Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
247 5.002
IMPRt~V~D YARN AND PROTECrIVE GARM-¢NT
BACKG~OU~ID OF THE IN VENTION
l'he present invention relates generally to yarns and protective
garments using such yarns and, more particularly, to an improved yarn which may be
knitted to form an improved, more comfortable, more flexible, protective garment.
Prior to the present invention, technological developments of
yarns for protective garments have cen~ered around the use of Kevlar, which is the
DuPont trademark for an aramid fiber, as the fiber used in yarns, ~vhich yarns are
ultimately used in protective garments. By way of example, and not by way of
limitation, aramid fibers have been used in yarns with the yarns thereafter knitted
to rnake protective garments ineluding bullet-resistant vests and protective gloves
as exemplified by B~rnes, 'United States Patent No. 3,883,898.
In addition to the use of an ~ramid yarn as aforesaid, aramid
fibers have been utilized in combination with other materials to form a yarn which
yarn may be thereafter knitted to form a protective garment such as a protective
glove with increased slash or cut resistance. Examples of this concept may be
found in Byrnes Wnited States Patent No. 4,004,295, and B~rnes et al. United
States Patent No. 4,384,449, each of which describes the use OI the Kevlar aramid
fiber in combination with wire; the first of these two patents discloses the use of
an aramid fiber yarn together with a metal wire~and the second of these two
patents describes a composite yarn itself; the yarn including a core of aramid fiber
plus flexible wire and a covering of ar~nid fiber.
There are, of course, certain recognized problems with the use of
the aramid fiber as the constituent in a yarn ~o thereafter be utilized in
protective garments. For example, aramid f ibers weaken in water. Second, the
aramid fiber has only a limited resistance to true abrasion. 'rhird, ultraviolet light
adversely affects the appearance of the aramid fiber and can cause discolorations
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in the aramid fiber, discolorations in the yarn and discoloration in the finished
product.
~ ecently, a new high strength fiber has been announced by
Allied Corporation. The fiber is an extended chain polyethylene, which is
understood to be a member of the polyolefin family. The fiber has been sold under
the trademark of Spectra with two different fibers being marketed, Spectra 1000
and Spectra 900. We understand that the Spectra 1000 is a 1200 denier fiber and
that Spectra 900 is 650 denier fiber.
SUMMAR~ OF T~E INVENTION
The present invention provides a new and improved yarn and
garment made from the yarn. The yarn includes a core and a covering, the core
includes at least one wire strand and one polyethylene strand. The covering may
be a polyethylene strand or a nylon strand.
The yarn and garment according to the present invention has
numerous suhstantial advantages over the prior art, commercially available yarns
such as those made of the Kevlar aramid f iber. For example, the polyethylene
fiber has approximately 50 to 75% greater tensile strength than a comparable
aramid fiber. The polyethylene fiber is resistant to ultraviolet light and thus does
not result in undesirable color change when the fiber, or yarn made from the fiber,
or finished product, are exposed to ultraviolet light. The fiber is inert, non-
absorptive, non-allergenic and stable. The density of the Spectra 900
polyethylene fiber is, by way of example7 only two-thirds the density of Kevlar 4~
aramid fiber. Nonetheless, the pol~ethylene fiber has a substantially increased
tensile strength, resistance to elonga~ion, a substantially increased abrasion
resistance, and maintains greater flexibility despite the increases in strength. The
fiber has a specific gravity of 1.0 or less7 typically 0.97. Thus the garment is
stronger, more flexible and yet more comfortable than Kevlar-based garments.
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2475.002
BRIEF DESCRIPTION OF THE DRAWINGS
The various benefits and advantages of the present invention will
be more easily understood upon reading the following detailed description of the
invention taken in conjunction with the drawingsO
In the drawings, wherein like reference numerals identify
corresponding components:
Figure 1 is an illustration of yarn used in accordance with the
principles of the present invention;
Figure 2 is an illustration of a protective garment made in
accordance with the principles of the present invention; and
Pigure 3 is an illustration of another protective garment.
DETAILED DESCRIPTION OF THE INVENTION
With reference to the drawings, the improved yarn 10 of the
present invention is illustrated in Figure 1 as being formed of a core 12 and a
covering 14. The core 12 ineludes two substantially parallel strands; one strand
16 is formed of wire such as filament grade 304 stainless steel wire. The second
strand 18 in the core is a strand of polyethylene fiber. The two strands are
placed parallel to each other.
At this point, it is believed helpful to digress momentarily and
provide details of the vnre and of the fiber which are included in the core. It
should be appreciated that the wire diameter and wire material should be selected
based upon the ultimate utilization of the yarn in a protective garment as well as
any restrictions based on the capability of the knitting equipment which will be
utili~ed to knit the yarn into the garment. If it is desired to make a cut resistant
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475~002
glove, apron, sleeve or the like for industrial use, there are numerous filamentgrade wires which may be utilized. The objective, of course, is to minimize the
wire diameter, to ma2cimize flexibility, while still maintaining the desired degree of
cut resistance and, furthermore, the wire cannot be so thin as to readily break
when either knitted into the garment or when the garment is utilized. Of s~ourse,
iE the garment is a protective glove, the flexing of the glove on the hand of the
wearer could cause the wire to break if the wire was too thin in diameter or if the
wire had insufficient strength.
