Abstract: A flame retardant, low dielectric constant, controlled coefficient of thermal expansion, low cost prepreg material which includes randomly distributed silane coated hollow microspheres has been prepared by standard impregnation and lamination techniques. Laminates made of this prepreg can be drilled cleanly for through holes and can be used as a substrate for surface mounted devices.

Abstract: A process for laminating discrete sections of a supported photosensitive layer onto a continuing series of sheet substrates. Each substrate is advanced to and through the nip of heated application rolls, and a continuous length of the supported photosensitive layer is also supplied to the nip. When the substrate reaches a first location positioned between the application rolls, all movement ceases except that the rolls move from an inactive disengaged position toward the substrate to an active position to cause pressure contact between the photosensitive layer and the substrate to thereby laminate the photosensitive layer to the substrate. There is a pause for a predetermined period of time with the rolls in the active positions before the substrate is again advanced with the rolls still in the active positions and the photosensitive layer again supplied to the nip.