The invention relates to a method for preparing a
polyurethane elastomer capable of rapidly expanding when contacting water, which comprises the following steps of: preparing a hydrophilic
polyurethane prepolymer and a hydrophobic
polyurethane prepolymer in a component A; then preparing a component B, namely an
epoxy resin modified triethylene
tetramine waterborne curing agent; and calculating
mass parts of the components A and B according to the
molar ratio of
isocyanate groups to active
hydrogen groups of 1:0.8-0.9, adding 0 to 0.5
mass part of black paste, uniformly mixing, carrying out vacuum defoaming, pouring into a die of which the temperature is 120 DEG C, heating, pressurizing and vulcanizing to obtain the
polyurethane elastomer material capable of rapidly expanding when contacting water. Compared with other polyurethane elastomers capable of expanding when contacting water, the
polyurethane elastomer material capable of expanding when contacting water, which is prepared by the method of the invention, has the advantages that: expansion multiplying power and expansion speed are high,
expansion rate in
fresh water can reach 400 to 600 percent,
hardness can reach
Shore A 40 to 60, tensile strength can reach 4.0 to 6.0MPa and time required for total expanding is 120 to 240 minutes; and the
elastomer material has excellent
mechanics characteristic and water expansibility and is convenient to use. The
mass fraction of the components A and B is calculated according to the
molar ratio of the
isocyanate groups to the active
hydrogen groups of 1:0.8-0.9 and the components A and B are uniformly mixed and the mixture is directly used for in-site concreting, solidification and sealing.