Abstract: An opaque, biaxially oriented polymeric film structure.

Abstract: A gel-forming composition capable of plugging highly permeable zones in a subterranean formation. The composition comprises water, a viscosifying amount of a water-dispersible polyvinyl amine copolymer and a crosslinking agent which is a mixture of an aldehyde and a phenolic component in an amount effective to cause gelation of the aqueous solution of the copolymer. The resultant gel is exceptionally thermally stable and, therefore, can be used as an effective profile control agent in all enhanced oil recovery operations, including steam flooding.

Abstract: A process for use with a polymer which is crosslinkable by reaction with an amino resin, which comprises the steps of determining a period of time within which full gelation of the polymer is to be achieved; preparing a gel-forming aqueous-based mixture comprising the polymer, a rapid amino resin crosslinking agent and a delayed amino resin crosslinking agent, the gel-forming aqueous-based mixture capable of complete gelation within the period of time so determined; partially gelling the aqueous-based mixture by reacting the polymer with the rapid amino resin crosslinking agent which is effective to complete the partial gelation by crosslinking the polymer within four hours; and fully gelling the aqueous-based mixture by reacting the polymer with the delayed amino resin crosslinking agent which is effective to complete the full gelation by crosslinking the polymer within the period of time so determined. A method of enhancing the recovery of oil from a subterraean oil-bearing formation is also provided.

Abstract: A liquid leak detector for above-ground tanks includes an upright standpipe connected to the tank so that the standpipe can be filled with liquid from the tank to the same level as the liquid in the tank. A pressure transducer is connected between the bottom of the tank and the bottom of the standpipe to measure the difference in pressure of the liquids in the tank and standpipe. Any change in the liquid pressure at the bottom of the tank as a result of leakage from the tank will change the pressure differential on the pressure transducer. This changes the output of the transducer which can be recorded to indicate leakage from the tank.

Abstract: Head pressure and extruder torque in the extrustion of linear ethylene polymers such as linear low density polyethylene (LLDPE) are reduced by adding a small amount (less than 5 weight percent) of a thermoplastic polyurethane. Films extruded from the blend exhibit better surface appearance by reduction of melt fracture.