TISSU DE HAUTE SECURITE

HIGH SECURITY FABRIC

Abrégé français

Étoffe de haute sécurité ayant une couche interne de nylon, deux couches internes de polyester placées sur chaque côté de la couche de nylon et deux couches externes d’étoffe synthétique ignifugée, chaque couche externe d’étoffe synthétique ignifugée s’étendant sur l’une des couches internes de polyester afin de former un assemblage à cinq plis de sorte que la couche interne de nylon soit positionnée centralement. L’assemblage résultant est cousu avec un fil de nylon dans un certain motif. Cette étoffe est particulièrement utile pour la fabrication de vêtements ou de couvertures ou d’autres types d’éléments de linge à utiliser dans des applications de haute sécurité telles que les prisons ou les hôpitaux psychiatriques où des personnes internées sont susceptibles de présenter des tendances suicidaires.

Abrégé anglais

Disclosed is a high-security fabric having an inner layer of nylon, two inner
layers of
polyester placed on either side of the layer of nylon and two outer layers of
fireproof synthetic
fabric, each outer layer of fireproof synthetic fabric extending on one of the
inner layers of
polyester in order to form a 5-ply assembly such that the inner layer of nylon
is centrally
positioned. The resulting assembly is stitched together with a nylon thread in
a pattern. This
fabric is particularly useful for manufacturing clothes or blankets or other
types of garments
for use in high-security applications such as prisons or asylums where
interned persons may
have suicidal tendencies.

Revendications

7
CLAIMS
1. A high-security fabric for use in high-security applications comprising:
- an inner layer of nylon, said inner layer of nylon having top and bottom
surfaces;
- two inner layers of polyester, one of said inner layers of polyester
extending on said
top surface of said inner layer of nylon, the other inner layer of polyester
extending on
said bottom surface of said inner layer of nylon;
- two outer layers of a fireproof synthetic fabric, each outer layer of
fireproof synthetic
fabric extending on one of the inner layers of polyester opposite to the inner
layer of
nylon
wherein all of said layers form a 5-ply assembly having a top and a bottom and
in
which inner layer of nylon is centrally positioned, and wherein said assembly
is
stitched together with a nylon thread in a pattern.
2. A fabric according to claim 1, wherein said fabric further includes at
least one hem,
said at least one hem being formed by an extension of at least one of said
outer layers of a
fireproof synthetic fabric and by an extension of at least one of said inner
layers of polyester,
said extensions being folded over from one of said top or bottom towards the
other of said top
or bottom, and being stitched to said assembly with another nylon thread.
3. A fabric according to claim 1 or 2, wherein said fabric further includes at
least one
hem, said at least one hem being formed by an extension of all of said layers,
said extension
being folded over from one of said top or bottom towards the other of said top
or bottom, and
being stitched to said assembly with another nylon thread.
4. A fabric according to claim l, 2 or 3, wherein said pattern is a "quilt"
pattern, and
wherein the nylon thread for stitching together said assembly has a resistance
of
approximately 6.9 pounds, and has a thread count of about 10 points per inch.

8
5. A fabric according to claim 4, wherein said quilt pattern is formed by rows
of stitches
separated by approximately 1 1/4".
6. A fabric according to claim 4 or s, wherein said other nylon thread has a
resistance of
approximately 16 pounds and has a thread count of about 10 points per inch.
7. A fabric according to claim 4, 5 or 6, wherein said extension is stitched
four times
with said other nylon thread.
8. A fabric according to claim 1 or 2, wherein said pattern is a generally
diagonal cross-
hatch, and wherein the nylon thread for stitching together said assembly has a
resistance of
approximately 6.9 pounds, and has a thread count of 12 points per inch.
9. A fabric according to claim 8, wherein said generally diagonal cross-hatch
is formed
by rows of stitches separated by approximately 1.1 ".
10. A fabric according to claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, wherein said
nylon layer is bullet-
proof.
11. A fabric according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, wherein:
said nylon layer has a warp count of 34/inch and a weft count of 34/inch; and
said fireproof synthetic fabric layer has a warp count of 69/inch and a weft
count of
48/inch.

