U.S. patent application number 09/971435 was filed with the patent office on 2002-02-21 for selective coating of a balloon catheter with lubricious material for stent deployment.
Invention is credited to Belovi, Annette, Madenjian, Arthur R., Seiber, Russ, Sydney, Gregory T..
Application Number | 20020022849 09/971435 |
Document ID | / |
Family ID | 24977805 |
Filed Date | 2002-02-21 |
United States Patent
Application |
20020022849 |
Kind Code |
A1 |
Sydney, Gregory T. ; et
al. |
February 21, 2002 |
Selective coating of a balloon catheter with lubricious material
for stent deployment
Abstract
A predetermined arrangement of differentially lubricious areas
on a balloon catheter for controlling against unexpected movement
of a stent carried thereon when in situ in the body.
Inventors: |
Sydney, Gregory T.; (Sharon,
MA) ; Seiber, Russ; (Brookline, MA) ;
Madenjian, Arthur R.; (Winchester, MA) ; Belovi,
Annette; (Watertown, MA) |
Correspondence
Address: |
VIDAS, ARRETT & STEINKRAUS, P.A.
6109 BLUE CIRCLE DRIVE
SUITE 2000
MINNETONKA
MN
55343-9185
US
|
Family ID: |
24977805 |
Appl. No.: |
09/971435 |
Filed: |
October 4, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09971435 |
Oct 4, 2001 |
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08740727 |
Nov 1, 1996 |
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6306144 |
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08740727 |
Nov 1, 1996 |
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08409797 |
Mar 24, 1995 |
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Current U.S.
Class: |
606/108 ;
604/103.08; 604/265; 604/96.01; 606/144 |
Current CPC
Class: |
A61F 2002/9583 20130101;
A61F 2/958 20130101 |
Class at
Publication: |
606/108 ;
606/144; 604/96.01; 604/265; 604/103.08 |
International
Class: |
A61F 011/00; A61M
029/00; A61M 005/32 |
Claims
What is claimed is:
1. A balloon catheter having a shaft and a balloon associated
therewith and a stent carried on said balloon, the balloon having a
proximal end portion, a distal end portion and a central portion,
the improvement comprising a lubricious coating means associated
with the catheter, said means being constructed and arranged to
provide relatively more lubricity with respect to a major portion
of the shaft than with respect to at least a portion of the
balloon, whereby said stent is provided with a secure seating area
on the balloon.
2. The catheter according to the claim 1 wherein the lubricious
coating means is constructed and arranged to provide a lubricious
coating on the shaft portion and wherein at least a portion of the
balloon is uncoated.
3. The catheter according to claim 2 wherein the central portion of
the balloon is uncoated.
4. The catheter according to claim 2, wherein the proximal end
portion of the balloon is uncoated.
5. The catheter according to claim 2, wherein the distal end
portion of the balloon is uncoated.
6. The catheter according to claim 2, wherein the distal and the
proximal end portions of the balloon are uncoated.
7. The catheter according to claim 1, wherein the lubricious
coating means is constructed and arranged to provide a more
lubricious coating on the shaft and a relatively less lubricious
coating on at least a portion of the balloon.
8. The catheter according to claim 7 wherein the more lubricious
coating comprises a polyethylene oxide composition.
9. The catheter according to claim 7 wherein the less lubricious
coating comprises silicone.
10. The catheter according to claim 7 wherein the less lubricious
coating is only on a central portion of the balloon.
11. In a stent carrying balloon catheter of the type including a
shaft, a balloon having a cone and a waist at each end, a distal
tip portion, a stent positioned on the balloon and a lubricious
coating associated with surfaces of the catheter, the improvement
comprising a predetermined arrangement of relatively more
lubricious and less lubricious coatings on surface areas of the
catheter whereby the shaft is provided with a relatively more
lubricious coating over a substantial portion of its length
extending from the balloon toward the proximal end of the shaft,
both cones of the balloon are similarly coated as the shaft, as is
the distal tip while at least a substantial portion of the balloon
body per se is coated with a relatively less lubricious
coating.
