Textile substrate

The term textile printing is used to describe the production of colored designs or patterns on textile substrates through a combination of various mechanical and chemical means. In printing on textiles, a localized dyeing process takes place, whereby in general the chemical and physical parameters of dyeing apply. 

The process of textile print coloration can be divided into three steps. First, the colorant is appHed as pigment dispersion, dye dispersion, or dye solution from a vehicle caUed print paste or printing ink, containing in addition to the colorant such solutions or dispersions of chemicals as may be required by the colorant or textile substrate to improve and assist in dye solubUity, dispersion stabUity, pH, lubricity, hygroscopicity, rate of dye fixation to the substrate, and colorant-fiber bonding. The required viscosity characteristics of a print paste are achieved by addition of natural or synthetic thickening agents or by use of emulsions. 

Reflectance Spectrophotometry. Because of discrepancies that can occur between strength and shade evaluations in solution and on textile substrates, the latter is often the preferred evaluation technique. In the case of dye manufacture, many dyes are standardized in solution but there is always a final control step where dyeings are prepared. Historically, such dyeings have been evaluated visually for the relative strength and the shade of the dye under test on the substrate, compared to the standard. More and more attempts are being made to do such evaluations objectively. Guidelines for the use of this technique have been pubflshed (43). 

Thus the detailed mechanism of peroxide bleaching is not yet finally resolved. It should be borne in mind, however, that the work of Dannacher and Schlenker was carried out at 60 °C on tea-stained cotton, whereas Spiro and Griffith studied the decolorisation of individual colorants at 21-25 °C in the absence of a textile substrate. 

FBAs can also be estimated quantitatively by fluorescence spectroscopy, which is much more sensitive than the ultraviolet method but tends to be prone to error and is less convenient to use. Small quantities of impurities may lead to serious distortions of both emission and excitation spectra. Indeed, a comparison of ultraviolet absorption and fluorescence excitation spectra can yield useful information on the purity of an FBA. Different samples of an analytically pure FBA will show identical absorption and excitation spectra. Nevertheless, an on-line fluorescence spectroscopic method of analysis has been developed for the quantitative estimation of FBAs and other fluorescent additives present on a textile substrate. The procedure was demonstrated by measuring the fluorescence intensity at various excitation wavelengths of moving nylon woven fabrics treated with various concentrations of an FBA and an anionic sizing agent. It is possible to detect remarkably small differences in concentrations of the absorbed materials present [67]. 

These are the only ranges of precursor products in the Colour Index that are still commercially significant. Azoic dyes have a close formal relationship to those monoazo pigments derived from BON acid or from acetoacetanilides (section 2.3.1) and some are chemically identical with them, although they are used in a totally different way. Azoic components are applied to produce insoluble azo dyes within the textile substrate, which is almost always cotton. Corresponding azoic components for the dyeing of cellulose acetate, triacetate and polyester fibres were once commercially important, but are now obsolete because of environmental hazards and the time-consuming application procedure. 

There are three basic ways of applying dyes to a textile substrate ... 

Dr. A. Shaw at the University of Maryland Eastern Shore in Princess Anne, Maryland, is evaluating textile substrate for pesticide barrier effectiveness and comfort. Tests will be conducted to assess effectiveness of decontamination processes for these personal protection devices. Diazinon emulsifiable concentrates will be used to contaminate fabrics. Simulated wear studies will be conducted in the laboratory to assess the efficacy of these fabrics in protecting human health. 

Surfactants. By definition every detergent product contains one or more types of surfactants. Basically, every surfactant is an organic compound consisting of two parts (I) a hydrophobic portion, normally including a long hydrocarbon chain, and (2) a hydrophilic portion, which renders the entire compound sufficiently soluble or dispersible in water or other polar solvent to serve its intended use. Together, these combined hydrophobic and hydrophilic moieties render the compound surface-active—able to concentrate at the interface between a surfactant solution and another phase, such as air. soil, and textile substrate to be cleaned. 

Iron Complexes. Iron complexes of tridentate o,o -dihydroxyazo compounds are prepared under weakly acidic conditions at 40-80°C. Both Fe11 and Fe111 salts can serve as iron source. The Fem complexes that result in both cases do not have sufficient stability to dye textile substrates, but the dyeings on leather have good fastness properties [21],... 