Description

CA 02225289 1998-O1-29
1
HIGH SECURITY FABR_1(''
FIELD OF THE INVENTION:
The invention relates to a fabric for use in high-security applications, such
as the
manufacture of garments or blankets for prisoners or the like.
DESCRIPTION OF THE PRIOR ART:
In prisons, or other high security areas such as asylums, there exists the
possibility that
inmates (or interned persons), have suicidal tendencies. In such cases, the
interned persons
will sometimes try to set fire to their clothes, or blankets, or any other
fabric or material
available, inside their cell. Other will try to rip the fabric apart or to
take the stitches out in
order to attempt hanging themselves. Some interned persons succeed because the
fabric which
makes up the garments and/or blankets is not fire-retardant or strong enough
to resist. It
should be noted that although such interned persons generally do not have
access to sharp
2 0 objects, in some cases the stitches can be undone by using the person's
fingers or nails to
break the stitches.
There exists therefore a need to provide an improved fabric that would be
non-flammable, would resist tearing and could not be unstitched.
SUMMARY OF THE INVENTION:
In accordance with the invention, this object is achieved with a high security
fabric for
use in high-security applications, comprising:
- an inner layer of nylon, the inner layer of nylon having top and bottom
surfaces;

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2
- two inner layers of polyester, one of the inner layers of polyester
extending on the top
surface of the inner layer of nylon, the other inner layer of polyester
extending on the
bottom surface of the inner layer of nylon;
- two outer layers of a fireproof synthetic fabric, each outer layer of
fireproof synthetic
fabric extending on one of the inner layers of polyester opposite to the inner
Layer of
nylon,
wherein all of the layers form a 5-ply assembly having a top and a bottom and
in
1 o which the inner layer of nylon is centrally positioned, and
wherein said assembly is stitched together with a nylon thread in a pattern.
BRIEF DESCRIPTION OF THE DRAWINGS:
The present invention and its advantages will be more easily understood after
reading
the following non-restrictive description of preferred embodiments thereof,
made with
reference to the following drawings where the same numeral designates the same
feature in
2 o all of the drawings, and
FIG. 1 is a perspective view of a fabric according to a first preferred
embodiment of
the invention for the stitching;
FIG. 2 is a perspective view of the fabric according to a second preferred
embodiment
2 5 of the invention for the stitching;
FIG. 3 is a cross-sectional view of the fabric showing a preferred embodiment
for the
hem; and
FIG. 4 is a cross-sectional view of the fabric showing another preferred
embodiment
for the hem.

CA 02225289 1998-O1-29
Fig. 1 shows a 5-ply assembly for a fabric 10 according to the invention. The
assembly
is composed of an inner layer of nylon I 1, two inner layers of polyester 13,
each extending
on each surface of the layer of nylon 11 and two outer layers of a fireproof
synthetic fabric 15
each extending on one of the inner layers of polyester 13, so that the nylon
11 layer is centrally
positioned and each surface of the nylon 11 layer has a layer of polyester 13
on top of which
is a layer of the fireproof synthetic fabric I 5. Preferably, this fireproof
synthetic fabric 15 is
one available under the trade-mark NOMEX and available through CONSOLTEX as
product
l 0 784657 NOMEX 200-A.
A11 of the layers 11, 13, 15 are stitched together in a pattern in order to
secure the 5-ply
assembly together. Preferably, this pattern is a "quilt pattern" 20, as shown
on Fig. 1 where
the rows of stitches are separated by approximately 1'/4". However, this
pattern could also be
a diagonal cross-hatch 20' as shown on Fig. 2 where each row of stitches is
separated by
approximately 1 ". The embodiment shown on Fig. 2 has the net result that the
assembly is
much more resistant to tearing, as will be explained hereinafter.
If the pattern is the quilt pattern 20 of Fig. 1, it is preferable for the
thread used to
2 0 stitch the assembly have a resistance of approximately 6.9 pounds and a
thread count of about
10 points/inch.
However, if the pattern that is used is the diagonal cross-hatch 20', the
nylon thread
that is used for stitching together the assembly preferably has a resistance
of approximately
2 5 6.9 pounds but has a thread count of approximately 12 points per inch.
The fabric 10 according to the invention, may also include at least one hem 30
as
shown on Figs. 1 to 4. It should be understood that if the fabric 10 is used
to make a blanket,
a11 of the sides of the blanket will be hemmed. Also, should the fabric 10 be
used to make
3 0 garments, all of the edges of the garment should be hemmed (i.e. sleeves,
lower edges, etc.)
so that the resulting garment cannot be unstitched.

