Application of hydroxyethyl cellulose in water-bound sand coatings

Compared with real stone paint and texture coating, colorful coating wins more and more users with its advantages of high simulation, light quality, fast construction speed and low cost. However, the colorful coating is a flat effect, without the texture of real stone paint, to make the colorful coating with a texture effect, the common method is to use real stone paint to do the modeling layer, and then spray the colorful coating on it, which not only increases a process but also increases the cost of materials. For this reason, the water-in-sand colorful coating came into being, which has both the simulation of colorful coating and the texture effect of real stone paint through one spraying.

As the dispersed phase of water-in-sand colorful paint contains sand with high density, the stability is poor. Due to the large particle size of the sand, the flexible continuous film formed by the gelation of protective glue on the surface of the color dots is defective, resulting in the easy crushing of the color dots, and the precipitation of the color paste in the color dots, which causes serious color bleeding and affects the color phase; moreover, the color dots in the finished product are easy to sink to the bottom, and can not be dispersed when they are sticking together, so the phenomenon of not being able to construct can not be found. Moreover, due to the addition of sand, the water whiteness of the water-in-sand colorful coatings also deteriorates. Due to the above-mentioned disadvantages, the use of water clad sand colorful coatings in the external walls of buildings is restricted.

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Kemox conducted parallel experiments on the main factors affecting the color bleeding, water whiteness and stability of water-clad sand formulations, i.e. the amount of protective gel GS, the type and amount of wetting agent, the type and amount of cellulose ether, to optimize the formulations and test the performance of the water-clad sand colorful coatings, and finally achieved excellent color bleeding resistance, water whiteness resistance and stability. The final product is a water-in-sand colorful coating with excellent color bleeding resistance, water whiteness resistance and stability.

The formulation using Kemox hydroxyethyl cellulose is as follows:

Under the rotational speed of 300~600 r/min, add hydroxyethyl cellulose, dispersant, wetting agent, defoamer and pigment filler in turn, adjust the rotational speed to 1,300~1,500 r/min with the increase of viscosity of the system, dispersing at high speed for 20~30 min, and then reduce the rotational speed to 700~900 r/min after measuring the fineness of ≤ 50 μm, and then add the emulsion, protective adhesive and the rest of the auxiliaries in turn, and finally thicken the base coat with a thickener. Finally, use the thickener to adjust the base paint to a suitable viscosity, add the quartz sand and continue to stir for about 10 min, that is, the base paint for color mixing. When the additional amount of 250HHBR is 1.2%~1.4%, the water-in-sand multicolor paint obtained after repeated tests has better stability.

Article source: hydroxyethyl cellulose in coatings