Study On The Reactive Dyeing Of The Aromatic Primary Amine Dyes On Silk Fiber And Their Dyeing Performances

Silk is a protein fiber and known as Queen of fiber, which is deeply loved by the people.Now the dyes used in silk dyeing mainly are acid dyes、reactive dyes、direct dyes and metallizedcomplexed dyes. Acid dyes easily influenced by solvation water, resulting in poor washingfastness. Reactive dyes have a serious hydrolysis problem in the process of fixing color,produced large amounts of waste water and treatment difficult. Direct dyes have poor wetfastness and easy to pollute environment when soar washing.Metallized complexed dyes dyeingfiber which have lots of heavy residual metal ions in the dye bath and fiber and easy to produce anegative impact on human health and the environment. Therefore,to development a new dyeingmethod which forming a strong covalent bond with silk fiber and saving energy will has greatsignificance to the development of dyeing and finishing industry.Silk protein contains a high content of tyrosine residues which molecular structurecontaining active-H, therefore can as the acid component through Mannich reaction with thearomatic primary amine acid dyes under the action of aldehyde, forming C-C-N covalent bondbetween dye and silk firmly, increasing the dyeing silk fabric washing fastness. This paper basedon Mannich reaction principle, designed and synthesized different color aromatic primary aminedyes containing orange dye D1, blue dye D2and purple dye D3.The products were characterizedwith UV-vis,MS,FT-IR,1H-NMR to confirm the structure of the product was consistent withthe desired,and realized reactive dyeing on silk fabric under the effect of formaldehyde.In this paper, the K/S value and levelness of the soap washing dyeing fabric as evaluationcriteria to study the best coloration process of silk fabrics based on the Mannich reaction ofaromatic primary amine acid dyes, dye concentration was4%(owf) optimum process conditionsof dyeing silk fabric: dye with formaldehyde molar ratio was1:3, dye bath pH5.5,bath ratio1:75,30℃temperature, dyeing time for10h. On the basis of exploring optimum process,thesynthesis of the three dyes and screening from commodity acid green20dye and cid brown4dye were dyed to silk through Mannich staining method in order to get different color dyeingfabric. This paper further study the color fastness and mechanical properties of Mannich methoddyeing the silk f.The results showed the washing fastness grades are not less than4. The dryrubbing fastness grades are not less than4, and the wet rubbing fastness grades are not less than3and the light fastness grades are not less than3. The colored silk fibers can not easily beextracted down by DMF that prove forming strong covalent bonds between dye and fiber.Inaddition,the breaking strength was tested after Mannich method dyeing fabric, the results showedthat the silk fabric breaking strength loss were less than5%,and no significant effect existed inthe mechanical properties.