Water-based paint, solvent-based paints, should be used in the formulation of various additives, which help disperse pigment wetting additives; improved storage stability of the finished paint additives, adjust smooth appearance of the coating additives; some achieve aid of special features. Most of these species belong to the aid of surfactants, can alter the surface tension of the coating, causing the coating itself there foaming or foam stable internal factors.

Paint manufacturing process requires the use of a variety of high-speed mixer, such as a three-roll mill, a sand mill and ball mill. Ways and means to be used when the paint coating, such as air spray, airless spray, roller coating, flow coating and curtain coating and the like. In these processes, will increase the degree of freedom of different coating systems can help produce foam, which is the external factors that bubble.

Defoamers classification, often have different ways on different reference. Generally points, can be divided into aqueous and solvent resistance; or silicon and non-silicon. More common on the market there are four main categories. 1, lower alcohols and esters include isopropanol, butanol, tributyl phosphate, etc. Due to certain toxic and VOC, and anti-foaming effect is not obvious, suds is bad, and therefore has been phased out. 2, a polar organic compound mainly refers to some low HLB value surfactants, such as polyether-based surfactants, polyethylene glycol fatty acid ester HLB because the relationship between them, and the market is also rare. 3, in addition to mineral oil mineral oil having a defoaming effect complexes, also contains hydrophobic particles, such as stearic acid metal soaps, polyurea. Also has some efficacy. 4, silicone-based mainly hydrophobic silicone oil as an active ingredient, together with a number of other carriers surfactants used in conjunction with, the better, but the amount of required discretion. General market with three, four types of more common, with work to do to ensure the integration of the problem and the whole system of defoamers, defoaming of foam suppression and long-term nature can be. As for the specific type of Chinese market a wide variety of defoamers are numerous, only through their own laboratory experiments to see whether specific fit.

Waterborne Coatings defoamers Profile
Water-based paint has been very let bubble production and user headaches here to talk about the bubble generation and stable, simply say that the lower the surface tension, the system free energy of formation of foam required for the smaller, more prone to bubbles. But such is not necessarily very stable foam, only if the system capable of forming an elastic film contains surface-active substances, such as: dispersants, thickeners, leveling agents, to stabilize the foam.

Understand the basic principles of stable foam, to defoaming easy to handle, first thing to note there is no foam stabilization components inside the system, and then select the appropriate defoamers, silicone-free defoamer general effect will be better, but Note that affects other properties. Also note that different systems use different types of anti-foaming agent, various systems such as an acrylic emulsion, a polyurethane dispersion, a water-soluble resin or the like is not applicable to the same type of anti-foaming agent, specifically to be verified by experiment. There are many defoamers have a strong foam breaking ability, but poor ability suds, bubble effect generated in the process is not, then we should consider a mixture of two or more anti-foaming agent, and we should look at Two added effect when added suds lapped defoamers, foam breaking effect of a good anti-foaming agent was added when a paint. Of course, anti-foaming and viscosity is also related to the viscosity of small anti-foaming natural fast. In addition, the volatile anti-foaming and systems are concerned, the volatile liquid paint quickly, the surface will be dry, float to the surface when the bubble burst too late, it was fixed, will be piled up.

Defoamers choice
Defoamers species are more substantially organic category, silica, silicones, etc., is divided into emulsified and non-emulsified. Everyone in the choice of water-based coatings defoamers time to note that (1) anti-foaming ability; good (2) stability; (3) does not affect the gloss; (4) no recoating and other barriers is recommended that you use Mixing speed test defoamers defoaming ability. Fixed speed, mixing time, the amount, viscosity and other parameters, and then comparing the foam height and the elimination of time.
The amount of defoamer: general high viscosity latex paint, because the anti-foaming difficulties, too much foam stabilizing factor, increase the amount slightly more, usually 0.3 to 1.0%. Low viscosity latex or water-soluble paint, particularly water-soluble paint, since a certain amount of co-solvent, the amount can be appropriately reduced, typically to 0.01 to 0.2%. Other water-borne coatings or resins, generally about 0.1%. Anyway, not increase the amount as high as possible, more will cause shrinkage, oil slick paint and other diseases, silicon defoamers more, will also affect the recoatability.
Incorporation
Most anti-foaming agent can be added directly to the diluted water-based paint to go, are generally required to join at a higher viscosity of the resin or paint, and a good dispersion. Also added is preferably twice, once in the grind, and again when the paint was added to each stage and half each.