Plastic and nonmetallic article shaping or treating: processes – With printing or coating of workpiece – Anti-stick or adhesion preventing coating
Reexamination Certificate
2001-11-27
2004-05-25
Lee, Edmund H. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
With printing or coating of workpiece
Anti-stick or adhesion preventing coating
C264S150000, C264S156000, C264S159000, C264S152000, C264S250000, C264S255000, C264S271100, C264S294000
Reexamination Certificate
active
06740273
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for making a silicon balloon catheter, and more particularly to a method for making a silicon balloon catheter in which a balloon is formed on a lumen tube having a fluid drainage lumen and an inflation lumen so that it is inflated when a liquid is injected into the balloon though the inflation lumen.
2. Description of the Related Art
In general, a catheter made of silicon is a thin and long tube adapted to be inserted into the human body in order to draw blood or to inject medicine. Also, such a catheter may be used to drain urine. In this case, the catheter is inserted into the bladder through the urethra so as to drain urine collected in the bladder.
FIG. 1
is a sectional view illustrating a conventional balloon catheter.
FIG. 2
is a flow chart illustrating a conventional method for manufacturing the balloon catheter.
As shown in
FIG. 1
, the conventional balloon catheter includes a lumen tube
13
formed with a partition
19
therein to define a primary lumen
12
and an inflation lumen
14
, and a balloon layer
16
partially bonded to an outer surface of the lumen tube
13
to provide a balloon. The primary lumen
12
serves to drain urine induced from the bladder through a urine drainage hole
17
, whereas the inflation lumen
14
serves to inflate the balloon provided by the balloon layer
16
. An inflation hole
15
is also formed at the lumen tube
13
in order to communicate the inflation lumen
14
with the interior of the balloon.
In order to manufacture the balloon catheter having the above mentioned configuration, an extrusion process is carried out to extrude an intermediate tube having the primary lumen
12
and inflation lumen
14
(Step S
1
), as shown in FIG.
2
. Thereafter, the extruded intermediate tube is vulcanized (Step S
2
), and then cut into tube pieces having a desired length, that is, lumen tubes
13
(Step S
3
).
Subsequently, the inflation hole
15
and urine drainage hole
17
are perforated through each lumen tube
13
(Step S
4
). A tip
11
is then formed at one end of each lumen tube
13
(Step S
5
). Thereafter, a balloon manufactured in a separate molding process (Step S
6
) is bonded, as the balloon layer
16
, to the outer surface of each lumen tube
13
by an adhesive (Step S
7
). Each lumen tube
13
is then subjected to an overcoating process (Step S
8
) to complete the balloon catheter having the configuration of FIG.
1
.
In the above mentioned conventional balloon catheter, however, there is a problem in that it may cause a patient great pain during a surgical operation because its balloon-bonded portion has a diameter relatively larger than that of other portions, Furthermore, the bonded portions of the balloon maybe separated.
Another conventional catheter manufacturing method is disclosed in U.S. Pat. No. 5,137,671.
This method will be described hereinafter with reference to
FIGS. 3
a
to
3
g
. First, a double lumen tube
100
is prepared, as shown in
FIG. 3
a
The double lumen tube
100
is formed with a first lumen
120
(a larger fluid conduit lumen) and a second lumen
140
(a smaller capillary lumen).
A capillary lumen access opening
160
is punched through at an intermediate portion of the prepared lumen tube
100
, that is, a balloon inflating portion, so that it communicates with the second lumen
140
, as shown in
FIG. 3
b
. The second lumen
140
is then filled with a polymeric fill material
180
such as silicon rubber between one end thereof (that is, the left end in
FIG. 3
b
)and a point just before the capillary lumen access opening
160
. A tip
200
is attached to one end of the lumen tube
100
corresponding to the one end of the second lumen
140
, so that both of the fast and second lumens
120
and
140
are closed at one end thereof.
Subsequently, a portion of the lumen tube
100
extending from one end of the lumen tube
100
to the balloon inflating portion, that is, up to the line A—A in
FIG. 3
c
, is dipped into a bond preventing agent solution (a liquid soap or petrolatum), and then dried, so that it is coated with a solidified bond preventing agent layer
300
. The bond preventing agent layer
300
fills the capillary lumen access opening
160
and a portion of the second lumen
140
. Thus, the bond preventing agent layer
300
has a cross section as shown in
FIG. 3
c
. That is, the portion of the second lumen
140
between the line A—A and the capillary lumen access opening
160
is filled with the bond preventing agent layer
300
, whereas the outer surface portion of the lumen tube
100
between the line A—A and the end of the lumen tube
100
adjacent to the tip
200
is coated with the bond preventing agent layer
300
, along with the tip
200
.
Thereafter, a portion of the lumen tube
100
extending up to the line B—B in
FIG. 3
c
, that is, just before the balloon inflating portion, is treated using a surface active agent, and then dipped into hot, water or other hot aqueous solution several times, so as to remove the bond preventing agent layer
300
therefrom. Thus, the bond preventing agent layer
300
remains only at the balloon inflating portion of the lumen tube
100
, as shown in
FIG. 3
d
. An overcoat layer
400
is then coated over the entire outer surface of the lumen tube
100
, as shown in
FIG. 3
e
. The overcoat layer
400
may have a multi-layer structure including laminated layers
410
and
420
.
The remaining bond preventing agent layer
300
filling and covering the balloon inflating portion is completely removed through the second lumen
140
of the lumen tube
100
, thereby forming a balloon cavity
440
, as shown in
FIG. 3
f
. Thus, a balloon catheter is obtained. Referring to
FIG. 3
g
, it can be seen that the conventional lumen tube
20
has a cross-sectional shape where its thickness ta and thickness Ta are relatively large. Typically, the conventional lumen tube
13
has a minimum thickness between the outer surface thereof and the surface of the inflation lumen
14
, that is, ta, corresponding to 0.5 mm, while having a minimum thickness between the outer surface thereof and the surface of the fluid drainage lumen
12
, that is, Ta, corresponding to 0.9 mm.
Accordingly, workability in a subsequent operation for perforating inflation apertures while allowing the fluid drainage lumen to have a size as large as possible is significantly reduced.
This balloon catheter manufacturing method has a problem in that it causes environmental pollution due to waste water produced during the procedure of dipping the lumen tube
100
into water several times in order to remove the bond preventing agent from the portion of the lumen tube
100
(between the line B—B and the tip-side end) other than the balloon inflating portion.
Additionally, where the bond preventing agent is incompletely removed, the residue thereof is moved to the peripheral edge of the balloon cavity formed at the balloon inflating portion when the balloon cavity is inflated, thereby causing the overcoat layer to be stripped around the balloon inflating portion. As a result, the overcoat layer may be inflated around the balloon inflating portion.
Also, the above mentioned conventional balloon catheter manufacturing method still has the problem caused by the diameter of the balloon inflating portion being larger than that of other portions
As another conventional example, there is a silicon rubber catheter disclosed in Japanese Patent No. 3015310 registered on Jun. 21, 1995.
In this catheter, a balloon is formed on the outer surface of a catheter body such that it is integral with the catheter body. The catheter body is formed using silicon rubber in accordance with a primary extrusion process so that it is defined with a fluid conduit lumen and a capillary lumen therein, and formed with a channel at the outer surface thereof The catheter body is subjected to a vulcanization process, and then coated with a bond preventing agent at a balloon forming portion thereof Thereafter, a balloon layer is laminated
Lee Edmund H.
Lee Hong Degerman Kang & Schmadeka
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