Dapeng Town Industrial Park, Tongshan District, Xuzhou City, Jiangsu Province, China
Colour steel tile refurbishment soon after the burst paint cracking is a relatively common problem, which is mainly caused by a combination of factors.
(1) rust cleaning is not complete
Colour steel tile will produce rust in the process of use, if the rust part is not completely removed before renovation, the residual rust will continue to spread under the coating. Rust is a kind of loose and porous material, it will absorb water, and with the passage of time, the volume of rust will expand, which will lead to the coating from the inside topped up, and eventually the phenomenon of burst paint.
For example, some renovation construction just simply sweeps and wipes the surface of colour steel tiles without using professional rust removal tools (such as sand blasting equipment, wire brush, etc.) to remove the rust layer completely, especially in some hidden parts or crevices where the rust is easy to be ignored.
(2) Improper treatment of old paint layer
If the adhesion between the old paint layer and the surface of the colour steel tile has been reduced and it is not removed effectively during renovation, the new paint layer coated on the unstable old paint layer will be prone to delamination. The performance of the old paint layer may have been degraded due to long-term exposure to the outdoors, UV irradiation, temperature changes and other factors, and a good bond cannot be formed between the old paint layer and the new paint layer.
(1)Poor weather resistance
The colour steel tile is exposed in the outdoor environment for a long time, need to bear the sun and rain, temperature change, wind and sand erosion and many other bad conditions. If the refurbishment of the use of paint weather resistance is not good, it is easy to appear aging, fading, cracking and other problems. For example, some poor-quality paints will undergo photochemical reaction after a short period of ultraviolet irradiation, which will destroy the molecular structure of the paint, thus leading to brittle paint layer and cracking.
(2) Poor adhesion
The adhesion between the paint and the surface of the colour steel tile is the key to ensure the quality of the paint layer. If the adhesion of the paint itself is not strong enough, the paint layer is easy to peel off from the surface of the colour steel tile when affected by external factors (such as wind blowing, vibration, etc.). This may be caused by unreasonable paint formula or not adding enough adhesion promoter.
(1)Unsuitable environmental conditions
Construction of the environmental temperature, humidity on the quality of the paint layer has a great impact. If the temperature is too low or too high in the case of construction, the drying speed and curing effect of the paint will be affected. For example, when the temperature is too low, the paint dries slowly and the phenomenon of sagging may occur; while when the temperature is too high, the paint may dry quickly and form a hard shell on the surface, but the solvent inside cannot be completely evaporated, and subsequent cracking may easily occur. At the same time, too much humidity will also cause the paint layer to absorb too much water in the drying process, affecting its performance.
(2) Uneven coating thickness
During the construction process, if it is not operated in accordance with the correct construction process, resulting in uneven coating thickness, the drying contraction stress is higher in the over-thickness, which is prone to cracking. And the uneven coating may make the local protective performance decline and accelerate the damage of the paint layer. For example, in the spraying process, the distance between the spray gun and the surface of the colour steel tile, spraying speed and other factors are not properly controlled, which will cause the coating thickness to be inconsistent.
