Note: Descriptions are shown in the official language in which they were submitted.
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TITLE OF THE INVENTION
COMPOSITE YARN AND PRODUCTS MADE
THEREFROM
BACKGROUND OF THE INVENTION
Field of Invention
The present invention relates generally to yarns, fabrics and protective
garments
knitted of such yarns. More particularly, the present invention relates to a
cut-resistant
composite yarn construction which provides effective cut resistance for a
protective garment
without the use of expensive high performance fibers.
Discussion of the Back rg odd
In many industries, it is desirable to provide protective garments,
particularly gloves,
to protect employees from being cut. Ideally, such garments should provide an
acceptable
amount of cut resistance wlule possessing suitable flexibility and durability.
To this point knit
garments having these qualities have been constructed from yarns that include
"high
performance" fibers to achieve enhanced cut resistant performance. These yarns
are
constructed using wrapping technique wherein in a core comprising of a single
or multiple
strands is wrapped with one or more additional strands. Either the core or the
wrap strands
may include strands comprised of a high performance fiber. Typical of these
include the cut
resistant yarn disclosed in U.S. Pat. Nos. 4,777,789; 4,838,017 and 5,119,512.
These patents
disclose the use of well-known "high performance" fibers which, as used
herein, means fibers
such as extended chain polyethylene (Spectra~. brand fiber by Allied) or
aramid (Kevlar~
brand fiber by DuPont).
The use of these high performance fibers to make cut-resistant composite yarns
and
garments has not come without certain disadvantages. First, articles made from
these high
performance fibers may be stiff and, particularly in the case of protective
gloves, may cause
the wearer to lose a certain amount of tactile sense and feedback. This loss
of sensitivity can
be important for workers in the meat processing industry.
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Another potential drawbacl~ to the use of high performance fibers is their
cost. For
example, the unit length cost for high performance fiber easily may be several
times that of
the next most expensive component of a composite, cut-resistant yarn. It would
be very
desirable to substantially reduce or eliminate the high performance fiber
content of a cut-
resistant composite yarn.
One solution to these issues has been proposed in U.S. Patent 6,363,703 to
Kolines.
In that patent, the composite yarn has a core of at least one fiberglass
strand, and requires at
least one wire strand wrapped axound the fiberglass core strand, followed by
one or more
cover strands wrapped around the wire and fiberglass, with the cover strands
being made
from non-metallic non-high performance materials.
There remains a need for a cut-resistant yarn construction offering an
effective level of
cut resistance performance at a cost savings compared to composite yarns that
include high
performance fibers, without the need for wrapped wire constructions.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to provide a composite
yarn
containing no high performance fibers that has the cut-resistance of
composites containing
high-performance fibers, while maintaining good feel and flexibility, without
a wrapped wire
component.
A further object of the present invention is to provide a protective garment,
including
but not limited to, gloves, aprons, arnz sluelds, jaclcets and sporting
equipment such as fencing
uniforms, made from the composite yarn of the present invention.
These and other objects of the invention have been satisfied by the discovery
of a
composite yarn comprising:
a. a core comprising at least one fiberglass strand and at least one wire
strand of diameter
sufficient to provide cut resistance, wherein the at least one fiberglass
strand and the at least
one wire strand are parallel to one another or twisted about one another and
wherein only the
core of the yarn contains metal; and
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b. at least one non-metallic non-high performance fiber cover strand wrapped
around the core
in a first direction;
and its use in preparing a cut and abrasion resistant fabric, and articles and
garments
prepared from the fabric.
DETAILED DESCRIPTION OF THE INVENTION
The term "fiber" as used herein refers to a fundamental component used in the
assembly of yarns and fabrics. Generally, a fiber is a component which has a
length
dimension which is much greater than its diameter or width. This term includes
ribbon, strip,
staple, and other forms of chopped, cut or discontinuous fiber and the like
having a regular or
irregular cross section. "Fiber" also includes a plurality of any one of the
above or a
combination of the above.
