| 摘要 |
Water stop compositions and methods of preparing same are disclosed. The compositions exhibit a controlled swelling or volumetric expansion upon immersion in water. The compositions swell about 5-8 % after 1 day's immersion and about 35-65 % after 28 day's immersion. A blend of fast acting sodium bentonite clay and a slower acting calcium bentonite clay contribute to this desirable controlled expansion along with a specific combination of thermoplastic elastomer, cros s- linked butyl rubber components and polyisobutylene. Another important factor in providing the desired expansion is a thorough mixing ste p to ensure product homogeneity whereby mix components are blended in a Sigma mixer for an excess period of time after all components have been added to the mixer.
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