Laminate including fluid compression rolled polymer

Claim 1

A biaxially tearable laminate having a low moisture vapor transmission rate, comprising: (a) a fluid compression rolled, uniaxially oriented base film about 0.5 to 2.5 mils thick comprised of at least a major proportion of high density polyethylene, said base film having, in the direction of the axis of orientation, a tensile strength of at least about 15,000 pounds per square inch, an elongation value of less than about 150 percent, and a tear strength of about 5 to 100 grams, having, in the direction transverse to the direction of orientation, a tensile strength of about 2000 to 6000 pounds per square inch, an elongation value of less than about 75 percent, and a tear strength greater than about 500 grams, and having a moisture vapor transmission rate of less than 0.2 gram per 100 square inches per 24 hours; and (b) a substantially unoriented heat seal film of synthetic resinous polymer bonded in full surface contact to said base film in a thickness ratio of heat seal film to base film of about 0.5-1.5:1.0, said heat seal film having a sealing temperature which is significantly less than that of said base film and which is below the temperature at which substantial deorientation occurs in said base film, having a tensile strength of less than about 12,000 pounds per square inch, and having an elongation value of at least 75 percent; said laminate having, in said base film orientation direction, a tensile strength of at least about 11,000 pounds per square inch and a tear strength of less than about 175 grams, having, in said base film transverse direction, an elongation value of at least about 100 percent and a tear strength of less than about 450 grams, and having a moisture vapor transmission rate of less than about 0.2 gram per 100 square inches per 24 hours.