Defoaming solutions for waterborne coatings

Waterborne coatings use water as a solvent or as a dispersion medium.It includes water-soluble coatings, water-dilutable coatings, and water-dispersible coatings (latex coatings).

Water-soluble coatings:water-soluble resins as film-forming materials, for example,polyvinyl alcohol and its various modifications,  water-soluble alkyd resins, water-soluble epoxy resins, and inorganic polymer water-based resins.

Water-dilutable coatings:prepared from post-emulsified emulsions as film-forming materials.The solvent-based resins are dissolved in organic solvents, and then, with the help of emulsifiers, the resins are dispersed in water by strong mechanical stirring to form emulsions.

Water-dispersed coatings:formulated with synthetic resin emulsions as film-forming materials.

Waterborne ink is mainly made of water-soluble resin, organic pigment, solvent and related additives through compound grinding.

The waterborne coatings includes waterborne industrial paint,waterborne automotive paint,waterborne wood paint,waterborne plastic paint,waterborne anti-corrosion paint,waterborne putty,waterborne printing ink,waterborne adhesive.

Waterborne paints composition:

1.Acrylic acid is the main component,which has good adhesion,but poor wear resistance and durability.It is the primary product of water-based wood paint.

2.The composition of acrylic acid and polyurethane is the main component.Compared with the previous product,the wear resistance and chemical resistance are much better,the hardness of the paint film is good,and its comprehensive performance is close to that of paint.

3.Polyurethane waterborne wood paint,its performance is very good in all aspects, and its wear resistance even exceeds that of paint.

4.Waterborne ink is a uniform paste-like substance composed of binders,pigments,additives and other substances.

The waterborne coatings has many advanges.For example:it uses water as the solvent, which is safe in construction,reduces pollution, is low odor and improves the working environment.etc.

Reasons for foaming of waterborne coatings:

Waterborne coatings use water as the solvent,and the surface tension of water is as high as 72.5mN/m (millinewtons per meter), while the surface tension of general organic solvents is 20-40mN/m.In addition to water-soluble coatings,waterborne coatings are mostly heterogeneous systems.The high surface tension brought by water is not conducive to the defoaming of water-based paints,and reduces the wettability, permeability and spreadability on the substrates of waterborne paints.

Waterborne coatings foaming hazards:

The construction performance is poor,the paint film is prone to defects such as bubbles, prickly heat, shrinkage, fish eyes, pinholes, etc. and it may also reduce the adhesion of the paint film to the substrate due to poor wetting and permeability. From the perspective of paint production and construction, compared with solvent-based paints, waterborne paints have more serious technical problems such as defoaming and antifoaming, flow and leveling, mildew resistance, and thickening that affect the quality of paints.

Addition method and common problems of waterborne coatings Defoamer:

Add method:Directly added in the middle of the process or directly added in the last process.

Common problem:poor compatibility,precipitation,defoaming but less transparency,poor durability,affecting the adhesion of the product,high cost

https://www.nvchemical.com/product/Defoamers-For-Waterborne-Coatings-and-Inks-Systems.html