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4
In a preferred embodiment, the hem 30 is constructed from an extension 31 of
at least
one layer of fireproof synthetic fabric 15 and an extension 33 of at least one
layer of polyester
13 where these two extensions 31, 33 are folded over from one of the top or
bottom towards
the other of the top or bottom. As can be seen in Figs. 1 and 3, the hem 30 is
made from the
extension of the layer of fireproof synthetic fabric 15 and polyester 13 which
is folded over
from the bottom towards the top. These extensions 31, 33 are stitched to the
assembly as
shown on Figs. 1 and 3 with another nylon thread. Preferably, the other nylon
thread which
is used for stitching the hem 30 has a resistance of approximately 16 pounds
and has a thread
count of about 10 points/inch. Also preferably, the hem is stitched to the
assembly by four
l0 rows of stitches 41 as can be seen on Figs. 1, 3 and 4. This substantially
increases the strength
of the hem 30.
In another embodiment, the hem 30 could be made of the extension 40 of all of
the
layers 11, 13, 15 folded over, shown on Fig. 4. In this other embodiment also,
the other nylon
thread which is used to stitch the extension to the fabric in order to form
the hem 30,
preferably has a resistance of 16 pounds and a thread count of about 10
points/inch. Also
preferably, this other nylon thread is stitched in four generally parallel
rows 41 to the
assembly.
2 0 In a preferred embodiment of the invention, the nylon layer is preferably
bullet-proof.
To that effect, this nylon layer preferably has a warp count of 34/inch and a
weft count of
34/inch. It is also preferable for the NOMEX layer to have a warp count of
69/inch and a weft
count of 48/inch. Accordingly, the nylon that is used for the nylon layer is
preferably the one
sold by CONSOLTEX under the trade-name 784489 HT NYLON 35X35.
In order to evaluate the resistance of the fabric to various events, the
following tests
were performed: the first one was a flammability test, the second one was a
test for the
resistance to the breakage of the seams, the third one was a test for the
resistance to ripping.
The results showed that of six specimens tested, none ignited.
With respect to the breaking strength to the seams, a dynamometer with a
constant rate
of extension was used on the existing seams. For the seams parallel to the
warp, the average

CA 02225289 1998-O1-29
breaking level was 3,161.9 newtons or 124.5 pounds/foot. What was noticed
during the
breaking test of the seams parallel to the warp was that the exterior layers
of NOMEX broke
at the seams. With respect to the seams parallel to the weft, the average
breaking force was
3,747.6 newtons or l47.5 pounds/foot. During this test, it was noticed that
the seams broke
5 at these levels.
As to ripping strength, a dynamometer with a constant rate of extension was
used and
the average force required for ripping the fabric in the direction parallel to
the warp was 461
newtons or 103.6 pounds/foot; with respect to the force required to rip the
fabric in the
direction of the weft, the force was 615.4 newtons or 138.3 pounds/foot.
It should also be noted that an "extension" test was performed, where the
fabric was
longitudinally stretched; the fabric resisted up to l000 lbs, and only the
NOMEX layer ripped.
These tests were performed on a fabric as shown on Fig. 1.
It is also to be noted that should the pattern be the diagonal cross-hatches
20' shown
on Fig. 2, the strength of the stitching which binds the 5 layers of fabric
together is in the
order to 10 to 15 pounds stronger than the quilt 20 pattern.
Accordingly, the fabric according to the invention, comprising the five
different layers
of individual fabrics stitched together and in some cases hemmed, is an
appropriate fabric for
the manufacture of clothing for use in high-security applications such as
prisons or asylums
where some of the interned persons may have suicidal tendencies. This fabric
resists
2 5 flammability and it is very difficult to pick at the stitches is order to
recuperate the nylon
thread to attempt hanging oneself. The fabric also resists ripping in order to
recuperate the
resulting shreds of fabric. Furthermore, since the hem is stitched four times,
it more than
adequately resists picking with the finger-nail to try unsew the stitch. This
is due to, first of
all, the strength of the nylon thread used and secondly, to the quadruple
lines of stitching.
The present invention has been explained hereinabove by way of preferred
embodiments thereof. It should be pointed out any modifications to these
preferred

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6
embodiments within the scope of the claims is not deemed to alter or change
the nature and
scope of the present invention. For example, any other type of pattern for
stitching the five
layers together is acceptable as long as it provides the necessary strength
and is of sufficiently
small thread count so that it cannot be easily undone with a person's hands.
Also, the preferred
types of fabric which have been identified above could be replaced by the same
fabrics having
different grains, again as well, as long as the resulting assembly provides
the necessary
strength and resistance.

Dessin représentatif