There are four types of commonly use waterproof base oil: cellulose ether, polyacrylate, association type thickener and inorganic thickener. The most commonly use cellulose ether thickener is hydroxyZ-base cellulose (HEC). There are different specifications, depending on the viscosity. HEC is a powder water-soluble product, is a non-ionic thickening agent. Its thickening effect, water resistance, alkaline resistance is good, the disadvantage is easier to grow mildew corruption, poor smoothness. CMC
Polyacrylate thickener is a carboxylic group containing a higher acrylate copolymer emulsion. The biggest characteristic is a good resistance to mold invasion. When pH is 8 ~ 10, the water phase viscosity increases. But when pH is greater than 10, it solves in water and loses the thickening effect. Therefore, there is a large sensitivity to the pH values, such as the ASE-60 produced by Luo i] Haas Company. At present, the pH value regulator most commonly used in domestic latex paint is ammonia water.
Therefore, when this thickener is use, the pH value will be reduce, and its thickening effect will also be reduce. Associate thickener have different thickening mechanisms for other types of thickener. Most of which bring viscosity through hydration and weak gel structures formed in the system. However, the association thickener is like a surfactant, which has both the hydrophilic part and the oily part. The water part can be hydrate to thicken the water phase, the oily end base and emulsion particle pigment W You jiao moss 0 Zuxiang Mao ridge inorganic thickener is represente by bentonite. Usually water bentonite water absorption expansion of tactile gel minerals, water absorption volume is several times of the original volume. It not only plays a thickening role, but also can prevent sink, prevent flow hanging, prevent floating color hair flower, its thickening effect is better than the same use. CMC
The alkali swelling acrylic acid and polyurethane thickener. In addition, it has wide pH adaptability, good freeze-thaw stability and biostability. Because it contains no water-soluble surfactant, the fine particles in the dry membrane have the characteristics to prevent water migration and diffusion, and can enhance the water resistance of the coating membrane. Organic thickeners are water soluble or water swelling, remaining in the coating after film formation, bringing adverse effects on the water resistance of the coating. Therefore, considering the particularity of waterproof coating function, under the premise of organic thickening agent should be used as little as possible to ensure the thickening effect of coating, and use more bentonite effect with better water resistance series inorganic thickener.