The production process requirements of color masterbatch are very strict, and the wet process is generally used. The color masterbatch is ground and phase-inverted by water, and a series of tests should be carried out while the pigment is being ground, such as the determination of the fineness, diffusion performance, solid content and color paste fineness of the sanding slurry.
There are four wet production processes for color masterbatch: washing method, kneading method, metal soap method, and ink method.
(1) Washing method: The pigment, water and dispersant are sanded to make the pigment particle smaller than 1pm, and the pigment is transferred into the oil phase by the phase transfer method, and then dried to obtain the color masterbatch. Organic solvents and corresponding solvent recovery devices are required for phase inversion. The process is as follows:
Pigment, dispersant, auxiliary amount – ball mill – homogenization and stabilization treatment – drying – resin mixing – extrusion granulation color masterbatch
(2) Kneading method The process flow of the kneading method is as follows:
Pigment, auxiliaries, resin kneading – dehydration – drying – resin mixing – extrusion granulation into masterbatch
(3) The metal soap method pigment is ground to a particle size of about 1um, and the soap solution is added at a certain temperature to make the surface layer of the pigment particles evenly wetted by the soap solution to form a layer of saponification solution. Add the metal salt solution and the surface of the pigment. The saponification layer chemically reacts to form a protective layer of metallic soap (magnesium stearate), so that the finely ground pigment particles do not flocculate.
The process flow of metal soap method is as follows:
Pigment, auxiliaries, water mixing – separation and dehydration – drying – resin mixing – extrusion granulation into masterbatch
(4) Ink method In the production of color masterbatch, the production method of ink color paste is used, that is, through three-roll grinding, a low molecular protective layer is coated on the surface of the pigment. The milled fine paste is mixed with the carrier resin, then plasticized by a twin-roll mill, and finally granulated by a single-screw or twin-screw extruder.
The process flow is as follows:
Pigments, additives, dispersants, resins, solvent ingredients – three-roll mill color paste – desolventizing – resin mixing – extrusion granulation into masterbatch.
Process flow of dry production of color masterbatch: pigment (or dye) auxiliary, dispersant, carrier – high-speed mixing, stirring and shearing – twin-screw extrusion granulation – cold cutting and granulation into color masterbatch
References
[1] Zhong Shuheng. Color Composition. Beijing: China Art Publishing House, 1994.
[2] Song Zhuoyi et al. Plastic raw materials and additives. Beijing: Science and Technology Literature Publishing House, 2006.
[3] Wu Lifeng et al. Masterbatch User Manual. Beijing: Chemical Industry Press, 2011.
[4] Yu Wenjie et al. Plastic Additives and Formulation Design Technology. 3rd Edition. Beijing: Chemical Industry Press, 2010.
[5] Wu Lifeng. Design of plastic coloring formula. 2nd edition. Beijing: Chemical Industry Press, 2009
Post time: Jul-01-2022