Best Paint for Aluminum

In outdoor environments, such as aluminum siding, doors and windows, fences, roofs, etc., the best aluminum paint is PVDF or acrylic polyurethane topcoat. These two paints are weather-resistant and corrosion-resistant, can resist UV and environmental erosion, and maintain color and gloss.

In the field of industrial anti-corrosion, such as marine engineering, ships and other fields, epoxy zinc-rich primer, acrylic polyurethane or PVDF is used for topcoat.

In indoor environments, such as furniture, tables and chairs, tool boxes, etc., epoxy primer with PE paint is already a good paint. If you want to further ensure the service life, PVDF or acrylic polyurethane topcoat may be your best choice.

In general, PVDF or acrylic polyurethane paint is the best topcoat. As for the primer, you can choose the one that suits you best according to the different usage environments.

However, usually, while pursuing perfect paint, we also need to consider the cost of paint, the production process of color aluminum and other practical issues.

Aluminum paint under roller coating process

This process is suitable for flat objects. According to the different dispersion media, roller coating can be divided into solvent-based and water-based coatings.

According to the coating process, roller coating includes primer, back paint, topcoat and finishing paint.

• Back paint: polyester coating or clear coat is often used.
• Primer: polyester coating, epoxy coating, etc.
• Topcoat: Commonly used topcoat coatings include polyester coating, fluorocarbon coating, silicon-modified polyester, acrylic coating, etc.
• Finishing paint: Provide high gloss or specific gloss effect to improve the appearance texture.

According to the coating material classification, fluorocarbon resin, polyester resin, epoxy resin, acrylic resin, etc. are commonly used.

Coating performance

Appropriate viscosity and good leveling: The roller coating process requires the coating to have a certain construction viscosity to ensure that the coating roller can carry enough coating and has good leveling on aluminum.

Fast curing: Due to the fast running speed of the roller coating production line, the coating needs to be completely cured in a short time, usually within 5 to 60 seconds.

Decorativeness: The coating should meet certain decorative requirements. For example, polyester coating can meet the decorative requirements with one coat, while fluorocarbon coating requires one coat of primer and topcoat.

Weather resistance: The coating should have good weather resistance to meet the needs of outdoor use, especially PVDF fluorocarbon coating is widely used due to its super weather resistance.

Paint brand

The paint used in the coating mainly adopts well-known brands such as PPG, Beckers, and AkzoNobel.

Coating thickness

It can be divided into single coating, double coating, and triple coating.

• Single coating: 4μm-20μm
• Double coating: 25μm-28μm
• Triple coating: 35μm-38μm

Various surface patterns

In addition to the common single-color coating, the surface of roller-coated colored aluminum can also be roller-coated with various common patterns, including imitation wood grain aluminum coil, marble & granite aluminum, brick pattern, camouflage aluminum coil, etc.

Environmental protection and corrosion resistance

Roller paint contains active chemical molecules, which promote the formation of a protective layer on the surface of the material to meet environmental protection requirements.

Because there is a tight oxide film on the surface, it has strong adhesion, oxidation resistance, acid and alkali resistance, corrosion resistance, decay resistance, UV resistance and other characteristics.

Paint for aluminum under spraying process

If the surface of the spraying target is not flat, such as aluminum special-shaped parts, garage doors, gutters, etc., then the spraying process is your only choice. The spraying process is generally divided into paint spraying and powder electrostatic spraying.

Water-based paint spraying process

Water-based paint uses water as a solvent, does not contain organic solvents, is environmentally friendly, does not pollute the environment, and has a full, crystal clear, flexible, and is water-resistant, wear-resistant, aging-resistant, yellowing-resistant, and fast drying.

Water-based acrylic paint

Features: Water-based acrylic paint is an environmentally friendly water-based paint with acrylic resin as the main film-forming substance. It has the advantages of fast drying, non-toxic and odorless, and good weather resistance.

Application: Widely used in indoor walls, furniture, decorations and other fields, especially suitable for indoor colored aluminum coating.

Waterborne polyurethane coating

Features: Waterborne polyurethane coating has excellent weather resistance, wear resistance and chemical properties.

Application: Suitable for indoor and outdoor metal, wood, plastic and other substrates, especially suitable for indoor colored aluminum coating.

Waterborne PVDF coating

Features: Waterborne fluorocarbon coating has long-lasting weather resistance, excellent anti-fouling and ideal scrub resistance.

Application: Suitable for various building walls requiring long-term protection, especially suitable for walls in humid and foggy areas and coastal areas

Spraying process steps of waterborne paint

1. Preparation: Clean and polish the surface to ensure that the surface is flat and smooth, and remove oil, dust and impurities.
2. Dilution: According to the consistency and spraying requirements of the waterborne paint, dilute the waterborne paint to the appropriate concentration, usually with an appropriate amount of water.
3. Covering and masking: Use materials such as plastic sheets to cover and mask the parts that do not need to be sprayed to prevent the paint from splashing to other areas.
4. Coating amount control: Control the spray amount of the paint by adjusting the spray pressure of the spray gun and the diameter of the nozzle to ensure uniform coating.
5. Spraying: Pour the diluted water-based paint into the spray gun or spraying equipment, spray the paint on the surface of the object through the spray gun, maintain a certain spraying distance and angle, and evenly cover the entire surface.
6. Drying and curing: According to the instructions for use of water-based paint, wait for a certain time to allow the sprayed paint to fully dry and cure.
7. Painting and finishing: As needed, spray a second coat to achieve a better coating effect.

