Note: Descriptions are shown in the official language in which they were submitted.
WO 95/06419 PC'T/US94109883
P~~° d~~~ RQZ.~. ~~" ~~5~~:
background
Elastic wraps are primarily used to wrap
injuries. When correctly placed, elastic wraps impart
support to strained tendons ligaments or muscles and/or
apply continuous pressure to lacerations to reduce
bleeding. Some of the most effective wraps exhibit
both stretch and elasticity. Stretch is important to
l0 ensure that movement of a wrapped limb or joint is not
unduly restricted by a wrap and also to ensure that
blood flow to the affected area is not restricted.
' Elasticity ensures that the wraps return to their
initial shape after being stretched by the patient i.n
order to provide continuing support to the wrapped
injury.
Elastic wraps are increasingly used in
industries where injuries are quite prevalent.
Examples of such industries include the meat packing
industry and professional, athletics. The private
sector also uses elastic wraps for juries incurred
during recreational activities. When the wraps are
used in the private sector or in industry, the injured
individual commonly will apply the wrap to the injury
without assistance from another person. Ideally,
dispensing elastic wraps would not require assistance
from another person.
Elastic wraps are commonly sold in strips in
roll form. Rolling, condenses the strips and also eases
dispensing of the wrap wiahout risk of tangling the
wrap. In order. to dispense elastic wrap, the desired
length of elastic wrap is unrolled by unwinding the
desired length. The wrap is then cut with a pair of
scissors or similar cutting instrument. This method of
dispensing is quite cumbersome and very difficult if an
injured person must dress her own injury. Ideally, a
-1-
ct~.e~rnn~ c~~t «~~t ~'~~
i
t
WO 95/06449 PCTIUS94109883 ;
cutting instrument would not be required to sever the
wraps at the appropriate length. However, due to the
construction of elastic wraps,' a cutting instrument
such as a scissors is usually required to cut the wrap. '
Elastomeric wraps are known in the art and
are described in U.S. Patent Numbers 5,230,701, '
3,575,782, 4,366,814, and 4,984,584. The wraps are
formed of varied materials including but not limited to
nonwoven fabrics, films and foams.
Many wraps are comprised of unoriented
nonwoven fabrics. The random orientation of fibers of
these fabrics provides useful properties and
- characteristics. One of these characteristics is the
ability of such fabrics to resist continued linear
tearing in the cross direction after introduction of an
initial tear in the fabric. While this
resistance-to-split characteristic of nonwoven fabrics
is a beneficial attribute-for various apglications, it
presents certain difficulties when nonwoven fabrics are
used for wraps dispensed from a roll because a cutting
instrument such as a scissors is necessary to dispense
a
the fabric. Beyond the properties of the fabrics used
to manufacture wraps, the fact that the wraps are
elastic make the wraps exceedingly difficult to tear.
25' When one attempts to tear an elastic wrap, the elastic
wrap is stretched rather than torn due to the
resiliency of the wrap. If one does succeed in tearing
an elastic wrap, the resulting tear is usually uneven.
Due to the difficulty in tearing elastic wraps and the
resulting nonlinear tears if the wrap is torn, a
tearable elastic wrap is needed.
one approach to providing a tearable nonwoven
web is disclosed in Greenway, United States Patent
4,772,499. Greenway suggests applying binder to the '
nonwoven web in spaced linear bands so that the web can
be torn in a linear fashion along the binder-free bands
-2-
~.IB~~T~"E SN~~' ~RU~ 26~
. ,. _. ..: . ~ ~. .. .. .~ . : . ~; : r
WO 95/OG449 PC;TI~S94/0988~
of web. Unfortunately, the cost of producing such a
banded nonwoven web is prohibitive for many purposes
and differences in the surface characteristics of the
web as between the binder-free and binder-containing
bands would significantly complicate manufacture of the
web. It is also perceived that such bands would
detract from the performance of the tape.
Patent Cooperation Treaty Publication
WO 93/15245 filed by the Minnesota Mining and
Manufacturing Company of St. Paul, Minnesota discloses
an embossed nonwoven tape including both staple and
binder ffibers. The specific composition of the tape in
combination with the embossed pattern on the tape
renders the tape tearable in the cross-machine
direction along an embossed pattern in the tape. The
tearable tapes disclosed by this publication are
limited to those which include a significant proportion
of melt-activated binder fibers.
A need exists for elastic wraps in roll
form which can be dispensed without the need for
scissors or other cutting tools and which tear cleanly
n
and evenly.
