초록 ▼

In the manufacture of plastic bags having interlocking profiled extrusions for the closure, the extruded plastic profiles are applied to a moving web of film immediately after extrusion of the profiles. The profiles are fused to the web on a first section of a fusing/cooling arcuate plate-like suppo

In the manufacture of plastic bags having interlocking profiled extrusions for the closure, the extruded plastic profiles are applied to a moving web of film immediately after extrusion of the profiles. The profiles are fused to the web on a first section of a fusing/cooling arcuate plate-like support member. Thereafter, the web is moved to a second cooled section of the arcuate plate-like support which is maintained at a temperature to allow the profiles to freeze to the web. The moving web of film is maintained under tension so that contraction of the film upon release compensates for the contraction of the locking profile as it cools to prevent puckering of the web. The locking profiles are applied to the web in an in-line process, which includes folding and heat sealing the moving web of film to form plastic bags.

대표청구항 ▼

An apparatus for attaching locking profile extrusions to a plastic film, comprising: first and second serially arranged arcuate plate-like support sections for receiving and supporting a web of film; means for moving a web of film over said first and then said second arcuate plate-like support secti

An apparatus for attaching locking profile extrusions to a plastic film, comprising: first and second serially arranged arcuate plate-like support sections for receiving and supporting a web of film; means for moving a web of film over said first and then said second arcuate plate-like support sections; an extruding assembly positioned adjacent to said moving web, comprising first and second means for extruding first and second locking profiles onto said web while said web is positioned on said first arcuate plate-like support section, and means for supplying molten thermoplastic to said extruding assembly; means for cooling said profiles while on said second arcuate plate-like support section to freeze said profiles onto said web; and means for maintaining said moving web under tension as it passes over said first and second arcuate plate-like support sections so that upon release of said moving web contraction of said film upon release compensates for the contraction of said profiles as the profiles cool to prevent puckering of said moving web. A method of attaching locking profile extrusions to a plastic film, comprising: moving a web of film over first and second serially arranged arcuate plate-like support sections for receiving and supporting a film web; extruding from an extruding assembly first and second locking profiles of molten thermoplastic onto said moving web; joining said profiles and said web on a fusing section of said first arcuate plate-like support section; freezing said profiles to said web on said second arcuate plate-like support section; and maintaining said moving web under tension as it passes over said first and second arcuate plate-like support sections so that contraction of said film upon release of said tension compensates for the contraction of said profiles as said profiles cool to prevent puckering of said moving web.