Acrylic acid Basic dyes

Depolymerised Carpet printing/dyeing acid, metal-complex dyes Cotton, viscose vat, direct, azoic dyes Polyester disperse dyes Nylon acid, metal-complex dyes Acrylic fibres basic dyes... 

Uses Acid/basic dye compatibilizerfor cationic/disperse dyes, acrylic dyeing Features Low foam good in-bath scour Properties Thick liq. 80% cone. 

Basic Dyes. These are usuaUy the salts of organic bases where the colored portion of the molecule is the cation. They are therefore sometimes referred to as cationic dyes. They are appHed from mild acid, to induce solubUity, and appHed to fibers containing anionic groups. Thein main outiet is for dyeing fibers based on polyacrylonitrile (see Fibers, acrylic). 

HPLC-UV is a popular technique to analyse textile dyes extracted from polyester fibres [697], acidic dyes from wool fibres [698] and basic dyes from acrylic fibres [699]. HPLC provides better sensitivity and resolution than TLC [697-699]. GE-RPLC has been used for the determination of 18 disperse dyes (e.g. Navy D-2G-133, Orange CB, Yellow D-3R and Red D-2G) extracted from polyester [700]. Compared with the traditional TLC method, HPLC offers lower detection limits, better observation of contaminant peaks, and reproducible quantitative results. HPLC has also been used to determine azo dyes [701,702]. 

The dye-fibre systems of obvious interest for approach (b) are milling acid and 1 2 metal-complex dyes on wool or nylon, basic dyes on acrylic fibres and disperse dyes on various fibres. With wool and nylon there is often some overlap with approach (c) (section 12.2). 

Non-destructive partial stripping techniques for basic dyes on acrylic fibres are carried out at 100 °C (or higher if possible) using, for example, 1-10% o.w.f. anionic retarder and 1 g/1 acetic acid (60%), or 1-5 g/1 Marseilles (olive oil) soap. Destructive stripping requires acidified (pH 5.5-6.0) sodium hypochlorite, followed by an antichlor treatment in sodium dithionite or sodium bisulphite. In some cases a preliminary boiling treatment in 5 gA monoethanolamine and 5 g/1 sodium chloride is said to improve the effect of the stripping treatment. 

Controversy has arisen at times [52] regarding the apparent synonymity of the terms basic dye and cationic dye . The Society of Dyers and Colourists defines a basic dye as characterised by its substantivity for the acidic types of acrylic fibres and for tannin-mordanted cotton , whereas a cationic dye is defined as one that dissociates in aqueous... 

Difficulties of incompatibility can arise with mixtures of basic dyes on acrylic fibres because of competition for the limited number of dyeing sites available and the differences between dyes in terms of affinity and rate of diffusion. The rate of uptake of each dye when applied in admixture with another is invariably slower than when the dye is applied alone at the same concentration. Competition effects of this kind can lead to serious practical problems unless the dyes are carefully designed and selected to have similar dyeing characteristics [97,98,104,105]. Dyes with exceptionally low affinity and rapid rates of diffusion have been developed, offering improved migration on acrylic fibres [106]. These dyes have migration properties not unlike those of monosulphonated acid dyes on nylon. 

Basic (Cationic) Dyes. The use of basic dyes is confined mainly to acrylic textile fibers, acetate, and as complementary dyes for acid-modified polyester libers that accept this class of dyes. 

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. 

Acrylic fibers are dyed most frequently with basic dyes. This is made possible by copolymerizing acrylonitrile with an acidic monomer such as styrene-para-sulfonic acid. Acrylic fiber suitable for acid dyeing can be made by using a basic comonomer such as a vinyl pyridine or a vinyl pyrrolidone. 

A dispersing agent for disperse dyes when applied to nylon having no affinity for the nylon An anti-precipitant in the dyeing of wool and acrylic fibers where a neutral dyeing acid and a basic dye is used in the same bath. 

In 1970, an acid-dyeable polypropylene fiber was described [158]. It was claimed that this fiber could be dyed like nylon and could produce one-batch union shades in blends with cotton and acrylics. The dye site in this fiber was present as a microfilament dispersed within the polypropylene. These microfibers extended to the surface of the fiber and water was readily absorbed in order that acid dyes could penetrate at a reasonable rate to react with the basic dye sites. Acid-dyeable polypropylene fiber products have been available from Phillips [159] and, from Polyolefin Fibres Engineering (PFE) Ltd. [160]. PFE has also introduced a bicomponent fiber readily dyeable with disperse dyestuffs [161]. 