Summary of the Invention
According to the present invention, elastic
wraps are provided which are capable of being dispensed
without the need for cutting tools. The roll of
elastic wrap includes~a plurality of longitudinally
spaced, laterally extending, perforated separation
lines defined by a series~of about 0.2 to 5 mm
perforations separated by about 0.1 to 1 mm connecting
segments of wrap where the ratio of perforation length
to connecting segment length in each separation line is -
about 1:1 to 10:1. The perforations allow the wrap to
be torn along the perforation line. However., the
perforations do not unduly weaken the stretch and/or
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CA 02148250 2005-03-03
'60557-4989
the elasticity of the wrap. The invention therefore
provides an elastic wrap which is tearable yet functional
enough to provide support to injuries.
In particular, according to one aspect of the
present invention, there is provided an elastic wrap
comprising an elastic substrate which can be longitudinally
elongated between about 7 to 280 percent, the substrate
having a longitudinal axis and a lateral axis having a
plurality of longitudinally spaced, laterally extending,
l0 perforated separation lines defined by a series of
about 0.2 to 5 mm perforations separated by about 0.1
to 1 mm connecting segments of wrap and a ratio of
perforation length to connecting segment length of
about 1:1 to 10:1, said elastic substrate selected from the
group consisting of foam, woven fabric and nonwoven web,
wherein the elastic wrap exhibits a longitudinal stretch and
recovery across said perforations.
In particular, according to another aspect of the
present invention, there is provided a roll of elastic wrap
comprising: a. a core, and b. a length of elastic wrap
wound around the core; c. wherein the wrap comprises at
least (i) an elastomeric binder-containing nonwoven fabric,
and (ii) a plurality of longitudinally spaced, laterally
extending, perforated separation lines defined by a
plurality of about 0.2 to 5 mm perforations separated by
about 0.1 to 1 mm connecting segments of tape and a ratio of
perforation length to connecting segment length of
about 1:1 to 10:1, wherein the elastic wrap exhibits a
longitudinal stretch and recovery across said perforations.
-4-
CA 02148250 2005-03-03
60557-4989
According to a further aspect of the present
invention, there is provided a roll of elastic wrap
comprising an elastomeric binder-containing nonwoven web
having a longitudinal axis and a lateral axis which is
coated on a major surface with a cohesive material; the
cohesively-coated web having a plurality of longitudinally
spaced, laterally extending, perforated separation lines
defined by a series of about 0.2 to 5 mm perforations
separated by about 0.1 to 1 mm connecting segments of
dressing and a ratio of perforation length to connecting
segment length of about 1:1 to 10:1, wherein the elastic
wrap exhibits a longitudinal stretch and recovery across
said perforations.
Brief Description of the Drawings
Figure 1 is a perspective view of one embodiment
of a roll of elastic wrap manufactured in accordance with
the present invention.
Figure 2 is a top view of the elastic wrap of
Figure 1.
Figure 3 is a top view of a first alternative
embodiment for the separation line in the elastic wrap of
the present invention.
Figure 4 is a top view of a second alternative
embodiment for the separation line in the wrap of the
present invention.
Detailed Description of the Invention
The elastic wrap 10 of the present invention is
comprised of a nonwoven web, a film, a foam or a woven
-4a-
CA 02148250 2005-03-03
60557-4989
fabric which exhibits stretch and recovery in one or more
directions.
For the purposes of this disclosure the term
elastic is defined as having the property of generally
returning to an original size or shape after stretching.
One skilled in the art will recognize that the property of
elasticity is a continuum. Some surgical tapes are mostly
nonelastic while other tapes and wraps may exhibit a large
degree of elasticity. The elastic property as characterized
l0 by the materials of the invention is defined as having a
recovery, after stretching, wherein the material returns to
at least 90% of its original shape within a two minute time
period with a recovery force of at least 50% of the force
required to stretch the material.
-4b-
WO 95/06449 ~ PCT/US94/09883
As stated above, elastic nonwoven fabrics are
among the materials suitable for constructing the wraps
of the invention. Elastic nonwoven fabrics are best
known as constructed of 1) a composite of an elastic
web and a nonwoven fabric, 2) a resin bonded to a web
of elastic nonwoven fabric, or 3) stretchable nonwoven
fabric bonded by an elastomer. The present invention
anticipates that other constructions of elastic
materials comprised of nonwoven webs will also be
suitable for practicing the present invention. U.S.
Patent Numbers 5,230,701, 4,984,584, 4,366,814 and
3,575,?82 all disclose elastic materials comprised of
- nonwoven webs.
Other fabrics, films and foams are also
suitable for constructing the wraps of the invention.
