Method for preparing polyurethane elastomer capable of rapidly expanding when contacting water

Abstract

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.

Description

technical field [0001] The invention relates to a method for preparing a polyurethane elastomer, in particular to a method for preparing a polyurethane elastomer that rapidly expands when exposed to water. Background technique [0002] Water-swellable elastomer is a kind of rubber that not only has the rebound performance of general rubber, but also has the characteristics of rapid expansion of water absorption volume after contact with water. It is made by introducing hydrophilic functional groups or hydrophilic components on traditional elastic substrates. Water-swellable elastomers have attracted more and more attention because of their unique dual water-stop characteristics of elastic sealing and water-absorbing swelling. Especially in dam construction, tunnel construction, arsenal, granary, urban water supply facilities and other anti-seepage and water leakage projects are widely used. At present, the closest prior art with the present invention is as follows: [000...

AI Technical Summary

Problems solved by technology

The obtained water-swellable material has good mechanical properties and good expansion rate, but the expansion rate is not specified

[0010] In addition, the chain extenders used in the above polyurethane water-swellable materials are all low-molecular chain extenders commonly used in the production process of polyurethane, which can help to improve the mechanical properties, but the expansion rate and magnification will be limited to a certain extent.