Appeal No. 95-1112
Application 07/969,121
Parry discloses a stretch film of LLDPE laminated with a reinforcing band of LLDPE film having
substantially smaller width (col. 1, lines 56-58; Examples I and II). The band is preferably
traversed across the width of the stretch film (col. 2, lines 5-9). The laminated stretched film can be
stretched to twice its length (Example IV). According to Parry, if a tear or hole is placed in a single sheet
of stretched LLDPE, the tear will rapidly propagate across the width of the wrapping (Example I).
However, when the tear was made in between the reinforcing bands on the laminated stretch film, the tear
propagated only as far as the band (Example II). From this teaching we conclude that a person having
ordinary skill in the art would have a reasonable expectation that a laminate of two layers of LLDPE such
as that disclosed by Briggs will be far more resistant to tearing than a single layer of LLDPE.
Parker discloses perforating at least a two layer laminate comprising at least two sheets of
a thermoplastic polymer such as polyethylene using a heated needle (col. 1, lines 46-56). The hot needle
punctures the film. The heat causes the films to melt and fuse at the periphery of the perforation. When
the needle is withdrawn, the fused periphery cools and solidifies (col. 2, lines 28-47) to form a hole and
weld approximately 1-2 mm in diameter (Table at col. 3). Parker’s method is substantially similar to that
disclosed by appellants for forming the welds and perforations recited in the claims on appeal. Taking
Parker’s method for making perforations in polyethylene in view of appellant’s acknowledgment that it is
known in the art to perforate stretch films and in view of the expectation that a two layered stretch film is
far less likely to tear than a single film, we conclude
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