| 摘要 |
This invention is concerned with an aqueous liquid composition comprising unsaturated monomers including (1) magnesium diacrylate and/or calcium diacrylate, (2) a polyol monoacrylate selected from hydroxyethyl acrylate and hydroxypropyl acrylate, and (3) a polyethylenically unsaturated monomer copolymerizable with (1) and (2) to produce covalent cross-linking bonds in the copolymer besides the ionizable magnesium bonds. The weight ratio of (3) to the sum of (1) and (2) is in the range of about 3:97 to about 5:95. Examples of monomers that can be used as part or all of component (3) include N,N'-methylene-bis-acrylamide and ethylene glycol diacrylate. The relative proportions between the several monomers are selected to provide on polymerization a cross-linked vinyl addition polymer gel containing both covalent (non-ionic) cross-linking bonds and ionic cross-linking bonds and the relative proportions between the several components are predetermined to render the composition suitable for application by conventional mixing packer equipment hereinafter described. In such equipment, means is provided to direct a second aqueous solution or suspension containing a water-soluble free radical initiator, such as a persulfate or peroxide, separately but concurrently with the first monomer-containing solution to a common distributor head of the movable packer positioned in the sewer conduit adjacent the joint or crack to be repaired. The monomer solution is provided with a tertiary amine which serves as a reducing agent, thereby providing a redox polymerization system so that when the two liquids mix, upon discharge from the head, a rapid polymerization to a polymer gel occurs at the ambient temperature.
|
