★ Preliminary screening of dispersant

(1) Select dispersant with appropriate polarity range according to system polarity

(2) Select the type and amount of anchoring groups according to the types and requirements of pigments used

(3) According to the formula design scheme to decide how to choose the dispersant, such as thick slurry type or non-thick slurry type; Color grinding or monochrome grinding; Universal color paste or special color paste;

(4) Gravity sedimentation method was used to initially screen dispersants: pigment, dispersant and resin dilute solution were simply stirred to observe settling speed and suspension; The slower the sedimentation, the more suitable the dispersant may be.

(5) Viscosity reduction ability test method: Measure the viscosity reduction of different dispersants to the same pigment resin slurry after high-speed stirring, and measure the viscosity once every time. Dispersants with lower viscosity may be more suitable (except for controlled flocculation dispersants).

(6) Daniel flow method was used for preliminary screening of dispersants, and the smaller the wet flow point difference, the more suitable.

(7) Test the compatibility between dispersant and resin.

(8) There is no reactivity between the dispersant and resin: some dispersants such as polymer amide dispersant and resin such as some resins such as epoxy resin reaction, thus affecting the storage stability of the slurry.

★ pour out

The grinding good color paint or color paste into the resin and diluent to adjust the construction viscosity or lower than the construction viscosity viscosity, slow mixing evenly, with 300 mesh screen filter, flow coated on the transparent PET film, after drying to observe the transparency or covering power, luster or fog shadow, flocculation, granulated, color power, etc.

rub out (rub out)

Add the ground color paste or paint into the white paint and resin solution, stir evenly and filter, and then scrape and paint on the LENETA black and white paper with a 100um wire rod. After the film is half dry, gently rub the paint film on the white paper until the paint film is nearly dry. Observe and measure color changes between the finger and other areas (rating and comparison can be done using gray cards or measuring △E).

★ Viscosity and rheological curve test

The rheometer or viscometer was used to evaluate the viscosity or rheological curve of the color paste. Generally speaking, for dispersants of flocculation, the better the viscosity reduction effect is, the better the dispersion effect is.

★ Storage stability test of color paste

The color paste is placed in the oven at 50-60℃ for 15 days (thermal storage stability) or in the refrigerator at -50℃ for 10 days before evaluation, comparison of flow coating, finger grinding, coloring force comparison, rheological curve changes, etc.