Type of finish paint and film thickness of color coating roll
Summary: The commonly used color coating roll finish includes ordinary polyester, silicon modified polyester, high weather resist...
The commonly used color coating roll finish includes ordinary polyester, silicon modified polyester, high weather resistant polyester, PVC PVC plastic sol, PVC plastic sol, polyvinylidene fluoride, polyurethane, acrylic resin, etc.
(1) Ordinary polyester (PE, Polyester)
PE coating has good adhesion to materials. Color-coated steel plate is easy to be processed and formed, cheap and has many products. There is a wide choice of color and gloss. Polyester coating is not ideal for ultraviolet light resistance and powdering resistance of the coating film. Therefore, the use of PE coating still needs to be limited. It is generally used in areas where air pollution is not serious or products that need to be molded and processed many times.
(2) Silicone Modified Polyester (SMP)
Because polyester contains active radical - OH/- COOH, it is easy to react with other macromolecules and substances. In order to improve the sunlight resistance and pulverization of PE, Silicone resin with excellent color retention and heat resistance is used for the denaturation reaction, and the denaturation ratio with PE can be between 5% and 50%. SMP provides better durability of steel plate, and its anti-corrosion life can be as long as 10-12 years. Of course, its price is also higher than PE, However, because the adhesion and processing formability of Silicone resin to materials are not ideal, SMP color coated steel plate is not suitable for occasions requiring multiple molding and processing, most of which are used for building roofs and exterior walls.
(3) High durable polyester (HDP, High durable polyester)
As for the shortcomings of PE and SMP, the British company HYDRA (now acquired by BASF) and the Swedish company BECKER developed a 60-80% weather-resistant HDP polyester coating that can reach PVDF coating at the beginning of 2000, which is superior to the ordinary silicon modified polyester coating, and its outdoor weather-resistance reaches 15 years. During the synthesis of high durability polyester resin, the monomer containing cyclohexane structure is used to achieve the balance of flexibility, weatherability and cost of the resin, and aromatic polyols and polybasic acids are used to reduce the absorption of UV light by the resin to achieve the high weatherability of the coating. Ultraviolet absorber and steric hindrance amine (HALS) are added into the coating formulation to improve the weatherability of the paint film. The high durability polyester coil coating has been recognized by the market abroad, and the cost performance ratio of the coating is very outstanding.
(4) PVC Plastisol
PVC resin has good water resistance and chemical resistance, and is generally coated with high solid content, with coating thickness of l00-300 μ M, can provide smooth PVC coating or light embossing treatment as embossing coating; Because PVC coating is thermoplastic resin with high film thickness, it can provide good protection for steel plate. But the heat resistance of PVC is weak. It was widely used in Europe in the early stage, but now it is less and less used due to its relatively poor environmental protection properties.
(5) Polyvinylidene fluoride (PVDF)
Due to the strong bond energy between the chemical bond and the chemical bond of PVDF, the coating has very good corrosion resistance and color retention. Among the color coated steel plate coatings used in the construction industry, it belongs to Z advanced products, and its molecular weight is large and it is a direct bond structure. Therefore, in addition to chemical resistance, mechanical properties, ultraviolet resistance and heat resistance are also outstanding. In general environment, the corrosion prevention period can be as long as 20-25 years. In recent years, fluorine-containing resins co-polymerized with trifluoroethylene and vinyl ester monomers have become popular in China, and are widely used in exterior walls and metal plates of buildings. Since the use of easily hydrolyzed vinyl ester monomers and fluorine content is about 30% lower than PVDF, its weatherability is somewhat different from PVDF. The PVDF content of the fluorocarbon coating produced by Baosteel is not less than 70% (the other is acrylic acid resin).
(6) Polyurethane (PU)
A new type of finish paint developed in recent years, with excellent comprehensive performance and high price, is being promoted.
(7) Acrylic resin
With good comprehensive performance and high price, it is only used in specific fields (such as containers).