Adhesive tapes

Claim 1

IN THE METHOD OF PREPARING A PRESSURE-SENSITIVE CELLULOSIC ADHESIVE SHEET BY MIXING ONE TO THREE HUNDRED AND FIFTY PARTS BY WEIGHT OF A POLYFUNCTIONAL ISOCYANATE HAVING THE FORMULA R(N=C=O)X WHERE X IS AT LEAST TWO R IS A POLYVALENT ORGANIS RADICAL SELECTED FROM THE GROUP CONSISTING OF AN ERYL, ALKYL, SUBSTITUTED ARYL AND A SUBSTITUTED ALKYL, AND ONE HUNDRED PART OF A RUBBERY MATERIAL SELECTED FROM THE GROUP CONSISTING OF NATURAL RUBBER, COPOLYMERS OF BUTADIENE AND STYRENE COMPRISING AT LEAST 30% OF BUTADIENE, POLYBUTADIENCE, AND COPOLYMERS OF ISOBUTYLENE AND ISOPRENE; APPLYING THE RESULTING COMPOSITION IN THE AMOUNT OF FROM ONE-ONE HUNDRETH OF AN OUNCE TO ONE-HALF OUNCE PER SQUARE YARD TO A FLEXIBLE, REGENERATED CELLULOSE FILM BACKING, AGING SAID COMPOSITION IN SAID BACKING, AND APPLYING A PRESSURE-SENSITIVE ADHESIVE COMPRISING A RUBBER MATERIAL TO SAID COATED BACKING, THE IMPROVEMENT COMPRISING AGING THE COMPOSITION IN THE BACKING AT A TEMPERATURE BETWEEN ABOUT ROOM TEMPERATURE UP TO ABOUT 150* C. AND FOR A PERIOD OF TIME BETWEEN ABOUT 8 SECONDS UP TO ABOUT 8 DAYS, THEREBY CAUSING THE PRIMER TO BOND TO THE BACKING WITHOUT DELETERIOUSLY AFFECTING THE BACKING, SAID TEMPERATURE RANGE AND SAID TIME RANGE BEING IN INVERSE ORDER WITH RESPECT TO ONE ANOTHER, AND SAID TIME BEING LESS THAN ABOUT THREE MINUTES AT A TEMPERATURE ABOVE 80* C. AND NOT MORE THAN ABOUT ONE MINUTED AT A TEMPERATURE OF 100* C.