Note: Descriptions are shown in the official language in which they were submitted.
132~ 8
HIGH ELASTIC MODULUS BANDAGE
5 BACKGROUND OF THE INVENTION
This invention relates to elastic shirred materials and the use
thereof as a support bandage.
It is well recognized in the art that shirred fabrics can be made
by stretching a sheet of rubber, holding it in a stretched condition,
10 adhering a fabric to each side, and removing the restraining force to
pucker or shirr. U.S. Patent No. 22,038 describes material consisting
of threads of India rubber stretched and bonded between two laminae
of cloth and then permitted to retract, thereby causing puckering of the
fabric to provide the desired shirred effect. U.S. Patent No. 3,575,782
15 describes an elastic shirred web product consisting of partially
extended spaced aligned elastic yarns sealed between two thin porous
gathered nonwoven fibrous webs, or between a web and a non-porous
film, by means of a soft flexible polymeric coherent binder.
Elastic shirred web materials have been used in commercially
20 available products such as Coban~ and Vetrap~, both available from
the Minnesota Mining and Manufacturing Company. Vetrap~ is sold for
use on horses and other animals, and is covered by above-mentioned
U.S. Patent No. 3,575,782. It is used primarily for decorative
purposes and as a rundown bandage. It is also used as a holding wrap
25 for applying compresses, medicated pads and the like; and for
providing support for injuries.
The present invention also involves elastic shirred sheet material
but has several advantages over that taught in the art. The material of
the invention has a higher elastic modulus, is more cohesive and is
30 more durable.
~- - In one preferred form, the product of the invention
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has utility as an equine bandage. The banda~e is durable enouqh to
be used as a rundown bandage without the addition of rundown
patches which are ~enerally necessary when currently available
bandages are used. The hi~her elastic modulus of the banda~e allows
it to provide additional joint support, yet surprisin~ly it has been found
that it does not unduly constrict circulation.
In one preferred method of the invention, a banda~e of the
invention is applied to the front le~ of a horse in a serles of fi~ure 8's
extendin~ below the fetlock joint as low as the coronary band, and
above the fetlock joint as hi~h as the knee. This provides support for
the suspensory li~aments and flexor tendons, thereby reducin~ the
potential for injury due to hyperextension of the fetlock joint.
SUMMARY OF THE INVENTION
The present invention describes a cohesive elastic banda~e
comprisin~ a series of spaced elastic yarns between coextensive thin
nonwoven fibrous cover webs, the banda~e bein~ uniformly
impre~nated throu~hout and bonded to~ether in a unified structure with
a polymeric binder having a basis wei~ht at least equal to the basis
- 20 wei~ht of the cover webs. The yarns are maintained under tension in
the resultin~ uniform structure. The yarns are from about 550 to about
.~ 1700 denier and are uniformly spaced at about 10 to 36 yarns per inch
of width. The banda~e is further characterized by havin~ an elastic
modulus F26 value of from about 0.3 to about 2 pounds per inch of
- 25 width, an elastic modulus F50 value of from about 0.5 to about 3
pounds per inch of width, an elastic modulus F76 value of from about
0.7 to 4 pounds per inch of width, and an elastic modulus Floo value of
from about 1 to 6 pounds per inch of width.
A method of supportin~ the suspensory li~aments and
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flexor tendons in the leg of a horse is also described.
BRIEF DESCRIPTION ()F THE DRAWINGS
Figure 1 is a schematic representation showin~ the manufacture
of the elastic sheet material. Figure 2 is a representation in plan view
of a portion of the product.
DETAILED DESCRIPTIOI~I OF THE INVENTION
As shown in Fi~ure 1, elastic yarns 10 from a beam 11 are
unwound under tension provided by brake 12 and throu~h comb 14.
Thin nonwoven fibrous webs 15 and 17, from supply drums 16 and
18, respectively or directly from the forming machine, if desired, are
brought into contact with the yarns and with each other between
squeeze rolls 19 and 20, the latter dipping into a pan 21 containing a
fluid binder mixture 22. The composite web passes directly into a
dryin~ oven 24 and thence between pull drums 25 and 26. The web
next passes around idler roll 27, between heating platens 28 and 29,
around pull drum 30 and idler roll 31, and is wound up to form stock
roll 32.
. 20 Squeeze rolls 19 and 20 rotate at a considerably yreater surface
speed than does beam 11, and the yarns 10 are accordingly stretched
a corresponding amount. This stretch is maintained by operating pull
drums 25 and 26 and turn-around drum 27 at approximately the same
speed compared with rollers 19 and 20. Pull drum 30 and windup
drum 32, however, are again operated at a slower speed to permit
shrinkage of the web as it passes between the heater plates 28 and
.~ 29. The composite web 34, which is smooth as it reaches the roll 27,
becomes increasin~ly puckered or shirred as it passes through the
- heatiny zone, the result being further indicated in Figure 2.
