Blue wool light fastness

X. The numbers indicate the blue wool light-fastness equivalent (Section 2.2). Lack of a number... 

Fastness to Light. The ISO test for colorfastness to light is DajlightlSO 105-B01. The textile specimen is exposed to daylight under prescribed conditions, including protection from rain, along with a series of blue wool reference samples that fade at defined, prescribed, different rates. 

In many applications ultramarine blue is stable to around 400 °C, violet to 280 °C and pink to 220 °C. All have excellent light fastness with a 7-8 rating (full and reduced shades) on the International Blue Wool Scale. Color fade attributed to light exposure or moderate heat is almost always caused by acid attack. Ultramarines react with all acids, and if there is sufficient acid, the pigment is completely decomposed, losing all color, to form silica, sodium and aluminum salts, sulfur, and hydrogen sulfide. Evolution of hydrogen sulfide with acids is a useful test for ultramarine. 

This consists of the phthalocyanine dyes, an example of this group being Coomassie Turquoise Blue 3G. This is a trisulphonated derivative of copper phthalocyanine. It dyes wool a very bright greenish blue shade. Its fastness to light is better than the triphenylmethane acid dyes which alone will give comparable shades. 

Other Names C.I. Acid Blue 89, trisodium salt Acid Blue Sh Acid Light Blue Acid Sky Blue Acilan Fast Navy Blue B Atul Acid Sulfon Blue B C.I. 13405 C.I. Acid Blue 89 Calcocid Wool Blue B Cirene Brilliant Blue B Eniacid Brilliant Blue B Fast Wool Blue B Hispacid Fast Blue B Russian Acid Blue Sulfonine Acid Blue B Sulphon Acid Blue B Tertracid Fast Flue SB CA Index Name 2,7-Naphtlialenedisulfonic acid, 4-hydroxy-5-[[4-[(4-methylphenyl)amino]-5-sulfo-l-naphthalenyl]azo]-, trisodium salt CAS Registry Number 10359-95-2 Merck Index Number Not listed Chemical Structure... 

Dyeings on wool are a dull maroon but after treatment with a chromium compound gives a bright blue shade of moderate light fastness but good wet fastness properties. 

Acid—mordant dyes have characteristics similar to those of acid dyes which have a relatively low molecular weight, anionic substituents, and an affinity to polyamide fibers and mordant dyes. In general, brilliant shades caimot be obtained by acid—mordant dyes because they are used as their chromium mordant by treatment with dichromate in the course of the dyeing procedure. However, because of their excellent fastness for light and wet treatment, they are predominandy used to dye wool in heavy shades (navy blue, brown, and black). In terms of chemical constitution, most of the acid—mordant dyes are azo dyes some are triphenyhnethane dyes and very few anthraquinone dyes are used in this area. Cl Mordant Black 13 [1324-21 -6] (183) (Cl 63615) is one of the few examples of currentiy produced anthraquinone acid—mordant dyes. It is prepared by condensation of purpurin with aniline in the presence of boric acid, followed by sulfonation and finally by conversion to the sodium salt (146,147). 

The leuco compound (7.9 grams, 0.01 mole) is dissolved in 100 cc. 50 per cent acetic acid, and to the well stirred solution are added, simultaneously, 30 cc. 10 per cent oxalic acid solution and 12.5 cc. 10 per cent sodium bichromate solution. The mixture turns blue immediately and the oxidation is complete in 10 minutes. The solution is mixed with an equal volume of saturated salt solution and the acetic acid is neutralized with ammonia. The dye precipitates as a reddish, bronzy slime which soon becomes glass-hard. The product is dissolved in hot water, the solution is filtered, and the dye is then salted out by adding an equal volume of saturated salt solution. In this way, 7.8 grams of pure dye is obtained. It gives bright blue tints on wool from neutral or weakly acid solution. The dye is not very fast to light. 

Like most ammonium bases, methylene blue does not dye wool easily, but is readily fixed on silk and tannined cotton. It has also a slight affinity for unmordanted vegetable fibres. Methylene blue is principally used in cotton-dyeing. It dyes a greenish shade of blue, which shows a dull tone similar to that of indigo. It is very fast to light, and the shades may be readily modified by other basic dyestuffs, such as methyl violet or malachite-green. 

Thiocarmine. — This compound is a sulphonic acid of the methylene-blue series, and is obtained from ethylhenzylaniline-monosulphonic acid. Thiocarmine is an acid dyestuff and produces very pure greenish shades of blue on wool, which are, however, not very fast to light. 

DRIFT spectroscopy of microscopic amounts of dye mixtures extracted from small textile samples has been reported raw and pretreated data matrices were interpreted with the use of chemomet-rics (PCA, SIMCA, FC) [145]. DRIFTS can readily detect 200 ng quantities of pure, standard dyes. Bridge et al. [42] have qualitatively characterised acid dyes (Cl Acid Red 17, Red 18, Red 44, Red 88, Blue 45 and Yellow 17) applied to wool and nylon. Near-infrared diffuse reflectance spectroscopy was evaluated for its ability to analyse solid antioxidant blends [146]. These opaque materials do not transmit near-IR light. This fast method effectively predicts weight percentage composition with a precision comparable to the currently accepted HPLC method of analysis, and can identify blend types and contaminated materials. 

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