12. The catheter according to claim 11 wherein the more lubricious
coating is comprised of a polyethylene oxide composition.
13. The catheter according to claim 11 wherein the less lubricious
coating is comprised of silicone.
14. The catheter according to claim 11, wherein the entire balloon
body is coated with the less lubricious coating.
15. The catheter according to claim 11, wherein the central portion
of the balloon body is uncoated, as defined by the balloon material
forming the outer surface thereof.
16. The catheter according to claim 11, wherein only the central
portion of the balloon body is coated with the less lubricious
coating.
17. In a balloon catheter of the type including a shaft and a
balloon associated therewith, the balloon having a proximal end
portion, a distal end portion and a central portion, the
improvement comprising including a first lubricious hydrophilic
coating means bonded to said balloon catheter, said lubricious
means being constructed and arranged to provide relatively more
lubricity with respect to a major portion of the shaft than with
respect to at least a portion of the balloon.
18. The catheter of claim 17, wherein both ends of the balloon are
coated with the lubricious coating.
19. The catheter of claim 17, wherein the entire central portion of
the balloon is uncoated with the lubricious coating.
20. The catheter of claim 17, the balloon having a collapsed state
in which a surface is exposed and an expanded state wherein the
balloon is at least partially coated with a tacky coating, such
that a stent may be securely held in place on the balloon during
location of the stent at a targeted area of a vessel, after which
the stent may be released by expanding the balloon, wherein the
tacky coating has a higher coefficient of friction than the
lubricious coating.
21. The catheter of claim 20, wherein the tacky coating comprises a
water-based dispersion based on high-molecular weight ethylene
interpolymers.
22. The catheter of claim 20, wherein the tacky coating comprises
an aqueous dispersion of ethylene vinyl acetate.
23. The catheter of claim 21, wherein the entire balloon is coated
with the tacky coating, wherein the tacky coating has a static
coefficient of friction of about 0.2-0.4.
24. The catheter of claim 22, wherein the entire balloon is coated
with the tacky coating, wherein the tacky coating has a static
coefficient of friction of about 0.2-0.4.
Description
RELATIONSHIP TO OTHER APPLICATION
[0001] This application is a continuation-in-part of co-pending
U.S. patent application Ser. No. 08/409,797, filed Mar. 24, 1995,
which is herein incorporated by reference.
FIELD OF THE INVENTION
[0002] The invention pertains to the manufacture of a stent
carrying balloon catheter having a predetermined arrangement of
differentially lubricious areas on the balloon catheter to prevent
unexpected movement of the stent when in situ in the body and to
insure precise stent deployment.
BACKGROUND OF THE INVENTION
[0003] This invention relates to stent carrying balloon catheters,
sometimes referred to as dilatation catheters, for use in
angioplasty and other various vessel repair procedures. Angioplasty
has become recognized as an efficient and effective method of
opening stenoses in the vascular system. In the most widely used
form of angioplasty, a balloon catheter is guided through the
vascular system until the balloon, which is carried at the distal
end of a catheter shaft, and which may carry an expandable stent,
is positioned across the stenosis or lesion, i.e., vessel
obstruction. The balloon is then inflated to apply pressure to the
obstruction which is essentially remolded by pressing it against
the inner wall of the vessel whereby the vessel is opened for
improved flow. Due the expansion of the balloon, the stent, which
is situated on the balloon, is also expanded and released to aid in
support and/or repair of the vessel wall.
[0004] Balloon catheters are of various types. One type is fed over
a guide wire (i.e., "over-the-wire" catheters) and another type
serves as its own guide wire (i.e., "fixed-wire" catheters).
