Appeal No. 1997-3497 Page 2
Application No. 08/312,295
one propylene polymer-containing ply, said
film structure:
having been stretched longitudinally at
a stretching temperature in the range of 80
to 150°C and with a longitudinal stretching
ratio of 5.5:1 to 9:1 and having been
stretched transversely at a stretching
temperature in the range of 120 to 170°C and
with a transverse stretching ratio of 5:1 to
9:1, said longitudinal and transverse
stretching ratios having been selected and
employed in combination to provide a modulus
of elasticity of the film structure in the
longitudinal direction which is greater than
2,500 N/mm2 and a modulus of elasticity of
the film structure in the transverse
direction which is greater than 4,000 N/mm2,
said moduli of elasticity having been
determined in accordance with German
Engineering Standard DIN 53 457;
said propylene polymer of said propylene
polymer ply having an n-heptane-insoluble
fraction which has a triad-related chain
isotaxy index, measured by means of 13C-NMR
spectroscopy, of at least 95%;
said propylene polymer-containing ply
containing less than 1% by weight, based on
the total weight of the film structure, of
hydrocarbon resin having a molecular weight
less than 5,000;
the water vapor transmission, WVT, of
the film structure, as defined in accordance
with German Engineering Standard DIN 53 122,
being determined by the formula
c
WVT Ÿ-
d
where d is the thickness of the film in µm
and C is 22.5 g@µm/m2.
28. A biaxially oriented polypropylene
film structure comprising at least one
polypylene polymer-containing ply, said
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Next
Last modified: November 3, 2007