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Color coated steel coil coating types

Jul 20, 2021

The main component of the color-coated steel coil coating is resin, which is used as the base material in the coating formulation. In addition, most coatings require solvents and can also contain various additives. Furthermore, many coatings also contain a crosslinking agent, which chemically reacts with the resin in the curing stage after the coating is applied to the substrate to form a paint film with a network-like crosslinked structure. This network structure is necessary to produce good film properties. After high-speed coating of coil coatings, they are quickly cured at high temperature (15-30 seconds), and the solvent must evaporate during the curing stage to form a coating film. A number of properties are important to a coating film, including hardness, flexibility, weatherability, chemical resistance, solvent resistance, corrosion resistance, adhesion to various substrates, impact resistance, and more. These properties depend on many factors, including resin type, molecular weight, monomer composition, and glass transition temperature (Tg); crosslinker type and amount; curing conditions; curing catalysts; and adjuvants. Varying these parameters can vary widely in film properties to meet the requirements of many different applications.


According to different steel coil coatings, coatings can be divided into three categories: primer, topcoat and backcoat:


Primers are divided into polyester primers, polyurethane primers, epoxy primers, etc. according to different film-forming resins. Different primers can be selected according to different needs of users. Commonly used are epoxy primers and polyurethane primers, which are processed and manufactured with anti-rust pigments such as zinc chrome yellow and strontium chrome yellow.



Generally, polyester resin, high weather-resistant polyester resin, silicon-modified polyester resin, acrylic resin, polyvinylidene fluoride resin, polyurethane are used, and methyl etherified amino resin or blocked isocyanate resin is used for the thermal curing cross-linking curing system. Use pigments with good heat and weather resistance.


Back Paint

At present, in our system can be divided into 2/1, 2/2, 2/1M system. The back of 2/1 system can be coated with one layer of primer or only one layer of back paint. It is mainly used for sandwich panels and requires the coating to have good bonding and foaming properties. The 2/2 system adopts a two-coat system of primer and back paint, generally does not require foaming performance, and is used as a veneer. The 2/1M system is generally coated with a 3-micron primer and a 6-micron backcoat, which can replace 2/1, requiring the backside to be foamed.


We offer a variety of pre-painted steel coils in a full range of shades, both PPGI and PPGL, contact us for more information.

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