Preparation Of Hydrophobic Pre-dispersed C.I.Pigment Yellow 14

C.I.Pigment Yellow 14(PY14)is one of the typical benzidine yellow organic pigment with excellent performance which is used widely in the modern society.On one hand,a long filtration time is necessary due to the small size of pigment particles and the high water content of pigments after the synthetic reaction of PY14.On the other hand,the unavoidable aggregation of pigment particles in the drying process leads to the growth of particle size and a hard filter cake after drying,which is responsible for the high energy consumption and high dust pollution of the filter cake crushing process.Hence,a realizable solution to solve the aggregation problem oforganic pigments particles is of great significance for the cleaner and more effcient industrial production.In this study,the synthesized PY14 particles were pretreated with PE wax or EVA wax as a mixture in the water phase before filtration.The novel core-shell structural pigments P-PY14 or E-PY14 were prepared successfully.By adjusting the important experimental factors,the effects of mass ratio,heating temperature,heating time,stirring speed,particle size of PE wax on the particle morphology,filtration properties and pigment properties of P-PY14 were investigated systematically.The particle size of P-PY14 was 0.5-0.6 mm.The P-PY14 particle is composed of a "core" with PE wax and a "shell" with PY14.The materials of core and shell were proposed to combine with each other via physical interaction.A pre-dispersed E-PY14 with a diameter of 0.8-0.9 mm,uniform particle size and nuclear-shell structure was prepared under the optimal conditions of mass ratio of PY14 to EVA wax 1:2,heating temperature 90?,heating time 20 min,particle size of EVA wax 40-60 mesh,stirring speed 250 r/min,p H=8.The core material is EVA wax and the shell material is a mixture of EVA wax and PY14.The bonding mode of PY14 and EVA wax is demonstrated briefly.P-PY14 and E-PY14 exhibited high hydrophobicity.The water content of filter cake is reduced by 19.7% and 27.4%,respectively.The filtration time used for separation from water is 1/20 and 1/26 of the original pigments PY14,which significantly shortens the filtration time of production,saves 50% drying time and 40% washing water.Furthermore,high dust pollution could be avoided,because the filter cake of P-PY14 or E-PY14 is easy to crush.In addition,P-PY14 or E-PY14 not only keep the crystal form of the pigments,but also exhibited enhanced colouring power of pigment to 104.47% and 121.32%,respectively,and improved the thermal stability of pigments at the same time.The preparation method is cost-effective and meets the application requirements well.The developed technology has a great benefit for environmental protection and is easy to industrialize.