| 摘要 |
PURPOSE:To provide a water cut-off tape having extremely rapid initial water cut-off effect to salt water of high concentration by compounding a foaming agent that forms gas by being brought into contact with water, with a specific ratio of water absorbing resin, and by fixing the mixed composition to a base material. CONSTITUTION:A foaming agent of 2-30 pts.wt.or preferably 5-20 pts.wt. that forms a gas when being brought into contact with water, is mixed with 100 pts.wt. of water-absorbing resin. As the water-absorbing resin, a cross-linking polymer containing 1-10mg equivalent/g of dissociation radical consisting of carboxylic group and/or sulfonic group is preferred, such as a cross-linking polymer of (metha) acrylic acid (salt)-acrylic amide. As the foaming agent, lithium carbonate or sodium hydrogencatbonate and the like is used. The compounded composition is applied to a base material (such as nonwoven fabric or synthetic film) by using an organic binder (such as buthyl rubber), and is fixed thereto. A water cut-off tape of excellent salt resistance can thus be provided, the water cut-off performance of which can be ensured for a long time. |
