06/05/2025
๐๐ฒ๐ ๐ฃ๐ผ๐ถ๐ป๐๐ ๐ณ๐ผ๐ฟ ๐ค๐๐ฎ๐น๐ถ๐๐ ๐๐ผ๐ป๐๐ฟ๐ผ๐น ๐ผ๐ณ ๐ฅ๐ถ๐ด๐ถ๐ฑ ๐ฃ๐ผ๐น๐๐๐ฟ๐ฒ๐๐ต๐ฎ๐ป๐ฒ ๐๐ผ๐ฎ๐บ ๐ ๐ฎ๐ป๐๐ณ๐ฎ๐ฐ๐๐๐ฟ๐ฒ๐ฟ
๐ฉ01. ๐๐๐ฌ ๐๐๐ฉ๐๐ง๐๐๐ก ๐๐ช๐๐ก๐๐ฉ๐ฎ ๐พ๐ค๐ฃ๐ฉ๐ง๐ค๐ก
Strict Inspection of Incoming Raw Materials: The raw materials for rigid polyurethane foamโsuch as isocyanates, polyether polyols, blowing agents, catalysts, and flame retardantsโmust comply with relevant national or industry standards and specific design requirements.
For example, key indicators like the functionality and hydroxyl value of polyether polyols and the purity of isocyanates should be tested. Only when the performance of these base materials meets the required standards can the quality of the produced rigid polyurethane foam be ensured.
Control of Raw Material Storage Conditions: Raw materials must be properly stored according to their properties to maintain quality. Isocyanates, for instance, should be kept in a cool, dry, and well-ventilated warehouse, away from fire sources and strong oxidants, and protected from direct sunlight. Their containers should remain sealed to prevent moisture absorption and degradation. Polyether polyols should also be kept dry and clean, stored in a ventilated area at temperatures between 5โ35ยฐC. If the temperature is too high, viscosity decreases and layering may occur, affecting performance.
๐ฉ02. ๐พ๐ค๐ฃ๐จ๐ฉ๐ง๐ช๐๐ฉ๐๐ค๐ฃ ๐๐ง๐ค๐๐๐จ๐จ ๐พ๐ค๐ฃ๐ฉ๐ง๐ค๐ก
Proper Substrate Preparation: Before construction, thoroughly clean the substrate surface. Remove oil stains, dust, and debris to ensure the base is flat, dry, and free of hollows or cracks. For example, uneven areas in concrete or masonry substrates should be leveled with cement mortar. Steel structures must be derusted to the specified level before applying rigid polyurethane foam to ensure good adhesion.
Control of Foam Thickness Uniformity: When spraying or pouring rigid polyurethane foam, control the thickness of each application to be even and consistent. For instance, when using high-pressure airless spray equipment for external wall insulation, adjust the parameters based on design thickness and maintain a consistent spray speed. Each layer should generally not exceed 15 mm to avoid uneven insulation performance and potential cracking.
Environmental Condition Monitoring: Environmental temperature and humidity significantly impact the quality of rigid polyurethane foam during construction. Ideal conditions include a temperature range of 15โ35ยฐC, relative humidity below 80%, and wind speeds less than level 5. Low temperatures slow the foaming reaction, while high humidity causes water to participate in the reaction, creating bubbles and reducing foam strength. High winds can scatter spray material, affecting construction quality and efficiency.
๐ฉ03. ๐๐ช๐๐ก๐๐ฉ๐ฎ ๐๐ฃ๐จ๐ฅ๐๐๐ฉ๐๐ค๐ฃ ๐๐ฃ๐ ๐ผ๐๐๐๐ฅ๐ฉ๐๐ฃ๐๐
Appearance Quality Inspection: After construction, visually inspect the foam insulation layer. Its surface should be smooth, free of sagging, bulging, holes, or cracks. Tactile checks can detect surface smoothness or slurry accumulation. Use visual inspection or a magnifying glass to identify pinholes or bubbles; defects should be promptly repaired.
Dimensional Measurement and Performance Testing: Measure parameters like thickness, flatness, and verticality per relevant standards to ensure design compliance. Also, sample and test the foam's physical properties, such as thermal conductivity, compressive strength, dimensional stability, and water absorption.
For example, use the guarded hot plate or heat flow meter methods to ensure the thermal conductivity remains within design limits (typically less than 0.025 W/(mยทK)). To measure water absorption, immerse samples in water and compare weights before and after. Qualified foam typically has water absorption below 1%, which helps maintain insulation and wall durability.
System-Wide Performance Evaluation: For external wall insulation systems, test overall system performance, such as tensile bond strength and weather resistance. During weathering tests, subject specimens to cycles of high temperature, water spray, and freezing per standards, then check for chalking, peeling, delamination, or detachment. This ensures the system's long-term insulation and safety performance over the building's service life.