For example, elastic films such as polyurethane films
are readily available and are suitable for the
invention. Likewise, elastic foams such as
polyvinylchloride, polyethylene and polyurethane foams
are also suited for the invention.
The invention is described both by its
appearance and also by its composition. To describe
the appearance of the wrap of the invention, we turn to
Figures l through 4.
In a preferred embodiment, the elastic wrap
10 is rolled onto core l00 (Figure 1). Elastic wrap l0
has a longitudinal direction 11 or machine direction
and a lateral direction 12 or cross machine direction.
To facilitate dispensing individual sheets of elastic
wrap 80 from the roll, perforated separation lines 50
extending laterally across the elastic wrap are
uniformly spaced longitudinally along the length of the
roll. As seen in Figures 2 and 3, each separation line
50 is defined by a series of perforations 60, each of
which has a perforation length 60D between about 0.2
and 5 mm. The connecting segments ?0 between the
-5-
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WO 95106449 ~ PGTIUS94/09883
perfarations 60 are between about 0.1 and 1 mm in
length (~GD). The ratio of the perforation length 60D 1
to the connecting segment length 9oD is about 1:1 to
10:1. For the purposes of this disclosure a "roll" is
defined as wraps wound on a core, wound about itself
without a core, or loosely folded.
Perforation length 60D is measured as the
distance between the longitudinal lines passing through
the lateral extremities of the two connecting segments
bonding the perforation 60. Connecting segment length
70D is the shortest distance between adjacent
perforations 60.
- Elastic wraps benefit by incorporating the
separation lines 50 described herein. One would expect
elastic wraps incorporating the separation lines of the
invention to fail, either by prematurely tearing during
dispensing or during application or by limiting the
elasticity of the wrap. However, when prepared
according to the present invention, the perforated
elastic wraps do not fail but instead remain elastic
and stretchable. The perforations also allow the user
A
to tear the wrap in a linear fashion.
composition
Nonwoven Webs
Where the wrap of the present invention
consists of a nonwoven web, the web may be manufactured
by any of the well known methods for manufacturing
nonwovens including but not limited to melt-blowing,
chemically=blowing,~sp~in-bonding, carding, and
hydrodynamic entanglement. A particularly preferred
method for making a nonwoven web useful in the practice ,
of this invention is by a technique known as
hydroentangling. This process is described in United ,
States Patent NOS. 3,485,706, 3,486,168, 3,493,462,
3,494,821 and 3,508,308. Briefly, fibers are supported
-6-
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W~ 95106449 ~ PGT/US94/09883
_-,
on a perforated plate or similar support screen and
traversed with high energy liquid streams so as to
consolidate the material in a repeating pattern of
entangled fiber regions and interconnecting fibers. An
alternate method of forming a nonwoven web is needle-
tacking as described in United States Patent No.
5,016,332.
In order to make nonwoven webs elastic,
elastic filaments must be bound to the web. This
process is more fully described below. Other methods
of elasticizing which are commonly known in the art may
alternatively be used to make the web elastic.
_ When manufacturing elastic wraps of nonwoven
webs, the thickness of the nonwoven web is about 0.1 to
about 0:4 mm. The weight of the nonwoven web is
preferably about 10 g/m~ to about 120 g/rn2. The fabric
composition and weight selection of the nonwoven web is
determined by the product construction and the desired
properties of the finished product. Webs used in
laminated fabrics banded together with elastomers or
thermally bonded to stretched elastomeric filaments or
other webs are usually light weight,qabout 10-25 g/m2.
Single layer fabrics bonded with elastomeric binders or
elastomeric fiber fabrics are typically medium weight
fabrics in the range of about 30-90 g/m2 basis weight.
Preferred nonwoven webs include a family of
high-strength nonwoven fabrics available from E.I.
Dupont de Nemuours & Company of Wilmington, Delaware
under the trademark SONTARA~ including SONTARA~ 8010,
a hydroentangled polyester fabric. Other suitable
nonwoven webs include a hydroentangled polyester fabric
available from Veratec, a division of International
Paper of Walpole, Massachusetts. This fabric is
preferably bonded with HYSTRETCH~ V-4.3 binder, an
elastomeric terpolymer available from the BF Goodrich
suesrrru~ s~~r ~RU~ xs)
WO 95106449 ~ ~,. ~ PGT/US94/09~~3
F
Company. Another suitable nonwoven web is the nonwoven
elastomeric web described in iJ.S. Patent No. 5,230,701.
