Process for forming peelable seals
AssigneeVonco Products, Inc.
InventorLouis Lawrence Laske
Life of this patent
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Abstract
A process for forming peelable seals between a layer of spunbonded olefin material and an unsupported film of polyethylene or to a supported film of a laminated or coated backing, such as polyethylene coated Mylar, to form a peel-seal packet, container or pouch. The spunbonded olefin material is first pretreated with a heated die in the areas that are to form the peel-seal with heat and pressure suitable to render uniform surface characteristics to the spunbonded olefin. The heat, pressure and dwell time of the pretreatment are sufficient to eliminate the high spots and internal weaknesses of the spun-bonded olefin material following which a web of synthetic polymeric material having a heat sealable surface may be peelably sealed by a conventional heat sealing method.
Claims9
A method for forming peelable seals between uncoated spunbonded olefin sheet material and a synthetic polymeric thermoplastic sheet material comprising maintaining a substantial portion of said spunbonded olefin sheet untreated and breathable, modifying the surface of the spunbonded olefin sheet in the area of the desired peelable seal by pretreatment with heat and pressure to sbustantially eliminate high spots and internal weaknesses to render the sealing area susceptible to having said synthetic polymeric thermoplastic material peelably joined thereto in said pretreated area by conventional heat-pressure sealing, and peelably sealing said pretreated spunbonded olefin sheet to said synthetic polymeric thermoplastic sheet material by conventional heat-pressure sealing only in said pretreated area.
The method of making a peel-seal container which comprises steps of:
- drawing a first web of an uncoated spunbonded olefin material into a pretreatment area;
- subjecting the peel-seal area of said uncoated spunbonded olefin to heat and pressure for a time sufficient to modify the surface in the area of said peel-seal to substantially eliminte the high spots and internal weaknesses to render said desired sealing area susceptible to having a second sheet of heat sealable synthetic polymer material peelably joined thereto by conventional heat-pressure sealing while maintaining a substantial portion of said spunbonded olefin web untreated and breathable;
- drawing a second web of a heat sealable synthetic polymeric material into an overlying relationship to said first web;
- and
- subjecting both said layers to heat and pressure for a time sufficient to cause said layers to be peelably joined together only in the peel-seal area.
Dependencies are inferred from the claim text.