| 摘要 |
A water swellable sealing material is prep by polymerising water soluble or miscible monomer(s) which are amide derivatives of (meth)acrylic acid or the free acids in the presence of a water-dispersible polymer as a latex or dispersion. The monomer: polymer ratio is 100:1 to 25:75, pref. 90:10 to 35:65 and esp. 40:60 to 60:40. The monomers consists of salts of quaternary gp. contg. derivatives of (meth)acrylic acids in 1-100, pref. 2.5-50, esp. 5-30%, amount based on total monomer content. The monomers may contain (meth)acrylic acid derivatives containing several unsaturated gps. in 1-30, pref. 1.5-10,% amount. The mixt. contains plasticisers selected from glycol, glycol ether or propane triol or their derivs. in 1-60% amount. The mixt. contains 1-2500, pref. 10-100% of a fillter selected from quartz, talc, mica, kaolin, chalk, dolomite, basalt, barytes, lime, gypsum or feldspar. The mixture contains 1-50, pref. 2.5-25 and esp. 5-20% of a reinforcing agent selected from (in)organic fibres, pyrogenic or precipitated silica or carbon black. The mixture contains 0.01-10% of a dyestuff, pigment, dispersant, surfactant, antioxidant, inhibitor antifoam, rheological agent or flow agent. ADVANTAGE - Rapid and easily controlled swelling with good gel strength, good property maintenance over time and good retention of swellability over frequent wet/dry cycles. The products can be flexible or rigid.
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