Leather Basic Dyes

The nomenclature given for these componnds is a nniversally recognised system for the naming of dyestuffs devised by the Society of Dyers and Colourists as part of their Colour Index (Cl). The Cl Generic Name is made up of the application class, the hne and a nnmber. Acid dyes are nsed on wool and polyamide, direct dyes on cel-lulosic fibres, paper and leather, disperse dyes on polyester fibres, reactive dyes on cellnlosic fibres and basic dyes on polyacrylonitrile and paper. 

Other Dyes. Other dye classes listed in the Colour Index include dyes lor leather, solvents, paper, and food. Leather dyes arc those acid, direct, mordant, and basic dyes that show substamivily for leather, good diffusion into it. and acceptable fastness. They are essentially applied in an analogous... 

Basic dyes of the azo class were among the earliest known synthetic dyes. They were used originally for dyeing cotton mordanted with tannin and potassium antimonyl tartrate and wool from neutral solution. They continue to have minor importance for dyeing leather, paper, plastics, and waxes, and as constituents of graphic arts colors. 

The triarylmethane dyes were also very important leather dyes in the past. The central carbon is sp2-hybridized (triarylmethine) and can add a hydroxyl group to form the respective carbinol base with spP-hybridized carbon. The dyes react like Lewis acids and some species act as pH indicators (e g., phenolphthaleine). The term cationic dyes is therefore recommended for this dye class instead of basic dyes. Nowadays only the sulfonated triphenylmethine dyes are used for leather. 

Basic dyes are used almost exclusively for overdyeing, e g., to achieve deep black shades by laking. Recent research indicates that new cationized sulfur dyes for leather will shortly become commercial products. In the 1970s dicationic azo dyes for paper were introduced by azo coupling of aromatic diazonium ions with heterocylic components. The resulting cationic azo dyes are also applied on leather e.g. C.I. Basic Black 11. The constitution is not disclosed. 

In 1862 Nicholson sulfonated basic dyes and thus created the first amphoteric and acid leather dyes. Triaiylmethane (triarylmethine) dyes (Table 5.3) and their different uses are typical examples of this development. 

Almost all basic dyes have been sulfonated, including Nigrosine Spirit Soluble (see Section 5.4.1) The sulfonated variant C./. Acid Black 2, 50420 [8005-03-6] is still applied to leather, mainly as a shading component for deep black. 

Synthetic dyes are mainly aromatic organic compounds, and they can be classified as cationic (basic dyes), anionic (direct, acid, and reactive dyes), or nonionic (disperse dyes) type [134]. Synthetic dyes are mainly used in the textile industries, but they have many other applications such as in printing, leather, papermaking, drug, and food industries [85]. Total world colorant production is estimated to be... 

Materials used for leather dyeing are usually acid dyes, direct dyes, mordant dyes (Thorstensen, 1993) and reactive dyes (Shao and Zhao, 1984). Basic dyes are primarily used for dyeing vegetable tanned leather (Sandoz, 1949). 

Acid dyes Azoic colouring matters Basic dyes Developers Direct dyes Disperse dyes Fluorescent dyes Food dyes Ingrain dyes Leather dyes Mordant dyes Natural dyes Oxidation dyes Pigments Reactive dyes Reducing agents Solvent dyes Sulphur dyes Condense sulphur dyes Vat dyes... 

Basazol . [BASF AG] Basic dyes for ptqjermaking, leather. 

USE In manuf of smokeless powder and dynamite as a solvent for basic dyes in tanning leather. 

Storage Hygroscopic store in a tightly closed container in a cool, dry, well-ventilated area away from incompat. substances Uses Basic dye for bast, silk, leather solvent... 

Hazardous Decomp. Prods. Heated to decomp., emits acrid smoke and irritating fumes Storage Very hygroscopic Uses In mfg. of smokeless powd., dynamite solvent for basic dyes In tanning leather plasticizer for cellulose acetate, cellulose nitrate pigment dispersant in cellophane for food pkg. 

Ammonium persulfate Arsenic trioxide dye, animal Sodium arsenate dye, anodized aluminum Acid violet 49 dye, aq. inks Direct green 1 dye, aq. writing inks Direct blue 1 dye, azoic acetate 2-Methoxy-5-nitroaniline dye, azoic cotton 2-Methoxy-5-nitroaniline dye, azoic nylon 2-Methoxy-5-nitroaniline dye, azoic silk 2-Methoxy-5-nitroaniline dye, basic acrylic fiber Basic blue 9 Basic green 4 dye, basic bast Basic orange 14 dye, basic cotton Basic brown 1 dye, basic leather Basic blue 9 Basic violet 10 dye, basic paper Basic violet 10 dye, basic silk Basic orange 14 dye, basic textiles Basic brown 1 dye, bast... 

Almost every leather is dyed, mostly with synthetic organic colors. The majority of the dyes used are anionic azo dyes which bind to the cationic surfaces of the leather. For completion of the dyeing process, formic, acetic or lactic acid is added. Afterwards, basic dyes can be applied which give the leather a brilliant... 

Basic dyes are water-soluble in the form of their salts and are used for colouring paper, leather, cellulose- and polyacrylonitrile fibres. The free bases dissolve in many organic solvents and find application similar to that of the solvent dyes. Basic dyes can function as pigments in lacquer form. Mixtures of basic dyes are usually responsible for brown, green and black tones. 

The data on / y values of some dyes used in the leather industry (75,76) are recorded in Tables 9A-9D. The leather dyes are divided in four groups, i.e., acid dyes, direct dyes, basic dyes, and premetallized dyes. 

Milk of Magnesia is an alkaline (basic) water suspension and creamy-like suspended form of magnesium hydroxide, MglOH). It is used as an antacid to neutralize excess stomach acid. Magnesium can also be used in the form of Epsom salts as a treatment for rashes and as a laxative. A more important commercial use of Epsom salts is in the tanning of leather, as well as in the dyeing of fabrics. 

Oxazine, azine and thiazine dyes are named for the characteristic heterocyclic ring systems 1,4-oxazine, 1,4-diazine, and 1,4-thiazine. The dyes are generally cationic (basic) or acid dyes. They also can be reduced to colorless forms, then oxidized back to the dye, as in vat dyeing. The dyes also have been used to a limited extent in disperse and fiber reactive applications. They are used as titration indicators and may be applied to acrylic fibers and leather. 

Azo dyes with relatively low molecular masses and one to three sulfonic acid groups serve as acid azo dyes for dyeing and printing wool, polyamide, silk, and basic-modified acrylics and for dyeing leather, fur, paper, and food. The main area of application is the dyeing of wool and polyamide. 

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. 

Basic azines are predominantly of historical interest. Yellow, red, brown, blue, and black shades can be obtained with these dyes. Today, Nigrosine Spirit Soluble is still used in shoe polish and creme. The sulfonated variety is applied as a leather dye. It is a polymeric dye containing phenazine ring systems, similar to Aniline Black. C.I. SolventBlack 5, 50415 [11099-03-9] (Nigrosine, spirit-soluble) C.I. Solvent Black 7, 50415 1 [8005-02-5] (4) is the free base. 

Dyes and color pigments Leather tanning and leather processing Rayon and synthetic hber manufacturing Sodium/potassium cyanide-associated industries Basic drugs manufacturing Foundry industries Storage batteries (lead acid type)... 

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