertheless, already now there are enough proposals for painting single parts and body parts. So, for example, powder coating is actively used in the process of restoration of rims - after the pigment has cooled, the hubs look like new ones.

Powder coating can be applied to all surfaces that heat up to a temperature of 200 degrees Celsius without negative consequences. And this can be not only body parts, but also some types of plastic, car body kit elements, as well as a trunk, trailer and much more.