Variations of these two basic types also have been developed such
as the so called "rapid exchange" type, "innerless" catheters, and
others. As used herein, the term "balloon catheter" is meant to
include all of the various types of angioplasty catheters which
carry a balloon for performing angioplasty and any other type of
stent carrying balloon catheter. Balloon catheters may also be of a
wide variety of inner structure, such as different lumen design, of
which there are at least three basic types: triple lumen, dual
lumen and co-axial lumen. All varieties of internal structure and
design variation are meant to be included by use of the term
"balloon catheter" herein.
[0005] When used in percutaneous transluminal coronary angioplasty
(PTCA), the balloon catheter is typically advanced through a guide
catheter to a preselected vessel location, such as the aorta, for
example. Using fluoroscopy, the surgeon manipulates the catheter
until the balloon is located across the stenosis or obstruction. As
already pointed out, this may involve the use of a guide wire over
which the catheter is moved or alternatively the catheter may act
as its own guide wire, depending on the particular design. The
manipulation of the stent carrying balloon catheter through the
guide catheter and through the vessels to the obstruction requires
the balloon catheter to have a number of different features.
[0006] One such feature is the use of a lubricious coating over the
exterior surfaces of the catheter and balloon to facilitate
movement of the catheter through the sometimes tortuous paths
within the vascular system to the preselected vessel location for
performing the angioplasty. A wide variety of such lubricious
coatings have become commonplace for use with respect to catheters
and other devices which are insertable into the body in connection
with surgical procedures and the like. All such coatings are
intended to be included herein with respect to the use of the term
"lubricious coating". Examples of such coatings include silicone
and most preferably hydrophilic coatings involving hydrogel
polymers or the like, such as polymer networks of a vinyl polymer
and an uncrosslinked hydrogel, for example. Polyethylene oxide
(PEO) is a preferred hydrogel. A preferred vinyl polymer is
neopentyl glycol diacrylate (NPG). Such compositions are more fully
disclosed in co-pending U.S. patent application, Ser. No.
07/809,889 which is assigned to the same assignee as is the present
invention and which is incorporated herein by reference.
[0007] These coatings have even been known to include certain
agents such as drugs which may be permanently entrapped in the
coating or leachable therefrom into the body. For example, heparin
has been used in such a fashion. Heparin is well known as an agent
which is often used to inhibit clot formation in the blood. Again,
the term "lubricious coating" is meant to include all such
variations.
[0008] One problem with a stent carrying balloon catheter having a
lubricious coating is that during location and release of the
carried stent, the stent tends to slip off the balloon due to the
lubricious coating on the balloon. Coating both the shaft and
balloon of the catheter inhibits the doctor's ability to locate,
activate and deploy stents at any particular lesion. The stent is
sometimes worked off the balloon portion during the insertion of
the catheter and during the expansion of the balloon. This
unexpected movement of the stent might be regarded negatively by a
surgeon. The present invention provides for more secure connection
between the balloon and the stent to prevent such slippage. Thus,
though high lubricity is desirable for general movement, it is also
desirable to provide a means of anchoring or positioning the stent
in a fixed location on the balloon so as to avoid unexpected
movement thereof upon the balloon during positioning and
expansion.
SUMMARY OF THE INVENTION
[0009] The invention is a stent delivery catheter which has a
lubricious coating on the shaft and, either, partial or no
lubricious coating or an adhesive coating, or a combination thereof
on the balloon. The lubricious coating, which is preferably
hydrophilic, provides lubricity to the catheter while the uncoated
or partially coated or adhesive coated balloon is able to retain
the stent during positioning and release without concern for
coating induced slippage. This is accomplished by the present
invention through the selective arrangement of lubricious and/or
adhesive coatings on the balloon catheter in which at least a
portion of the balloon body is uncoated or less slippery or tacky
while a relatively more lubricious coating is placed on at least a
substantial portion of the catheter shaft extending in a proximal
direction from the balloon toward the proximal end of the catheter
shaft.