The heat supplied by the platens 28 and 29 is sufficient to cause
considerable fuming of the sheet
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material and to relax the structure sufficiently to permit the elastomeric
yarns to retract and produce the desired de~ree of puckerin~ or shirrin
as controlled by the speed of the pull drum 30. The temperature may
be re~ulated by adjustin~ both the ener~y input to the platens and the
5 distance between the platens and the web. In a typical installation for
producin~ a web havin~ a finished width of 32 inches before trimmin~,
the electrically heated platens are each 15 inches hi~h and 40 inches
wide, and are spaced between six and nine inches from the web. A
- thermometer placsd adjacent the web between the platens re~isters
about 200-250F. The duration of the heat treatment may be
re~ulated, for a ~iven iength of platen, by adjustin~ the speed of travel
of the web, sufficient time bein~ provided to permit retraction of the
web to the desired de~ree. The platens are maintained at a
temperature sufficient to keep the web taut durin~ the shrinkin~
operation between rolls 27 and 30 at the speed indicated but not so
high as to cause deterioration of the web as evidenced by excessive
fuming and discoloration thereof. The length of the relaxed web after
retraction will be within the ran~e of about one-third to about two-
thirds the fully extended len~th. ThE elastic yarns are initially stretched
. 20 to a len~th of about three to five times their fully relaxed len~th, and
are permitted to relax only partially durin~ the puckerin~ step.
Nevertheless, the shirred product is dimensionally stable, the heat
treatment serving to provide an effective degree of heat-setting or
stabilizin~, and neither shrinks nor expands when allowed to stand at
normal temperatures and under no external stress; and it returns to
such dimensions when first stretched and then permitted to retract.
The thin fibrous matts are conveniently prepared on a ~arnettin~
machine or preferably on a "Rando-Webber" machine. Matts of
polyester or rayon staple fibers or mixtures are preferred. The fibers
are desirably of about
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2 inch denier and about 0.75 to 1.5 inch in length, and the matt is
about 0.25 to 0.50 oz./sq. yd. or about 5-10 Ib. per 320 sq. yd.
These very thin matts are fra~ile and flimsy, but show surprising
strength when combined in composite structures of the type and in the
5 manner hereinabove indicated. Where the flimsiness of the untreated
matt presents inordinate difficulties in handling, the matt as first
formed may be reinforced by lightly treatin~ with a compatible bonding
agent. As an example, the reinforced matt may consist of 90 parts by
weight of polyester staple fibers and ten parts of polyethyl acrylate, the
10 latter being applied at the forming machine by saturating with a dilute
emulsion of the polymer, removing the excess between squeeze rolls
and drying in an oven.
Concentrated natural rubber latex is preferred as the
impregnatin~ and bonding or unifying medium. Other elastomers or
15 blends of elastomers having similar properties may be used. The dried
rubbery residue, although presenting a sli~htly tacky feel, does not
adhere to the skin, but coherently bonds ~o itself with sufficient force
to hold the contacting layers together against reasonably high shearin~
stresses. The impregnating and bonding materials may be used
20 without further modification, but will ordinarily be blended with
pi~ments or other visual modifiers.
In an illustrative example, the varns 10 or 700 denier spandex
~; ~ spaced 18 ends per inch of width and each of the webs 15 and 17
consists of.a polyester matt (0.3 oz./yd.2). Centrifuged natural rubber
25 latex at 60% concentration lavailable from the E. P. Lambert Company
or from Stein Hall, Inc.) serves as the fluid binder mixture 22. The
beam 11 has a surface speed of 39 feet per minute, whereas the speed
at rolls 19 and 20 is 91 ft./min., that at rolls 25, 26 and 27 is 86-88
~` ft./min., and that at rolls 30 and 32 is 40 ft./min. The resulting sheet
30 material was
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slit into bandages 4 inches wide and 5 yards lon~. This material is
referred to as Example 1 in the discussion below.
In a second illustrative example, the yarns 10 are 1680 denier
spandex spaced 10 ends per inch of width and each of the webs 15
and 17 consists of polyester matt 10.3 oz./yd.2). Centrifuged natural
rubber latex at 60% concentration serves as the fluid binder mixture
22. The beam 11 has a surface speed of 45 feet per minute, whereas
the speed at rolls 19 and 20 is 83 ft./min., that at rolls 25, 26 and 27
is 84-87 ft./min., and that at rolls 30 and 32 is 40 ft./min. This
material is referred to as Example 2 in the discussion below.
