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Commonly used anti-shrinkage cavity leveling agent

Solvent levellers are mainly high boiling solvent mixtures. Solvent-based coating only by increasing the solvent to reduce the viscosity to improve the leveling, will make the coating solid drop and lead to flow hanging and other ills; Or maintain the solvent content, adding only high boiling point solvent to adjust the volatilization rate to improve leveling, drying time is also prolonged. Therefore, neither plan is ideal. Only THE ADDITION OF a high boiling point solvent MIXTURE is ideal for displaying various increasing characteristics (volatile index, distillation curve, solubility). The main components of solvent levelling agent are various mixed solvents with high boiling point, which has good solubility and is also a good wetting agent for pigments. Ambient curing paint due to solvent volatilization too fast, paint viscosity increases too fast to prevent the flow caused by brush marks, solvent volatilization leads to poor solubility of the base material caused by shrinkage holes, or in baking paint to produce boiling marks, bubbles and other ills using this kind of additives is very effective. In addition, using high boiling point leveling agent to adjust the evaporation speed can also overcome the disadvantage of whitening.

Compatibility is limited by the long chain resin commonly used polyacrylic acid, cellulose vinegar, etc. Their surface tension is low, can reduce the surface tension between the coating and the substrate and improve the wettability of the coating on the substrate, eliminate the solid surface of the adsorbed gas molecules, prevent the adsorbed gas molecules from being excluded too late and the formation of concave holes, shrinkage holes, orange peel and other defects in the curing film surface; In addition, they are not completely mixed with resin, and can quickly migrate to the surface to form a monolayer to ensure the surface tension uniformity on the surface, increase the anti-shrinkage effect, so as to improve the smoothness of the coating surface. Polyacrylate leveling agent can be divided into pure polyacrylate, modified polyacrylate (or combined with silicone), acrylic acid alkali capacity resin, pure polyacrylate flow

Flat agent and common epoxy resin, polyester resin or polyurethane coating resin compatibility is very poor, when applied to form a mist film. In order to improve its compatibility, the copolymer with better miscibility is usually used.

The compatibility is limited by the long chain silicone resin commonly used are polydimethylsiloxane, polymethylphenyl siloxane, organic modified polysiloxane, etc. This kind of material can improve the wettability of the substrate and control the surface flow, play a role in improving the leveling effect, when the solvent volatilizes, the silicone resin on the coating surface to form a monolayer, improve the gloss of the coating. Can be divided into the polyether modified polysiloxane modified organic silicone, silicone modified polyester reactive silicone, the introduction of organic groups is helpful to improve the compatibility of polysiloxane and coating resin, even if the concentration increase also won't produce side effects and incompatibility, modified polysiloxane can reduce the interfacial tension of coating and base material, improve the wettability of base material, improve adhesion, prevent hair flower, Orange peel, reduce shrinkage hole, needle eye and other coating surface sickness.

Fluorinated surfactants, whose main components are polyfluorinated olefins, also have good compatibility and surface activity for many resins and solvents, which helps to improve WEttability, dispersity and leveling, and can also adjust the solvent volatilization speed in solvent based paints.

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