Chrome mordanting

Mordant Dyes. MetaUizable azo dyes are appHed to wool by the method used for acid dyes and then treated with metal salts such as sodium chromate [7775-11-5] sodium dichromate [10588-01-9] and chromium fluoride [1488-42-5] to form the metal complex in situ. This treatment usually produces a bathochromic shift ia shade, decreases the solubUity of the coloring matter, and yields dyeiags with improved fastness properties. The chromium salts can be appHed to the substrate before dyeiag (chrome-mordant or chrome-bottom method), together with the dye ia a single bath procedure (metachrome process), or as a treatment after dyeiag (afterchrome process). 

Absud, m. decoction, extract (Dyeing) specif., iron or chrome mordant. 

Chrom bad( n. chrome bath. beizet /. chrome mordant. 

Chrome-magnesite brick, 6 495 Chrome Manganese Zinc Brown, pigment for plastics, 7 369t Chrome-mordant dyeing, 9 399 Chromenes... 

Technically important dyes are salicylic acid derivatives that function as chrome mordant dyes for wool. Thus Cl Mordant Blue 1 (6.187) is made by the aldehyde synthesis from 2,6-dichlorobenzaldehyde and 2-hydroxy-3-methylbenzoic (o-cresotinic) acid in concentrated sulphuric acid. Oxidation of the leuco base is achieved by the addition of sodium nitrite. On wool the product, which is isolated as the sodium salt, is a dull maroon colour, changing to a bright blue on treatment with a chromium salt. Some dyes of this type, such as Cl Mordant Violet 1 (6.188), also contain a basic group. This compound is also prepared by the aldehyde route. 

Dyes used Acid, milling, chrome, mordant, vat, and indigo. 

Yield.—70—80% theoretical (70—-80 gms.). Dyes wool brown with chrome mordants, chromium fluoride giving the best shades. (J. S. C I, 3, 141.)... 

A large number of naphthoquinone and benzoquinone dyes occur naturally as plant constituents, and in the past many of these have found use as colorants. The chemistry of synthetic analogues began with the discovery of naphthazarin (1) [475-38-7] by Roussin in 1861. Naphthazarin and its derivatives first found use as black chrome mordant dyes for wool and silk. In contrast to the naphthoquinones, synthetic benzoquinone dyes are few in number and are generally of the... 

A naturally-occurring mordant dye, used extensively until a few years ago, and now probably the only one still in use, is logwood. It yields a navy blue or a black, with what is called a good bloom, when dyed on chrome mordanted wool. Until the advent of acid mordant dyes, which will be described later, it was the only dyestuff with which wool could be dj ed black with any measure of fastness. 

Chrome mordant dyes are normally used in dyeing of wool and polyamide fibers. The limit prescribed for them is 3 ppm and the testing method snggested is EN ISO 17075 2007. The dyestuff manufacturer should supply MSDS for verification. 

When colorfastness against harsh external environmental exposures, such as UV light and acid moisture, is required, natural and synthetic (chrome) mordant dyes are employed. Synthetics are primarily used, whereby the dyed substrate is commonly overcoated with potassium dichromate as the mordant or dye-setting agent. 

Uses Dispersant for dyeing cellulosic fibers with vat dyestuffs proteefive colloid for wool dyeing with 1 2 metal complex dyestuffs leveling agent with add and chrome mordant dyestuffs also suifable for polyamide and cotton dyeing Features Stable to add, alkali, and salts Properties Bm. powd. sol. in water (any hardness)... 

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