2021-8-16 09:30| 发布者: steelfu4mo| 查看: 899| 评论: 0 |原作者: 佛山万庆物资
There are many factors to consider in the choice of color coated steel plate coating, which mainly includes coating type, coating thickness, coating color and coating gloss.In addition, sometimes you also consider the coating primer and the requirements of the back coating.
Currently used for color coating steel plates are polyester coating (PE), fluorocarbon coating (PVDF), silicon modified coating (SMP), high hou tolerance coating (HDP), etc.
Silicon-modified polyester (SMP)
Since the polyester contains the active group-OH / -COOH, Easy to react with other polymermers and objects, To improve the sunshine resistance and powder properties of PE, Using Silicone resin with excellent color retention and heat resistance, The denaturation ratio to the PE is between 5% and 50%, SMP provides better durability, Its corrosion prevention life can be up to 10-12 years, Of course, its price is also higher than the PE, However, because the attachment and processing and molding of Silicone resin are not ideal, Therefore, the SMP color-coated steel plate is not suitable for multiple molding and processing occasions, Most of it is used for the building roof and exterior walls.
High tolerance polyester (HDP)
For the disadvantages of PE and SMP, weather-resistant HDP polyester coatings, and better than ordinary silicon modified polyester coatings, its outdoor weather resistance reaches 15 years.High weather resistance polyester resin uses monomer containing cyclohexane structure to achieve the balance of flexibility, weather resistance and cost of resin, using no aromatic polyols and polyacid to reduce the absorption of resin to UV light, to achieve the high weather resistance of coating.UV absorbent and bitamine (HALS) are added to improve the weather resistance of paint film.High weather resistance polyester coil coating is very effective.
PE coating has a good attachment to the material, color coated steel plate is easy to process and shape, low price and many products, color and gloss choice is large.Polester coating to UV resistance and film powder resistance, but not ideal, so the use of PE coating still needs to be subject to some restrictions, generally used in the air pollution is not serious areas or need multiple molding processing products.
Due to PVDF bond and chemical bonds, has a strong bond energy, so the coating has very good corrosion resistance and color retention, in the construction industry with color coated steel paint, is the highest product, and large molecular weight and direct bond structure, so in addition to chemical resistance, mechanical performance, ultraviolet resistance and heat resistance is also very outstanding.In the general environment, its corrosion protection life can be up to 20-25 years.In recent years, fluorine-containing resin with trifluorinated vinyl chloride and vinyl ester monomer began to prevail in China, which is widely used in the external wall and metal plate of buildings. Because the content of vinyl ester monomer and fluorine is about 30% lower than that of PVDF, there is a certain gap in its weather resistance compared with PVDF.Fluorocarbon coating produced by Baosteel, its coating PVDF content is not less than 70% (other is propionacid resin).