Лако-красочные материалы — производство

As discussed before, low viscosity of the film is an important factor for better flow and leveling. With progressive evaporation of the sol­vents, the viscosity of the coating film increases rapidly. Therefore, slowly evaporating, active solvents are good leveling agents that allow sufficient time for the liquid film to level out any unevenness. Among the […]

The term flow and leveling in coatings is associated with smoothe — ning of a coating film after application and during curing that leads to evenness of the coating surface. Though flow and leveling has no influence on a coating’s performance properties, it plays a vital role in aesthetics. The term leveling can be defined […]

Hydrophobically modified ethoxylated urethane thickeners, also known as polyurethane thickeners, are a more recent type of asso­ciative thickeners that are more popular for premium quality paints with low pigment volume concentration, which require excellent flow and leveling, and better spatter resistance and coverage. Alkyd-like rheology, hydrophobic properties, and enzyme resistance are some of the other […]

Associative acrylic thickeners are also known as hydrophobically modified alkali-swellable emulsions (HASE). Chemically, they are copolymers composed of three blocks: • Hydrophilic monomers such as acrylic acid, methacrylic acid or maleic anhydride • Hydrophobic monomers such as butyl acrylates or methyl metha­crylates • Associative monomers with long alkyl chains such as alkyl vinyl ethers. Like […]

Associative cellulose ethers are primarily used in the paint industry to increase spatter resistance and coverage of paint. They are generally derived from hydroxyethyl cellulose and ethylhydroxyethyl cellulose by modifying them with hydrophobic groups (alkyls or alkyl aryls). The concentration of hydrophobic groups is normally kept low (<2 %). The hydrophobic groups are able to […]

Cellulosic thickeners are among the most commonly used thi­ckeners for decorative latex-based paints. They are produced by chemical modifications of cellulose such as carboxymethylation or etherification. The most widely used derivatives are hydroxyethyl cellulose, ethylhydroxyethyl cellulose, methylhydroxyethyl cellulose, methylhydroxypropyl cellulose, and sodium carboxymethyl cellu­lose. The important characteristics that control the properties of dif­ferent grades of […]

Acrylic thickeners, also known as alkali-swellable emulsions, are used to a limited extent in cheap interior wall paints. They are acids containing acrylic copolymers supplied in liquid form as an emulsion. The main limitation of these thickeners is that the thickening action is a function of the pH of the paint system and therefore the […]

Due to environmental concerns, waterborne coatings are becoming increasingly popular. The binders used for aqueous coatings, such as latex, are stabilized polymer particles in water; therefore, their rheological properties are independent of MW and more complex than simple resin solutions. Thus it is much more necessary to use a proper rheology modifier in aqueous coatings […]

Alkyd resins chemically modified with polyamide resins are often used as thixotropic agents for air-drying non-drip paints and high — solid alkyd-based paints. Polyamide modified alkyds form a highly viscous mass that becomes reversibly free-flowing when shear force is applied. The mechanism for developing thixotropy is based on hydrogen bonding along the polymer structure.

This type of thickener is based on modified ureas dissolved in N-methylpyrrolidone, which are insoluble in common coating sol­vents. Upon careful incorporation into coating systems, the controlled precipitation of additive forms very fine, needle-like microcrystals. The crystals form a three-dimensional lattice structure via hydrogen bonding, which results in thixotropic behavior of the system.