What are the classifications and applications of thickeners?

Adding a small amount of coating additives can make the coating have excellent mechanical properties and stable chemical properties, and become an indispensable component of the coating. Thickener is a coating aid. In water-based coatings, the viscosity is low, which is a very important additive. Because of the high water content and fluidity, it is necessary to add some thickeners to neutralize its viscosity. In addition, latex paints often encounter water diversion problems during production, transportation, storage and construction. Although increasing the viscosity and dispersity of latex paint can delay water diversion, the adjustment effect is often limited, and the choice and use of thickener solve this problem.

Thickener action one. Avoid sagging when drawing vertical surfaces. Coating thickener is a rheological additive, whose main function is to increase consistency, control the precision of fluid products, improve fluidity and leveling, and prevent sagging during construction. Especially, it can be coated on vertical wall or corner, with more uniform coating and fuller color, without affecting the next working procedure. Coatings without coating thickeners flow like water.

Thickener action ii. Stable paint storage. The chemical properties of coating thickener are stable, which can coexist well with various additives in the coating without thinning and delamination, and can also prevent the coating from precipitating. After adding thickener to the coating film, the viscosity increases, which can prevent the particles dispersed in the coating film from aggregating and precipitating during storage and make the storage more stable.

Thickener action three. Flow control of paint. Adding thickener in the process of roller coating and brush coating can prolong the film forming time, reduce dripping and splashing in the coating process, and realize the leveling effect of the coating film. According to their differences, coating thickeners can be divided into two categories.

Non-associative thickener can effectively improve the low shear viscosity of coating system and has high pseudoplasticity. Non-associative thickeners in coatings are the main components with high gel structure, including inorganic thickeners, cellulose ether thickeners and acrylic acid alkali swelling thickeners Adhesive thickener is a hydrophobic association type water-soluble polymer, which usually refers to water-soluble polymer with a small amount of hydrophobic groups in hydrophilic macromolecular chain, including hydrophobic modified alkali swelling thickener, nonionic polyurethane and hydrophobic modified cellulose.

A better thickener should meet the following requirements:

Improve the viscosity of the coating and inhibit the separation of the coating during storage.

Rapid spraying can reduce viscosity.

Increase viscosity after coating to prevent coating from sagging.

Store paint thickeners.

Coating thickeners should be stored at 5~40℃ in a dry and ventilated place. In case of accidental freezing, the product should be put into warm water, mixed thoroughly and thawed. In addition, thickeners should also be stored in original containers or other containers made of glass, stainless steel, plastic or epoxy resin, and should not be stored in containers made of low carbon steel, copper or aluminum.