The paint is not dry or poorly dried
Related statements:
False dry, insufficient baking, too slow drying, low hardness
Related instructions:
The paint film is dry (after drying or baking) and can not be completely dried within the specified time. The hand touch paint film has a moist and moist feeling. The overall hardness of the paint film is low, failing to reach the specified hardness or not drying in the surface. The phenomenon. In severe cases, it is sticky back after being exposed to sunlight for a long time.
Related reasons:
1. The temperature from drying or drying does not meet the requirements. In general, the drying speed of the two-component coating will be greatly reduced below 10 degrees Celsius, and the drying process of the coating will be extremely slow or even stopped. For every 10 degrees decrease in temperature, the time for chemical crosslinking doubles.
2. After the temperature rises in the barn, the set temperature is reached, but there is no heat for a while and the heating is stopped.
3. One continuous spraying is too thick, resulting in abnormal accumulation of solvent in the coating film. Especially in the continuous spraying using ordinary paint, it can be sprayed 2 to 3 times according to the regulations, but in order to pursue a better appearance or leave a margin for polishing, spray 4 or 5 lanes, so that the paint film is thick, However, the drying performance of the coating is greatly reduced, and it is difficult to achieve the drying requirement within a prescribed time.
4. Curing agent and thinner are not used together. In the use of curing agents and thinners and other accessories must adhere to the principle of matching, can not easily use different brands of accessories to replace each other. It is the same brand of products, but also in accordance with the manufacturer's regulations.
5. Poor ventilation or excessive humidity in the dry place, so that the solvent contained in the paint can not be normally volatilized, and the drying speed of the paint is greatly reduced.
6. The bottom of the painted surface is poorly cleaned, leaving wax, oil, water and other substances that affect the drying. In the small area repair, there are many drying problems that are caused by this.
7. Excessive high boiling point solvent is added to the coating. In order to improve the phenomenon of "whitening" during leveling or rainy days, an excessive amount of high-boiling solvent such as "cyclohexanone" is added. Such a solvent evaporates very slowly and remains in the coating film for a long time, which affects drying.
8. The amount of curing agent is insufficient or excessive. The curing agent is not optional in the two-component coating. It is cross-linked with the resin in the coating in a certain ratio to form a paint film. Insufficient or superfluous curing agents can cause poor drying. Be sure to add as required by the paint regulations.
9. The diluent contains excess water, alcohol, and acid. This situation is more common in the case of using cheap substitute thinner. In particular, it is used in place of 2K thinner instead of various nitro thinners. Such a thinner not only contains a lot of impurities such as water and alcohol, but may also contain a substance that reacts with the curing agent, causing abnormal drying of the coating.
10. Improper polishing. Especially before the coating is not completely dried, that is, before the solvent in the coating is completely evaporated, the polishing is started. In addition to the loss of the surface of the paint film, the coating is dried abnormally due to solvent erosion in the wax liquid.
11. Some coatings caused by incorrect spraying processes cannot be completely dry or dried. For example, in the two-pass painting of plain paint, if a 2K plain paint is used, but no curing agent is added, and then the varnish is sprayed on it, the result of such an operation is that the paint film does not dry.
12. Errors occurred during the coloring process. The typical phenomenon is that the paint film is soft due to insufficient resin, which is caused by insufficient replenishment of the resin during the fine adjustment process or incorrect calculation of the resin amount when the formula is added. This situation is rare, except that the paint film is soft, usually accompanied by low gloss, easy to scratch off, and the particles are easy to powder. If the resin is used incorrectly in the coloring, for example, if 2K resin is used in the two-pass plain paint, the phenomenon of not drying for a long time may occur.
Precaution
The above-mentioned causes of abnormal drying of the paint film are human factors, and can be effectively avoided as long as they are constructed in accordance with the correct operating procedures. Some are conditional constraints that need to be addressed to improve working conditions. However, the following basic operational requirements must be observed:
1. Paints and accessories must be used together.
2. Use different drying speed accessories according to the season.
3. When using the paint, it is required to use a standard container and add it according to the scale.
4. Keep the ventilation circulation of the paint booth or painting place good.
5. Do not use cheap inferior thinner.
6. The mixing work of the coating after adding the curing agent and the diluent cannot be ignored.
7. Master the correct coating performance requirements, do not barely make thick coating.
8. Polish after the specified polishing time.
9. Conditional repair shop, you can use the infrared drying mode, using the principle of infrared drying from the inside to the outside to heat up, completely solve the drying problem of the paint.
Solution
1. Severely dry, or appear to be sticky, or forget to add curing agent, or the wrong addition of resin, remove the topcoat to the bottom, and re-do the bottom and spray. When removing the topcoat from such problems, it can be rubbed off with a thinner problem topcoat, then cleaned with a degreaser and repainted.
2. In a very serious situation, when the paint is only dry slowly, it can continue to heat in the baking room for 60 minutes and 45 minutes to continue drying.
3. In most cases, the bottom surface of the problem can be closed with a barrier primer and then repainted.
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