As used herein, the term "high performance fiber" means that class of
synthetic or
natural non-glass fibers having high values of tenacity greater than 10
g/denier, such that they
lend themselves for applications where high abrasion and/or cut resistance is
important.
Typically, high performance fibers have a very high degree of molecular
orientation and
crystallinity in the final fiber structure.
The term "filament" as used herein refers to a fiber of indefinite or extreme
length
such as found naturally in silk. This term also refers to manufactured fibers
produced by,
among other things, extrusion processes. Individual filaments making up a
fiber may have any
one of a variety of cross sections to include round, serrated or crenular,
bean-shaped or others.
The term "yarn" as used herein refers to a continuous strand of textile
fibers, filaments
or material in a form suitable for butting, weaving, or otherwise
interl;wining to form a textile
fabric. Yarn can occl~r in a variety of forms to include a spun yarn
consisting of staple fibers
usually bound together by twist; a multi filament yarn consisting of many
continuous
filaments or strands; or a mono filament yarn which consist of a single
strand.
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The term "air interlacing" as used herein refers to subjecting multiple
strands of yarn
to an air j et to combine the strands and thus form a single, intermittently
commingled strand.
This treatment is sometimes referred to as °°air
tacking.'° This term is not used to refer to the
process of "intermingling" or "entangling" which is understood in the art to
refer to a method
of air compacting a multifilament yarn to facilitate its further processing,
particularly in
weaving processes. A yarn strand that has been intermingled typically is not
combined with
another yarn. Rather, the individual multifilament strands are entangled with
each other
within the confines of the single strand. This air compacting is used as a
substitute for yarn
sizing and as a means to provide improved pick resistance. This term also does
not refer to
well known air texturizing performed to increase the bulk of single yarn or
multiple yarn
strands. Methods of air interlacing in composite yarns and suitable apparatus
therefore are
described in U.S. Patents 6,349,531; 6,341,483; and 6,212,914, the relevant
portions of which
are hereby incorporated by reference.
The present invention is directed to the concept of a cut-resistant composite
yarn
having cut-resistant properties comparable to yarns with high performance
fiber, yet which
have no expensive high performance fibers therein, and which contains no
wrapped wire
layers. In general yarns are formed of a core containing at least one strand
of fiberglass, and at
least one strand of wire, with one or more covers of conventional non-high
performance yarn.
Any one, two, or all of the core, and cover may include two strands. FIGS. 1-3
are exemplary
of the various embodiments. Previously it was believed necessary to use a
wrapped layer of
wire, in order to avoid injury to the wire from stretching or from the
impingement of an edge
(such as a blade) against the wire. This injury to the wire typically
manifests itself in the
formation of bends or crimps, from the stretching and subsequent relaxing of
the wire.
The present inventor has found, however, that it is possible to provide a yarn
construction using adjacent fiberglass and wire strands in the core, without
the need to wrap a
strand of wire around the core, while avoiding the above noted injury to the
wire. Within the
context of the present invention, the term "adjacent strands" indicates that
the strands are
side-by-side, including both parallel arrangement and being twisted about each
other.
However, in the present invention, the construction contains no wrapped wire
layer. While
not wishing to be held to any particular theory of operation, it is believed
that the presence of
the parallel strand of fiberglass provides a cushioning effect for the yarn,
particularly the wire,
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which avoids production of the above mentioned bend or crimp. Further, since
the fiberglass
itself does not stretch, it is believed to serve as an "anchor" for the core
of the yarn, thus
avoiding high stretching forces from acting on the wire.
Turning to FIG. 1, there is illustrated one embodiment of a composite cut
resistant
yarn 10 which includes a core 12 formed of a single fiberglass strand 16 and a
single strand of
wire 18 (these strands are not shown to scale and can be a variety of sizes as
noted below).
This embodiment of the present invention cut resistant yarn 10 further
includes a cover 14
having two cover layers formed from non-metallic, non-high performance fiber,
22 and 24.
The first cover 22 is wrapped around the core 12, with the second cover 24
being wrapped
around, preferably in the opposite wrapping direction from, the first cover
22.
