TAPE HAVING IMPROVED TEAR STRENGTH

摘要

The present invention relates to reinforced pressure-sensitive adhesive tapes, and to a method for making these tapes. Reinforced tapes, also known as filament tapes, generally comprise a backing having adhered to one major surface thereof by means of an adhesive a plurality of yarns, which comprise a multiplicity of glass or synthetic polymeric filaments. Typically, a layer of pressure-sensitive adhesive is then applied over the yarn- or filament-bearing surface of the tape. Although filament tapes are extremely useful, the cost of making them is high because of the high cost of filaments and the high cost of processing. In order to reduce the cost of making filament-reinforced tapes, some manufacturers have resorted to reducing the number of filaments adhered to the backing. However, this expedient reduces the tear strength of the tape. It is desired to have a tape having a reasonably high level of tear strength, but at a much lower cost than that of high quality filament-reinforced tapes. This invention provides a tape comprising a backing bearing on at least one major surface thereof a plurality of ribs disposed substantially longitudinally thereon, and further bearing on at least one major surface thereof a layer of adhesive. The ribs are joined to the backing such that there exists a notch-like separation between each end of the rib and the surface of the backing. No more than 50% of the cross-section of the ribs should project from the rib-bearing surface of the tape. It is preferred that the adhesive be a pressure-sensitive adhesive. The tape of this invention can be prepared by means of coextrusion techniques.