Exterior coating production process

(PA containing carboxyl) polyurethane (PU containing carboxyl) nano-silica exterior wall paint production.

Production points:  

1. Add water to the mixer, add glass beads, ultrafine calcium bicarbonate, barium sulfate, calcined kaolin and talcum powder, stir evenly, pump into the dispersion grinding tank, disperse and grind, and wash the mixing tank with the remaining water. The dispersion grinding time is 2 hours.

2. Water-soluble acrylic resin (PA) and diacetone acrylamide are mixed and stirred, copolymerized and grafted, and copolymerized and cross-linked at room temperature, and the reaction time is 1 hour. After adding water-soluble polyurethane resin (PU), adipic acid dihydrazide and ammonia water and mixing thoroughly, the emulsion is slightly alkaline. At normal acidic temperature, the ketone carbonyl and hydrazine groups will undergo dehydration reaction to form hydrazone compounds, thereby realizing room temperature crosslinking of the emulsion. The crosslinking reaction formula between ketone carbonyl and hydrazine groups: =C=O+HN2NH2— =C=N-NH -Ten H2O, improve the stability of 2-resin blending, self-crosslinking when dry, and the formed film quality is good. Then add nano-silica colloidal liquid, so that the resin is riveted on the surface of the silica, and the lipophilic group is facing outward, so as to improve the water resistance of the coating. 

3. Pump the ground material into the cross-linked riveted resin nano-emulsion, stir, add styrene-acrylic milk, defoamer, smoothing agent, fully stir, OK