Лако-красочные материалы — производство

8.4.1 General Methods “Are crystal structures predictable? [42]” This question is still a “Holy Grail” for crystallographers, solid-state physicists and solid-state chemists, and has been the subject of controversial discussions for more than a decade. In order to calculate a crystal packing, it must first be constructed from mole­cules of specific shape to obtain a […]

In the process of mapping molecular functionality to the physical and technical properties of a pigment, crystal structure is key information which can be looked at as a molecular property itself. Therefore, the determination and simulation of crystal structures provide core know-how for all aspects of designing high perfor­mance pigments. About a hundred crystal structures […]

Creative concepts in crystal engineering make use of supramolecular synthons to define specific interactions in molecular solids, which may be employed to design crystal packings [1, 4]. The synthon approach has been used to produce close packed structures, and, on the contrary, to build open network structures [21]. In the packing motifs of high-performance pigments […]

In general, the low solubility and high thermal stability of pigments are indicative of large packing energies due to the strong intermolecular attractive forces within crystals. These intermolecular forces may be evaluated using various molecular modeling methods. For practical reasons, lattice or packing energies of molecular crystals are calculated by force field methods. The packing […]

8.2.1 Close Packing The molecules in organic crystal structures are usually close packed. The ratio of the volume occupied by the molecules to the cell volume, the Kitaigorodskii pack­ing coefficient CK, ranges from ca. 0.65 to 0.8 [5]. Organic pigments usually can be found in the regime above 0.74, thus packing more efficiently than equally […]

Peter Erk 8.1 Introduction With few exceptions, pigments exist as crystalline solids, and all of their essential properties depend on structural and morphological features associated with the solid state. For an efficient design of high-performance pigments it is necessary to analyze and to understand the molecular reasons behind those solid properties which give rise to […]

Grinding of holographic films, when done in a suitable manner, can lead to small holographic particles [8, 42]. These so-called holographic or hologram pigments are relatively new materials for attaining special optical effects in different applica­tion media. A structure of a holographic pigment particle is shown in Figure 7.20. Generally, any hologram base material on […]

The phenomena of light interference can also be produced using diffraction tech­nology. Diffractive pigments are manufactured by vacuum deposition on a spe­cially patterned surface [49, 50]. Diffraction can be observed when light waves encounter obstacles of dimen­sions similar to their wavelength. A diffraction grating is regarded as an optical component made by a periodic assembly […]

Interference and angle-dependent color effects can also be achieved by layers or particles based on liquid crystal polymers (LCP) [8, 35]. Such effects can, for exam­ple, be produced by small plate-like substances which consist of an LCP material itself, or by small platelets which are uniformly coated with a cross-linked liquid crystalline polymer in a […]

Optical coatings that shift color with viewing angle have been adapted into opti­cally variable films, pigments, and inks during recent years [8, 33]. These coatings are based frequently on metal-dielectric multilayer thin structures having large color shifts with angle, high chroma, a large color gamut, and light fastness. Dif­ferent colors are produced by precisely controlling […]