Positive valve closure for plastic-lined bags and method for making same
View Patent ↗A plastic valve bag construction is provided having structure enabling positive closure of the outer opening of the valve, once filling of the bag has been completed. Closure is provided by the placement of adhesive on one or more regions adjacent the outer opening of the valve which one or more regions of adhesive are covered by a removable shield. A method for making such plastic valve bags is also disclosed.
1. A positive sealing apparatus, in combination with a valve bag, wherein the valve bag has a tubular body, with an outer lap overlying an inner lap with a seal extending longitudinally therebetween, the valve bag having a valve opening formed by a gap in the longitudinal seal, the valve bag further having portions of the outer and inner laps disposed adjacent and to the outside of the valve opening, the positive sealing apparatus comprising:
a valve seal liner, disposed in juxtaposed overlying relation to at least one of the portions of the outer and inner laps disposed adjacent and to the outside of the valve opening,
at least one strip of adhesive material, disposed between the valve seal liner and the at least one of the portions of the outer and inner laps disposed adjacent and to the outside of the valve opening,
the adhesive having a first adhesive affinity for the material from which the bag is fabricated, and a second adhesive affinity for the material from which the valve seal liner is fabricated, the first adhesive affinity being greater than the second adhesive affinity, whereupon removal of the valve seal liner, the adhesive remains on the at least one of the outer lap and the inner lap, and further upon pressing of the outer lap against the inner lap, the outer lap and inner lap are adhered to one another, the at least one strip of adhesive material being located so as to completely seal a region between the outer and inner laps that completely surrounds the valve opening of the bag, for creating a positive seal, toward precluding undesired escape of material contained within the bag
said valve seal liner further comprising a first portion disposed in juxtaposed overlying relation to the portion of the outer lap disposed adjacent and to the outside of the valve opening and a second portion disposed in juxtaposed overlying relation to the portion of the inner lap disposed adjacent and to the outside of the valve opening, so that the valve seal liner extends across the valve opening, along a distance greater than a length of the valve opening.
2. The positive sealing apparatus according to claim 1 , wherein the at least one strip of adhesive material comprises a first strip of adhesive material disposed between the first portion of the valve seal liner and the portion of the outer lap disposed adjacent and to the outside of the valve opening, and a second strip of adhesive material disposed between the second portion of the valve seal liner and the portion of the inner lap disposed adjacent and to the outside of the valve opening.
3. The positive sealing apparatus according to claim 1 , wherein the valve seal liner comprises a perforation line extending at least partially between the first and second portions of the valve seal liner, the perforation line being substantially aligned with the valve opening of the valve bag, the perforation line being configured to be breached by a filling nozzle of a filling apparatus to permit entry of the filling nozzle into the valve, to provide access into an interior region of the valve bag.
4. The positive sealing apparatus according to claim 1 , wherein the valve seal liner comprises a sheet of siliconized plastic material.
5. The positive sealing apparatus according to claim 4 , wherein the plastic material is one of: high density polyethylene, polyester, polypropylene.
6. The positive sealing apparatus according to claim 1 , wherein the at least one strip of adhesive material is fabricated from a synthetic rubber material.