Determination of Pigment-to-Base Ratio and Deposition of Electrophoresis Paint

Determination of color-to-base ratio

Sintering method

The sample is placed in a crucible, first baked at 110°C for 1 hour, then preheated at 200-250°C for 10 minutes, then burned in a muffle furnace (800°C) for 30 minutes, weighed after cooling, and the residue is the quality of the pigment, usually That is the ash content.

Pigment-base ratio=ash content/(sample weight x solid content-ash content)

Pigments that are thermally decomposed at high temperatures need to be centrifuged multiple times and dissolved in resin, and then dried after washing to obtain the weight of the pigment. During electrophoresis, the deposition ratio of resin and pigment will not be consistent with the pigment-base ratio, so it needs to be measured regularly. To determine whether to add emulsion or color paste.

The sampling amount of this method is generally a few grams, and it is also stipulated that it should be dried in an oven to a constant weight, and then sintered to a constant weight.

Or after the crucible has a constant weight, add the sample, adjust from 100°C to 660°C within 60 minutes, bake at 660°C for 30 minutes, and dry for a total of 90 minutes.

centrifugation

Take a certain amount of coating liquid, separate the water from the solid by centrifugation, wash the precipitate with acid (ammonia) and distilled water, then take it out and dry it, and then measure the pigment content; then take the same coating liquid, measure the solid content, and perform conversion. That is Yanji ratio.

Determination of deposition amount of electrophoretic paint

This method is suitable for the determination of the deposition amount of electrophoretic paint, which is expressed by the weight of dry film deposited per unit area (g/m2).

Materials and Instruments

①Tinplate 50mmX120mmX(0.2~0.3)mm;

②Balance sense 0.00lg;

③Measurement method of steel plate scale division 1mm,, 21.1.l0.2

①Take three tinplate plates, according to the provisions of HG2-1046-77 "Preparation Method of Electrophoretic Paint Film", after the surface treatment of the test plate, weigh on the balance, accurate to 0.00lg,

② Prepare the paint film on the above-mentioned test panels according to HG2-1046-77 "Preparation Method of Electrophoretic Paint Film", then cool it to room temperature in a desiccator, and weigh it on a balance, accurate to 0.001g.

③Use a steel ruler to measure the width and height of the test plate, accurate to 1mm, ④Calculate the deposition amount D (g/m2) according to the following formula:

In the formula, G, the mass of the test panel after painting, g;

G--the mass of the test panel before painting, g;

W is the width of the test panel, cm;

H is the height of the test plate, cm.

Test results and errors

The test results are the average of three parallel experiments.

The difference between the value of each test and the average value shall not exceed 5%, otherwise it shall be re-measured.