Hinders
In one embodiment of the invention, the .
nonwoven web may include one of the well known binders
for enhancing bonding of the individual fibers within
the web. Selection of a suitable binder (i.e., one
which has a suitable affinity for the fibers of the
nonwoven web) is well within the judgment of one
skilled in the art. Briefly, binders for nonwoven
fabrics are typically selected from such materials as
_ homopolymer and copolymer latexes of acrylics,
butadienes, styrene/butadiene rubber copolymers,
urethanes, vinyl acetates, vinyl acetate/acrylate
copolymers, vinyl acetate/ ethylene copolymers,
polyvinyl alcohols, polyvinyl chlorides, vinyl esters,
vinyl ethers, etc.
Specific examples of latex binding agents
include, RHOPLEX~ E°2559 (an approximately 45% solids
acrylic latex binder) available from the Rohm & Haas
Co. of Philadelphia, Pennsylvania; UNICAL~ 76°4402 (an
approximately 50% solids styrene/butadiene rubber
latex) available from the UNICAL Corp. of Charlotte,
North Carolina; NATIONAL STARCHY No. 78°6283 (an
approximately 45% solids acrylic/vinyl acetate
copolymer latex) available from the National Starch
Corp. of Bridgewater, New Jersey; and the KRATONTM
family of thermoplastic rubbers available from the
Shell Oil Company of Oak Brook, Illinois.
Additional binders include the various
thermoplastic fibers which may be incorporated directly ,
in the nonwoven web. The nonwoven web is bonded by
simply incorporating about 5 to about 10 wt% of a .
compatible thermoplastic fiber into the nonwoven web
and heating the web above the softening temperature of
_g_
suas~~ seer ~RU~ 2s~
W~ 95/06449 ~ PCTlI3S94/09883
the thermoplastic fibers so as to bond the
thermoplastic fibers to the staple fibers in the web.
A compatible thermoplastic fiber is a fiber capable of
melt-bonding to the other fibers in the web without
substantially weakening the web.
Binder fibers are available in a wide variety
of configurations including totally meltable binder
fibers, side-by-side binder fibers, bicomponent binder
fibers, elliptical core-sheath binder fibers,
concentric core-sheath binder fibers, and combinations
thereof .
Examples of suitable binder fibers include,
binder fibers of polyester, polyethylene,
polypropylene, polybutylene, polyamide and combinations
thereof. The binder fibers are preferably from about 1
cm to about 20 cm in length and display a fineness of
from about 0.1 denier to about 20 denier.
Specific examples of suitable core-sheath
binder fibers for use in the nonwoven web include,
DIAWA"~ binder fibers (12 denier by 38 mm crystalline
polypropylene core with meltable polyethylene sheath)
and.MELTYTM binder fibers (2 denier by 38 mm oriented
polyester core with meltable polyester sheath)
available from Chori America, Inc. of Los Angeles,
California; and K-52'~''~ binder fibers (2 denier by 38 mm
oriented polyester core with meltable polyester sheath)
and K-54T'~ binder fibers (2 denier by 38 mm oriented
polyester core with meltable polyester sheath)
available from Hoechst Celanese Corp. of Charlotte,
North Carolina.
The enhanced fiber bonding achieved with
binders tends to stiffen the web and thereby facilitate
tearing of the web, improve handleability of the wrap
10 during application, and control fraying of the
r
fibers along the tear line. However, as understood by °'
those skilled in the art, when intended for use as
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'W~ 95!06449 PG'I'1US94/09883
elastic wrap 1.0, the amount. of binder employed must be
controlled so as to provide the wrap 1C with a softness
and conformability acceptable: to both health care
professionals and patients.. The surgical wrap 10
should possess sufficient stiffness to facilitate
application of the wrap ZO while retaining sufficient '
conformability to be comfortable to the patient and
maintain contact with the skin over prolonged periods
of use .
Elastic Filaments
Elastic filaments are bound to the nonwoven
- web with an elastomeric binder such as concentrated
natural rubber latex to obtain a highly elastic wrap.
A wrap which is bonded with concentrated natural rubber
coherently bonds to itself. Alternatively, wraps may
be bound with polymers such as styrenebutadiene
copolymers, such wraps do not coherently bond to
themselves.
Films and Foams
A
A description of elastic films suitable for
use with the present invention can be found in U.S.
Patent Nos. 5,088,483 and 5,160,315. Particularly
preferred films are elastomeric polyurethane,
polyester, or polyether block amide films.
Foams such as polyvinylchloride, polyethylene
and polyurethane foams are suitable foams for use with
the present invention.
Adhesive
If an adhesive is employed, the adhesive is a
pressure sensitive adhesive which, in the case of
elastic wraps, is physically and biologically
compatible with human skin. A wide variety of
suitable, skin-compatible, pressure sensitive adhesives
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sss~~~ ~~~~ ~su~ Zs~
CA 02148250 2004-O1-21
60557-4989
are known to those skilled in the art and include
specifically, but not exclusively, acrylic-based
adhesives, polyolefin adhesives, rubber-based
adhesives, tackified styrene block copolymer adhesives,
and the like.
