W. R. Grace & Co., Cryovac Div.

W. R. Grace Co.

Francesco Pezzana

Cesare Quacquarella

Paolo Colombo

Ezio Ghirardello

The invention relates to laminated films and articles of manufacture based on such films and having improved resistance to heat treatment, wherein said films comprise a heat sealing layer of copolyamide obtained by random copolymerization of precursor monomers of at least two different polyamides. Said laminated films, or the articles of manufacture formed therefrom, such as bags or preformed containers, are useful for packaging applications, particularly in connection with food products.

Laminated packaging films and related articles of manufacture having

A plurality of multi-walled bags of flexible plastic material is formed by taking a longitudinally folded flat web of a first flexible plastic film; at least partially separating the superposed plies of said first flexible plastic film at the edge opposite the fold line and moving the film past a corona discharge electrode between the separated plies of the film to pre-treat at least a part of the inwardly facing surface of each of said two plies; taking a longitudinally folded flat web of a second flexible plastic film; corona discharge-treating the outwardly facing surfaces of the two plies of said second flexible plastic film; passing the pre-treated web of said second flexible plastic film over a diverter guide into the space between the two at least partially separated plies of said first flexible plastic film to bring the fold lines of the first and second flexible plastic film webs substantially into register with the two webs moving synchronously in a single direction; and sealing the composite of the two folded webs at a sealing station, along spaced transverse seal lines to form a plurality of open-ended bags having the bottom of each bag defined by the registered fold lines of the two webs and the mouth region of the bag defined at the web margin opposite the said fold line. The bags may be either wound up in a roll without severing or severed from one another and then stacked or attached to feed tapes in a imbricated way.

Apparatus for making multi-walled plastic bags

A plurality of multi-walled bags of flexible plastic material is formed by taking a longitudinally folded flat web of a first flexible plastic film; at least partially separating the superposed plies of said first flexible plastic film at the edge opposite the fold line and moving the film past a corona discharge electrode between the separated plies of the film to pre-treat at least a part of the inwardly facing surface of each of said two plies; taking a longitudinally folded flat web of a second flexible plastic film; corona discharge-treating the outwardly facing surfaces of the two plies of said second flexible plastic film; passing the pre-treated web of said second flexible plastic film over a diverter guide into the space between the two at least partially separated plies of said first flexible plastic film to bring the fold lines of the first and second flexible plastic film webs substantially into register with the two webs moving synchronously in a single direction; and sealing the composite of the two folded webs at a sealing station, along spaced transverse seal lines to form a plurality of open-ended bags having the bottom of each bag defined by the registered fold lines of the two webs and the mouth region of the bag defined at the web margin opposite the said fold line. The bags may be either wound up in a roll without severing or severed from one another and then stacked or attached to feed tapes in an imbricated way.

Growing community of inventors

Pregnana Milanese, Italy

Francesco Pezzana