Adhesive sheet and method of making it

Claim 1

A PRESSURE-SENSITIVE ADHESIVE SHEET WHICH COMPRISES A FLEXIBLE SYNTHETIC NON-FIBROUS FILM BACKING, A LAYER OF A HYDROPHOBIC RUBBERY PRESSURE-SENSITIVE ADHESIVE, AND A PRIMER LAYER BETWEEN SAID BACKING AND SAID ADHESIVE LAYER, SAID PRIMER LAYER COMPRISING A PRIMARY LAYER APPLIED DIRECTLY TO THE BACKING AND CONSISTING ESSENTIALLY OF A NONVOLATILE WATER-SOLUBLE POLYAMINE WITH AT LEAST TWO AMINE GROUPS SELECTED FROM THE GROUP CONSISTING OF PRIMARY AND SECONDARY AMINES AND A SECONDARY LAYER BETWEEN THE PRIMARY LAYER AND THE PRESSURE-SENSITIVE ADHESIVE LAYER AND COMPRISING A MIXTURE OF AN ISOCYANATE REACTIVE ELASTOMER AND A POLYFUNCTIONAL ISOCYANATE REPRESENTED BY THE FORMULA R(N=C=)X WHEREIN X IS AN INTEGER OF TWO OR LARGER AND R IS A POLYVALENT ORGANIC RADICAL SELECTED FROM THE GROUP CONSISTING OF A SUBSTITUTED OR UNSUBSTITUTED ARYL, ALKYL OR ARALKYL HYDROCARBON IN PROPORTIONS RANGING BETWEEN ABOUT ONE PART ISOCYANATE TO 99 PARTS ELASTOMER AND 20 PARTS ISOCYANATE TO 80 PARTS ELASTOMER, THE WEIGHT OF THE PRIMARY LAYER BEING AT LEAST ABOUT 0.0001 OUNCE PER SQUARE YARD AND THE WEIGHT OF THE SECONDARY LAYER BEING AT LEAST ABOUT 0.001 OUNCE PER SQUARE YARD.