Universal sprayed polyurea, as a high-performance protective material, plays a key role in many fields. Its spraying process and technical points are directly related to the quality and performance of the coating.
First of all, preparation before construction is crucial. Surface treatment of the base layer is the basic link. The concrete base layer needs to be polished and smooth, and dust, oil and loose particles need to be removed to ensure that the surface is solid and dry. The steel base layer needs to be rust-free to reach the Sa2.5 level or above standard, so as to provide a good adhesion basis for polyurea and avoid coating peeling. At the same time, the material dosage should be accurately calculated according to environmental conditions to avoid waste or construction interruption.
Secondly, equipment debugging cannot be ignored. The spraying equipment needs to be accurately calibrated to ensure that the A and B components are accurately mixed according to the designed proportion. Pressure control is the key. Generally, the main agent pressure is maintained at 15-25MPa, the curing agent pressure is slightly lower than the main agent, and the deviation is controlled within 0.3-0.5MPa to ensure that the material is sprayed evenly and stably to prevent poor coating curing or uneven performance due to imbalance of proportions.
Furthermore, there are strict requirements for spraying operations. Keep the spray gun perpendicular to the surface being sprayed, and control the distance between them at 40-60cm to ensure uniform coating thickness. Use multiple spraying methods, with the first thin spraying for primer, the thickness is about 0.2-0.3mm, and the thickness is gradually increased in subsequent spraying. The total thickness depends on the project requirements. Generally, the waterproofing project is 1.5-2mm, and the industrial protection can reach 3-5mm. Keep the spraying speed stable, about 30-60cm/s. Too fast is prone to leakage and uneven thickness, too slow will affect efficiency and easy to sag.
Environmental factors control is also extremely critical. The temperature should be 5-35℃, and the humidity is less than 85%. If the temperature is too low, the polyurea will cure slowly and soften easily. If the temperature is too high, it may cause bubbles and cracks; if the humidity is too high, water vapor will easily mix into the coating and affect adhesion and performance. If the conditions cannot be met, a protective shed needs to be built and equipped with dehumidification, heating or cooling equipment.
Coating repair and maintenance are equally important. If pinholes, bubbles and other defects appear during construction, they should be polished and repaired in time. Small areas should be sprayed manually, and large areas need to be re-sprayed as a whole. After the coating is cured, it should be maintained for 7-14 days. During this period, avoid heavy objects and water immersion to ensure that the coating performance is fully developed and lay the foundation for long-term protection.
Quality inspection runs through the whole process. Before construction, the raw materials are sampled to ensure quality. During construction, the appearance, thickness and adhesion of the coating are checked at any time. After completion, pull-out tests, water resistance tests and other comprehensive tests are carried out according to standards to ensure that the quality of universal sprayed polyurea projects meets the standards and effectively exert its excellent protective performance.
