The Influence Of Aldehyde Components To The Dyeing Of Silk By Aromatic Amine Dyes

Silk is one of the high-grade textile materials which is light,soft and fine.At present,the silk can be dyed with direct dye,acid dye,reactive dye and metal complex dye,but there are still many problems,such as high energy consumption in dyeing processing,high pollution,poor color fastness for some dyeing methods.Therefore,it is important to explore a kind of environmentally,friendly dyeing method with low energy consumption and high color fastness for promoting the development of China's silk industry.In order to solve the dyeing problem of silk fiber,our group used dye which contains aromatic primary amine groups to stain the silk fabric by formaldehyde bridging based on Mannich reaction at low temperature,and developed a new dyeing method which has low consumption and high color fastness.However,the existence of formaldehyde on the human body has great harm,so this paper study the dyeing effect of different low toxicity aldehyde components in Mannich dyeing,screen for suitable aldehydes for Mannich staining,and discussed its mechanism.We select a commercial dye C.I.Acid Green 20 which contains an aromatic primary amine group to stain the silk fiber under different aldehydes(glutaraldehyde,methylglyoxal,benzaldehyde,furfural,paraformaldehyde)based on Mannich reaction.Test the K/S curve of the silk which were stained by various aldehydes.The results show that the silk using the methylglyoxal as the aldehyde component gains the best color depth.Then optimize the Mannich dyeing conditions on the basis of previous results.Finally test a series of physical properties of the optimum methylglyoxal Mannich stained silk and compare with formaldehyde.Found that the formaldehyde was substituted by methylglyoxal for Mannich reaction Dyeing silk has the feasibility.Under the optimized dyeing conditions,we use the commercial dye Acid Brown 4 and group made Acid Orange D3 to stain the silk fabric based on Mannich reaction.Test the dyeingproperties and physical properties of dyed silk fabrics.It was found that the fixation rate of the three dyestuffs was more than 61% when the silk fabrics were treated by Mannich method.The K/S value of the silk fabrics after dyeing obtained over 7,and the washing fastness was above 4,rubbing fastness has reached a 4-5 level,and dyeing silk fabrics containing aldehyde residues have reached the highest standards of textile products.The mechanical properties of the silk fabrics stained by the Mannich method were decline,but within the acceptable range,indicate the effect of the Mannich dyeing silk fabrics on the strength was not significant.We use the acid green 20,acid orange D3 and acid brown 4 as the amine component,methylphenol as the mimetic of silk tyrosine,via methylglyoxal conduct the Mannich reaction to dicuss the dyeing mechanism of Mannich reaction.The results of IR and MS showed that the simulation products were consistent with the expected products,which indicated that the Mannich reaction occurred within the aromatic primary amine dye,methylglyoxal and methylphenol.It can be concluded that the aromatic primary amine dye were also stained the residues of tyrosine residues in silk according to Mannich reaction mechanism in the presence of methylglyoxal.