Publish Time: 2025-02-27 Origin: Site
The primary purpose of surface treatment for hand-layup fiberglass reinforced plastic (FRP) products is to enhance appearance, weather resistance, and corrosion resistance. Below are some common surface treatment processes:
Grinding: Sandpaper, grinding wheels, and other tools are used to grind the surface of the product. Coarse grinding removes burrs, protrusions, and mold release agent residues, ensuring a smooth surface. Fine grinding further improves surface smoothness. Grinding should follow a sequential process, transitioning from coarse to fine sandpaper for an even surface finish.
Polishing: Polishing wheels and polishing compounds are used to polish the ground surface, achieving a mirror-like gloss. This process significantly enhances the product’s visual appeal and is commonly used for decorative items and high-end products requiring superior surface finishes.
Sandblasting: Compressed air propels sand particles onto the product’s surface, removing oxidation layers, contaminants, and impurities while creating a certain level of roughness. This improves adhesion for subsequent coatings. The sandblasted surface exhibits a uniform matte texture, making it ideal for applications requiring strong coating adhesion.
Degreasing Treatment: Organic solvents (e.g., acetone, alcohol) or alkaline degreasing agents are used to clean the product surface, removing oil stains and organic contaminants. This step ensures strong adhesion between coatings and the substrate, preventing peeling or blistering.
Chemical Conversion Treatment: A chemical reaction forms a conversion film on the surface, such as phosphating or passivation films. These films improve corrosion resistance and enhance coating adhesion. For example, phosphating creates a uniform and dense phosphate layer on the FRP surface, effectively blocking external corrosive agents.
Acid Etching Treatment: Acid solutions lightly corrode the surface, removing oxidation layers and impurities while creating microscopic roughness to improve coating adhesion. The concentration, time, and temperature of the acid solution must be strictly controlled to avoid excessive corrosion that could compromise the product’s integrity.
Primer Coating: The primer layer provides strong adhesion and rust protection, forming a solid foundation for subsequent coatings. Before applying primer, the surface must be clean and dry. Application methods include brushing and spraying, with a uniform thickness typically in the micron range.
Topcoat Application: The topcoat provides decorative and protective functions, giving the product an attractive appearance and resistance to weathering and chemicals. Different types of topcoats, such as acrylic and polyurethane, are selected based on environmental and functional requirements. Similar to primer application, multiple layers of topcoat are often applied to achieve the desired thickness and gloss.
Gelcoat Coating: Gelcoat is a specialized resin coating applied directly onto the mold surface during the forming process. It enhances surface smoothness, corrosion resistance, and wear resistance while concealing minor defects. The color and gloss of the gelcoat can be customized to meet specific design requirements.
Film Application: Various decorative and protective films can be applied to the product surface for aesthetic and protective purposes. Film application is a cost-effective and convenient method to alter the product’s appearance while preventing scratches and contamination. Common films include PVC and PET films, widely used in architectural decoration and automotive interiors.
Electroplating: Metal coatings such as copper, nickel, and chrome can be deposited onto FRP surfaces via electroplating. This enhances conductivity, wear resistance, and corrosion resistance while giving the product a metallic appearance. However, electroplating on FRP requires specialized pre-treatment to ensure strong adhesion between the metal layer and the substrate.