A preferred pressure sensitive adhesive is
any of the acrylate copolymers such as copolymers of
isooctyl acrylate and acrylic acid or acrylamide
described in United States Patent No. Re. 24,906 issued
to Ulrich. Such adhesives are preferred for use on
elastic wraps since they are relatively nonirritating
to the skin.
The adhesive is optionally coated on a major
surface of the elastic wrap. The wrap shown in Figure
1 includes a top surface 32 and an opposing bottom
surface. The adhesive may be coated on the top
surface 32, the bottom surface or on both surfaces.
Low Adhesion Backsize
If an adhesive is employed, a layer of low
adhesion backsize is preferably applied to the opposite
side of the substrate. For example, if adhesive is
coated on the bottom surface, the low adhesion backsize
would preferably be applied to opposing surface 32
shown in Figure 1 of the elastic wrap. Application
of low adhesion backsize to the elastic wrap provides a
surface with a reduced adhesive affinity for the
pressure sensitive adhesive. Such reduced adhesion
facilitates the unwinding of wrap from a linerless roll
of the wrap.
Materials suitable for use as a low adhesion
backsize in this invention, include acrylates,
fluorochemicals, polyethylenes, silicones, vinyl
copolymers and combinations of these compounds.
Compounds suitable as a low adhesion backsize are
disclosed in United States Patent No. 4,728,571 issued
-11-
WO 95!06449 ~, ~ ~ . PGTlUS94/098$3 ,
I'..: ::,
,, ..
to Clemens et al. A specific example of a suitable low
adhesion backsi2e is SYL-OFF, a silicone compound
available from Dow Corning Corp. Preferred low
adhesion backsize are the siloxane and acrylate based '
compounds disclosed in United States Patent No.
4,973,513 issued to Riedel and the water-insoluble '
hydrophobic urethane (carbamate) copolymer of polyvinyl
alcohol and octadecyl isocyanate disclosed in United
States Patent No. 2,532,011 issued to Dahlquist et al.
Separation Lines
The relative lengths 60d and 70d of
perforations 60 and connecting segments TO control
several fundamental properties of wrap to related to
dispensibility and performance. For example, length
?Od of the connecting segments ?0 is one factor
controlling the tensile strength between individual
sheets 80 of wrap 10. Separation of sheets 80 becomes
difficult when the connecting segments 7o are too long
while accidental and unintended separation is more
likely when the connecting segments 70 are too short.
The physical dimensions of the perforations
60 and connecting segments ?o defining the separation
lines 50 are important aspects of the invention. An
acceptable balance must be achieved between the
competing interests of adequate tensile strength to
prevent premature separation and sufficient reduction
in tensile strength to ensure easy and consistent
separation of sheets 80 along a single separation line
50. ,
The parameters of separation lines 50
necessary to define performance are perforation length
God, connecting segment length 7od and the ratio of
perforation length God to connecting segment length
70d. Acceptable values for achieving proper
performance of the perforated wrap l0 of this invention
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SUBSl'ITUTE StiEEt (RULE 26)
WO 95/06449 ~ PCTIUS94109883
r. ~ ~~.
e.
are set forth below in Table One. The interdependence
of these variables and the cooperational manner in
which they effect and influence performance of the wrap
requires that they be considered together.
5 The tensile strength of the perforated
section of wrap 10 in the longitudinal direction ll
(Figure 2) measured in accordance with the protocol set
forth herein, is desirably from about 400 to about 3000
grams/cm width, preferably from about 600 to about 2000
10 grams/cm width, and most preferably from about 800 to
about 1700 grams/cm width. A longitudinal tensile of
less thain about 400 grams/cm width tends to result in
premature separation of the sheets 80 while a
longitudinal tensile of greater than about 3000
grams/cm width tends to require excessive force and
thereby hinder separation of the sheets 80.
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SUBSTITUTE SHED' (RULE 26)
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WO 95/06449 ~ a PCTIUS94/09583
a
Tabl~ ~ ne i
r
~ariable Aoceptable Preferred R3.gheat
' performance !
