Abstract:
The present invention relates to a process for applying optical brightening agent (OBA) to a sheet of paper or paperboard substrate. The process comprises the step of spraying an aqueous composition comprising an optical brightening agent onto at least one surface of a sized paperboard substrate to form a treated paperboard substrate. The treated paperboard substrate includes a layer of OBA on at least one surface of the paper or paperboard substrate in which the brightness of the treated paper or paperboard substrate is greater than the sized paper or paperboard substrate before treating thereof.
Abstract:
A process for providing printable substrates by separately treating one or both surfaces of a paper substrate with an optical brightening agent (OBA) and a multivalent metal salt drying agent, where one or both surfaces of the paper substrate is treated with one of these two agents at the size press, and where the surface(s) is treated with the other of these two agents before or after the size press.
Abstract:
A composition is provided, which comprises a water-soluble salt of a divalent metal; a complexing agent having an affinity for the divalent metal; and an optical brightening agent. Methods of using the composition, and recording sheets which include the composition, are also disclosed.