The bonding mechanism of silicone sealant is formed by chemical reaction with the surface of the material, so the surface treatment of the aluminum alloy profile has a great influence on the adhesion of the silicone structural sealant. The surface treatment methods used for building curtain wall aluminum alloy profiles are: anodizing, powder coating and fluorocarbon coating.
Anodizing

1 Anodizing: Electrochemical oxidation of a metal or alloy. The process in which aluminum and its alloys form an oxide film on an aluminum product (anode) due to the action of an applied current under the corresponding electrolyte and specific process conditions, usually refers to anodization of sulfuric acid. Anodizing is a widely used aluminum alloy surface treatment method. Its surface is slightly darker than the smooth surface, and the hand feel is slightly rough. The common color is silver white. In general, the silicone structural sealant and the anodized aluminum alloy profile are better bonded.
Powder Coating

2 powder coating: coating powder coatings (polyurethane, polyurethane resin, epoxy resin, hydroxy polyester resin and epoxy/polyester resin) on the workpiece under the action of high voltage forming electrostatic field, and then passing through The process of baking the time temperature to form a coating. The powder-coated aluminum alloy is a color aluminum, which can be formulated in a variety of colors. Its surface is uneven and rough, and the common colors are gray, dark gray and brown. Silicone structural sealants and most powder-coated aluminum alloy profiles can form a good bond, but some need to be pre-treated by brushing, grinding, etc. to form a good bond.

Fluorocarbon coating

3 fluorocarbon spray: using a liquid phase spray method, a fluorocarbon spray coating made of polyvinylidene fluoride resin nCH2CF2 baking (CH2CF2)n (PVDF) or a metal aluminum powder as a coloring material is applied. The surface of the aluminum alloy. Fluorocarbon coating is widely used in aluminum (plastic) panels/curtain walls. Due to its excellent characteristics, it is more and more favored and favored by the construction industry and users. The surface of fluorocarbon coating is fine and smooth, and the common colors are flash silver. Gray, dark gray. The fluorocarbon sprayed aluminum alloy profile is basically subjected to primer pretreatment, and the silicone structural sealant can form a good bond with it. Therefore, powder coating and fluorocarbon sprayed aluminum alloy profiles are used for glass curtain walls. Under normal circumstances, the adhesive surface will not be sprayed (especially fluorocarbon spray) and only the previous chromium treatment, after chromization Common colors are golden yellow, silver white, and blue white. The bonding of the silicone structural sealant to the chromed aluminum alloy profile is also preferred. In practical applications, even if the surface characteristics of the aluminum alloy profiles produced by the same surface treatment method and different manufacturers are not the same, the silicone structural sealant may have a completely different bonding effect, and must be carried out before the glue is used. The adhesion test was pre-judgmented.