American Can Company

Dennis E Kester

Roger P Genske

William F Ossian

Ronald C Christensen

Sheldon I Schlesinger

Joseph M Guarnery

The invention provides improved films and pouches made therefrom for use in sterile packaging, wherein the package and product are sterilized after the process of filling and sealing the pouch. The improved films are a family of foil-based, multiple layer structures incorporating an improved combination of layers which form the sealant layer and the adhesive bonding to the foil layer. The sealant layer is linear low density polyethylene. The layer adjacent the sealant layer is a blend of 20% to 80% propylene ethylene copolymer and 80% to 20% linear low density polyethylene. The foil layer is primed with an anhydride modified propylene-based primer. Additional layers comprising propylene based polymers may be used between the blend layer and the primer.

Retortable foil-based packaging structure

Retortable packaging is made entirely with polymeric materials. The improved heat sealable structure has an inner heat seal layer of linear low density polyethylene. The second or adjacent layer is linear low density polyethylene with an optional 0% to 80% medium density polyethylene blended into it. A third layer is anhydride modified medium density polyethylene. Fourth, fifth and sixth layers respectively are nylon, ethylene vinyl alcohol and nylon. An optional layer between the second and third layers is at least 20% linear low density polyethylene and up to 80% medium density polyethylene. The entire multiple layer structure is firmly adhered together so that the layers mutually support each other in the unitary package.

Retortable packaging structure

A retortable pouch is made without the use of metal foil. The improved heat sealable structure has an inner heat seal layer of linear low density polyethylene. The second, or adjacent layer is a blend of 20% to 80% linear low density polyethylene and 80% to 20% propylene ethylene copolymer. Optional third, fourth and fifth layers are propylene ethylene copolymer. A sixth layer is anhydride modified polypropylene. A seventh layer is nylon, the eighth layer is ethylene vinyl alcohol copolymer and the ninth layer is nylon. The entire multiple layer structure is firmly adhered together so that the layers mutually support each other in the unitary package.

Photopolymerizable compositions using sulfonium salt photoinitiators to effect polymerization of cationically polymerizable monomers as essentially the sole polymerizable material additionally include an organic sulfur compound scavenger to reduce or eliminate the sulfur odor generated upon photodecomposition of the sulfonium salt photoinitiator. The scavengers are simultaneously activated by the electromagnetic radiation to react with the organic sulfur compound concurrently generated and are selected from the group consisting of aromatic ketones, benzoin compounds, aryloin oxime compounds, organic peroxide compounds, and benzil compounds.

Cationically polymerizable compositions containing sulfonium salt

A polymerizable coating composition comprises 35-80 parts of an epoxy prepolymer material and 20-65 parts of a vinyl chloride dispersion polymer together with 0.5-10 percent by weight, based upon the weight of the epoxy prepolymer material, of an onium salt photoinitiator which decomposes upon exposure to electromagnetic radiation to initiate polymerization of the epoxy prepolymer material. The vinyl chloride polymer has a high molecular weight represented by an inherent viscosity of 0.60-1.60 and a particle size of 0.5-20.0 microns. The coating is applied to the surface of a substrate and then exposed to a source of electromagnetic radiation to decompose the photoinitiator and initiate polymerization of the epoxy prepolymer material to a tack-free surface condition in which the vinyl chloride polymer is dispersed within the epoxy polymer. This is desirably effected by maintaining the coating at a temperature of about 50.degree.-90.degree. C. for a limited time following exposure to radiation. After the coating has been cured to a tack-free condition, it is desirably baked at a temperature of at least 150.degree. C. to effect substantial fusion of the vinyl chloride polymer and cross-linking of the epoxy polymer.

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Neenah, WI, United States of America

Dennis E Kester