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3M
Films : Scotchshield™ :
Film Thickness
Thickness Is No Substitute
for Technology
The 3M understanding
that thickness is no substitute
for technology was the motivation
behind the development and production
of the latest generation of
Scotchshield™ window films.
It was generally accepted that
protection increased as a film's
thickness increased. As other
manufacturers sought to produce
films in excess of 10 mils (.010
inches), 3M
understood that such thicker
films create two fundamental
problems:
Loss of film elasticity
Increased optical distortion
Loss of film elasticity
A bomb blast has two phases
- a positive phase, where the
glass is pushed away from the
source charge, and a negative
phase, where the glass is pulled
back toward the source charge.
These two phases subject glass
to significant stress. A film
with little elasticity provides
little cushion during such shock.
Consequently, thicker films
provide less protection throughout
the course of a bomb blast.
Increased optical distortion
Thick window films cause
optical distortion from both
sides of the window in a fashion
similar to that of a thick pair
of eyeglass lenses. This reduces
an occupant's ability to see
outside with visual clarity
and alters a building's cosmetic
appearance.
3M's
Response
In March 2002, Fortune magazine
named 3M as
America's most innovative company.
The underlying technology of
3Msecurity
films illustrates such innovation.
Without sacrificing blast protection
or building aesthetics, 3M
developed a thinner security
film comprised of an industry
unique and patented system of
multi-layered, cross-woven polyester
fibers. For every 2 mils of
film, there are thirteen of
these layers.
A multi-layered manufacturing
technique creates product elasticity
to allow the film to "give"
with the glass during an explosion.
This "give" provides
the glass with a cushion during
the related stress and shock.
That cushion better protects
occupants from flying glass
shards than would a non-elastic
film.
The main benefit afforded by
cross-weaving the polyester
fibers is that tear resistance
is maximized. Regardless of
how a window breaks, the applied
film will always be torn against
its grain. Consequently, a 4
mil thick 3M
film is more difficult to tear
than a competitor's 7 mil thick
product. This strong, thin film
increases tenant safety without
creating optical distortion.
Only the 3M
Company manufactures multi-layered
security films. However, for
clients (especially government
clients) who must adhere to
a set specification for film
thickness, 3M
offers single-layered films
in 7, 8, and 14 mil thicknesses.
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