Media applications

Application Medium Temp. Wide Temp. High Temp. Ultra High High Temp Teni) ... 

In this chapter, the correlation between chemical constitution and pigment performance is outlined in terms of empirical rules. These correlations essentially apply independently from the application medium for all industrial uses of pigments. 

A pigment is said to bleed if some portion of it migrates from the application medium in which it is partly dissolved to a similar colorless or differently colored medium with which it is in contact. This phenomenon is of particular concern to the plastics and coatings industry. 

Achieving a statistically uniform distribution of pigment particles throughout all volume units of the entire application medium is a question of the equipment and... 

The dispersibility of a pigment in a particular vehicle system is also reflected by the viscosity of the pigmented medium and by the gloss that it produces in application. Viscosity and gloss are frequently considered more suitable parameters to indicate the state of dispersion of a pigment in an application medium than the tinctorial strength, which reaches its optimum at a point at which other parameters, such as gloss, can be improved. 

Chemical interaction between pigment and application medium... 

Special consideration should be paid to metal complexes such as azomethine pigments (Sec. 2.10). At high temperatures, the yellow copper complex with the chemical constitution 10, incorporated in PVC, will exchange its chelated copper atoms with the metal atoms present in the application medium. Stabilizers containing barium/cadmium or lead produce yellow shades, while dibutyl tin thiogly-colate or other tin compounds produce a brilliant medium red. Color change is slow at low temperatures, but at 160°C the effect is rapid [108],... 

These are the changes that are observed in a pigment powder as it is processed or heated in the application medium. Modifications in the sizes of the crystallites of a polycyclic pigment which is treated in its application medium under varying conditions [108] maybe derived from X-ray crystallographic data. Table 5 reflects a clear correlation between crystallinity and thermal stability increased crystallinity leads to improved heat fastness. 

As an example, a given pigment, incorporated in one medium, may match grade 8 on the Blue Scale for lightfastness, which is an excellent value while a change of application medium may render the same pigment sensitive enough to reach only... 

Incorporated in its application medium, P.R.208 affords medium shades of red. The pigment exhibits good fastness to chemicals and solvents. Its main area of application is in the mass coloration of plastics and in packaging gravure printing inks. 

Apart from displaying the desired physical properties, such as light and weather fastness, heat fasmess, solvent resistance etc., there is a prime requirement that the pigment be readily and evenly dispersible in the application medium. Most pigments are sold as solids and the ease of dispersion in the medium to be used in the application is very dependent on the size of the particles in these solids. 

While any of the above sources find specific applications, medium-pressure mercury (microwave and arc) and xenon lamps are most widely used in industrial applications. 

Another concern is the volatility of the application medium. Table II shows the heats of vaporization of commonly used solvents. 

Recommended Dilutions 5-20 1 Applications Medium Duty HSC Formula NP-102... 

An important issue that has been recognized recently concerns the potential adverse effect of absorption enhancers on the rectal mucosa, as shown in rats after a single application [61,62], Safety evaluation of the applicability of absorption enhancers is imperative. In clinical application, medium-chain fatty acids such as sodium caprate are used only for suppositories containing antibiotics [36],... 

Acid, basic, and direct dyes are all ionic in nature. Acid dyes contain free acid groups which are ionized in the aqueous application medium (dyebath). They generally used to dye polyamine, wool, or silk and are primarily azo, anthraquinone, or triarylmethane structures. 

In applications, where aluminum powder is requested (e.g. in powder coatings) or where the rest of the remaining mineral spirit would not be compatible with the application medium (e.g. in printing inks, waterborne coatings and inks, master-batches etc.), the mineral spirit of the press cake is removed in vacuum driers and substituted by any kind of solvent, water, plasticizer, mineral oil or other liquids. 

The pigment must be present in the application medium largely as primary particles. The transparency of a colored pigment with a given chemical composition depends entirely on obtaining primary particles of a particular size during manufacture (Figure 5.35). 

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