Process for producing a laminate

A process for producing a laminate comprising a sheet layer and a plastic film laminated on at least one side of the sheet layer, which comprises vacuum-packaging the sheet layer by a vacuum packaging film material by disposing the sheet layer in laminatable relationship between two sheets of film material whose peripheries are brought into superimposed contact in the process, the two sheets forming the two sides of a package containing the sheet layer when the peripheries are sealed to each other, and hermetically sealing the peripheries to each other so that a vacuum may be sustained within the hermetically closed package so formed after the vacuum has been created therein, at least the final sealing occurring after evacuation of the space between the two sheets of film material between which the sheet layer is disposed, of which package at least the sheet of film material corresponding to said side of the sheet layer is made of a plastic film to be laminated on the sheet layer, press-bonding the plastic film to the sheet layer, at least the final press bonding occurring after the final sealing forming the hermetically closed package, and removing the film material from the sheet layer except for the plastic film portion laminated on the sheet layer, wherein the vacuum packaging film material is a pair of film sheets not attached to one another disposed in a vacuum chamber, and wherein one of the two film sheets is the plastic film to be laminated on the sheet layer and the other is a film other than the plastic film, the other film is disposed to divide the vacuum chamber into two compartments, the sheet layer is inserted between the plastic film and the other film in one compartment, the entire vacuum chamber is then vacuumed, the two films are then brought close together to enclose the sheet layer and the periphery of the films is sealed under the vacuumed condition to obtain a vacuum-package sheet material, and after the press-bonding of the plastic film to the sheet layer the periphery of the plastic film is cut off along the outline of the sheet layer.