Abstract: The present invention relates to polyurethane elastomer systems for industrial and paper mill rolls and more particularly to polyurethane covered rolls made from a new polyurethane composition of a polyurethane prepolymer cured with an aromatic diamine and a hydroxyl-terminated polybutadiene resin. Rolls made with this new polyurethane composition exhibit improved dynamics, hydrolytic stability, and reduced water vapor transmission over conventional polyurethane elastomer systems.

Abstract: The problems caused by chemical and thermal shrinkage of hard roll covers, are reduced by the inclusion of one or more intermediate compressive layers between the metal roll substrate and the outer cover, or cover. A compressive layer has the properties of being rigid enough to allow the cover to be applied to the roll, and compressible enough to deform and absorb the stresses which occur as the cover is shrinking during processing.In one embodiment, the intermediate compressive layer comprises a three dimensional fabric that is filled preferably with a thermoset resin system which cures at lower temperature than cover. In a second embodiment, the precise amount of shrinkage in the roll is predetermined to a high enough degree of accuracy so that a depth for the fabric layer can be used to compensate for the amount of shrinkage, thereby eliminating the need for filling. In a third embodiment, the compressive layer is comprised of a meltable material wherein said material melts at cure temperatures.

Abstract: The problems caused by chemical and thermal shrinkage of hard roll covers, are reduced by the inclusion of one or more intermediate compressive layers between the metal roll and the outer cover, or topstock. A compressive layer has the properties of being rigid enough to allow the topstock to be applied to the roll, and compressible enough to buffer and absorb the stresses which occur as the topstock is shrinking during processing.In one embodiment, the intermediate compressive layer comprises a three dimensional fabric that is filled preferably with a thermoset resin system which cures at lower temperature than topstock. In a second embodiment, the precise amount of shrinkage in the roll can be predetermined to a high enough degree of accuracy so that a depth for the fabric layer can be used to compensate for the amount of shrinkage, thereby eliminating the need for filling. In a third embodiment, the compressive layer is comprised of a wax material.

Abstract: A roll system for use particularly in a papermaking press nip for dewatering a fibrous web, comprising a roll disposed so as to rotatingly cooperate with another roll in a press nip, the roll having a helical sensor for sensing pressure exhibited on the roll, and transmitting pressure signals to a processor as the roll rotates. Trigger signals are generated at certain times as the roll rotates, the time of the occurrence of the trigger signal representing a specific location on the helical sensor. The pressure signals are coordinated with the trigger signals, such that the pressure corresponds to the angular position of the roll where it is sensed. The operator may thus be given a visual or audible indication of the existence of non-uniformities in pressure sensed at various locations along the roll, thereby enabling corrective action to be initiated if necessary.

Abstract: Elastomers are plasticized with a polymerizable monomer, in homogeneous admixture therewith, by adding the monomer to a latex of the elastomer, free of polymerization initiator, followed by coagulation of the monomer and polymer solids. The coagulated solids recovered from the latex may be compounded with a polymerization initiator for the monomer and a vulcanizing agent for the polymer and, optionally, an inorganic filler, and shaped into the desired product form. Polymerization of the polymer and vulcanization of the elastomeric polymer are initiated after shaping.