a flexible film laminate and retortable pouch therefrom comprising a first layer of heat - sealable polyolefin film ; a syndiotactic poly - 1 , 2 - butadiene adhesive be bonding said first layer to a second layer of polyacrylonitrile homopolymer film ; said laminate having been subjected to conditions sufficient to effect the generation of free radicals in the system to an extent resulting in greater bond strength between layers than in the absence of said conditions .