Slow flat means that after the paint is painted, the drying time of the paint film exceeds the specified standard. Sticking back refers to the fact that after the paint film dries for several days, it still sticks to the touch with fingers, or the paint film does not stick to the hand when it is operated for a long time, but it softens and becomes sticky after a long time. The two morbid states of slow drying and sticking back appear almost at the same time, and the reasons are:
(1) The paint quality is poor. The resin content in the paint formula is low, or the solvent with poor volatility or non-drying and semi-dry oil is used; the use of long-term stored paint or tung oil with too low refining temperature will also slow down the paint film. dry, sticky back;
(2) The paint is too thick, so that the oxidation is limited to the surface, the solvent at the bottom layer cannot be volatilized, and the paint film cannot be fully dried;
(3) Mixing different types of paint or using excessive drier will make the paint dry very slowly (causing the surface conjunctiva to be closed and the inner layer to dry slowly), and even stick back;
(4) The construction environment is bad. The paint film is attacked by cold, dew, smog, acid, alkali or lake gas; or the paint is removed in a humid and airless room; or in the rainy season or foggy day, there is a large amount of moisture accumulated on the surface; In addition, when painting slow-drying paints in cold seasons, not adding an appropriate amount of drier to the paint, or the surrounding lake air is too small when painting large-scale paints, etc., will easily cause slow-drying or back-sticking of the paint film ;
(5) Improper surface treatment. There are residual oil stains, acids, alkalis, salts, etc. on the surface of the object that have not been effectively removed, turpentine, wax, and asphalt have not been removed, and the top coat is applied before the primer is dry, which will cause slow drying or partial stickiness. Not even for a long time.
To prevent slow drying of the paint, it is necessary to address the above situation, ensure that the paint formula is correct, choose a good paint, and the thickness is appropriate; different types of paint should not be mixed; the surface needs to be pre-treated before painting to remove dirt and moisture; the topcoat cannot be painted when the primer is not dry; for the turpentine that is not easy to remove, it should be sealed with shellac paint two or three times, and then covered with paint; for long-term back-adhesive coatings, gasoline or alkaline water should be used to remove Wash off all the coatings, and then repaint; never cover the topcoat without treatment, so as not to cause unnecessary trouble.
