System and method for welding a seam between thermoplastic liner sheets
AssigneeLinabond Inc.
InventorRichard L. Bertram
Life of this patent
Estimating the term…
Abstract
Sheets of thermoplastic material for lining structural containers and conduits, and having portions of their surfaces at the edges to be joined to each other treated with urethane, are joined and sealed by a strip of polyvinyl chloride, the interacting surface of which is prepared by hydroxyl modification for sealing with the thermoplastic sheets. The joinder is accomplished by a method that dispenses with any necessity of specially treating the surfaces at any prescribed time prior to accomplishing the joinder, and dispenses with any requirement for heat elevation during joinder. A method of joinder with the thermoplastic sheets alone is also shown.
Claims24
A method for bonding polyvinyl chloride to polyurethane, comprising:
- a) providing a base polyurethane layer, said base polyurethane layer having an excess isocyanate component in its composition;
- b) applying a resin containing free hydroxyl groups to one or more portions of one or more polyvinyl chloride sheets to create treated portions of said one or more polyvinyl chloride sheets, said resin being applied in a solution containing a solvent;
- and
- c) bonding said one or more polyvinyl chloride sheets to said base polyurethane layer, said bonding taking place between said treated portions of said one or more polyvinyl chloride sheets and said base polyurethane layer,
- wherein said solvent is operative to allow said resin to dissolve and become impregnated in said treated portions of said one or more polyvinyl chloride sheets.
A method for bonding polyvinyl chloride to polyurethane, comprising:
- a) providing a base polyurethane layer, said base polyurethane layer having an excess isocyanate component in its composition;
- b) applying a resin containing free hydroxyl groups to one or more portions of one or more polyvinyl chloride sheets to create treated portions of said one or more polyvinyl chloride sheets, said resin being applied in a solution containing a solvent;
- c) bonding said one or more polyvinyl chloride sheets to said base polyurethane layer, said bonding taking place between said treated portions of said one or more polyvinyl chloride sheets and said base polyurethane layer;
- d) arranging said one or more polyvinyl chloride sheets such that adjacent ones of said one or more polyvinyl chloride sheets are positioned with one polyvinyl chloride sheet overlapping an adjacent polyvinyl chloride sheet to create overlapping regions, and said treated portions of said one or more polyvinyl chloride sheets including said overlapping regions;
- and
- e) applying an intermediate polyurethane layer, said intermediate polyurethane layer having an excess isocyanate component in its composition, between said overlapping regions of adjacent ones of said one or more polyvinyl chloride sheets;
- wherein said solvent is operative to allow said resin to dissolve and become impregnated in the treated portions of said polyvinyl chloride sheets.
Dependencies are inferred from the claim text.