A related methylphosphate/phosphonate oligomer has primary alcohol end groups, and can coreact with amino resins to form a water-resistant flame retardant resin finish on paper or on textile substrates. The application of this oligomer with a coreactant methylolmelamine on cotton upholstery fabric can enable furniture covered with this fabric to pass the Consumer Product Safety Commission s proposed cigarette ignition test. 

Nanoparticles with homogeneous size can be embedded on textile substrates by plasma polym-erization/etching process or by plasma polymerization/co-sputtering process. To this effect, work is in progress in our laboratory. 

The presence of surfactants also influences the overall efficiency of other active ingredients of detergents, e.g. bleach and enzymes. Afirst requirement for the efficacy of these ingredients is a wetting of the textile substrate and hydrophobic or oily soils by the washing liquor. Besides this wetting function, all the other effects of soil removal of surfactants which have been... 

Various authors have shown that non-ionic surfactants have a beneficial effect on the hydrolysis of cellulosic and lignocellulosic substrates, whereas anionic and cationic surfactants alone interfere negatively (Castanon and Wilke, 1981 Helle et al, 1993 Park et al, 1992 Ooshima et al., 1986 Traore and Buschle-Diller, 1999 Ueda el al., 1994 Eriksson el al., 2002). Increases in the amount of reducing soluble sugars and substrate conversion were reported. The effect depends on the substrate and is not observed for soluble substrates, such as carboxymethylcellulose or cellobiose. Nonionic surfactants increased the initial rate of hydrolysis of Sigmacell 100, and when they were added later in the process they were less effective (Helle et al, 1993). They same authors found also that the addition of cellulose increases the critical micelle concentration of the surfactant, which indicates that the surfactant adsorbs to the substrate. Surfactants are more effective at lower enzyme loads and reduce the amount of adsorbed protein (Castanon and Wilke, 1981 Ooshima et al, 1986 Helle et al, 1993 Eriksson et al., 2002) which can be used to increase desorption of cellulase from the cellulosic substrate (Otter et al., 1989). Anyhow, the use of surfactants to enhance desorption of cellulases from textile substrates in order to recover and recycle cellulases was not successful (Azevedo et al., 2002b). 

It is difficult if not impossible to determine when mankind first systematically applied color to a textile substrate. The first colored fabrics were probably nonwoven felts painted in imitation of animal skins. The first dyeings were probably actually little more than stains from the juice of berries. Ancient Greek writers described painted fabrics worn by the tribes of Asia Minor. But just where did the ancient craft have its origins Was there one original birthplace or were there a number of simultaneous beginnings around the world ... 

Single-constant theory assumes that the individual pigments do not significantly contribute to the total scattering of the sample. An example of this theory is the exhausting of transparent dyes into a textile substrate. 

Optically Thin. The scattered light that is observed in optically thin systems is scattered only once much unscattered light emerges from the sample [6]. An example of such an application would be transparent dyes being exhausted into a textile substrate. 

Attempts to disrupt this cycle for textile substrates have focused on several approaches. One method is to provide a heat sink on or in the fibre by use of materials that thermally decompose through strongly endothermic reactions. If enough heat can be absorbed by these reactions, the pyrolysis temperature of the... 

Laminating polymer with high wet tack and excellent adhesion to most textile substrates. 

Coated and laminated textiles usually consist of a textile substrate, which will typically be a woven, knitted or nonwoven fabric, combined with a thin, flexible fdm composed of a natural or synthetic polymeric substance. A coated fabric is one in which the textile substrate has a polymer film applied directly to one or both surfaces as a viscous liquid in a solvent or water, the thickness of which is controlled by application via a blade or similar aperture. A transfer coated fabric is an intermediate product in which a thermoplastic film is first prepared on a release paper prior to thermally bonding to the textile substrate. A laminated fabric usually consists of one or more textile substrates that are combined with a pre-prepared polymer film or membrane by adhesives or heat and pressure (Hall, 2000). 

Other Moisture regain adds weight to textile substrates... 

Deposition on Fibers/Fabrics. Following pioneering studies by Kuhn and coworkers,89 a wide variety of textile substrates have been successfully coated with... 

Grancoat . [Grant Industries] Coating for textile substrates. 

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