| 摘要 |
New water-stopping agent for cables comprises a cross linked polymer contg. at least 0.5 mg equiv./g of a sulphonic acid gp. or a sulphonic acid slt and at least 1.0mg equiv./g of an ionisable gp.. The water-absorbing ability of the crosslinked polymer for de-ionised water is more than five times greater than the dead load of the crosslinked polymer. The sulphonic acid gp. or the sulphonic acid salt is specified as gp(s). selected from among a sulphonic acid gp., sodium-, potassium-, calcium-, magnesium-, or ammonium-salt of sulphonic acid, organic amino salts. The crosslinked polymer is obtd. by a polymerisation reaction between (A) unsatd.-monomers contg. sulphonic acid gps. (5-100 mol.%) and (B) other unsatd. monomers (95-0 mol.%) in the presence of a crosslinking agent. The amt. of crosslinking agent is specified to be 0.001-0.3 mole ratio to the amt. of the mixt. of monomers. (A) can be monomer selected from sulphoethyl or sulphopropyl-(metha)acrylate, 2-acrylamide-2-methylpropan sulphonic acid, salts of these acids. The crosslinking polymer is obtd. by polymerising the polymerisable monomers in the presence of a crosslinking agent and sulphonising the polymer in the presenc of a sulphonising agent. The water stopping process is achieved by filling a sheath cable with the water-stopping agent or fibrous water-stopping materials, tapes, etc.. Water-stopping tapes are obtd. by attaching the water-stopping agent to the surface of a film or sheet with an organic binder opt. with inorganic powder. |
