| 摘要 |
PROBLEM TO BE SOLVED: To provide a composition for filling cavities, which yields a lightweight highly-expanded foam having a compression strength of 0.05 MPa or higher and is used for filling cavities behind the lining concrete in old tunnels, etc. SOLUTION: This composition comprises a liquid A containing a polyol, a chelating catalyst and water, and a liquid B mainly comprising an isocyanate. The mixing weight ratio of liquid A to liquid B is within the range from 1:3 to 1:7, and the amount of water blended is within the range of from 0.8 to 2.5 wt.% of the total amount of liquid A and liquid B. Preferably, the polyol contains a low-molecular weight glycol, and the glycol content is 30 wt.% or higher based on the total weight of the polyol.
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