[0010] Generally then, the invention contemplates an improvement in
the arrangement of lubricious coating(s) and/or adhesive coating(s)
on the catheter to avoid stent slippage and to better anchor the
stent in position for performing angioplasty or other vessel
repair. This is accomplished by what may be termed herein as
"differential coating" or "selective lubricating". By this is meant
that the lubricious properties of the catheter are selectively
designed or constructed and arranged in a predetermined manner such
that the catheter shaft i.e, substantially all of the catheter
generally exhibits more lubricity than the balloon generally. In
short, the catheter is more slippery than the balloon, relatively
speaking. It can be seen that an important feature of the invention
lies in the uncoated or less slippery balloon or portion thereof
relative to the rest of the catheter so that the stent is more
controllable.
[0011] Such an arrangement may be accomplished in a number of
different ways. For example, in one embodiment, a lubricious
coating may be provided over substantially the entire catheter,
except for the balloon per se. In this embodiment, the balloon does
not include any lubricious coating at all. The stent, which is
placed over the balloon, is therefore not susceptible to slippage
due to the greater coefficient of friction than a balloon with
lubricant might have.
[0012] The balloon also may be coated partially or with a less
lubricious or less slippery coating than the coating covering the
shaft of the catheter. In such an instance, two different coatings
may be used, such as a PEO composition as aforementioned on the
catheter shaft and so forth, while a silicone coating is placed on
the balloon per se. The balloon may also have specific areas
coated, while leaving others uncovered to provide suitable contact
with the stent.
[0013] In another variation, different compositions of PEO may be
used on the shaft and balloon. In the PEO compositions
aforementioned, comprised of PEO and NPG in isopropyl alcohol and
water, variations in the amount of PEO content affect the final
lubricity of the composition; the higher the percentage PEO, the
higher the lubricity. Therefore, one may utilize a relatively
higher percentage PEO composition on a catheter shaft and a
relatively low percentage composition on the balloon to achieve the
ends of this invention also i.e., "differential" or "selective"
lubricity over a catheter. Of course, other compositions may also
be utilized in this way.
[0014] Another embodiment comprises a coated catheter shaft, coated
balloon cones and a coating on at least the distal waist of the
balloon extending to the distal catheter tip, the balance of the
balloon body having no coating or one of less lubricity.
[0015] In an additional embodiment, both the proximal and distal
balloon cones are so coated similarly to the catheter shaft or at
least the distal cone. In accordance with the invention, the
balance of the balloon body is uncoated or coated with a relatively
less lubricious coating.
[0016] In still a further embodiment, the balloon is partially or
entirely coated with a tacky adhesive.
[0017] The advantage of the present invention is the ability to
have a coated catheter which offers ease of movement through the
vasculature along with the ability to effectively engage and deploy
stents at any particular lesion without slippage or premature
activation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] A detailed description of the invention is hereafter
described with specific reference being made to the drawings in
which:
[0019] FIG. 1 is a diagrammatic showing of a balloon catheter in
which the balloon is positioned across an obstruction in a vessel
prior to inflation and an expandable stent is positioned over the
balloon.
[0020] FIG. 2 is a diagrammatic showing of the positioned balloon
catheter of FIG. 1 with the balloon inflated against the
obstruction and the stent expanded.
[0021] FIG. 3 is a schematic showing of a typical balloon catheter,
having a stent loaded thereon.
[0022] FIG. 4 is a schematic diagram showing the basic anatomy of a
catheter balloon coated according to one preferred embodiment of
the invention and a stent loaded thereon.
DETAILED DESCRIPTION OF THE INVENTION
[0023] FIGS. 1 and 2 show a stent carrying balloon catheter,
generally indicated at 10, of the over-the-wire type having a guide
wire 12 over which the catheter has been moved within a vessel 14
to the location of an obstruction 16. As can be seen in the
Figures, balloon 18 and stent 17 are positioned across obstruction
16 while the balloon 18 is uninflated (shown in FIG. 1). Upon
inflation (shown in FIG. 2), as the balloon expands and exerts
pressure against stent 17 and obstruction 16, it is possible for
the stent to slip out of place, either forward or backward along
the balloon, if care is not taken to make sure the catheter is in a
fixed position. As shown in FIG. 2, if the catheter is held in a
fixed position, the expanding balloon expands the stent 17 and
presses against obstruction 16 molding it against the inner walls
of vessel 14 to open the vessel. This method is also used for a
collapsed or damaged vessel. In such a case, the expanded stent
supports the vessel wall and/or repairs damaged tissue. As already
indicated with respect to the present invention, the surface of
balloon 18 shown contacting stent 17 is best not coated, or coated
with a less lubricious coating than the catheter proper, or coated
with an adhesive, in order to provide an "anchoring" effect so that
the balloon engages the stent. This is more fully described
hereinbelow with reference to FIGS. 3 and 4.
