Development of Pre-painted Metals and Coating Methods

Pre-painted metals are produced by continuously adding paint or film coatings to strip metals, primarily steel and aluminum. This process is called coil coating. The process involves cleaning and chemical pretreatment of the metal surface and one or both sides as necessary, single or multiple applications of (liquid) paint or coating powder, followed by curing or lamination with plastic film.

 

Pre-painted metals are produced by continuously adding paint or film coatings to strip metals, primarily steel and aluminum. This process is called coil coating.
The process involves cleaning and chemical pretreatment of the metal surface and one or both sides as necessary, single or multiple applications of (liquid) paint or coating powder, followed by curing or lamination with plastic film.
The coated surface can have a wide range of colors, gloss levels and surface textures. It is the end use of the finished product that determines the coating choice. The user may require non-stick properties, high flexibility or high chemical resistance. Modern developments offer many new coating types to meet the growing needs of users. Learn Moregives you an overview of developments in metal coating technology and paint technology.

Painting metal industry

There are several options for applying paint to metal. In the field, it is common to spray or brush; in the factory, you can spray, powder coat or coil coat. However, when it comes to the performance requirements of today's metal buildings, products such as metal composites use the coil coating process almost exclusively to apply finishes that look nearly flawless and are built to last.
Coil coating is a method of coating metal coils in a continuous process prior to fabrication. The metal coils are passed through an uncoiler, a wire loading accumulator, processed and painted as required, through an end line exit accumulator and then rewound on a winder. These coils are finished and cured in a continuous process. Although traditionally used for aluminum substrates, this process can be applied to other metals, such as steel.

 

economic 1-side 1-coating line apply to thin ACP coil coating

 

Coating Methods

The application of metal coatings has moved beyond spray systems and is now more typical in single sheet batch processes. Continuous coil coating is manufactured using roll or die coating methods. Reverse roll coating is common in metal fabrication, which uses two rolls running in opposite directions to apply the paint. The metering roll loads the paint and transfers the paint to the coating roll, which then applies the paint to the substrate.
Paint thickness is carefully controlled in a single, seamless application. Both the paint system and the coil need to meet strict quality standards during the coating of the mold. The result is the smoothest coating possible and is more sustainable due to reduced waste.

 

2-Sides 2-Coatings Production Line (Integrated)

Paint Systems

Over the years, paint systems have evolved as the industry began to demand finishes beyond what polyester and polyurethane coatings could provide. The only coating system that meets the most common building performance specifications listed in AAMA 2605 is a fluoropolymer. The unique chemistry provides superior weatherability and durability.
The first generation of fluoropolymer coatings, introduced in 1948, was polyvinylidene fluoride (PVDF), a relatively low gloss finish. Due to the addition of acrylics, the color palette was limited and bright colors could be a challenge.
The second generation of fluoropolymer coatings introduced in 1982 was fluoroethylene vinyl ether (FEVE). This coating system is thermosetting and is chemically cross-linked with fluorocarbon components so that it will not remelt under high pressure and temperature. FEVE is a clear resin that allows for brighter, more vibrant finishes with a smooth surface.

 

Food Grade High-Speed Coating Line

Advances in coil coatings and paint systems allow a virtually unlimited palette of finishes to last for decades. The introduction of metal composite materials (MCM) into the architectural landscape was another revolutionary innovation. Over the past 40 years, these advances have fundamentally redefined the possibilities for manufacturers and designers.

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