Study And Synthesis Of Modified Starch And Application In The Printing

Sodium alginate as a reactive dye printing paste, there is bleeding edge when printing fine patterns, and high cost of the problem, this paper developed a new printing paste to fill these gaps.Preparation of carboxymethyl starch by dry method, carboxymethyl starch, measured the average degree of substitution (DS) of0.89. Compared with sodium alginate, carboxymethyl starch’s pseudoplastic is more obvious, the value of PVI is0.286, which is more low, So carboxymethyl starch as printing paste for printing hydrophilic fibers and fine patterns in theory analysis. But it was found that carboxymethyl starch hold less water, it is the problem that the network structure of paste could not wrapped in the water. The chemical compatibility is poor with urea, baking soda and so on, increase the dosage, the viscosity decreased highly. Analysis of infrared spectra, the original paste of carboxymethyl starch and the paste without dyes, additives,their-OH peak spectrum is almost unchanged, it means hydroxyl group which on carboxymethyl starch’s2,3-position reactivity of K-type reactive dye is small. In summary, carboxymethyl starch as the printing paste, there are still some deficiencies. This paper attempts to carboxymethyl starch compound with other paste, to improve their water holding, chemical compatibility and other properties.The carboxymethyl starch mixed with guar gum paste and so on obtained LD printing paste. testing their physical properties, its main advantages are:compared with sodium alginate, LD printing paste have a higher rate, so that in the same viscosity, LD paste’s solid content is less, which is beneficial to reduce production costs; The pseudo-plastic obviously, PVI values lower than the sodium alginate, as reactive printing paste for printing hydrophilic fibers and fine patterns; Compared with sodium alginate, the chemical compatibility with Of urea, sodium bicarbonate is similar; The storage stability is better than sodium alginate. Inadequacies are: compared with sodium alginate, LD’s water holding is poorer, and chemical compatibility of resist salt is worse.Printing performance, the same dye concentration in the paste, LD paste to color is higher than sodium alginate, indicating the LD paste transfer of dye is better than sodium alginate. The color uniformity of LD paste is better than sodium alginate. The paste off rate of LD paste is lower than sodium alginate, resulting in the fabric after LD paste printing feel worse than sodium alginate. LD paste and sodium alginate for textile printing respectively, the two fabric are the same color fastness basically, pattern the same definition essentially.This article also tried LD paste mixed with different proportions of sodium alginate, observe whether it can meet different printing needs. Test their physical properties and print performance found that, the mixed Paste’s viscosity the first decreasing after increasing with sodium alginate paste in the proportion increased, LD paste and sodium alginate paste at the ratio of25:75, the viscosity is minimum. PVI value of mixed pasteis is more and more larger with the he proportion of sodium alginate increased, PVI values change linear essentially. In the printing performance, with the mixed paste of the proportion of LD paste increased, mixed paste to the amount of color the better. As the proportion of LD paste increased in mixed paste, paste off rate the lower, leading to the fabric feel worse. Mixed paste’s mixing ratio have no significant impact on pattern definition and color fastness.Finally, this paper discusses when the LD paste used for actual production, the produced effect under different process conditions. It is found that The same printing process with sodium alginate, LD paste is used less, but compared with sodium alginate, its color giving is better, paste printing permeability is low,it means that LD paste’s penetration is lower than sodium alginate paste, which useful for saving dyes; The fabric which two kinds of paste printed, color fastness are similar, but the breaking strength of zonal, the fabric printed by LD paste is better; with the final product which printed by LD paste are feel worse.