Application of water-based pigment paste| Pearlescent mica pigment covered dyeing

The raw materials of pearlescent mica pigment is mica powder. If no surface treatment of mica powder, it can not absorb the colors, and can not be dyed to pearlescent pigments! Mica powder must be covered by aluminum chloride first, and then dyed it with water-based pigment paste to complete the coloring of pearlescent mica pigment.  

The technical staff has made the mica pigment dyeing testing:

In the experiment,  put 5 grams pearlescent mica (which had been covered with aluminum chloride) into 50grams water, and disperse it at 1000r/min.  Then separately add 0.25grams of CAISON resin free pigment paste 8 series product into the dispersion liqiud and check the covering effect.

The PH value of added water in the test is 8.0, and adding the pearl powder to adjust it to 7.5,then respectively put CAISON resin free black pigment paste in two batch number, one liquid PH value is 7.8, another liquid PH value is 7.3. At last, all of their PH will be 6.6 to 7.0 when they are being dyed, partial to acidic. Principle analysis: In the actual production of pearlescent mica pigment,  aluminum chloride hydrolysis into aluminum hydroxide precipitation, and makes the solution is acidic. so adding sodium hydroxide to adjust to maintain PH stability to promote the reaction.

Shanghai Caison experimental staff has found that: acidic environment is more conducive to dyeing and adsorption with water-based pigment dispersion, the coloring of pearlescent mica pigment is better!