Fastness to acids

Skure-echtheit, /. fastness to acid, -eiweiss, n. acid protein. 

Calcobond dyes was that the colour fastness to light was adversely affected. The fastness to acid treatment was no better than that of the resin finish, i.e. the dyeings could be stripped by boiling at a pH below 5. 

P.R.17 provides medium reddish shades. As a result of poor fastness properties, its commercial significance is somewhat limited and it is sold only in small volume. P.R.17 has the advantage of being fast to acid, alkali, and soap. It is therefore used in offset, gravure, and flexo printing inks wherever tolerance to alkali and soap is a major concern. Moreover, P.R.17 is also employed in connection with mass coloration and surface coloration of paper. 

P.Y.153 is a nickel complex which was introduced to the market in the late 1960s. It produces slightly dull reddish shades of yellow. Although not fast to acids, the pigment may safely be exposed to alkali. It is fast to mineral spirits and alcohols, but only moderately so to aromatic solvents, such as xylene, and to esters, such as ethyl acetate. 

P.Y.139 is sometimes used in conjunction with inorganic pigments for paints, especially to replace Chrome Yellow pigments. The systems are fast to overpainting (up to 160°C for 30 minutes), but they are not entirely fast to acids. The pigment performs very poorly in contact with alkali, therefore it is not suitable for use in amine hardening systems or in emulsion paints which are to be applied on alkaline substrates. 

As early as 1907, A.V. Braun and J. Tscherniak first obtained phthalocyanine from phthalimide and acetic anhydride [5]. The prepared blue substance, however, was not investigated further. In 1927, de Diesbach and von der Weid, in an attempt to synthesize phthalonitrile from o-dibromobenzene and copper cyanide in pyridine at 200°C, obtained a blue copper complex. The substance was found to be exceptionally fast to acid, alkali, and high temperature [6], Approximately one year later, in trying to manufacture phthalimide from phthalic anhydride and ammo-... 

P.Y.108 is applied in various types of industrial finishes, especially in original automotive (O.E.M) and in automotive refinishes. It is also recommended for metallic finishes, although it is much less weatherfast in such systems. The pigment tends to seed, i.e., it forms specks upon storage. The mechanism behind this phenomenon remains to be elucidated. Besides, P.Y.108 also lends color to emulsion paints, in which it is durable enough to satisfy the requirements for exterior paints based on synthetic resin dispersions. It is also fast to acids, alkali, and plaster. 

Prints containing Alkali Blue are not fast to the standard DIN 16524 solvent mixture, but they are fast to acid, paraffin, butter, and other materials. Tested in accordance with normative testing standards (Sec. 1.6.2.2), the prints unexpectedly also show fastness to alkali. It should be noted, however, that at higher alkali concentrations the tinctorial strength of the system declines and the shade becomes duller. This is a result of the fact that the pigment reacts with alkali. 

In the case of aromatic amines as coupling components, one of the oldest azo dyes is C.I. Acid Yellow36, 13065 (1) 587-98-4], Because of the basic group suitable for salt formation the dye is not fast to acid, but it is still used today for dyeing wool and in special areas (leather and paper) primarily for price reasons. 

The azo yellow prepared in this way is quite insensitive to dilute mineral acids, but is not satisfactory for certain purposes in silk dyeing. By using more nitric acid and more vigorous conditions, grades of azo yellow are produced which are more greenish in shade and completely fast to acids. 

This dye is one of the most widely used direct azo dyes as it is an extraordinarily strong dye. It is not fast to acid or to light. The first step in its preparation involves the preparation of the monoazo dye, sulfo chrysoidine G ... 

Technical Observations. If 1,2,4-toIuyIenediamine is used in place of m-phenylenediamine, an analogous dye is formed which is somewhat more fast to acids. In this case, one of the positions para to the amino group is occupied, and hence the formula given above for the m-phenylenediamine dye must be correct, i.c., the second azo group must enter the position between the two amino groups, and not the position para to the —NHa. ... 

MAJOR USES Used in the production of ion exchange resins, dyes, rubber and blue-black textiles reagent in glucose analysis makes colors fast to acids. 

OTHER COMMENTS used in the preparation of ion exchange resins used in the synthesis of dye stuffs and other intermediates antioxidant in rubber manufacturing laboratory reagent in glucose analysis used in the manufacture of rodine products used in printing textiles blue-black used in making various colors fast to acids. 

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