coated with the heat seal polymer hs1 additional layers can be incorporated anywhere in the structure one example would be a thin flavor barrier layer over the hs2 layer for certain applications in which heat sealability is not a requirement one or both of the heat seal layers may be eliminated the significant part of the invention is a method for combining silica coated film with board in such a way as to maintain the benefits of the silica coating during the extrusion lamination step the film comes into contact with molten polymer a1 because the film has such a low thermal mass and the temperature of the molten polymer is high the surface of the film contacting the molten polymer during this step is subject to large thermal stresses during the coextrusion step the board a1 film combination is contacted by the molten polymer a2 hs2 in this step the thermal mass of the board a1 film combination is large and therefore the heat of the coextrusion is more quickly dissipated into the substrate resulting in less thermal stress than in the extrusion lamination step for this reason it is advantageous to laminate the glass coated film with the glass coated surface oriented away from the board in this orientation the glass coated surface is subject to as little thermal stress as possible and the least amount of damage to barrier properties will result cartons made from a structure incorporating silica coated film.