Polyester based powder coatings MT-620 AM

Surface Finish Options Overview

Product Description

MT-620 AM is a series of polyester based powder coatings, formulated without the use of TGIC, designed for the exterior environment, offering the benefits of MT 600 in combination with specific antimicrobial activity. MT-620 AM powders are available in a wide range of colors in gloss, satin, matt, metallic and textured effects and can be custom matched to the user’s requirements.

Powder properties

Test conditions

The results shown below are based on mechanical and chemical tests which (unless otherwise indicated) have been carried out under laboratory conditions and are given for guidance only. Actual product performance will depend upon the circumstances under which the product is used.

Mechanical tests

Pretreatment

Aluminium, steel or Zintec surfaces to be coated must be clean and free from grease. Iron phosphate and particularly lightweight zinc phosphating of ferrous metals improves corrosion resistance. Aluminium substrates may require a chromate conversion coating. Detailed advice should be sought from the pre-treatment supplier.

Application

MT-620 AM powder coatings can be applied by corona electrostatic equipment. In all application processes the aspect obtained is subject to variation, depending on the method of application (type of gun, nozzle, etc) and the shape/type of component. We recommend that the actual application parameters are adapted and adjusted depending on the type of component and with each powder batch to give a finish in accordance with our color card. The following procedure is given as a guideline when using these finishes. We recommend the use of flat jet spray nozzles. To ensure powder homogeneity, the complete content of the boxes should be emptied completely into the feed hopper. For manual application it is essential to ensure that an even film thickness is applied, and, in all Instances, sinusoidal gun movements should be avoided. All powders can show small color differences from batch to batch, this is normal and unavoidable. Applicators and fabricators are advised to use a single batch for parts that will be assembled together. Differences are more likely with special effect powders. Bonded products have better application properties than blended products (more stable) but attention should still be paid to line settings to avoid “marble effect” and changes in aspect after recycling. Different substrates (Aluminium, steel, galvanized steel, etc.), use of primer, and big changes in film thickness may give a different aspect. Products with different codes should not be mixed even if same color and gloss.

FAQ

1. What is Powder Coating?

Powder coating is a dry finishing process used to apply a protective and decorative coating on metal or other surfaces. Instead of using liquid paint, fine powder particles (usually made of polyester, epoxy, or hybrid resins) are electrostatically charged and sprayed onto a conductive surface. The coated object is then baked in an oven, where the powder melts, flows, and cures into a smooth, durable finish.

Key features:

Durable, hard finish

Resistant to scratches, corrosion, and UV

Environmentally friendly (no VOCs)

2. Benefits of Powder Coating

Powder coating offers several advantages over traditional liquid painting:

Durability: Resistant to chipping, scratching, fading, and wear.

Corrosion Protection: Provides excellent protection against rust and chemicals.

Environmentally Friendly: No volatile organic compounds (VOCs) and minimal waste.

Efficiency: Overspray can be collected and reused, up to 99% material utilization.

Uniform Finish: Smooth, even coating without runs or drips.

Cost-Effective: Single-coat systems can achieve high film thickness, reducing labor and energy.

Aesthetic Variety: Wide range of colors, textures, and effects.

3. What Temperature to Cure Powder Coating

The curing temperature depends on the type of powder used:

Epoxy powder: ~160–200°C (320–392°F)

Polyester powder: ~180–210°C (356–410°F)

Hybrid (Epoxy-Polyester) powder: ~180–200°C (356–392°F)

Typical curing time: 10–20 minutes depending on thickness and oven type.

Always follow the powder manufacturer’s specifications for best results.

4. Process for Powder Coating

The powder coating process usually follows these steps:

Surface Preparation:

Clean the surface thoroughly (remove oil, grease, rust, or dirt)

Methods: chemical cleaning, sandblasting, or phosphating

Pre-Treatment:

Apply a conversion coating or primer if needed to improve adhesion

Powder Application:

Spray the powder using an electrostatic spray gun or fluidized bed

Curing:

Bake the coated object in an oven at the recommended temperature for the powder type

The powder melts and forms a continuous, smooth film

Cooling & Inspection:

Let the coated item cool

Inspect for defects, uniform coverage, and desired thickness

5. How to Spray Powder Coat

Equipment Needed:

Electrostatic spray gun

Compressed air supply

Powder feed hopper or container

Grounding of the object

Steps:

Ground the object: Ensures the charged powder is attracted to the surface.

Spray evenly: Hold the gun 6–12 inches from the surface, moving in smooth, overlapping strokes.

Apply sufficient powder: Ensure full coverage without excessive buildup.

Cure immediately: Transfer the sprayed item to the curing oven to fuse the powder into a solid coating.

Tips:

Maintain consistent speed and distance while spraying.

Use proper ventilation to reduce airborne powder accumulation.

Test a small area to check film thickness and color before full application.