The invention discloses a preparation method of
carboxymethyl starch used for
reactive dye printing.
Starch is taken as a main
raw material, a compound modification technology is adopted, different modification reactions are successively completed in
slurry taking a mixed
solvent as a reaction medium, and finally the
carboxymethyl starch is generated. The preparation method comprises the following steps: firstly dispersing
starch in the mixed
solvent containing ethyl
alcohol and
isopropyl alcohol, adding alkaline liquor for carrying out low temperature alkalization, then adding an etherifying agent for carrying out high temperature etherification, then adding a crosslinking agent at a certain temperature for carrying out micro-crosslinking, after crosslinking reaction is finished, washing,
drying, and smashing, so that the
carboxymethyl starch is obtained. The preparation method disclosed by the invention has the advantages that the mixed
solvent is adopted in the technology, so that carboxymethylation reaction of the
starch can be promoted, and substitution uniformity of the product is improved; the
starch is subjected to low temperature alkalization, so that starch pasting can be effectively prevented, and the
solubility and transparency of the product are improved; high temperature etherification can promote the
permeation effect of feed liquid to the starch, and the
reaction rate is accelerated; and micro-crosslinking can improve the structural
viscosity and
salt resistance of the product to a certain degree. The carboxymethyl starch product can completely replace
sodium alginate.