What is the process of film-faced birch plywood edge sealing

Film-Faced Birch Plywood is the main material for high-performance building formwork and industrial flooring. It has excellent structural strength, surface wear resistance and weather resistance. In practical applications, edge water absorption, cracking and mildew are the main factors affecting its durability and service life. To address this problem, edge sealing has become an important part of the production process. Through professional edge sealing technology, the moisture and corrosion resistance of plywood can be significantly improved, interlayer peeling can be reduced, and the product life cycle in harsh environments can be extended.
The edge sealing process is a systematic operation process, which usually includes six main steps: edge pretreatment, edge sealing coating selection, coating method control, drying and curing, repeated coating (if applicable) and quality inspection. Each link directly affects the final edge sealing effect and its stability.

Edge pretreatment
After the film-faced plywood is hot-pressed, cooled and sawed, the wood fiber structure will be exposed on the four sides of the board. In order to improve the adhesion and penetration of the edge sealing coating, the edge needs to be physically pretreated first. Common methods include:
Manual or automatic sanding: Use fine sandpaper to evenly sand the edges to remove burrs and loose fibers;
Blowing dust removal: Use a high-pressure air gun or industrial vacuum equipment to remove residual wood powder to avoid affecting the adhesion of the coating;
Humidity detection: Ensure that the moisture content of the wood edge is within a reasonable range, usually 8%-12%, to avoid bubbles or coating shedding after edge sealing.
Edge pretreatment is the first step to ensure the stability of the edge sealing process.

Edge sealing coating selection
Different application scenarios have different requirements for edge sealing performance, and the choice of coating is directly related to the protective effect. The mainstream edge sealing coatings currently used in the industry mainly include:
Phenolic resin edge sealing agent: suitable for phenolic film-coated panels, with high compatibility with surface film materials;
Acrylic waterproof coating: low cost, suitable for general outdoor or short-term use scenarios;
Polyurethane coating: high adhesion, strong chemical resistance, suitable for high-frequency, humid construction environments;
Oil-based penetrating edge sealing paint: has good wood fiber permeability, which can improve the edge sealing effect.
The edge sealer should be waterproof, mildew-proof, weather-resistant and UV-resistant, and meet environmental protection standards to avoid releasing harmful substances during subsequent use.

Edge Sealing Coating Operation
The coating operation is one of the most critical links in the process, which determines the uniformity of coating thickness, penetration effect and overall appearance. Common coating methods are as follows:
Brushing (manual): suitable for customized sizes or small batches of boards, flexible operation, but low efficiency and poor consistency;
Rolling or scraping: The thickness of the edge sealer is controlled by equipment, suitable for standardized production lines;
Spraying (automation): Use an automatic spraying system to achieve high efficiency, high precision, and no dead angle edge sealing, suitable for large-scale industrial production.
The ideal coating thickness should be controlled between 50-100 microns per dry film to ensure protection strength without affecting the thickness tolerance of the board.

Drying and curing treatment
After the coating is completed, it is necessary to enter the drying and curing stage to allow the coating to complete the cross-linking reaction and firmly adhere to the edge surface of the board. Drying methods can be divided into:
Natural drying at room temperature: suitable for general-purpose edge sealers, which require 12-24 hours to fully cure;
Hot air forced drying: using hot air furnaces or drying rooms to accelerate the curing process, shorten construction periods, and improve production efficiency;
Infrared fast curing: used for high-end fast production lines to achieve complete film formation in a short time.
During the drying process, avoid stacking multiple boards in an overlapping manner to prevent the edges from sticking to each other or leaving marks.