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Core Principles for Determining Curing Temperature and Time
The curing process of isocyanate-cured polyester resin is primarily influenced by temperature, time, humidity, and the isocyanate index. The key to determining the curing parameters is to ensure that the resin undergoes complete cross-linking without over-reaction that could lead to aging or performance degradation.
1. Refer to the Product Data Sheet
This is the most direct and reliable method. As a leading supplier in the industry, Jiangsu BESD New Materials Co., Ltd. typically provides recommended curing temperature ranges (e.g., 160℃ - 200℃) and corresponding curing times (e.g., 15-30 minutes) in our product data sheets.
2. Bench Testing
In actual production, it is recommended to conduct small-scale tests first. A "temperature ramping" method can be used, observing the resin's flowability and surface drying time at room temperature, and then conducting curing experiments at different temperatures (e.g., 150℃, 170℃, 190℃). The optimal temperature can be determined by testing hardness, adhesion, and chemical resistance.
3. Consider Substrate and Coating Thickness
Substrate thermal conductivity: Metal substrates have good thermal conductivity, so the curing temperature can be appropriately lowered; while glass or plastic substrates have poor thermal conductivity, requiring higher temperatures or longer times.
Coating thickness: Thick coatings have slower heat transfer, requiring longer curing times; thin coatings are the opposite.
4. Influence of Environmental Humidity
Although isocyanate-cured polyester resin is less sensitive to humidity than water-based resins, in extremely high humidity environments (>80% RH), moisture may react with isocyanates (forming diamines), leading to bubble formation. In this case, it may be necessary to appropriately increase the curing temperature to accelerate evaporation.
