词条 | Acid dye |
释义 |
An acid dye is a dye that is typically applied to a textile at low pH. They are mainly used to dye wool, not cotton fabrics.[1] Some acid dyes are used as food colorants.[2] UsesFibersIn the laboratory, home, or art studio, the acid used in the dye-bath is often vinegar (acetic acid) or citric acid. The uptake rate of the dye is controlled with the use of sodium chloride. In textiles, acid dyes are effective on protein fibers, i.e. animal hair fibers like wool, alpaca and mohair. They are also effective on silk.[3] They are effective in dyeing the synthetic fiber nylon, but of minimum interest in dyeing any other synthetic fibers. MedicalIn staining during microscopic examination for diagnosis or research, acid dyes are used to color basic tissue proteins. In contrast, basic dyes are used to stain cell nuclei and some other acidic components of tissues.[4] DescriptionAcid dyes are generally divided into three classes which depend on fastness requirements, level dyeing properties and economy. The classes overlap and generally depend on type of fiber to be colored as well as the process used.[5] Acid dyes affix to fibers by hydrogen bonding, Van der Waals forces[6] and ionic bonding. They are normally sold as the Sodium salt, therefore they are in solution anionic. Animal protein fibers and synthetic nylon fibers contain many cationic sites. Therefore, there is an attraction of anionic dye molecule to a cationic site on the fiber. The strength (fastness) of this bond is related to the tendency of the dye to remain dissolved in water over fixation to the fiber. StructuresThe chemistry of acid dyes is complex and diverse. Most acid dyes are related in basic structure to the following:
Classes of acid dyesThree typical classification of acid dyes are:[1]
References1. ^1 {{cite encyclopedia|last=Booth|first=Gerald|title=Dyes, General Survey|year=2000|publisher=Wiley-VCH|place=Weinheim|doi=10.1002/14356007.a09_073}} {{Dyeing}}{{DEFAULTSORT:Acid Dye}}2. ^{{cite web|last=Trowbridge Filippone|first=Peggy|title=Food Color Additives|url=http://homecooking.about.com/library/weekly/blfoodcoloradditives.htm|accessdate=September 8, 2016}} 3. ^1 {{cite web|title=How Acid Dye Works|url=http://www.dharmatrading.com/home/did-you-know-how-acid-dye-works.html|accessdate=September 8, 2016}} 4. ^{{cite web|last=Bruckner|first=Monica Z.|title=Basic Cellular Staining|url=http://serc.carleton.edu/microbelife/research_methods/microscopy/cellstain.html|accessdate=December 12, 2013}} 5. ^{{cite web|title=Mechanism of Dyeing with Acid Dyes|url=http://textilelearner.blogspot.com/2012/01/acid-dyes-properties-of-acid-dyes_21.html|website=Textile Learner|publisher=Mazharul Islam Kiron|accessdate=2012-01-08}} 6. ^{{cite web |url= http://www.chemguide.co.uk/atoms/bonding/vdw.html |title=Intermolecular bonding - van der Waals forces |first=Jim |last=Clark |work=chemguide.co.uk |year=2012 |accessdate=15 June 2014}} 7. ^{{cite encyclopedia|first1 = Klaus|last1 = Hunger|first2 = Peter|last2 = Mischke|first3 = Wolfgang|last3 = Rieper|first4 = Roderich|last4 = Raue|first5 = Klaus|last5 = Kunde|first6 = Aloys|last6 = Engel|title = Azo Dyes|encyclopedia = Ullmann's Encyclopedia of Industrial Chemistry|year = 2005|publisher = Wiley-VCH|place = Weinheim|doi = 10.1002/14356007.a03_245}} 1 : Dyes |
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