Perforation 0.2 5.0 0.5 - 3.0 1.0 - 2.0
Lengtsh (mm)
Connecting 0.1 - 1.0 0.2 - 0.8 0.3 - 0.6
Segment
Length (mm)
Ratio
Perforation
Length -to- 1:1 to 10:1 1:1 to 6:1 1:1 to 3:1
Connecting
Segment
Length
A secondary consideration is the shape of the
perforations 6o and connecting segments 70. Shape is
designated as a secondary consideration because, while
a
relevant to dispensability and performance of the wrap
10, its impact is not as critical as the primary
considerations of perforation length 604, connecting
segment length 704 and ratio of perforation length God
to connecting segment length 704. The perforations 60
may be shaped in accordance with any of the accepted
perforation patterns including linear, angled,
Y-shaped, ~'-shaped, dual-angled offset, sinusoidal,
etc. When angled, the perforations 60 are preferably
angled about 30 to 60° from the lateral axis 12 of the
wrap 10. The preferred shape, based upon ease of
manufacture and minimization of fraying along the torn
edge, is a simple linear pattern extending laterally
across the wrap l0 as shown in Figure 2.
7
t
-14-
SU~STiTi~'~ Si~E~' ~RiILE Z~~
1
~VO 95/06449 =.- PCT/US94/09883
~~.~$~~
Similarly, the longitudinal distance 70d
between the separation lines S~ must be selected so as
to balance the competing interests of permitting
substantially any length of wrap 10 to be created (more
separation lines 5A) and limiting the accidental and
unintended separation of the wrap 5L0 along a separation
line 5o during dispensing, application or use (fewer
separation lines 5~). Generally, a longitudinal
spacing of about 1 to about 20 cm, preferably about 2
to about 10 cm provides an acceptable balance between
these competing interests.
_ Method of Manufacture
Nonwoven Web Construction
Application of Binder
A binder may optionally be applied after
formation of a nonwoven web by any of the conventional
water or solvent-based coating technie~ues including air
knife, trailing blade, direct and offset gravure, Meyer
bar, wire-wound rod, reverse roll, roll coating, print
bond and spray coating. Where the binder is a
thermoplastic fiber, the fiber is simply dispersed into
the fiber matrix prior to formation of the web and then
melted.
At~t~lication of Elastic Filaments
For wraps having a high degree of elasticity,
elastic yarns or filaments such as LycraTM Spandex or
linear polyurethane monofilament are bound to the
nonwoven web with a fluid binder. A suitable binder is
i
natural rubber latex at 60% concentration as disclosed t
a
in U.S. Patent Number 3,575,782. The elastic filaments
are stretched before and during binding and drying.
Relaxing the bound elastic f ilament/rubber/nonwoven web
composite causes shirring of the nonwoven web and
results in an elastic wrap.
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SUBSTf~U'tE SHEET (RULE 26)
,.
WO 95/05449 ~ ~;; ~ ~ '~ PCTIUS94/09883
c~.. ~
Application of Low Adhesion Backsize
Similarly, the low adhesion backsize may be
applied by any of the conventional coating techniques
discussed in connection with the application of a
binder.
A dried coating weight of about 0.1 to about
0.4 mg/cm2 is preferred for the low adhesion backsize
and about 0.2 to 0.3 mg/cm2 for the binder.
The binder and the low adhesion backsize may
optionally be mixed together and simultaneously coated
onto the nonwoven web in accordance with the procedure
outlined in the Examples section of this disclosure and
- disclosed in United States Patent No. 4,967,740 issued
to Riedel and assigned to Minnesota Mining &
Manufacturing Company of St. Paul, Minnesota,
Application of Adhesive
The pressure sensitive adhesive may be
applied to the substrate by any of the well known
techniques for coating pressure sensitive adhesives
such as dispersion coating, solution coating and hot
a
melt application. A convenient method of coating the
substrate with the pressure sensitive adhesive is
disclosed in United States Patent No. 3,121,021 issued
2~ to Copeland, Briefly, a pressure sensitive adhesive is
coated on a smooth release liner. The release liner
carrying the adhesive film is then laminated to the
substrate, the release liner peeled away, and the
linerless wrap 10 wound into a "jumbo" roll.
Alternatively, the adhesive may be applied by
such conventional coating techniques as air knife,
trailing blade, direct and offset gravure, wire-wound
rod, reverse roll, print bond, spray coating, etc.
r
. i
i
-16
i
suBSr~ s~~r ~~ ~~
WO 95/06449 ~ PC'!'/US94109883
Perforating
The separation lines 50 are conveniently
created with a rotary die having a serrated perforator
blades) positioned along the periphery of the die so
as to perforate the wrap 10 at the desired intervals.
Other perforation methods known in the art, e.g., laser
perforation, may also be used.
Converting
The "jumbo" rolls of wrap 10 are converted
into multiple rolls of commercially sized wrap 10 by
conventional converting techniques including unwinding,
_ longitudinal slitting, rewinding, and lateral cutting.