[0024] By "anchoring" the stent 17 to the balloon 18 according to
the invention, the stent 17 is also prevented from slipping off
during the navigation of the balloon through the body to the
targeted area. Prior to the present invention, when the balloon was
coated with a lubricious coating along with the majority of the
rest of the catheter, the loaded stent had a tendency to slip off
the balloon or be shifted out of place. This effect is due to the
vessel wall and other obstructions which act as a drag on the
carried stent as it is transported to the targeted area. The
present invention remedies this problem.
[0025] FIG. 3 shows a typical stent carrying balloon catheter which
may incorporate any of the various aforementioned design variations
for catheters. For purposes of understanding the present invention
it is only important to note that catheter 10 includes a balloon
generally indicated at 18, a stent 17, a distal tip 20, a shaft 22
and a manifold portion generally indicated at 24. Shaft 22 is
comprised of a proximal end portion 26 and a distal end portion 25
where it joins balloon 18. Shaft 22 preferably is made from
Nylon-11 and low and high density polyethylene.
[0026] As can be seen in FIG. 4, balloon 18 includes a body portion
30, a proximal cone portion 36, a proximal waist portion 38, a
distal cone portion 32 along with a distal waist portion 34 and a
stent 17 loaded thereon.
[0027] In accordance with one embodiment of the selective
arrangement of the lubricious coatings on the catheter as
contemplated herein, such a coating is shown at 40 extending over
proximal cone 36 (optional), in a proximal direction over shaft 22
toward the proximal end portion 26 thereof to thereby cover a
substantial portion of shaft 22. Coating 40 is also optionally
included on the distal cone 32, distal waist portion 34 and the
distal tip of the catheter 20 as can be seen best in FIG. 4. The
balance 30 of the balloon is either uncoated or coated with a less
lubricious composition or coated with an adhesive. The absence of a
lubricious coating on the balloon allows the stent 17 to remain
more firmly in contact with the balloon itself. The balloon may be
partially covered with lubricious material as long as a portion of
the balloon is uncoated, or coated with a less lubricious material,
in order to firmly hold the stent in place.
[0028] As is known in the art with respect to balloon catheters and
lubricious coatings, the coating will be relatively thin and
preferably bonded to the catheter body surfaces, although not
necessarily. Silicone is an example of an unbonded lubricant. The
PEO based coating cited earlier is an example of a bonded one. In
the Figures, the relative thickness of coating is greatly
exaggerated for clarity. However, in accordance with standard
practices in the art, such coatings may nominally be of a thickness
on the order of 20-50 um or less and will be applied in a variety
of ways depending on the type of coating involved and the
particular selective arrangement of the coating desired. For
example, in the case of various polymeric hydrophilic coatings it
has been found convenient to utilize an elastic mask to block the
body portion of the balloon from being coated with the slippery
hydrophilic coating. The mask, in a preferred form, is a heat
shrink polyolefin sized to provide a slight interference fit around
the balloon to keep the mask in place during processing. In one
preferred form, the uncoated length of the area masked has been
about 5/8" of an inch centered on the body portion of the balloon
and extending around its peripheral surface. Such an arrangement is
indicated in FIG. 4. Of course, at least some of body of the
balloon is left uncoated as well or coated with a relatively less
lubricious coating than the balance of the catheter proper.
