Method and apparatus for laying up laminates of adhesive backed sheets

Abstract

A paper web having a longitudinally extending zone coat of adhesive is continuously wound around the cylindrical surface of a rotating drum for a selected number of wraps to form a multi-layer cylindrical master stack. Web tension is controlled during winding to cause each succeeding wrap to be placed in relatively greater tension, so that when the completed cylindrical stack is cut transversely and unwrapped from the drum, equalization of the tensile stresses in the web wraps results in a flat master stack of rectangular sheets of equal length. The stack is further processed by cutting along transverse and longitudinal cut lines to form individual pads of adhesive-backed notes. Tension control may be based directly on the increase in drum radius resulting from the buildup of web wraps or by maintenance of print pattern register between continuous equally spaced print patterns in overlying wraps. By utilizing a pair of rotatable lay-up drums which are translatable between preparatory and wrapping positions, the process of the present invention may be operated continuously. A lay-up drum with a compressible outer surface may be used whereby the initial web wraps will result in compression of the drum, some reduction in drum diameter, and a reduction in the tensile stress in initially applied wraps. The lay-up process is completed in the manner set forth above.