Preparation of plastic-metal laminates

Claim 1

IN A METHOD OF HEAT BONDING A PREFORMED, PLIABLE CONTINUOUS PLASTIC FILM COMPRISING A FLUOROCARBON POLYMER TO A METAL SURFACE WITHOUT EMPLOYMENT OF APPLIED COMPRESSIVE PRESSURE TO SAID OR USE OF BONDING ADDITIVES; WHEREIN THE SAID FILM IS FIRST SUPERIMPOSED UPON THE METAL SURFACE OF A THIN FLEXIBLE METAL SHEET IN ATMOSPHERIC ENVIRONMENT OVER A SUBSTANTIAL BONDING AREA, AND THEN THE UNBONDED COMBINATION IS SUBJECTED TO PAARTIAL OR NEAR TOTAL VACUUM, AND, NEXT BROUGHT TO THE SOFTENING AND BONDING TEMPERATURE OF THE PLASTIC, THE PLASTIC FILM HAVING NO CONFINING CONTACT ON ITS SURFACE AT ANY TIME DURING HEATING AND BONDING WITHIN THE BONDING AREA AND ENTRAPPED AIR BETWEEN THE PLASTIC FILM AND THE METAL SURFACE BEING LINERATED BY THE VACUUM UPON PRIMARY EXPANSION OF THE PLASTIC AS ITS TEMPERATURE IS RAISED, THEREBY PROVIDING AIR FREE BONDING WHEN SAID FILM SHRINKS AND BONDS AS THE TEMPERATURE IS ELEVATED, THE IMPROVEMENT WHEREIN, PRIOR TO SUBJECTING TO VACUUM AND HEATING, THE SUPERIMPOSED LALYER OF METAL SHEET AND PREFORMED PLIABLE PLASTIC FILM ARE WRAPPED IN COILS AROUND A SHAFT OR CORE, WITH SUPERIMPOSED SPACER MEANS AT EACH END OF THE COIL TO PROVIDE AN EXPANSION SPACE FOR A LAYER OF FILM BETWEEN EACH COIL, BOUND WITH SECURING MEANS TO PREVENT UNCOILING, AND THEN SUBJECTED TO VACUUM AND HEATING, TO BOND PLASTIC FILM TO THE METAL SHEET WITHIN THE BONDING AREA, INTERMEDIATE SAID SPACE MEANS AND SAID SECURING MEANS.