HEAT SEALING AND PACKAGING

WRAPPING Heat sealing of wrapper laminates made of foam supported by a porous substrate sheet is improved by coating on the foam-engaging face of the substrate a barrier layer such as polyvinylalcohol to keep the heated foam from bleeding through the substrate. The support for the foam can be non-porous film such as polyethylene terephthate. The foam face of supported foam wrappers has a cohesive-nonadhesive layer containing improved volatile corrosion inhibitor and/or antistat compositions that do not shorten its shelf life below about six months. One such composition is a mixture of dicyclohexylamine with 2-amino-2-lower-alkyl-propadiol-1,3. Protective colloid such as polyvinylpyrroliodone is preferably also added to improve the compatability of the volatile corrosion inhibiting composition with the rubber latex that provides the cohesive-nonadhesive characteristics. Heat sealing of wrapper can be effected with the help of hot melting shoes.