Influencing factors and selection of defoamers in coating formulations

Factor 1: Surface stress
The surface pressure of the coating has a greater impact on the desiccant, the surface pressure of the desiccant must be lower than the surface pressure of the coating, otherwise it will not be possible to deblister and inhibit the foaming effect. The surface strain of the coating is a variable factor, so the surface strain should be constant when using desmoist, and then the surface strain change factor is taken into account.
: Effects of other additives
Most of the surfactants used in coatings are incompatible with the tending function of desiccants
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. In particular, emulsifiers, moisturizing dispersants, leveling agents, thickeners, etc. will have an effect on the effect of deblisters. Therefore, in the various additives to cooperate must pay attention to the relationship between different additives, choose the best balance point.
Factor 3: Baking temperature
coating at room temperature into the high temperature baking, began to instantly viscosity back down, bubbles can be moved to the surface, however, due to solvent volatilization, coating curing, surface viscosity increase, will make the foam more stable, cut to the surface, resulting in shrink holes and pinholes, so baking temperature, fixed speed, solvent volatility rate on the effect of defrosting agent also has an impact.
factor four: the solid content of the coating, viscosity, elasticity
high solid thickness coating film, high viscosity, high elasticity coating are very difficult to defrost, in these coatings defrosting agent diffusion difficulties, micro-foaming speed is slow, foam to the surface migration capacity decreased, foam viscosity elasticity and many other adverse defrosting factors. Foams in these coatings are quite difficult to remove and are best used with defrosting agents and defrosting agents.
factors five: coating methods and construction temperature
coating construction methods are many, brushing, roller coating, spraying, scraping, spraying, screen printing and so on. Different coating methods are used to foam different coatings. Brush coating, roller coating foam more than spraying and scraping, high temperature than low temperature foam more, but high temperature foam to eliminate.
different applications of desiccant selection
there are many types of desiccants, characteristics are also different, so in different formulations of the choice of desiccants are also different.
ping coating
formula features: low viscosity, less deblistering pressure
recommended: mineral oil or mineral oil modified polyether
elastomer coating
formula characteristics: high viscosity, de-foaming pressure
formula recommendations: polyether modified silicone
-face coating and coating glue
formula recommended: Polyether class, can effectively prevent surface defects, and the gloss effect is small
water-packed water colorful
formula characteristics: more surfactants, stable foaming
formula recommendations: the use of polyether or mineral oil modified polyether
deflation agent use precautions
before use must be fully stirred, mixed evenly;
in the case of paint mixing to add;
, generally without water dilution;
dosing should be appropriate, excessive dosing, will cause shrink holes, shrink edges,
poor brushing and other issues; That is, in the grinding stage and painting phase to join, generally for half of the total amount at a time, in the grinding phase with a good anti-foaming effect of debobbing agent, in the painting phase with a good foaming effect.