In a second embodiment, illustrated in FIG. 2, the composite cut resistant
yarn 10
includes a core 12 formed of a single fiberglass strand 16 and a single strand
of wire 18 (again
not to scale). This embodiment further includes a single cover 22 formed from
a non-
metallic, non-high performance fiber.
In an alternative embodiment, the core may include one or more additional
strands.
These one or more additional stra~.ids may be made of any non-high performance
material,
including but not limited to, fiberglass, wire, and conventional non-high
performance fibers.
These additional one or more strands may be arranged in the core either
paxallel or co-twisted
with either or both of the fiberglass and wire core strands. Alternatively, if
two or more
additional core strands are present and are made from materials that are
suitable for air-
interlacing, these additional core strands may be air interlaced. One
embodiment containing
an additional parallel strand in the core is shown in FIG. 3, which
illustrates a core 12, formed
from a strand of fiberglass 16, a strand of wire 18 and an additional core
strand of non-high
performance fiber 19, with the cover 14 containing two cover layers 22 and 24
as described
above.
W a further embodiment, the core contains a single strand of fiberglass
parallel to a
single strand of wire, wherein the single strand of wire is wrapped with a
sheath strand of a
non-high performance fiber. This core is then wrapped with one or more cover
layers of non-
high performance fiber to provide the composite yarn.
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In yet another embodiment, the composite yarn of the present invention can
contain
more than two cover layers, so long as no high performance fiber is used. This
embodiment
is illustrated in FIG. 4, which shows a core 12 formed of a single fiberglass
strand 16 and a
single strand of wire 1 ~ (not to scale). The cover 14 contains three cover
layers, 22, 24 and
26, each formed of a non-high performance fiber, and each successive cover
layer being
preferably wrapped in a direction opposite from the immediately underlying
layer.
The wire used in the practice of the present invention desirably has a
diameter of from
about 0.0013 and about 0.0036 inch, preferably from about 0.0016 to about
0.0020 inch.
Where two wires are used, they should preferably be of a diameter at the lower
end of the
range, e.g. about 0.0013 to about 0.0020. The wire strands of the present
invention can be
made from any metal conventionally used in yarns, and preferably are formed
from an
annealed stainless steel with the particular diameter of wire selected from
the ranges specified
above based on the desired properties and end use of the composite yarn.
The first cover strand and, if used, the second cover strand are comprised of
a non-
metallic, non-high performance fiber. The strands may be provided in either
spun or filament
form within a denier range of about 50 to about 1200. Suitable materials for
the cover strands
include, but are not limited to, polyester, polyester/cotton blends, acrylic,
various types of
nylon, wool and cotton. The choice of a particular material for the cover
strand or strands will
vary depending on the end use of the composite yarn and the physical
characteristics
(appearance, feel, etc.) desired for the yarn. The non-metallic, non-high
performance fiber
cover strands are wrapped about the core, or core covered with one or more
cover layers, at a
rate sufficient to enable processing of the composite yarn in conventional
knitting and
weaving equipment. Each successive cover strand is wrapped in a direction that
is either the
same as or opposite to the inunediately preceding cover strand, preferably in
the direction
opposite that of the immediately preceding cover strand. While it is not
necessary for the
cover to be wrapped such that the underlying portion of the composite is
completely covered,
it is preferable to do so. More preferably, the cover strands are each,
independently, wrapped
at a rate of from about 6 to about 13 turns per inch.
The fiberglass strand (or strands) in the core may be either E-glass or S-
glass of either
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continuous mufti-filament, monofilament or spun, and can be of any desired
size or denier.
The practice of the present invention contemplates using several different
sizes of commonly
available fiberglass strand, as illustrated in Table 1 below:
TABLE 1
FiberglassApproximate Nominal
Size Denier Denier
G-450 99.21 100
D-225 198.0 200
G-150 297.6 300
G-75 595.27 600
G-50 892.90 900
G-37 1206.62 1200
The size designations in the Table are well lalown in the art to specify
fiberglass strands.
