Types of defoaming agents Character Application Mineral oil Strong anti-bubble ability Low price Poor system compatibility Easy migration Primer Matte Organic silicon class Strong defoaming ability higher price Different product performance differences Large adjustment space Improper selection can cause film defects Influence gloss, flow equality Various coatings Non-silicone non-oil Good security Low probability of defects Does not affect the gloss But the amount is slightly larger Insufficient bubble breaking ability higher cost Various types of coatings, especially in high gloss finishes There are many defoamers on the market, and the choices are very cautious and can be noted in several ways: 1. Controlled compatibility, that is, to achieve the balance between defoaming and surface effects, both defoaming and prevention of defects such as shrinkage cavities and poor leveling. 2. Defoaming according to the construction conditions and methods, such as brushing, spraying and roller coating, face different degrees of foaming, and also means different defoaming agents. 3. The balance between foam suppression and foam breaking can be reasonably matched according to different processing and construction methods. 4. Long-term defoaming performance. Many defoamers will gradually reduce their defoaming performance during storage of the paint, and the antifoaming agent content in the paint should be higher when designing the formula. The amount of defoaming agent is 0.05% to 0.5% of the whole formulation, preferably about 0.1%. If the defoaming agent used exceeds 0.5% to have a good defoaming effect, the defoaming agent should be considered.Different resin systems are sensitive to defoamers. The type and amount of aqueous defoamer selected must be determined experimentally, depending on the system.

Defoamer is one of the most difficult additives in waterborne wood coatings to control the balance between defoaming and leveling.The paint liquid will generate bubbles during the application due to agitation .If the bubbles present in the paint are not removed in time, the film will dry and form an unacceptable flaw.The paint also produces air bubbles during production, pumping and filling. Defoaming is a non-negligible factor in the formulation design process. The defoaming mechanism of the defoaming agent is to penetrate the foam film produced by the system by wetting and continuously spread on the film, so that the surface tension of the foam film is unbalanced and broken bubble.Generally speaking, the defoaming agent is divided into two types, a suds suppressor and a defoaming agent. The function of the suds suppressor is to inhibit the foaming of the waterborne wood coating under the action of an external force, and the defoaming agent is mainly on the surface of the foamed film. Rapidly spread, destroy the elastic membrane of the bubble, and make it rupture, but often the effect of the two combinations is better, otherwise at least one effective defoamer should be selected.Most antifoaming agents, especially silicone defoamers, will cause shrinkage of the wet paint film when the dosage is too large. Therefore, the amount of defoaming agent can be basically eliminated by the principle of eliminating bubbles, so that the defoaming effect cannot be excessively pursued. Side effects such as shrinkage holes. For waterborne wood lacquers, mineral oil defoamers are more tolerant than silicone defoamers, and adding a little more is not prone to severe shrinkage, which can be preferred. Sinograce Chemical produces water based additives, such as thickener, crosslinking agent, wetting agent.

The film-forming aids for waterborne wood coatings are generally alcohol ether type solvents. The most commonly used filming aids such as diethanol ethers, propylene glycol ethers and N-methylpyrrolidone have high and low boiling points.Water-based wood coatings in the summer construction, the water volatilization is faster, that is, the surface is relatively fast, some of the moisture may be enclosed in the coating film before drying, resulting in white coating or poor leveling.Therefore, it is possible to delay the drying speed of the coating film by adding a small amount of a suitable and suitable high boiling point solvent, to extend the opening time of the coating film, and to improve the workability and the appearance of the coating film. In winter, due to the lower temperature, the drying speed of waterborne wood coatings is slower, that is, the evaporation of water is slower, but the filming aids are relatively faster than water, and some may evaporate with water, so that waterborne wood coatings cannot The formation of a dense coating results in blushing and cracking of the coating of the aqueous wood coating.Therefore, when adding a film-forming auxiliary, it is necessary to consider overcoming the workability of the water-based wood coating in different seasons, and also considering the drying speed as much as possible. This is also the most difficult technical point of the water-based wood coating, especially the high Tg. Acrylic dispersion is more difficult to solve.Therefore, a variety of filming aids to match is the best choice. The film-forming auxiliaries have a problem of compatibility with the visit us sinograce chemical: https://www.sinogracechem.com Get a Quote Now :sales@sinogracechem.com Telephone               :+86 0551 63459511

Formulation design system for waterborne coatings - film forming AIDS The polymer constituting the emulsion or dispersion generally has a glass transition temperature higher than room temperature. In order for the emulsion particles to be well fused into a uniform paint film, it is necessary to reduce the minimum film formation temperature (MFFT) of the crystallization aid.Film forming agents are a kind of small molecular organic compounds, the film forming agents in the paint film will eventually gradually escape and volatilize most of the film forming agents is an important part of coating VOC, so the less film forming agents should be used, the better.The use of film-forming auxiliaries should give priority to compounds that are not within the VOC limits, but which are not too slow in volatility and have high film forming efficiencies.The amount of coalescent aid depends on the amount of emulsion or aqueous dispersion in the formulation and the glass transition temperature.The amount of the emulsion or water dispersion is large and the Tg of the polymer is high, and the amount of the film-forming auxiliary agent is also large. On the contrary, when the dosage is small, the formulation aid is first considered to account for about the emulsion or the aqueous dispersion. %-5%, or 5% to 15% of the emulsion or dispersion solids.However, for polymer emulsions with Tg over 35  C, it may be necessary to increase the amount of coalescent to ensure the reliability of low-temperature film formation. At this time, the amount of film-forming auxiliary should be gradually increased until low temperature (about 10   C or lower). The coating can form a uniform paint film without cracking or powdering, and find the minimum amount of filming aid.It is not advisable to use a filming aid in an amount of 15% or more of the emulsion or dispersion. It should be considered to replace other filming aids and try again.In addition to lowering the minimum film forming temperature and increasing the density of the film, the filming aid can improve the workability, increase the leveling of the paint, prolong the opening time, and improve the storage stability of the paint, especially the low temperature freeze resistance. Sinograce Chemical produces water based coating,Water-based glue, polyurethane coating visit us sinograce chemical: https://www.sinogracechem.com Get a Quote Now :sales@sinogracechem.com Telephone               :+86 0551 63459511