2021-09-28 Pageview:368
Principle of action:
silok7111w aqueous wetting and dispersing agent, Block copolymers containing pigment affinity groups
These additives deflocculate the pigments through steric hindrance. Because the deflocculated pigment particles are very small, high gloss, bright color and leveling are obtained, and the pigment content is also increased.
In the coating industry, the foam problem of water-based latex paint is the most prominent and the most typical, which is caused by its special formula and special production process.
① Latex paint uses water as a diluent, and a certain amount of emulsifier must be used in emulsion polymerization to prepare a stable aqueous dispersion. Due to the use of emulsifiers, the surface tension of the latex system is greatly reduced, which is the main cause of foam in the latex paint.
②The wetting agent and dispersant used in the production of latex paint to prepare the pigment paste wax emulsion for fruits and vegetables are also surface-active substances, which can also reduce the surface tension of the system. The foam in this process is the most serious. If you do not use a suitable defoamer , A large amount of foam will make the shearing force unable to be transmitted to the material, the motor idling, and the equipment utilization rate is seriously insufficient, resulting in insufficient pigment dispersion, and even unable to continue production.
③The latex paint has low viscosity and is not easy to apply, so it is necessary to use a tungsten enhancer. However, the use of thickeners will thicken the film wall of the foam and increase its elasticity, making the foam stable and difficult to eliminate.
The extraction of free monomers during the production of emulsions, the stirring during the preparation of latex paint, the spraying, brushing, and roller coating during the construction process, all these processes will change the free energy of the system to varying degrees and promote the production of foam. There is a lot of foam when filling the can, and it needs to be filled many times to reach a fixed weight. Causes of foam in solvent-based coatings. Although it is also caused by various surface active substances-the use of additives and the low surface tension of the solvent itself, compared with water-based coatings, the foam conditions are different. Water-based coatings have many bubbles and are easy to rise to the surface of the system and burst. Solvent-based coatings are mostly single independent bubbles, especially small bubbles in high-viscosity solvent-based coatings, which are difficult to rise to the face of the system and burst. There are many bubbles in water-based coatings, and a defoamer with strong defoaming ability is required.
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