Hydrophobically modified ethoxylated aminoplast thickener (HEAT) is a special amino resin that can be connected to four capped hydrophobic groups, but the activity of these four reaction points is not the same. If more hydrophobic groups are added, e.g. up to 8%, the reaction conditions can be adjusted to produce an amino thickener with more than one capped hydrophobic group. Of course, this is also a comb thickener.
This hydrophobic modified amino thickener can prevent color matching, due to the addition of color paste, bring in a large number of surfactants and diol solvents, and the coating viscosity drop problem. The reason is that the strong hydrophobic group can prevent desorption, as well as multiple hydrophobic group has a strong linkage effect. This kind of thickening agent such as Optiflo TVS.
Application examples of polymer dispersants
LUBRIZOL recommends that the company’s hyperdispersant can be used to produce resin-free color paste in hydrocarbon solvents. Inorganic pigment content is 80%, no change after 9 months of storage. The organic pigment content is 40% after storage for 2 years without change, no precipitation, no delamination, and no resin. In contrast, it has strong versatility and good compatibility. But pay attention to the solubility of the solvent in the color paste to the resin used, and the compatibility of the dispersant with the resin.
Table 2-11 shows the application of polymer dispersant in alkyd paint. In the color paste of alkyd paint in the table, one uses alkyd resin, the other does not use alkyd resin, and only uses hyperdispersant. The production efficiency of the latter is 2.1 times that of the former.
Zhao Huibin and He Leiming of Degussa Company  used 12 kinds of polymer dispersants produced by different companies in various countries, respectively in two-component polyurethane acrylic paint and amino alkyd. In baking paint, the dispersion effect and storage stability of carbon black (FW-200), phthalocyanine blue (BGS) and ptfe wax polish organic red pigment (A2B) are tested.
The amount of dispersant added is calculated based on the solid content of the additive to the mass of the pigment. Carbon black is 70%, phthalocyanine blue is 20%, and A2B red is 15%. The dispersion fineness measured in the same time is below 5pm. At room temperature, use Haake Roto visco to measure the viscosity when the shear rate is 10.3s- and 300s-1, and observe the thixotropy. The lightness value (△L) and finger rub color difference value (△E) were measured with a color difference meter to determine the dispersion effect. Do a heat storage experiment, store at 60°C for 7 days, and measure the above-mentioned indexes to test the storage stability.
Color paste is also used to make paint, and various indexes of normal temperature and heat storage are also measured to test the performance of the paint.
Leave a message
We’ll get back to you soon