How to determine Coating percent solids?

The determination of the solid content of the coating requires the use of glass petri dishes, glass watch glasses, 50ml millstone dropping bottles, glass dryers, crucible tongs, 0-300°C thermometers, 0.1g balances, and blast constant temperature ovens.

There are two methods for measuring the solid content of coatings , the Petri dish method and the surface method according to the viscosity of the coating .

(1) The petri dish method is to bake the dry and clean petri dish in an oven at 105±2°C for 30 minutes, take it out and put it in a desiccator to cool to room temperature and then weigh it. Then use a grinding mouth drop bottle to take a few grams of samples (2-2.5g for perchlorethylene paint, 4-5g for acrylic paint), put it in a petri dish to make it drip evenly at the bottom, put it in an oven at a specified temperature and bake it for a certain amount of time. After a period of time, remove it and put it in a desiccator to cool to room temperature and weigh until the mass difference between the two times is not greater than 0.01g.

(2) The watch glass method is mainly suitable for the determination of high-viscosity putty, emulsion and nitro cable paint and other coatings. When measuring, first bake two same dry and clean watch glasses in an oven at 105±2°C for 30 minutes, remove them and put them in a desiccator to cool to room temperature and weigh them, then put the sample on one watch glass and cover the other On the above, accurately weigh 1.5-2g on the balance, turn the covered watch glass upside down, make the two plates coincide with each other, press down lightly and then separate them, make the sample face up, and place them at the adjusted temperature. After drying in a special oven for a certain period of time, take it out and put it in a desiccator to cool to room temperature and weigh. Then bake for another 30 minutes, take it out of the desiccator and weigh it at room temperature until the non-rubbing weight weighed twice before and after is not more than 0.01g.

Calculation method for determination of coating solids content:

The solid content % (X) is calculated according to the following formula:

X=(W1-W)/G×100%

In the formula: W represents the mass of the container (g); W1 represents the mass of the sample and container after baking (g); G is the mass of the sample (g). The sample results take the average value of two parallel tests, and note that the relative error of the two times should not be greater than 3%