Preferably, the entire balloon portion which is in contact with the
stent is left uncoated.
[0029] Upon completion of the polymer coating procedure, the mask
is then removed to expose the uncoated balloon body portion. In
such an arrangement, the shaft and balloon cones and waists, being
unmasked during the coating procedure, are coated with the same
slippery coating as is placed on the rest of the catheter. As is
already known, such coatings are typically applied to the catheter
surfaces in the form of a solution which is allowed to dry and is
subsequently cured usually by heat or Ultraviolet light for a short
period of time.
[0030] Other means for achieving the selective placement of
coating(s) on the catheter may include the use of a release agent
such as an oil which may be spread over the area which it is
desired will remain uncoated. After curing of the coating, this
area is then exposed by simply peeling the coating off the area
carrying the oil. Also, if desired, one may rinse or wipe a portion
of the coating off the balloon before the coating is cured. Another
alternative is to modify the coating in the area of the balloon
which is to remain uncoated such as using an ultraviolet
blocker.
[0031] A final selective coating arrangement according to the
invention may also be made by first coating with a less slippery,
compatible coating over the balloon and possibly more of the
catheter, then masking, applying highly slippery coatings as
desired and proceeding as normal or vice versa.
[0032] This invention is equally applicable to balloons of the
compliant type and to those of the non-compliant type. A wide
variety for the materials of the balloons is well known, some
examples of which, to name a few, include ethylene vinylacetate
copolymer polyethylene terephthalate, polyethylene, polyolefin
copolymer and high density polyethylene.
[0033] Masking materials are most conveniently heat shrink
polyethylene on mandrels of sizes appropriate to the particular
balloon and are placed thereon. The coating may comprise a mix of a
higher molecular weight soluble polymer such as PEO and a UV
curable diacrylate in isopropyl alcohol and water containing a
trace of photoinitiator. The coating solution is wiped onto
selected areas of the catheter device which is then passed to a UV
chamber, purged of oxygen, exposed to UV and then removed. The mask
is removed, the area is cleaned ultrasonically with a water bath to
remove any drips. The uncoated portion of the balloon is left as is
or a less lubricious coating is applied to it such as silicone or a
polymer coating with a lesser percentage of hydrogel content. Other
methods of application will be known to those familiar with the
art.
[0034] In a further embodiment of the invention the balloon
exhibits different frictional characteristics in its inflated and
non-inflated states. The balloon catheter has a low coefficient of
sliding friction in a deflated state and a higher coefficient of
friction in a inflated state. The balloon has a high coefficient of
sliding friction in a deflated state for facilitating the transport
of a contracted stent and a lower coefficient of friction in an
inflated or expanded state. Further disclosure of such balloon
surface and material characteristics can be found in U.S. patent
application Ser. No. 08/609,274, filed on Mar. 1, 1996, which is
incorporated herein by reference.
[0035] In accordance with one aspect of this invention a medical
balloon is formed of a thin material for expansion from a compact
state to an expanded state in a patient's vessel. The balloon is
formed with a first material portion or spaced first material
portions such that the balloon in its compact state essentially
exposes the exterior surfaces of only the first material portion or
portions. In the expanded state the balloon exposes the exterior
surfaces of both the first and remaining material portions for
contact with surrounding vessels. The exterior surface on a first
material portion has an integral surface with a coefficient of
friction that differs from the coefficient of friction of the
exterior surface of a remaining portion of the balloon.
[0036] In accordance with another aspect of the referenced
invention a stent delivery system includes a catheter with an
inflation lumen, and a medical balloon formed of a thin material
positioned at the distal end of the catheter in communication with
the inflation balloon so the balloon is expansible from a compact
state to an expanded state in response to the injection of an
inflation fluid through the inflation lumen. A first material
portion or a plurality of first spaced material portions are
located so that the balloon essentially exposes the exterior
surfaces of only the first material portion or portions in its
compact state. As the balloon expands, it expands the stent and
exposes the exterior surfaces of the first material portion and of
the remaining material portion. The exterior surface of a first
material portion has a coefficient of friction that is greater than
the coefficient of friction of the exterior surface of the
remaining portion of the balloon, such that the balloon in its
compact state engages and provides friction to hold the stent in
place on the balloon and in its expanded state facilitates the
release of the balloon from the stent.
