Tham khảo tài liệu 'coatings technology handbook episode 2 part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Pigment Dispersion 76-3 FIGURE Scanning electron photomicrograph of copper phthalocyanine blue crude top and transmission electron photomicrograph of copper phthalocyanine blue pigment bottom showing particle size differences Pigment Blue 15. at the corners and edges in a looser type of arrangement. Aggregates are formed during the manufacturing process in the course of the ripening period of the precipitates. Agglomerates most often are formed during the drying of the presscakes and the subsequent dry milling of the pigment lumps. Figure shows typical arrangements of aggregated and agglomerated pigment particles. Flocculates consist of primary particles aggregates and agglomerates generally arranged in a fairly open structure as shown in Figure . Flocculates may be broken down easily under shear but they will form again when such shear forces are removed and the dispersion is allowed to stand undisturbed. 2006 by Taylor Francis Group LLC 76-6 Coatings Technology Handbook Third Edition pigments have been developed to aid in the reduction of energy requirements. Such pigments are produced by surface treatment of the pigment during manufacture with the purpose of reducing or inhibiting agglomeration-aggregation formation. In many cases such treatments are highly specific to a single ink paint coating or plastic medium. Dispersion Stabilization The third stage of great importance in the dispersion process is the stabilization of the pigment dispersion. This ensures that complete wetting and separation of the particles has been reached and also that the pigment particles are homogeneously distributed in the medium. If the dispersion has not been stabilized flocculation may occur as a result of clumping together of the pigment particles. Flocculation is generally a reversible process. Flocculates typically break down when shear is applied and will form again when the shear is removed. Where a pigment dispersion is not stabilized by the action of .
