Dyeing tests

Farb-base, /. color base, -becher, m. dye beaker (for dyeing tests), -bestimmung, /, color determination, -bier, n. dark beer for coloring. bruhe, /. dye liquor, -deck schicht, /. color coat, -druck, m. color printing color print. 

In a further exploration of the relationship between dye structure and wet fastness on silk, four novel monoazo J acid derivatives (3.169 X = Xx to X4), including 3.168 (X = X2) made from 2-aminobenzophenone, were synthesised. Silk was dyed at pH 4 and 85 °C and the dyeings tested for fastness to washing, perspiration and dry cleaning. The highest allround fastness was shown by the 4 aminobenzophenone derivative (X = X4), a structure that resembles the anti-parallel pleated sheet arrangement of polypeptide chains in silk [183]. 

The kinetics of reaction of DABCO (7.66) and nicotinic acid (7.67 R = COOH) with the aminochlorotriazine dye Cl Reactive Red 3 (7.2) were studied under neutral conditions at temperatures in the range 100-130 °C. Quaternisation by DABCO was much more rapid than by nicotinic acid under these conditions. Neutral exhaust dyeing tests at 130 °C using the bis(aminochlorotriazine) analogue Cl Reactive Red 120 (7.48 X = Cl) with the two catalysts confirmed these trends, in that the degree of fixation was greatly increased by DABCO but nicotinic acid showed no appreciable catalytic effect [60]. This difference may be attributable to steric strain of the C-N+ bond in the quaternised triazine structure by the non-planar DABCO substituent. 

Institute and Ref. Dye Test conditions Components Term Results... 

To ascertain if the cognac is coloured with artificial organic colouring matters, the alcohol is evaporated off, ammonia solution added and the liquid extracted with amyl alcohol evaporation of the amyl alcohol gives the colouring matters, which may be detected by their characteristic reactions and by dyeing tests with wool in acid or alkaline solution (see also Wine, and Colouring Matters). 

In testing dye woods and barks, these are ground as finely as possible. The moisture and ash are determined on the ground product, and a weighed quantity of the latter is extracted with hot water and the solution made up to the desired concentration for each test, this solution being used for the identification of the product and for the dyeing tests by which the value is established. 

The best results in this direction are obtained by dyeing tests with suitable mordants (see later), followed by examination of the colouring matter fixed on the fibre (see chapter on Textile Fibres). 

Artificial organic dyes may also be detected in dyeing extracts by dyeing tests and subsequent examination of the colouring matters thus fixed on the fibre (see Textile Fibres). 

Dyeing Value.—The best criterion of the dyeing value of a dyeing extract is obtained by a small dyeing test, which is made also on a genuine extract for purposes of comparison. This test is carried out differently with different extracts and according to whether the colour is to be applied to cotton, wool or silk most commonly the tests are made with wool. 

Dyeing Test.—To ascertain the actual dyeing value of a logwood extract, the most important test is a dyeing test with wool mordanted with bichromate. 

If a dyeing test with cotton is required, this is mordanted by boiling with 5% aluminium acetate solution and then exposed for some time to hot, moist air for each gram of cotton 20 c.c. of the extract solution are used. 

Dyeing Test.—Alizarin is fixed on fibres by means of mordants and, according to the nature of the latter and of the fibres, produces colours varying from yellowish-red to brownish-red and to more or less bluish violet. 

For the dyeing test it is hence necessary to vary the procedure in accordance with the fibre to be dyed and the colour desired. In general, comparative tests are made with a standard alizarin and that under examination, using strips of cotton material (calico) mordanted in different ways, namely ... 

Their examination comprises especially certain qualitative tests for the identification of the product and for the detection of adulteration, and a dyeing test sometimes certain quantitative determinations are required. The analytical methods followed are indicated below. 

Dyeing Test.—1 gram of the powdered cochineal is boiled repeatedly with water, all the solutions obtained being united and made up to a litre. For each gram of woollen fabric, 100 c.c. of this solution is used, this being diluted with water with addition of 3% of oxalic acid and 1-5% of tin salt (referred to the weight of the fabric). 

With each of these four groups the procedure is as described later. In the first place, however, the colouring matter is investigated with reference to its tintorial properties by means of dyeing tests on non-mordanted cotton or wool, on wool mordanted with aluminium sulphate and cream of tartar, on wool mordanted with chromium fluoride and cream of tartar, on cotton mordanted with tannin and then with tartar emetic, on cotton mordanted with aluminium acetate and on cotton mordanted with chromium acetate. 

Dyeing Test.—The two colouring matters are then used to dye equal quantities of wool, silk or cotton yarn or fabric, according to the uses for which the colouring matter is intended, the colours obtained being compared. 

Dyeing tests give reliable results only when carried out under identical conditions as regards concentration and temperature of the bath, additions made to it, duration of the operation, preliminary (e.g., method of mordanting) and subsequent treatments (washing, drying, etc.). 

The nonaqueous dressings successfully formed continuous and nonpermeable films on agar plates and porcine skin (removed from the animal). The laboratory DD C dye test showed no penetration into the dressing, agar, or tissue. 

Hou (1992) used a simple screening test to determine whether acid and direct dyes precipitate at calcium concentrations typical of hard waters of the SE Piedmont region of the U.S. Of the 52 dyes tested, only three direct dyes (Direct Black 19, Direct Black 22, and Direct Blue 75) and seven acid dyes (Acid Red 88, Acid Red 114, Acid Red 151, Acid Brown 14, Acid Black 24, Acid Orange 8, and Acid Blue 113) precipitated. Although the Ca salts of acid and direct dyes were thought to be the most likely metal salts to precipitate after dye discharge to natural waters, the precipitation is not likely to occur unless dye concentrations exceed 0.02 to 0.6 mg/L, a level far greater than reported concentrations of dyes in surface waters. 

Stream 1 was temporarily shut down for a period of 10-days. To ensure this was a sufficient amount of time for its clearance from the wastewater distribution system, a dye test was conducted to determine the retention time of waste from this stream in the sewer system, including the length of time to pass from the influent,... 

As mentioned earlier, emulsions do not always occur in the idealized form of drops of one phase dispersed in another. The occurrence of double and multiple emulsions, of the types O/W/O, W/O/W, O/W/O/W, etc., has already been mentioned (See Figure 1.2). In these cases the above techniques can sometimes be used to determine the continuous phase, but not always. For example, the dye test may produce misleading results when applied to a multiple emulsion, or to a bi-continu-ous emulsion. In particular, it is very difficult to follow the aggregation and/or coa-... 

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