[0037] In a further embodiment of the present inventive concept,
the balloon itself may be coated either partially or completely,
but at least in areas in which a loaded stent would have contact
with, with a tacky composition which aids in retaining a loaded
stent in place during the tortuous location of the stent at a
target position of a vessel. The balloon is coated with an
adhesive, such as an elastomeric based adhesive, i.e.
polyisobutylene, and pressure sensitive-type adhesives, i.e.
polyamides and polyacrylate, making the surface of the balloon
which would be in contact with a loaded stent tacky. The bond which
is created between the coated balloon and loaded stent is only
strong enough to prevent slippage of the stent, but is weak enough
to release when the balloon is expanded. The portions of the
balloon which are coated and the tackiness of the adhesive may vary
to achieve this result. One such pattern involves coating
longitudinal strips along the balloon which are accessible for
engagement while the balloon is deflated. A similar pattern can be
seen in U.S. patent application Ser. No. 08/609,274, as discussed
above. With such a pattern, it is contemplated that the exposed
surface area when the balloon is collapsed would be coated with
adhesive to achieve a selective tacky coating on the balloon.
Preferably, the balloon is coated by a tacky coating or a coating
with a high coefficient of friction, i.e. a static coefficient of
friction of about 0.2-0.4. The coating utilized to coat the balloon
should be of higher coefficient of friction than the coating used
to coat the shaft.
[0038] Preferably, the adhesive used is a aqueous dispersion of
ethylene vinyl acetate (EVA) or a water-based dispersion based on
high-molecular weight ethylene interpolymers, such as ADCOTE.RTM.
37P147, which is manufactured by Morton.RTM.. The major use for
Adcote 37P147 is as an in-line laminating adhesive, a primer, or as
a base for compounding coatings and adhesives. Adcote 37P147 is
suggested for applications which require the property of low
temperature heat activation and hot tack. This product exhibits
good adhesion to Mylar, polyethylene, polypropylene, aluminum foil
and PVDC coated glassine. For surface coating, Adcote 37P147 must
be compounded. Typical Dispersion Properties are: Solids--45%;
Viscosity--500 cps; pH--10; and Weigh/Gallon--8.2 lbs. The
dispersion is stable in most alkaline systems, but may coagulate
under acidic conditions. Adcote 37P147 exhibits good storage
stability, but mixing just prior to use is recommended in order to
assure product uniformity. Freezing conditions should be avoided as
freezing will coagulate the dispersion. Standard coating
techniques, such as wire-wound rods and gravure, can be employed.
However, as these dispersions are water-based, care should be taken
to minimize the generation of foam. If a tendency to foam occurs,
the addition of 0.05-0.2% (based on wet dispersion weight) of
Foamkill 614 (Crucible Chemical Company, Donaldson Center,
Greenville, S.C. 29605) or Adcote 7R1 is recommended. The
dispersion may be reduced with water, preferably slightly basic
(buffer solution of about ph 10), if a large amount is to be added.
Drying should be effected by heat giving rise to an approximate
surface web temperature of 150-180.degree. F. Coating weights for
adhesive use of 1.0-2.0 lbs/ream is adequate for most
applications.
[0039] While this invention may be embodied in many different
forms, there are shown in the drawings and described in detail
herein specific preferred embodiments of the invention. The present
disclosure is an exemplification of the principles of the invention
and is not intended to limit the invention to the particular
embodiments illustrated.
[0040] This completes the description of the preferred and
alternate embodiments of the invention. Those skilled in the art
may recognize other equivalents to the specific embodiment
described herein which equivalents are intended to be encompassed
by the claims attached hereto.
* * * * *