For other major apparel fibers such as wool, silk, and nylon a dye class referred to as acid dyes is routinely used for coloration. Reactive dyes have also been developed for wool and are widely used for fashion apparel items because of their bright, broad color range. A range of mordant dyes is also available for wool and other animal fibers. The mordant dyes provide very high levels of fastness, but the shade range is limited, the shades are typically dull, and the application process is complicated. For acrylic fibers the dominant dye class is the basic dye. For polyester apparel, the insoluble disperse dye range is almost exclusively used. 

Acid dyes are compounds in which the chromophore is part of a negative ion (usually an organic sulphonate RSO2O-). They can be used for protein fibres (e.g. wool and silk) and for polyamide and acrylic fibres. Originally, they were applied from an acidic bath. Metallized dyes are forms of acid dyes in which the negative ion contains a chelated metal atom. Basic dyes have chromophores that are part of a positive ion (usually an amine salt or ionized imino group). They are used for acrylic fibres and also for wool and silk, although they have only moderate fastness with these materials. 

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... 

Poly(acrylonitrile) fibers have very good light and weathering stability, high bulk strength, and good heat retention properties. Their wool-like character makes them particularly useful for sweaters and other overwear. The poor dyeability is improved by copolymerization with 4% 2-vinyl pyridine or AT-vinyl pyrrolidone (basic dyes), 4% acrylic acid or methallyl... 

Basic dyes are cationic materials that have high affinity (typically over 6 kcal/mol) for binding to anionic sites (typically SOb" in acrylic and certain other fibers (e.g., copolymer versions of polyester and nylon). They are usually applied by batch dyeing procedures from acidic baths at temperatures of 200-220°F, using a procedure similar to the following ... 

In certain cases, identifying the specific garment or textile product and the allergen it contains will be an important undertaking. The fiber content of the fabric will narrow the possible dyes, as certain dyes are used to color certain fibers. Cotton, rayon, and linen fabrics are dyed with direct, fiber-reactive, mordant, azoic, sulfur, and vat dyes. Wool fabrics are dyed with acid, mordant, and fiber-reactive dyes. Polyester fabrics are dyed with disperse dyes unless the polyester is modified to accept basic dyes. Nylon fabrics are colored with acid and disperse dyes unless modified to accept basic dyes. Acrylic fabrics are dyed with basic and disperse dyes. Acetate fabrics are dyed with disperse dyes. Other synthetic fibers are dyed with disperse dyes. 

Dyes in this group are those in which the chromogen is positively charged (i.e., cationic) and water soluble. They owe their substantivity to the electrostatic attraction between the dye and the anions formed from acid groups on the polymer chains of the fiber. Consequently, basic dyes are used largely to dye acrylic fibers. They find some use as well in coloring basic dyeable polyester. Methylene Blue (4) (Fig. 4) is an example of a basic... 

The nature and distribution of acrylonitrile and comonomer or comonomers in the acrylic fibers affect the overall dyeability and the classes of dyes that may be used in dyeing these fibers. Both acrylic and modacrylic fibers can be dyed using disperse dyes, with the more hydrophobic and less crystalline modacrylic being more dyeable with this dye class. The polar cyanide groups in the acrylonitrile unit of these fibers have some affinity for acid dyes and particularly mordanted systems containing copper or chromium ions. Addition of an acid or basic comonomer such as acrylic acid or vinyl pyridine as comonomer imparts improved dyeability with basic and acid dyes, respectively, for these fibers. Vat dyes can be used on acrylic fibers to a limited extent. 

Basic dyes are applied from weakly acidic dyebaths and are used to dye acrylic and cationic dyeable polyester. The cationic positively charged portion of the dye molecule in solution aligns with an anionic, negative charged site on the fiber that the fiber manufacturers include in the polymer. The ionic bonding that occurs is the result of the anionic dyesite forming ion pairs with the quaternary amine group present as part of the dye molecule (Fiber-R NH3-Dye). 

Fixation Immobilisation of the dye molecules inside the fibre. Note Different methods include insolubilisation (e.g. for vat and sulfur dyes in cotton polymeric binders with pigments), chemical bonds (e.g. hydrogen bonding for direct dyes in cotton), ionic bonding (e.g. acid dyes in wool and nylon, and basic dyes in acrylic), covalent bonding (e.g. reactive dyes in cotton) and solubility in the fibre (e.g. disperse dyes in polyester, nylon and acetate). 

Acid dyes are synthetic dyes typically applied to natural fibers, such as wool and silk, as well as to polymer-based fibers, such as polyamides and acrylics. The method of dyeing is through the use of dye baths, and chemical affixation occurs in part by the formation of salts between cationic and anionic functional groups in the fibers and dyes, respectively. Water-soluble basic dyes are also applied to the same class of substrates. But even though they are also cationic, basic dye baths require an acetic acid additive to promote uptake to the fibers. Hence, basic dyes can be tailored for use with cellulosic fiber-based materials. 

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