Formulation colored pigments

However, there is no exact quantitative method which makes it possible to calculate the critical particle size that will produce an optimum in hiding power in a colored pigment formulation. Although the basic theory behind this phenomenon has been treated extensively, it is still most advantageous for practical R D purposes to experimentally determine the particle size that affords a maximum in hiding power. A more approximate than quantitative rule has been established by H.H. Weber, which makes it possible to estimate the particle size that will afford a maximum in scattering ... 

Generally, there are two basic types of inks. The first type contains finely dispersed carbon black or colored pigments in both solvent and water based systems. Pronounced improvements have been achieved in stabilizing aqueous pigment formulations for ink-jet applications by adding specific polymeric dispersing agents [18], The second type of ink is based on water or solvent soluble dyes. 

A fast-curing polymercaptan-epoxy adhesive formulation is shown in Table 11.11. The gel time for the mixed adhesive is about 8 min at room temperature. Tensile shear strength on aluminum is reported to be 2270 psi at 23°C. Note that the different color pigments used in parts A (carbon black) and B (titanium dioxide) are to assist by visually indicating when the two components are well mixed. 

The production of white coatings or bulk white solids and the lightening of formulations with colored pigments is currently only possible by pigmentation with white pigments. All white pigments are produced synthetically. 

The coating formulation includes other ingredients, such as a pigment for color and opacity, modifiers and additives for performance enhancement, etc. Because the coating will be baked at elevated temperatures, the pigment must also be resistant to heat and chemicals. Nonorganic color pigments, such as ceramic compounds, are preferred. 

Because these resins are acidic, care should be exercised in formulating ingredients which are basic. The basic ingredients most often encountered are color pigments. Extensive information regarding color pigment reactivity with these resins is available in the literature (I). 

Colored pigments or fluorescent UV indicators may be used to inspect for bleedout from adhesives during and after cure. They may also be used to inspect for particles of cured adhesives that may have detached, migrated and contaminated other parts of an electronic assembly. Particles of electrically conductive or nonconductive adhesives can cause failures in microelectronic assembhes, gyros, accelerometers, or other electromechanical systems and are especially serious in space electronics. Rhodamine B which is pink to red in both the visible and UV regions and 2,6-distyrylpyridine which is visually colorless but intensely blue in the UV region are effective indicators in some adhesives formulations. 

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