Dyed textiles, bleaching

In Berthollet s day the love of color and personal adornment was as strong as ever, and the demand for dyed textiles came from those who could afford it. Before dyeing textiles however they had to be bleached, which required spreading the cloth on the ground. This was not only labor intensive, but it kept fertile fields from being tilled. Berthollet developed a chemical bleaching process that used chlorine... 

In spin dyed secondary acetate threads, fibers, and films, P.B1.25 exhibits good textile fastness properties the only problem is a certain lack of fastness to bleaching with sodium hypochlorite (Sec. 1.6.2.4). Its fastness to light in 0.1% spin dyed specimens equals step 3-4 on the Blue Scale, while 1% samples equal step 5. 

Technical Tests.—To ascertain the suitability of a starch for use in the dressing of textiles, samples of fabrics dyed with sensitive colours (benzopurpurin, Turkey red, logwood black) or of bleached fabrics are treated with the starch the dry materials are examined as regards feel and change of colour, while the general appearance is compared with that of the same material dressed with a standard starch. 

PENTEX FR is a nonlonic/anlonic blended surfactant that is a biodegradable product for textile wet processing operations. Typical uses are in preparation of fabrics (bleaching), boil-off, and scouring of yarns and fabrics, soaping of fast dye yarns and fabrics particularly when dyed with fiber reactive dyes. 

Textile products are also finally bleached and then dyed. Physical and/or chemical processes participate in dying processes and discussion of these is more a domain for textile chemistry. Here, the dyeability of synthetic fibers can be increased by polymerizing in small quantities of certain comonomers which have a better affinity to the dyestuffs than the monomeric units of the actual fiber forming polymer. For example, certain acidic comonomers I and II in PET and PA for basic dyestuffs, basic comonomer III in PET and PA for acidic dyestuffs, acidic comonomers IV-VI in PAN for basic dyestuffs, and basic comonomers VII-IX in PAN for acidic dyestuffs ... 

Many thousands of colorant species have been synthesized in order to obtain the breadth of shade and dyeing properties desired by the textile industry, the largest user of dyestuffs. The principal requirement for a good textile dye is that it be substantive (i.e., have affinity for the fiber being dyed). This requires that there be some potential for attraction between the fiber and the dye as well as a mechanism for permanently affixing the dye to the fiber. This subject is discussed in more detail below. Other desirable dye properties include uniform dyeing, wash fastness, resistance to rub off (crock fastness), bleach fastness, and lightfastness. 

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