Defoamers are used to eliminate air bubbles in coatings, and sometimes it is advantageous to distinguish between “defoaming” and “defoaming”. First, the bubbles must reach the surface, a process called defoaming, and then the bubbles break up on the surface, called defoaming. The function of the defoamer is to increase the rate of rise of the bubbles. These additives cause adjacent bubbles to gather and merge with each other, and then the speed of movement to the surface is accelerated due to the increase in volume, and the defoamer must play this role effectively throughout the coating.
The important role of defoamer is to defoam, defoam and break the bubble, in order to achieve in the production and construction of defoaming or bubble but easy to defoam.
Defoamer effect test method.
(A) the same amount of the same resin in the test tube, add the same dose of different types of defoamer, oscillate the same time, observe the bubble rise, break the speed, record the time, while the shorter that the effect is better. (B) different doses of the same defoamer, can test the better dosage, but this method should be tested in the coating formula. In this way, different defoamers or different amounts of the same defoamer are added to the coating formulation system, and an effective defoamer is selected by observing the bubble elimination in the production and construction of the spray board and performance testing.
what is micronized wax? which is the additives that can improve the coating/paint performance.
The evaluation of defoamer cannot be based on the final judgment of the effect of the freshly formulated paint after construction. The paint should be done after rapid storage for 1 month (60 ℃ oven), and then take out the construction, still have the effect of defoaming and construction does not produce defects in the paint film, and just formulated the same effect, then to show that this defoamer effective, or natural storage for six months or a year to test the surface effect of defoaming and construction.
The stability of defoamer in the system is important. In solvent-based wood coatings may produce defects due to improper selection of defoamer, such as in glossy varnish due to poor compatibility of defoamer and lead to a decline in gloss, glossy varnish in the film fogging and thus affect the transparency, some produce shrinkage phenomenon.
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