1,Instruction:
SMP coating is shorted for Silicone Mobified Polyester coating.Since the polyester contains an active group -OH/-COOH, it is easily reacted with other macromolecular substances. The modified PE is resistant to sunlight and powdering, and is denatured by a Silicone resin having excellent color retention and heat resistance.
2,Life span:
Compare to PE coating,the denaturation ratio is between 5% and 50%.SMP provides better durability for steel sheetsand the corrosion resistance can last for 10-12 years. Of course, the price is higher than PE coating, but because the material is made of Silicone resin,the adhesion and formability are not ideal.SMP color coated steel sheets are not suitable for applications where multiple molding processes are required,and most of them are used for roofs and exterior walls of buildings.
Coating structure details:
3,Substrate:
-Hot dipped galvanized steel coils,according to JIS G3302,Zinc coating 275 g/m²；
-Hot dipped galvalume(5% aluminum coating added in),according to JISG3317,Zinc coating: 275 g/m²;
-Hop dipped galvalume(55% aluminum coating added in ),according to JIS G3321,AZ coating:150 g/m²,standard thickness:0.576mm,other thickness could follow customers’ requirement.
4,Coating system:
Coating system with double-sided two-coating.
Primer coating:
-Using highly corrosion resistant Polyurethane(Also called PU),film thickness:5μm.
Top coating:
-Using highly corrosion resistant SMP coating,film thickness 20-22μm.
Top coating color & gloss:
-Color could be customized;
-Top coating gloss is typically 25%(60° reflection angle,according to ASTM D523)
Back primer coating:
-Using highly corrosion resistant Polyurethane(Also called PU),film thickness:2μm.
Back coating:
-Using good corrosion resistant epoxy resin coating,polyester resin coating,film thickness:7-10μm.
Back coating color & gloss:
-Back coating color is usually using beige,grey or white grey color.Back coating gloss is typically 25%(60° reflection angle,according to ASTM D523).
