The invention discloses a
sulfonate type hydrophilic chain
extender and a preparation method thereof, and the preparation method comprises the following steps: adding a 3-mercapto-1-
sodium propane sulfonate aqueous solution and a certain amount of a catalyst N, N-
dimethylaniline into a reaction container, and slowly heating and stirring; and after the temperature reaches a set value, adding Z / E-1, 4-butylene glycol into the reactor. In the constant-temperature reaction process, taking samples once at set intervals, titrating the taken samples with an
iodine standard solution to measure the content of double bonds in the
system, and stopping the reaction until the content of the double bonds is basically unchanged. And after the reaction is finished, carrying out suction
filtration on the residual solution in the
reaction system to obtain a
solid, washing with absolute ethyl
alcohol,
drying, and weighing to obtain the
sulfonate type hydrophilic chain
extender. The
sulfonic acid type chain
extender prepared by the invention is higher in
ionization degree, better in
thermal stability, more in variety and stronger in hydrophilicity, so that when
polyurethane with equivalent hydrophilicity is prepared, the
molar weight of the
sulfonic acid type chain extender is less than that of
carboxylic acid groups, and the
viscosity rise is reduced by slowing down the hydration volume increase rate; the preparation of the high-
solid-content waterborne
polyurethane is facilitated.