Bubbles are caused by the following reasons – if the cause is not clear, there will be wars:
② There are components in the coating that produce bubbles by chemical reaction, such as olivine powder and bauxite containing CaO
③ The coating slurry is easy to ferment and produce bubbles, which are due to the fact that the additives have no antiseptic ability, and the additives themselves produce bacteria in the water and ferment
④ Improper mixing operation leads to the gas in the gap of additive powder can not be discharged and overflow, resulting in bubbles
Solution – to understand the source of bubbles, the direction of elimination is simple:
① The aggregates containing more harmful substances such as Cao should be used with caution — first mix with water and then add additives
② All kinds of “composite additives” without anti-corrosion ability should be used with caution or not. Guilin No.5 yiyitong additive does not contain any chemical preservatives, but the prepared coating slurry will not ferment even if it is kept for a long time in hot Xia days. This is another major invention of the international difficult problem that Professor Liu Yuman conquered in 2013.
③ “Thick” agitation is extremely efficient in eliminating air bubbles. Thick mixing is similar to rolling, in essence, it is to increase the friction and extrusion between the infiltrated powder particles (agglomerates), so as to strengthen the moisture of water to the powder. When the powder is 100% infiltrated, there is no gas hiding place. When the mixture is completely uniform, add water to adjust the required concentration, it is not easy for bubbles to remain in the slurry. If “dilute” stirring, once the additive and water form colloid first, the gas in the “powder” cannot be discharged.
The pulp is colloidal. A big mung bean bubble is surrounded by a colloid with a large adhesion. How does the defoamer break through the colloid and take out the small bubbles? It’s not easy. The coating pulp is non-Newtonian fluid. Don’t do this kind of idle work, and the defoamer is smelly. The so-called defoamer introduced in many articles is nothing more than n-butanol, n-pentanol and other things. Adding it into the paint slurry can not defoamer, but seriously deteriorate the paint performance, and there is a highly irritating odor, so-called defoamer use should not go wrong.