The Low Damage Pretreatment And Dyeing Technology Of Soybean Protein Fiber

China is the first country that realizes the industry production of soybean protein fiber in the world. This technical achievement fills up the vacancy of original innovation technology of China in the field of chemical synthetic fiber, and also influents the research direction of development of new fiber in the 21st century.Soybean protein fiber is a new kind of regenerated protein fiber, which meets the demands of environmental protection and is provided with basic advantages of other natural fibers. It has cashmere-like handle, silk-like gentle luster, cotton-like hygroscopicity and vapor permeability, wool-like warmth retaining. And what's more, its exclusive capacities of caring for people's health make it popular in the market.Nowadays the soybean protein fiber is widely applied in the fashion industry. But at the same time, the lack of sound dyeing and finishing technology is restricting soybean protein fiber's special capacities. Generally speaking, the effect of bleaching to soybean protein fiber is not so good as to gain the satisfactory light or bright shade. Meanwhile, blindly pursuing high whiteness only leads to seriously injured fiber.In this paper, it is mainly discussed about the low damage pretreatment and dyeing technology of soybean protein fiber. The nitrogen content is analyzed to judge the damage degree of soybean protein by Kjeldahl method of nitrogen determination. The nitrogen contents after processing fabric are evaluated by compared with those of the grey fabric. The processing experiments indicate that, when the value of pH closing to 7, the nitrogen contents are highest, and reduce quickly with the deviating degree of the value of pH from neutral. With the increasing of the temperature, not only the nitrogen contents reduce, but also the hand feeling becomes stiff. The nitrogen contents can keep on a high level if the processing time is controlled in less than 60mins. The protein of the fiber will be decomposed if the concentration of the alkali is too high and when the concentration of sodium carbonate exceeds 30g/L, thenitrogen contents are lower than 2.0%. After discussing the independent influence of temperature, time, pH value and the concentration of alkali, the optimum pretreatment conditions are confirmed by orthogonal experiments. In the pretreatment, starch enzyme and hydrogen peroxide are respectively applied in the process of desizing and bleaching.Soybean protein fiber is a kind of regenerated protein fiber, and can be dyed with reactive dye and acid dye. According to the dyeing behavior of reactive dye Argazol TW, it is found that the pH value has some influence on its dyeability. When dyeing the fabric on the condition of the pH value closing to neutral, the building up properties will be best while the damage of protein will be relative lower. Using Lanasol reactive dyes especially for wool dyeing only light shade can be obtained on the soybean protein fiber, so are the other reactive dyes with two functional groups. They can only be used when intensify the fixing process or to the dyeing of light to medium shade. As for the acid dyes, the milling acid dyes has better performance on the soybean protein fiber than the leveling acid dyes, and it gets deep and bright shade because of the mutual attraction between the fiber and the dye ion. The performance of the leveling acid dyes will be improved by adding more acid, but the protein of soybean fiber will be decomposed because of the effect of concentrated acids.In order to achieve better washing fastness of soybean protein fiber dyed with acid and reactive dyes, two kinds of fixing agents named Dinfix RF and Dinfix F-100 are applied on the dyed fabric. It is found that the washing fastness and rubbing fastness are improved greatly.