An additional factor in determining wire diameter is, of course,
any limitations imposed by the knitting equipment. There are two conventional
glove knitting machines presently on the market, one manufactured by Matuya and
the other manufactured by Shima Seiki. With both of these knitting machines,
there are limits as to the diameter of the yarn. Since the yarn includes both a
core and a covering, the machine thus presents a maximum limit as to the diarneter
of the wire which may be used. While other knitting machines may, of course, be
utilized depending on the nature of the protective garment to be fabricated, the
above description sets forth, in general terms, the type of parameters to be
evaluated in selecting the desired wire si~es. In addition, of course, the ultimate
utilization of the protective garment to be knitted from the yarn of the present
invention will, in fact, create additional restrictions. For example, if protective
gloves are being knitted from the yarn of the present invention, and if the
protective gloves are to used in food handling plants, meat packing facilities and
the like, then the wire must be compatible with these needs. 13y way of example, fi
stainless steel grade 304 wire having a norninal diameter of ~0045 inches has been
found suitable for use in connection with the polyethylene fibers of the present
invention and for knitting the yarn of the present invention into a protective ~love
for the meat paeking industry.
The polyethylene fiber referred to above and manufactured by
Allied Corporation has been described by the manufacturer as an extended chain
polyethylene with a polyethylene being, of course, a polyolefin. The materials
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2475.002 13~31~0
have also been referred to as polyethylene fibers. These materials have also been
described as based upon United States Patent No. 4,413,110, issued ~overnber 1,
1983. We understand that the term "polyolefin" is a more generic term and
"polyethylene" is an example of a class of products which fall within the definition
of polyolefin.
One additional aspect of ~he yarn used in the present invention
should be mentioned in connection with the description o~ the rnaterial utilized in
the core. When wire is utilized in the core of a yarn, for the purpose of
providing cut resistance, it should be appreciated that the wire has relatively low
resistance to elongation. It is for this reason that a strand of fiber having a high
resistance to elongation is placed parallel to the wire strand within the core. Por
exarnple, the ultimate elongation of the polyethylene of the present invention is
2.~% which is ten percent better than the aramid fiber.
It is not sufficient, however, to merely provide the parallel
strands of wire and fiber; a covering must be provided to hold the core and to
protect the user of the garment against breakage of the wire, abrasion from
exposed wire and the like. Accordin~ly, and as suggested in B~rnes et al. United
States Patent No. 4,384,449, a covering is provided for the core strands.
Referring back to Figure 1, the covering 14 is provided in the
form of two wraps or strands 22, 24. The covering strands are wrapped with fiber
22 wrapped over the core in a first direction, such as counter-clockwise, and the
second fiber 24 wrapped over the firs~ wire and over the core, of course, in the
opposite direction. The aforementioned B~rnes et_aL patent suggests the need for
an aramid fiber as the covering. However, we have discovered that one of the
advantages and surprising benefits of the use of the Spectra fibers is that a softer
covering may be utilized such as nylon to thus increase the comfort for the wearer
of the garrnent. In this respect, for example, 420, 8~0 or 1260 denier nylon "Type
6" rn~nufactured by Allied Corporation may be utili~ed. Alternatively, Nylon 66
may be used. The first or inner wrap rnay even be wire.
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2475.002
The wrapping of the coYering on the core will be further
explained. One of many standard types of wire covering machines, such as an
Arnold, OMM, Ratti or ~CBF may be used. The first or inner wrap holds,
protects, covers and cushions the core to protect the core and the user. The
second or outer core also serves to protect, cover and cushion. The comlbination
of the dual wrap, one clockwise and the other counterclockwise, further protects
and increases cut resistance of the yarn if the yarn is used in a protective
garment. The nylon, as is conventional, should be pre-shrunk.
Another embodiment or variation of the form of the present
invention includes the addition of a third strand to the core; depending upon the
desired utilization of the yarn and the protective garment, the third strand may be
either a wire strand such as a filament grade 304 stainless steel wire, or a
polyethylene fiber.
Referring now to Figure 29 the yarn of the present invention may
be utilized to knit a protective garment such as glove 3D. The glove may be
knitted on a conventional Matuya or Shima Seiki brand knitting machine and may be
knitted from a single end of yarn. If a heavier duty glove is desired, two ends of
yarn may be used in the Icnitting machine. If a very thin liner is desired, to go
underneath a protective glove, a liner of cotton, or nylon, or OI the plain
polyethylene fiber itself, without wire, may also be provided.
In addition to a protective glove, conventional knitting machines
other than glove knitting machines may be utili~ed to knit the yarn into a fabric
which may be used for cut-resistant aprons, arm protectors (sleeves), leg and foot
protectors, head protection or the like. Figure 3 illustrates a garment 32 such as
a protective apron.
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Accordingly, while a preferred utilization of the
yarn is for a cut resistant glove for use in meat packing
industries or other industrial aPplications, it should be
appreciated that the presont invention is not limited solely to
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