Powder electrostatic spraying process

Powder electrostatic spraying paint is a solvent-free, pollution-free, recyclable and environmentally friendly paint that does not contain volatile organic compounds (VOC) and meets environmental regulations.

Powder electrostatic spraying paint can be thermoplastic or thermosetting powder, of which thermosetting powder needs to be cured after spraying.

The one-time film thickness can reach 50-80μm.

Composition of powder coating

Powder coating is mainly composed of resin, curing agent, pigment, filler and various additives.

• Resin: The resin performance index of powder coating has an important influence on the performance of coating. Commonly used resins include polyester resin, etc.
• Curing agent: The type of curing agent and the selection principle have a significant impact on the performance of aluminum profile powder coating. Commonly used curing agents include TGIC (triglycidyl isocyanurate), etc.
• Pigment: The selection principle, classification and performance of pigments play an important role in the color and protective performance of coatings.
• Filler: Filler can enhance the physical properties of coatings, such as hardness and wear resistance.
• Additives: The role of additives and common varieties have an impact on the fluidity, leveling, gloss and other properties of coatings.

Powder electrostatic spraying process

The principle of electrostatic adsorption is used to make the powder coating carry an electric charge and adsorb to the surface of aluminum profiles to form a uniform coating.

After spraying, the workpiece needs to enter the baking oven for curing to achieve the required coating performance.

Construction requirements

Powder coatings are required to be stored in a ventilated, dry and clean environment below 30℃. They should not be near fire and heating, and should be kept away from direct sunlight.

Powder coating construction conditions require good ventilation, temperature below 35℃, away from fire, and avoid direct sunlight.

The surface of the coated object must be strictly pre-treated to ensure that the characteristics of powder coating can be fully utilized.

Application areas

Powder coatings are widely used in many fields such as architectural aluminum profiles, household appliances, automobiles, furniture manufacturing, and pipeline coating.

Special requirements

For powder coatings for aluminum alloy wheels, base powder and transparent powder must meet multiple requirements such as no color difference, excellent hiding power, excellent leveling, corner wrapping, easy powdering at angles, no fat edges, high transparency, and high fullness.

PVDF VS PE paint

PVDF coatings

PVDF coatings are widely used in construction, industry, and daily life for their excellent weather resistance, corrosion resistance, wear resistance, and decorative properties.

It has excellent UV resistance, can maintain color and gloss for a long time in outdoor environments, and is not easy to fade.

At the same time, PVDF coatings have strong tolerance to chemicals such as acids, alkalis, and salts, and are suitable for chemical equipment and marine environments. In addition, PVDF coatings are rich in color, high in gloss, strong in adhesion, and environmentally friendly and do not contain harmful substances.

PVDF coatings are divided into two forms: liquid coatings and powder coatings.

The specific ingredients include the following parts:

• PVDF resin: Polyvinylidene fluoride (PVDF) is the main component of paint and has excellent weather resistance, chemical resistance, and UV resistance.
• Acrylic resin: In order to improve the adhesion of PVDF and the dispersibility of pigments, acrylic modified resins are usually added to PVDF resins. This resin can help overcome the chemical inertness of PVDF and enhance the performance of the coating.
• Pigments: Used to give the coating color and hiding power, commonly used pigments include inorganic ceramic pigments and other pigments with good weather resistance to ensure the long-term stability of the coating.
• Additives: Including dispersants, leveling agents, defoamers, etc., to help improve the processing performance of the coating and the flatness of the coating.
• Solvents: Used to dissolve and disperse PVDF resin and other ingredients to form a uniform coating liquid. Water-based PVDF coatings usually use water as a solvent to reduce the emission of volatile organic compounds (VOCs).
• Fillers: Fillers are sometimes added to adjust the rheological properties and hardness of the coating.

PE paint

PE paint, also known as polyethylene paint, has good wear resistance, corrosion resistance and aging resistance.

It is widely used in the surface protection and decoration of materials such as metals, plastics, and paper.

For example:

In the field of automobile manufacturing, PE coating can effectively protect the car body from corrosion and wear;

In terms of architectural decoration, PE coating is often used for waterproofing and moisture-proofing.

PE coating is low-cost and non-toxic, but its strength and hardness are relatively low and may be easily affected by external forces.

PE paint components:

• Resin: The main film-forming substance of PE paint is resin, usually unsaturated polyester resin.
• Accelerator: Accelerator is an important component in PE paint, which is used to accelerate the curing process of the paint.
• Curing agent: Curing agent is also a key component in PE paint, which reacts with resin to form a hard coating film.
• Pigment: Pigment is used to provide the color required for the coating film, which can be inorganic pigments or organic pigments.
• Filler: Fillers are used to improve the physical properties of the coating, such as hardness and wear resistance, while also reducing costs.
• Defoamer: Defoamers are used to control bubbles generated during the production and construction of the coating, ensuring that the surface of the coating is smooth and defect-free.
• Color paste: Color paste is used to adjust the color of the coating to meet specific decorative or protective requirements.
• Solvent: Although water-based PE paint uses water as a solvent, traditional PE paint may use organic solvents such as toluene, acetone, etc. to adjust the viscosity and fluidity of the coating.
• Other additives: Some special additives such as leveling agents, anti-settling agents, etc. may also be included to improve the construction performance of the coating and the quality of the coating.