Meth~d of Use
The wrap 10 is dispensed by simply gripping
the free end of the wrap, unrolling the desired length,
and then,tearing the wrap along a separation line 50.
When separating the desired length of wrap from the
roll, it is generally desired to grip the sheet 80 of
wrap 10 closest to the roll to prevent other separation
lines 5o from tearing.
Utility of the wrap disclosed and claimed
herein is not limited to uses involving contact with
human skin.
EBpERIMENTAI.
Protocols
Tensile Strength.
% Elonqatiori
Thwing-Albert
Tensile strength determines the maximum
tension that a given sample can withstand without
tearing (samples are described below in Examples 1-5).
The tensile strength measurements allow comparison of
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SU~C1~'Ui'~E SNEE1 (RULE 261
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CVO 95/0449 ",~ PCT/US94/09883
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the different perforation/ separation lengths and their
relative strength when stretched.. Testing is conducted
upon a THWING-ALBERT INTELECT~ II (Model No. 1450-42-C) '
constant rate of eactensi.on tensile tester equipped with '
clamp-type jaws manufactured by the Thwing-Albert
Instrument Company of Philadelphia, Pennsylvania.
Rectangular test samples of 2.54 cm x 22.86
cm (1" x 9") are cut from a roll of the wrap to be
tested. The long dimension is cut in the direction
(machine or cross-machine) to be tested. The ends of
the teat samples are folded adhesive-to- adhesive to
form a two inch nonadhesive tab at each end. The
- nonadhesive tabs prevent the sample from being pulled
out of the jaws, reducing premature jaw breaks and
preventing the sample from leaving an adhesive residue:
on the jaws. The samples are positioned within the
jaws of the Thwing-Albert tester and the tester set at
a crosshead speed of 5 inches per minute, a chart speed
of ZO inches per minute and a gauge length of 5 inches.
The chart recorder is set at 0.1 inch per chart
division in the cross direction and 0.2 inch per chart
a
division in the machine direction. The machine is
activated and the sample pulled apart until the force
required to pull the sample decreases.
Tensile strea~gth is calculated in accordance
with the equation set forth below where '°Pen Heightm"~"
is the number of small divisions in th~~cross direction
reached by the pen in its maximum travel across the
chart.
Tensile Strength = (Load Range)(Pen Heightm"~)/(100)
Samples having high tensile strengths are , '
desirable since high tensile strength indicates that
the sample can withstand a large tension without .
breaking.
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SiiBSIITUTE SHEEN (RULE 26)
~O 95IOG449 PCT/IJS94/09883 .
El~ngation is calculated in accordance with
the equation set forth below where "Pen Distancem"~" is
the number of small divisions reached by the pen in the
machine direction from initiation of pen deflection to
sample break.
( 2 0 ) ( Pen D.istancem""c) ( Crosshead Speed)
% Elongation = _____________________________________
(Gauge Length)(Chart Speed)
The higher the percent elongation for a given
sample, the further the sample can be stretched without
breaking. Tt is desirable that elastic wraps are.
- stretchy, therefore, a high percent elongation is
desirable.
Hand Tear Test
Opposite ends of the samples for~Examples 1-5
were grasped between the thumb and forefinger of each
hand and then rapidly pulled in a pull apart motion
with one hand pulling toward the body and one hand
pulling away from the body.
0
The resulting tear for each sample was
evaluated according to the following scale:
0 no tear
1 poor
2 fair
3 acceptable
4 good
5 excellent
The higher the result on the hand tear test,
the more desirable the sample or the easier the sample
is to teat. Results from the Hand Tear Test are set
forth in Tables 2 through 6 below.
~Maahine.Direction. Tensile Strength of Perforated vs.
Nonperforate8 Lamples
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SUBSTITUTE SHEET (RULE 26~
i
WO 95/06449 ~ PG°TlUS94/09883
Far each of the samples of Examples 1-5
below, the machine direction tensile strength was
tested for a nonperforated sample as well as for a
perforated sample. The tensile strength of the
perforated samples as compared to the nonperforated
sample is shown as a percentage in the last column of
Tables 2-6 below. A perforated sample having 100% of
the tensile strength of its nonperforated counterpart
is ideal.
Test Samples
Perf orat incx
- Samples for Examples 1-5 were perforated as
follows. Samples were made in increments of about 15
cm wide by about 10 m long. The wraps were then
laterally perforated with a rotary die to form
separation lines with linear perforations. The
perforation lines were about 5.08 cm (2 inches) apart.
