Although the basic ingredients of paints are the same (i.e., binder, pigment, liquid, and additives), there are a few significant differences in the way that waterborne acrylic coatings are manufactured in comparison with solventborne coatings.

EQUIPMENT: When manufacturing waterborne paints, equipment made of galvanized steel, brass, copper and mild steel should be avoided. Kettles should be made of stainless steel, and piping should be either stainless steel or plastic.

PIGMENT DISPERSION: For waterborne paints, water and co-solvents make up the medium for dispersing pigments. Pigment grinding is generally not done in the resin, as it is with solventborne resins. If the waterborne acrylic binder is used as a portion of the liquid phase for pigment grinding, care should be taken that the temperature does not rise above approximately 125°F. Too high of a temperature can result in the formation of grit. Pigment dispersion is usually done in a smaller, separate kettle from the paint letdown. The pigment grind is then added to the resin in a larger kettle to finish the paint.

AGITATION: It is very important to monitor the batch for proper agitation. During pigment dispersion, good agitation during the introduction of additives is crucial. Maintaining a good vortex during the letdown phase of production is also very important. If mixing is too slow, insufficient suspension of the pigment and poor blending of the additives will result. If mixing is too fast, foam will be generated.

VISCOSITY: It is best to filter the batch while the paint is still fresh and warm, as it will have a lower viscosity. Most waterborne acrylic coatings will equilibrate to their final viscosity after one day, and the equilibrated viscosity can be up to 10 Krebs units higher in viscosity than immediately after the paint is made.

CLEANING UP: Fresh spills of waterborne acrylic paint are best cleaned up immediately with water. If the film is allowed to dry, or if skins have formed on equipment, clean-up with acetone or lacquer thinner or manual scraping may be required.

Click here to watch a short video describing the manufacture of waterborne acrylic industrial coatings