The reason why the powder cures badly

In powder coating, there are two main reasons for the bad curing of coating coating, one is that the formula design of powder coating is unreasonable, the performance of coating coating can not meet the requirements, and the other is that the performance of powder coating itself is not a problem, but in the coating process, the coating process control is unreasonable, resulting in the coating film performance failed to meet technical indicators.
I. From the powder coating formulation design considerations
if the resin and curing agent in the formulation design is not reasonable, such as resin reaction activity selection or curing agent variety and dosage selection is unreasonable, filler mass content or volume concentration is too large these problems will affect the physical and technical properties of the coating, resulting in the powder coating in the coating curing is not good.
2. Consider from the powder coating process
powder coating process affects the coating material curing is not good for the following reasons:
oven baking temperature did not meet the powder coating requirements of the baking temperature
Under load, due to the lack of total heat supply, sometimes may not be able to reach the design temperature or powder coating required baking temperature, especially in the northern region of the winter workshop temperature is low, if the oven insulation conditions are poor, the coating into the oven before the temperature is low, the coated material wall thick and large thermal capacity, it is more likely to have this problem
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when the oven temperature can not reach the powder coating baking curing temperature, you can increase the heating power to solve the temperature compliance problem, in addition, you can also extend the baking curing time to achieve the curing purpose!
In the oven, the baking curing time does not meet the baking time required by the powder coating
in the baking conditions of the powder coating, the baking time refers to the baking time calculated after the coating reaches the baking temperature, not the time that the coating begins after it is placed in the oven.
the thicker the coated material and the more pieces are hung, the greater the thermal capacity of the coated material, and the longer it takes for the coating to heat up to control the temperature. In a baking oven of a certain length, the shorter the effective baking time is when the speed of the conveyor chain does not change. If the effective baking time is not enough, the coating film curing is not complete, the physical and physical properties of the coating film can not meet the requirements.
Therefore, in powder coating, it is best to use the furnace temperature tracking meter to determine the temperature change in the oven under full load conditions, to determine a reasonable baking curing temperature and time, in order to ensure the complete curing of the coating film, but also to ensure the physical and physical properties of the coating film.
The surface of the coating is not treated well
if the surface of the coating oil is not cleaned, oxidizing skin or rust is not removed clean, or the quality of the phosphate film is not good, in the surface defilement of many phosphate residue, etc. , the adhesion of the coating film and substrate after the powder coating will be affected, but also lead to the coating film impact resistance is not good, this situation, it must be improved by the surface treatment quality of the coating.
In terms of coating performance inspection, should be strictly in accordance with the product standards prescribed test temperature and film thickness condition
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From the point of view of ensuring product quality, try to test the coating performance index under more demanding conditions, in order to ensure the quality of coating products without loss.
In addition, we should also take into account the baking curing temperature is too high, baking time is too long, due to the hot aging of the coating film so that the color of the coating film changes, while the flexibility of the coating film, impact resistance and other physical and mechanical performance decline phenomenon. Therefore, the baking curing temperature is too high, too long is also detrimental to the physical and physical properties of the coating film.
in powder coating, the baking curing temperature and time of powder coating play a decisive role in coating curing performance. Therefore, it is necessary to go through many tests, reasonable classification of the sprayed objects to determine the number and arrangement of pendants, as well as the corresponding baking temperature and time, in order to ensure the quality of coating products.