The causes and preventive measures of paint drying or drying

China Paint Online News Information
Paint does not dry or dry badly
related statement:
false drying, insufficient baking, too slow drying, low hardness
relevant notes:
paint film drying (since drying or baking) failed to completely dry within the prescribed time, hand-touched paint film has a wet re-moisture feeling, paint film overall hardness is low, failed to achieve the required hardness or the presence of drying phenomenon. In severe cases, the phenomenon of back-sticking occurs after prolonged exposure to sunlight.
related reasons:
1. Self-drying or drying temperature does not meet the requirements. In general, the drying rate of two-part coatings below 10 degrees Celsius will be greatly reduced, and the drying process of coatings will be extremely slow or even stopped. For every 10 degree drop in temperature, the time of chemical crosslinking doubles.
2. The oven heats up and reaches the set temperature, but there is no insulation for a period of time to stop the heating.
3. A continuous spray is too thick, resulting in abnormal solvent accumulation in the coating film. Especially in the use of ordinary paint for continuous spraying, in accordance with the requirements can be sprayed 2 to 3, but in order to pursue a better appearance or for the polishing residual amount, spray 4 or 5, so that although the paint film thick, but the drying performance of the coating greatly reduced, it is difficult to achieve the drying requirements within the specified time.
4. Curing agents and thin materials are not used in a matching. In the use of curing agents and thinners and other accessories must adhere to the principle of matching, can not be casually used different brands of accessories to replace each other. Is the same brand of products, but also in accordance with the provisions of manufacturers to use.
5. Poor ventilation or high humidity in self-drying places, resulting in the paint contains solvents can not be normal volatile, the drying speed of the coating greatly reduced.
6. Poor cleaning of the applied bottom surface, leaving wax, oil, water and other substances affecting dryness. In small area repair, there are many drying problems caused by this.
7. Too many high boiling solvents are added to the coating. In order to improve the leveling or rainy days to prevent the occurrence of "whitening" phenomenon, the addition of excessive "cyclosterone" and other high boiling point solvents, such solvents evaporate very slowly, will remain in the coating film for a long time, affecting drying.
8. The amount of curing agent is insufficient or excessive. Curing agent in the two-part coating is not something that can be nothing, it is in accordance with a certain proportion of the resin in the coating cross-linking reaction, the formation of paint film. Insufficient or redundant curing agents can cause poor drying. Be sure to add in accordance with the requirements of the paint regulations.
9. Diluents contain excessive amounts of water, alcohols, and acids. This is often the case when using cheap substitute materials. Especially in the use of a variety of nitro thinners to replace 2K dilute materials. Such a thin material will not only contain more water, alcohol and other impurities, but also may contain substances that react with curing agents, resulting in drying abnormal coatings.
10. Improper polishing. Especially before the coating is not completely dry, that is, the solvent in the coating is not completely volatile clean before, began to polish, in addition to causing the surface of the paint film to lose light, but also because of the solvent erosion in the wax solution caused by the paint drying abnormalities.
11. Paints caused by some incorrect spraying processes cannot be completely dry or fake dry. For example, in the second practice of plain paint coating, if the use of 2K pigment paint primer, but no reinforcement agent, and then spray varnish on it, the result of this operation is that the paint film is not dry.
12. Mistakes in the coloring process. More typical is the phenomenon of soft paint film caused by insufficient resin, mostly due to insufficient resin supplementation in the fine-tuning process or miscalculation of resin amount when adding formula. This situation is rare, in addition to the performance of the paint film soft, usually accompanied by low gloss, easy to scratch off, fragments easy to powder. If the resin is used incorrectly in the ton, for example, the 2K resin is used in the second practice pigment paint, there will also be a long time dry phenomenon.
precautions
the above causes of paint film drying abnormality are human factors, as long as the correct operating procedures in accordance with the construction, can be effectively avoided. There are constraints that need to be addressed when working conditions are improved. However, the following basic operating requirements must be
: 1. Coatings and accessories must be used in a matching.
2. Depending on the season, different drying speeds are selected.
3. Coating ratio requires the use of standard containers, according to the scale added.
4. Keep the ventilation circulation in the paint room or paint place good.
5. Do not use cheap and inferior thinners.
6. The stirring work of coatings after adding curing agents and thinners cannot be ignored.
7. Master the correct paint performance requirements, do not reluctantly do thick coating.
8. Polishing after the specified polishing time.
. Conditional repair shop, can use infrared drying mode, the use of infrared drying from the outside heating principle, completely solve the drying problem of coatings.
solution
1. Severely dry, or the appearance of brushed hair sticky, or forget to add curing agent, or resin add the wrong situation, remove the paint to the bottom, re-do the bottom after spraying. When removing this type of problem paint, wipe it off with the thinning problem paint, then clean it with an oil remover and re-spray it.
not very serious case, that is, when the paint is only dry slowly, it can continue to heat up in the oven for 60 degrees 45 minutes to continue drying.
most cases, the underlying surface in question can be closed with an isolated primer and then repainted.
。