Electro-coatings Determination of ash content and color-to-base ratio

The pigment-base ratio in electrophoretic coating refers to the ratio of pigment and base material (resin) in electrophoretic coating, bath or coating film. The determination of pigment-base ratio includes solvent method and ash method. The pigments used in electrophoretic coatings are generally non-combustible inorganic pigments except carbon black, so it is often used to calculate the pigment content by measuring the ash content, and the method is simple.

Testing instruments and materials

①Crucible and muffle furnace     ②Constant temperature Drying Oven

test methods

① Weigh a quantitative (about 10g) paint sample or bath liquid sample into the weighed crucible;

②Dry at 110±5°C for 1 hour, then bake at 200-250°C for 1 hour, then bake at 400-450°C for 0.5 hour, then heat up to 800°C for 0.5 hour;

③Reweigh the crucible after cooling;

④Calculation:

Ash = (C-A) × 100/[(B-A) × (D/100)]

Yan-base ratio (P/B)=(C-A)/K[ D(B-A)-(CA)K]

In the formula:

A The weight of the crucible (g)

B crucible plus sample weight (g)

C Crucible plus sample weight after calcination (g)

D Paint sample solid content (%)

K is the carbon black correction factor, in black paint K= 1.15