초록 ▼

Pigment dispersion is manufactured by continuously flushing pigment press-cake. First and second troughs supply hydrophobic liquid organic media and the pigment wet-cake respectively at a constant rate to a twin screw co-rotating extruder having a L/D (length/diameter) value of 25 or more. The twin

Pigment dispersion is manufactured by continuously flushing pigment press-cake. First and second troughs supply hydrophobic liquid organic media and the pigment wet-cake respectively at a constant rate to a twin screw co-rotating extruder having a L/D (length/diameter) value of 25 or more. The twin screw co-rotating extruder includes a feeding part where the hydrophobic liquid organic media and the pigment wet-cake are fed from the first and second troughs, a flushing part for flushing the pigment particles from water phase to form an organic medium phase, and a dehydrating part for removing water from the flushed mixture. The hydrophobic liquid organic media and the pigment wet-cake are fed to the twin screw co-rotating extruder, and the pigment press-cake is flushed and dehydrated continuously in the extruder to obtain the pigment dispersion.

대표청구항 ▼

A method of manufacturing pigment dispersion, said method comprising: providing a twin screw extruder including a housing having therein a pair of adjacent parallel screws, with the ratio of the length of said housing to the inner diameter thereof being at least 25, and with said extruder including

A method of manufacturing pigment dispersion, said method comprising: providing a twin screw extruder including a housing having therein a pair of adjacent parallel screws, with the ratio of the length of said housing to the inner diameter thereof being at least 25, and with said extruder including an upstream feed section, a flushing section downstream of said feed section and a dehydrating section downstream of said flushing section; feeding a hydrophobic liquid organic media by a first feeding means and feeding pigment wet-cake by a second feeding means, at a constant rate, into said feed section of said extruder; rotating said pair of screws in the same direction within said housing and thereby sequentially: transferring said media and said wet-cake from said feed section to said flushing section and therein continuously flushing pigment particles from a water phase to an organic medium phase by rotation of said pair of screws, thus forming a flushed pigment mixture; and transferring said flushed pigment mixture from said flushing section to said dehydrating section and therein continuously dehydrating said mixture by rotation of said pair of screws, said dehydrating comprising removing a majority of the water from said mixture through a first vent in said dehydrating section of said housing, and removing residual water from said mixture through a second vent in said dehydrating section of said housing by applying vacuum thereto, and thereby forming pigment dispersion.