The present invention relates to the technical field of
polymer compositions, particularly to a
polyurethane toughened vinyl resin preparation method, which comprises: mixing a
polyurethane prepolymer, a vinyl resin, a catalyst and a
polymerization inhibitor to obtain an initial
system, and stirring; the light
transmittance of the initial
system is detected, a phase separation starting point is determined according to the light
transmittance change rate value and the light
transmittance change acceleration value, and a homogeneous
system is obtained; determining
polymerization parameters according to the phase separation characteristic parameters; adjusting the homogeneous system to an initial
polymerization temperature and an initial polymerization
shear rate, and adding an initiator in batches according to the adding times of the initiator; and after the initiator is completely added, detecting the
viscosity and temperature distribution of the homogeneous system to obtain a polymerization state index, and adjusting the polymerization temperature and the polymerization
shear rate to obtain the high-
toughness vinyl resin. According to the method, the problems that a phase separation point is difficult to accurately judge and the polymerization process is uncontrollable in the preparation of the
polyurethane toughened vinyl resin, so that a
network structure defect is caused are solved.