These fiberglass strands may be used singly or in combination depending on the
particular application for the finished article. ~y way of non-limiting
example, if a total
denier of about 200 is desired for the fiberglass component of the core,
either a single D-225
or two substantially parallel G-450 strands may be used. In a preferred
embodiment either a
single strand or a combination of strands will have a denier of about between
200 and about
1200.
It should be understood that the table above illustrates currently available
fiberglass
strand sizes. The practice of the present invention contemplates the use of
other fiberglass
strand sizes as they become available in the market or as found to be suitable
for particular
applications.
Suitable preferred types of fiberglass fiber are manufactured by Coming and by
PPG.
The fibers have the desirable properties of relatively high tenacity, of about
12 to about 20
grams per denier, resistance to most acids and all~alis, being unaffected by
bleaches and
solvents, resistance to environmental conditions such as mildew and sunlight,
and high
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resistance to abrasion and to aging.
Preferably the overall denier of the yarn of the present invention to include
the
fiberglass strand(s), the wire strand(s), and the covers is between about 300
denier and about
5000 denier. Further the combined mill weight of the fiberglass and wire
components should
be between 25% and 60% of the composite yarn.
The composite yarn of the present invention can be used as is, or can be
subjected to
various treatments to provide antistatic, antimicrobial, selective radiation
absorbing (UV, IR,
etc), dyeing or other desired properties. Preferably, such treatments) include
imparting
antimicrobial properties using a commercially available antimicrobial agent,
such as those
described, for example, in U.S. Patents 6,260,344; 6,266,951; and 6,351,932.
These
treatments can be used individually or in combinations of two or more. Such
treatments are
well known in the art and can be applied to the finished yarn, any portion of
the yarn or the
individual components of the yarn or portions thereof prior to assembly of the
finished yarn,
using conventional yarn treatment equipment.
EXAMPLES
By way of non-limiting example, yarn constructions demonstrating various
embodiments of
the present invention axe illustrated as Examples 1-5 in Table 2 below.
Examples 6-9 are
included for comparative tests and will be explained hereinafter. The
nomenclature " X"
refers to the number of strands of a particular composite yarn component used.
In each
instance, the 1st and 2"a cover layers are wrapped in opposing first and
second directions (in
case of a 3ra cover layer, it is wrapped in the same direction as the first
layer, and opposite to
the 2"a layer).
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TABLE 2
Core
Wire 1St 2na 3ra Composite
Ex. Glass Diam (in) Cover Cover Cover Denier
1 G-450 2X0.0016 Polyester Polyester 623
parallel 150 Denier 150 Denier
9.4 tpi 8.2 tpi
2 G-450 0.0016 Polyester Polyester 546
parallel 150 Denier 150 Denier
11.1 tpi 8.8 tpi
3 G-37 0.0016 Polyester Polyester Polyester 3635
parallel 500 Denier 500 Denier1000 Denier
8.3 tpi 11.6 tpi 7.4 tpi
4 G-225 2X0.0016 Polyester Polyester 715
parallel 150 denier 150 denier
9.4 tpi 8.4 tpi
G-450 0.0016 Polyester Polyester 712
parallel 150 Denier 150 Denier
wire only wrapped textured textured
with
Z twist,150 denier no twist no twist
textured polyester 7.2 tpi 7.3 tpi
at 6.6 tpi
6 none 0.0016 Polyester Polyester 685
wire parallel 150 Denier 150 Denier
with 220 denier textured textured
polyester 7.0 tpi 6.8 tpi
7 G-450 none Wire Polyester Polyester 531
0.0016 in 150 Denier150 Denier
5.1 tpi 4.1 tpi
8 G-50 0.0020 Polyester Polyester Polyester 3381
wire wrapped 500 Denier 500 Denier1000 Denier
around glass at 8.5 tpi 9.9 tpi 7.5 tpi
9.1 tpi
9 G-37 none Polyester Polyester 3995
glass parallel with1000 Denier1000 Denier
500
Denier Polyester 7.1 tpi 6.9 tpi
G-150 none Spectra~ Polyester Polyester
200 Denier 70 Denier 70 Denier
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11 G-75 none Spectra~ Spectra~ Polyester
650 Denier 650 Denier 1000 Denier
12 G-37 none Spectra0 Spectra~ Polyester
650 Denier 650 Denier 1000 Denier
The Examples using a smaller denier core and cover would be knit using a 10
gauge
or similar knitting machine. The Examples using larger denier core and cover
would be knit
using a 7 gauge or similarly sized knitting machine.
