What routine performance tests should the paint manufacturer conduct on the emulsion?
General architectural coatings manufacturers should conduct the following routine performance tests on the purchased emulsions.
(1) Appearance
General visual inspection. Observe the hue of the emulsion and whether there are particles and impurities.
(2) Viscosity
Since polymer emulsions are mostly non-Newtonian fluids, the instruments used to measure emulsion viscosity should be able to measure the relationship between shear stress and shear rate in a wide range of shear rates. Rotational viscometers are usually used to measure the viscosity of emulsions, and Tu-4 cups are generally not used. .
(3) Determination of solid content
Put about 2g of the polymer emulsion sample into an aluminum pan (or glass pan) with a diameter of 4cm, cover it with an aluminum lid (or glass lid) and weigh it, then place it in an oven with a ventilation device, After drying at 115°C for 2o minutes and weighing, the solid content can be calculated.
The above method should adopt a higher drying temperature (such as 12o C) for polymers that are prone to peeling like acrylates. For plasticized polymer emulsions, due to the volatility of plasticizers, lower temperatures (such as 1o5°C) and longer drying times (such as 2 hours) should be used. ·
(4)pH value
Use precision test paper or an appropriate model of pH meter (PH meter) for measurement.
