Method of forming polymeric bags
AssigneePoly-America, L.P.
InventorsBrad A. Cobler, Anthony H Bertrand
Life of this patent
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Abstract
The present invention relates to improvements for the manufacturing of a wave-cut bag, more specifically a wave-cut bag with improved tie-flaps. Disclosed is a process for intermittently incrementally stretching and imparting a rib-like pattern to a collapsed tube of a blown film extrusion process. The incrementally stretched collapsed tube is particularly well suited for constructing wave-cut trash bags with a rib pattern on the tie-flaps of the trash bags. Further disclosed is a wave-cut trash bag with a rib pattern on its tie-flaps and surrounding area.
Claims20
A method of forming a bag of polymeric film, the method comprising:
- forming a collapsed tube of polymeric film, the collapsed tube having a machine direction,
- a pair of intermeshing rollers intermittently engaging and disengaging the collapsed tube to form a plurality of incrementally stretched sections and un-stretched sections on the collapsed tube,
- wherein each incrementally stretched section comprises a plurality of thick and thin ribs with each rib extending generally perpendicular to the machine direction,
- a length of each incrementally stretched section increased by the pair of intermeshing rollers, and
- each stretched section extending an entire width of the collapsed tube, and
- forming the collapsed tube into a plurality of bags, each bag comprising at least a fraction of one of the plurality of incrementally stretched sections.
A method of forming a bag of polymeric film, the method comprising:
- forming a collapsed tube of polymeric film, the collapsed tube having a machine direction,
- a pair of intermeshing rollers engaging and disengaging the polymeric film of the collapsed tube intermittently to form a plurality of incrementally stretched sections and un-stretched sections on the polymeric film,
- wherein at least one of the intermeshing rollers is not in contact with the collapsed tube when the pair of intermeshing rollers is disengaged from the collapsed tube, and
- forming the collapsed tube into a plurality of bags, each bag comprising at least a fraction of one of the plurality of incrementally stretched sections.
A method of forming a bag of polymeric film, the method comprising:
- forming a collapsed tube of polymeric film, the collapsed tube having a machine direction,
- a pair of intermeshing rollers intermittently engaging and disengaging the collapsed tube to form a plurality of incrementally stretched sections and un-stretched sections on the collapsed tube,
- each incrementally stretched section extending an entire width of the collapsed tube and increasing a length of the incrementally stretched section,
- each incrementally stretched section comprising a plurality of thick and thin ribs extending generally perpendicular to the machine direction,
- wherein each bag formed comprises at least a fraction of one of the plurality of incrementally stretched sections,
- forming sets of closely spaced, parallel seals extending transversely across a width of the collapsed tube at equally spaced intervals, each seal of the set of parallel seals defining a bag bottom,
- forming perforation lines extending transversely across the width of the collapsed tube, a perforation line between each set of parallel seals,
- generating a unique timing signal for each perforation line, each unique timing signal based on detection of a location of each perforation line, a location of each incrementally stretched section determined from the unique timing signal, and
- forming wave-shaped perforations extending across the width of the collapsed tube, each wave-shape perforation defining an upper opening for a set of bags.
Dependencies are inferred from the claim text.