The yarn of the present invention may be manufactl~red on standard yarn-making
equipment. If the yarn will be provided with three cover layers, preferably
the fiberglass and
wire core is wrapped with the first cover strand in a first step. Next, the
second and, if used,
third cover strands are added in a second operation on a separate machine.
However, other
procedures may be used as will be readily apparent to one of ordinary skill.
The yarn of the present invention has several advantages over the non-metallic
cut
resistant yarns described herein above. The fiberglass and wire core strands
and the cover
strands) mutually benefit each other. The fiberglass component acts as a
support for the
cut/abrasion resistant wire strand. Properties of the resulting yarn may be
varied by varying
the diameter and the rate of wrap (turns per inch) of the cover strands) about
the fiberglass
and wire core.
The cut resistance performance of the yarn of the present invention is shown
in Table
3 below which compares the performance of the yarn constructed according to
the present
invention (without a high performance fiber) to a similar structure that
includes a high
performance fiber. Testing was conducted using ASTM test procedure F 1790-97.
For this
ASTM test the reference force is the mass required for the cutting edge of the
test apparatus
to travel one inch and initiate '°cut through" in the material being
tested. Cut resistance data
collected using the ASTM test described above are summarized in Table 3 below.
Each of
examples 10-12 is a commercially available cut resistant composite yarn that
includes a
Spectra~ fiber/fiberglass combination. The Spectra~ fiber core strand is
wrapped around the
to
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fiberglass core strand in Examples 10 and 11. The Spectra. fiber core strand
is parallel to
the fiberglass core strand in Example 12.
TABLE 3
Cut Through Force
Example (in grams) Composite Denier (where
known)
1 2164 623
2 2006 546
3 2788 3635
4 2560 715
1317 712
6* 1855 685
7* 2293 531
8* 3139 3381
9* 2928 3995
10* 2017
11* 3251
12* 3386
* indicates comparative example
For comparable composite deniers, the yarn of the present invention provides a
comparable cut resistance performance of a high performance fiber yarn at a
significant cost
savings because of the elimination of the high performance fiber, and
comparable cut
resistance compared to composite yarns having wrapped wire layers, without the
need for
wrapping wire. In some instances the present invention provides significantly
improved cut
resistance compared to the other constructions at similar composite denier.
Examples 10-12 show steadily improving cut-resistance performance results as
the
amount of high performance fiber and the size of the fiberglass core strand
are increased.
Surprisingly, the yarn of the present invention compares favorably with each
of the examples
that include a high performance fiber (given comparable composite denier and
fiberglass
size). The test results show that the comparatively low-cost wire/fiberglass
combination
provides a cut-resistance performance that is comparable to yarns containing a
high
performance fiber.
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The composite yarn of the present invention can be used to prepare cut and
abrasion
resistant fabrics, which in turn can be used to prepare protective articles
and garments.
Turning to FIG. 5, a cut and abrasion resistant glove 40 according to the
present invention is
illustrated. The glove incorporates finger stalls 42 for each of the wearer's
fingers. The cut-
resistant yarn may be incorporated into a variety of other types of cut
resistant garments and
articles, including, but not limited to, arm sluelds, aprons or j ackets, as
well as sporting wear
for sports such as fencing.
Although the present invention has been described with preferred embodiments
and
examples of those embodiments, it is to be understood that modifications and
variations may
be utilized without departing from the spirit and scope of this invention, as
those skilled in the
art would readily understand. Such modifications and variations are considered
to be within
the purview and scope of the appended claims and their equivalents.
*********
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