How does the rainy season furniture paint prevent the paint film from whitening?

The main reasons for the whitening of the paint film:
1) substrate moisture content is high or the construction environment humidity is large, spray construction because
moisture can not be volatile from the paint film, and the water and paint film reclication rate is not the same, resulting in the phenomenon of whitening, the thicker the spray white more obvious.
2) Whiteen the paint film with a dilutor that evaporates too quickly.
3) Dark substrate uses a primer with excessive powder content, resulting in whitening of the paint film

.
4) the curing agent used does not match the paint, in some respects the performance does not meet the construction requirements of the standard.
problems with diluents:
1) Some products are cost-effective and add cheaper ingredients (e.g. solvent oil, dichloromethane), which contain hard-to-volatile residues that do not dissolve the resin. Spraying will slowly dissect out, resulting in whitening;
2) alcohol solvent dissolved in water, can even be added to 1:1, these are construction personnel can not measure out, the most direct consequence of excessive water content is to lead to paint film whitening
3) due to differences in different brands of product systems, the use of ammonia-type drying agent products on the solvent moisture requirements are very high, if the water content is large, it is easy to produce whitening phenomenon.
addition, the amount of trimer added in the fast-drying curing agent is also relatively large, and the solution and moisture content requirements of the trimer curing agent are very high. Therefore, if the thinner is not selected properly, it is also very easy to appear whitening phenomenon.
how to avoid the whitening of the paint film
Use method:
1) in accordance with product regulations
use of matching curing agents and thinners,
adjustment of suitable construction viscosity construction;
2) PU wood lacquer construction time (after painting): ≤ within 4 hours of construction (at a temperature of 25 degrees C, humidity ≤80% environment);
3)
in rainy days
humidity high environmental construction
,
strengthen the
dilution
solution (plus appropriate slow dry water).
substrate treatment:
1) on the wood water content of the high plate (greater than 12%), must first be dried in the use of the bottom to do closure;
2) in the high temperature and humidity of the construction environment, the plate paint before also need to be closed with the base treasure,
can not be closed with ordinary transparent primer (otherwise not closed effect)
.
construction conditions:
1) suitable construction environment:
temperature is not higher than 35 degrees C
(25 degrees C
best), humidity is not higher than 80%; High temperature and high humidity environment construction, easy to produce foaming, pinholes, whitening (white on the spot, or late whitening);
b. low temperature and high humidity environment construction, paint film dry slow, solvent volatile slow and incomplete, prone to late whitening phenomenon;
c. In order to avoid the above two environmental construction problems, must be thin spray, absolutely not thick coating, and to distinguish between winter and summer dilution agent.
3) Time interval between re-painting:
summer guaranteed more than 5 hours, winter guaranteed more than 10 hours;
4) before each painting, must be carefully polished to prevent poor adhesion;
5) before painting must wait for the primer to dry thoroughly, summer needs more than 24h, winter needs more than 48h (if the temperature is too low, you need to extend the drying time);
6) construction process, must maintain ventilation, so that the concentration of solvents in the air reduced, facilitate the drying of PU wood paint
;
Note:
Due to the differences in the construction environment and placement environment of PU paint, high moisture content of the plate in the high humidity environment coated furniture, placed in the low humidity environment, furniture is very easy to produce deformation or cracking, paint film is also very easy to whiten.