The perforations had perforation lengths, connecting
segment lengths and a ratio of perforation to
connecting segment lengths as specified in Tables 2-6.
Test samples were prepared using a 2.54 cm by 10 cm
rule die oriented lengthwise along the machine
direction of the wrap. Three samples were taken across
the width of the wrap by placing the die on the wrap
and striking it sharply to cut each test sample for
evaluation. The perforated wraps were then tested for
Tearability (Hand Tear Test) Average Machine Direction
Tensile Strength (T~) and Average Machine Direction
,,
Elongation (E~). The nonperforated counterpart of each
sample was also tested for Average Machine Direction
Elongation to allow the comparison for Percent Machine .
Direction Tensile for Perforated vs. Nonperforated
Sample. The results for each test are set forth in
Tables 2 through 6 below.
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SUBSTITUTE SHEET (RULE 26)
WO 95/Ob449 ~) PC'fIUS94109883
Example 1
A lOm long and 150 mm wide piece of Coban"'~
1584 self-adherent wrap (available from Minnesota
Mining and Manufacturing Company, St. Paul, MN) was
perforated as described above. The wrap consisted of
two layers of nonwoven web with one layer of spandex
filaments bonded between the layers using a natural
rubber latex binder as described in U.S. Patent Nos.
3,575,782 and 4,984,584.
Evaluations of these perforated samples are
set forth in Table 2. Sample numbers ?, 8, 9 and. l0
were acceptable and sample number il was preferred.
Example 2
A 10 m length of 150 mm wide nonwoven
meltblown polyurethane web coated with an acrylate
adhesive was dispensed on a release liner and was
perforated as described above.
The web is commercially available in a
converted (cut and shaped) form as SteriStrips~M brand
wound closure strips (3M Co., St. Paul, MN). The melt
blown web basis weight was 85-90 g/m2~ and the web was
about 0.30-0.33 mm thick. The web and processes for
its preparation are described in U.S. Patent Number
5,230,?O1.
Evaluations of these perforated webs are set
forth below in Table 3. Samples 9 and 10 were
acceptable whereas sample Number ? was preferred.
3 0 Exam,.p l a 3
A 10 m length of 150 mm wide chemically blown
polyvinylchloride foam having a thickness of 0.889mm
and coated with an acrylic gressure sensitive adhesive
was tested. The foam tape is available as Microfoam~'''
Surgical Tape (3M Company, St. Paul, MN).
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SUBSTITUTE SHEET (MULE 26~
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CA 02148250 2004-O1-21
60557-4989
The foam was perforated as described above.
Table Four sets forth the results of evaluating the
perforated samples. Sample numbers 7 and 11 were
acceptable and sample number 13 was preferred.
Example 4
A 10m length of 150 mm wide hydroentangled
polyester nonwoven fabric (HEF 140-084 available from
Veratec, Inc., Walpole, MA) which had been creped on a
Micrex~ machine (available from Bird Machine Co.,
Walpole, MA) was impregnated with about 16% by weight
of elastomeric binder (Hystretch V-43 available from B.
F. Goodrich Co., Akron, OH) and then coated with an
acrylate pressure sensitive adhesive (97:3 isooctyl
acrylate:acrylamide). The process of manufacture used
is described in U.S. Patent Number 4,366,814.
The samples were perforated and evaluated as
described above. Evaluation results are set forth in
Table 5. Sample 7 was acceptable and Sample 9 was
preferred.
Example 5
A lOm length of 150 mm wide hydroentangled
polyester nonwoven fabric having a thickness of about
.55-.58 mm which was chemically bonded with an
elastomeric binder (SF 9309.1 available from Veratec,
Inc. Walpole, MA) and coated on one side with the
acrylic pressure sensitive adhesive used on the samples
in Example D was perforated as described above. The
manufacturing process used is described in U.S. Patent
Number 4,366,814.
The samples were perforated and evaluated as
described above and results are set forth in Table 6.
Sample 10 was acceptable and Sample 5 was preferred.
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W~ 95/06449 ~ ~ PCT/US94J09883
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SUU~T(&~1~'E ~~C~~' ~~UL~ 2~1
WO 95hJ6449 ~ ~ ~~ ~ PG"TIUS94/09883
The Examples and the data in the .
corresponding Tables 2-6 illustrate that the present
invention is both hand tearable and functional as an
elastic wrap. That is, the invention wraps display the '
5' necessary tensile strength while still allowing hand
tearing of the wraps. The most preferred wraps
demonstrate easy hand tearing (a large number resulting
from the Hand Tear Test) and a high tensile strength
(large numbers resulting from the Machine Direction
Tensile Strength and Elongation).
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