In a third illustrative example, the yarns 10 are 1680 denier
; spandex spaced 18 ends per inch of width and each of the webs 15
and 17 consists of a polyester matt (0.3 oz./yd2). Centrifuged natural
rubber latex at 60% concentration serves as the fluid binder mixture
22. The beam 11 has a surface speed of 60 ft./min., that at rolls 25,
26 and 27 is 92-95 ft./min., and that at rolls 30 and 32 is 54 ft./min.
This material is referred to as Example 3 in the discussion below.
The physical characteristics of banda~es of Examples 1-3 the
invention were compared with those of Vetrap~. The characteristics of
cohesive strength, elastic modulus, and amount of latex solids were
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compared. The results are summarized in Table 1. The banda~e of
Example 1 of the invention was found to be more cohesive than
Vetrap~, perhaps due to the hi~her latex content of the banda~e of
Example 1 of the invention Ithe bandages of Examples 2 and 3 of the
invention were not tested for cohesive strength). Significant
differences in elastic modulus were seen. The Fn values show that the
bandages of the invention exert a hi~her compression force in the
usable ran~e of 25% to 100% elon~ation while still maintainin~ the
ability to
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stretch an additional 50% while in use without exerting an unduly high
compressive force which could constrict circulation and cause physical
damage to a horse's leg.
This performance has been borne out in repeated field trials
5 where horses le~s have been wrapped with the bandage of Example 1
by various trainers using varied techniques followed by normal race
activity. The bandage has provided support without imposin~ undue
constriction and has shown good durability.
- 10 COHESIVE STRENGTH
~- The cohesive strength of the bandages was measured on an
Instron Tensile Tester usin~ the following procedure. The 1" by 1"
facings of two aluminum T-section blocks were covered with double
- coated tape. One of the T-blocks was placed, with the adhesive side
15 down, on a sample of the bandage. The edge of the block was kept
parallel to the yarns in the sample. The sample was cut around the
edges of the T-block with a sharp razor blade. This procedure was
;~ ~ repeated until there were four layers of sample attached to the T-block.
All four layers had the same side towards the face of the block and the
20 yarns were running in the same direction. With the ed0es of the blocks
and sample in perfect alignment, the face of the second T-block was
. superimposed a~ainst the first. The resulting specimen was placed in a
jig and compressed with a 20 pound weight for 60 seconds. The
specimen was hooked to the hangers on the tensile machine and the
25 cohesive stren~th was recorded.
TENSILE AND ELONGATION MEASUREMENTS
This procedure uses a Instron Constant Rate of Extension Tensile
Tester to determine Fn modulus values. The Fn modulus value is the
30 force required to elongate the test specimen a certain percent ~n). The
machine conditions
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were set at a gauge length of 50 mm, a crosshead speed of
250 mm/min and a chart speed of 250 mm/min. A 1" wide by 8" long
sample was razor cut from a banda~e. In order to minimize the
incidence of jaw breaks, masking tape tabs were applied so that one
5 tab was located in each jaw of the apparatus. The sample was
clamped between the jaws, the crosshead was started and the stress
plot was recorded, and the Fn values were calculated from the stress
plot. The Fn values stated in the instant examples are an average of
the values determined according to this procedure for at least ten
. 10 samples of each example. The Fn vaiues stated in the claims are an
avera~e of the values determined accordin~ to this procedure for ten
samples of each example. This procedure is derived from ASTM*D
882-80a.
15 AMOUNT OF LATEX SOLIDS
~ Bandage samples were ozonized to break down the rubber and
; then rinsed in heptane. The heptane extracts were then analyzed by
~ infrared spectroscopy.
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132~1~8
TABLE 1
Elastic Modulus Vetra~n' Exam~le 1 Exam~le 2 Bxam~le 3
(Ib./inch width)
F25 0.08 0.45 0.56 0.93
F50 0.25 0.76 0.90 1.52
10 P~5 0.52 1.03 1.20 2.11
F,oo 1.87 1.64 1.56 2.80
F,25 3.04 2.32 1.98 4.01
Fl50 9.11 4.67 2.58 6.91
~` CohesiveStrength 17.7 24.1
. (lb./inch2)
- 20
Latex Solids 0.67 0.77
(g/24 inch2)
Vetrap~ is made with 10 ends/inch of 280 denier yarn. Example
- 25 1 is made with 18 ends/inch of 700 denier yarn as discussed
` - previously. Example 2 is made with 10 ends/inch of 1680 denier yarn
- as discussed previously. Example 3 is made with 18 ends/inch of
~ 1680 denier yarn as discussed previously.
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