Abstract: A back-up pad is provided over an anvil surface of a back-up plate, and between the anvil surface and a sealing surface of a sealing die, in an apparatus for forming seals between layers of film material. The back-up pad has a slip layer on one side thereof and a firm polymeric support layer on an opposite side thereof, the slip layer opposing the sealing face of the die so that the layers of film material pass between the sealing die and the back-up pad during seal formation. The polymeric support layer may have a Shore-A hardness of at least 10 at 20° C. and a dynamic loss tangent of less than 0.1 from 20° C. to 80° C. An example of a support layer is a polycarbonate pad, and an example of slip layer is a glass cloth coated with Teflon™. The back-up pad is particularly useful for forming lap seals in relatively thick film materials, such as laminated films having multi-layered films laminated together.

Abstract: A metallized biaxially oriented film has at least one polypropylene layer and a metallized skin layer. This skin layer is formed from a blend of polymers including syndiotactic polypropylene. The polymer which is blended with the syndiotactic polypropylene may be a butylene-propylene copolymer or a graft copolymer of propylene and maleic anhydride. The film may include a separate non-metallized biaxially oriented film laminated to the metallized biaxially oriented film. The metal layer provides a barrier to oxygen and water vapor. The metallized film can be processed through package forming machines without damage to the metal barrier layer.

Abstract: A multi-layer film has an improved composite structure for providing hermetic seals to packages manufactured in high speed packaging apparatus. The structure of the multi-layer film includes layers A/B/C/D. Skin layer A is formed from polypropylene copolymer with melt flow rate greater than one or linear high density polyethylene with melt index greater than one. Core layer B is formed from polypropylene. Intermediate layer C has the primary function of compliance during sealing, and sealing layer D has the primary function of providing adhesivity to the completed seal.

Abstract: The present invention is a multi-layer film which has an improved composite structure for providing hermetic seals to packages manufactured in high speed packaging apparatus. The structure of the multi-layer film of the present invention includes a main substrate and a sealant layer. The sealant layer, in turn, includes two components, an intermediate layer which has the primary function of compliance during sealing, and a sealing layer which has the primary function of providing adhesivity to the completed seal. As a result of this invention, high strength hermetic seals can be provided to multi-layer films effectively and efficiently, and hermetic seals are provided with the ability to be peeled open without destruction of several layers of the film.

Abstract: A base thermoplastic film, has a coextruded or coated heat seal layer formed from a polymer blend which provides good peel-apart heat seals. When the film is sealed to itself, the seal opens by separation at the original seal surface without film tear, or by delamination of the sealant material from the primary base film substrate without the formation of strands extending between the two base film. The heat seal layer which may be on one or both sides of the base layer comprises a ternary blend of a random ethylene-propylene copolymer, a butene polymer and a low density polyethylene.The films are cast, and oriented in the solid state up to about two times in the machine direction and six times or more in the transverse direction to give films having good dead-fold and water vapor transmission rate characteristics making them highly suited for packaging, particularly for dry foods.