U.S. patent application number 10/251683 was filed with the patent office on 2003-07-31 for laser weldable flexible medical tubings, films and assemblies thereof.
Invention is credited to Shang, Sherwin, Yang, Tahua.
Application Number | 20030143352 10/251683 |
Document ID | / |
Family ID | 27610196 |
Filed Date | 2003-07-31 |
United States Patent
Application |
20030143352 |
Kind Code |
A1 |
Yang, Tahua ; et
al. |
July 31, 2003 |
Laser weldable flexible medical tubings, films and assemblies
thereof
Abstract
The present invention provides a polymer blend for fabricating a
laser-weldable article having a first component of a material not
thermally responsive to a laser beam and selected from the group
consisting of polyolefins, ethylene and lower alkyl acrylate
copolymers, ethylene and lower alkyl substituted alkyl acrylate
copolymers, ethylene vinyl acetate copolymers, polybutadienes,
polyesters, polyamides, and styrene and hydrocarbon copolymers; a
second component of a laser responsive material having low
solubility in an aqueous medium and present in an amount by weight
of from about 20 ppm to about 2000 ppm; and the blend being
sufficiently thermally responsive to exposure to a laser beam
having a wavelength within a range of wavelengths from about 700 nm
to about 1500 nm to at melt upon exposure to the laser beam for a
short period of time.
Inventors: |
Yang, Tahua; (Woodridge,
IL) ; Shang, Sherwin; (Vernon Hills, IL) |
Correspondence
Address: |
BAXTER HEALTHCARE CORPORATION
RENAL DIVISION
1 BAXTER PARKWAY
DF3-3E
DEERFIELD
IL
60015
US
|
Family ID: |
27610196 |
Appl. No.: |
10/251683 |
Filed: |
September 20, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10251683 |
Sep 20, 2002 |
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10061835 |
Jan 31, 2002 |
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Current U.S.
Class: |
428/36.9 ;
156/158 |
Current CPC
Class: |
B23K 2101/06 20180801;
B29C 65/1616 20130101; B29C 65/1619 20130101; B29K 2031/04
20130101; Y10T 156/1313 20150115; A61M 2205/6081 20130101; B29C
65/2046 20130101; B29C 66/636 20130101; Y10T 156/12 20150115; B29C
66/91221 20130101; B29C 66/712 20130101; B29C 66/81267 20130101;
A61M 39/146 20130101; B29C 66/71 20130101; B29C 66/8748 20130101;
B29C 65/2061 20130101; B29C 66/71 20130101; B29C 65/7802 20130101;
B29C 66/91411 20130101; Y10T 428/1352 20150115; B29C 66/71
20130101; B29C 65/1687 20130101; B29C 66/5221 20130101; B29C 66/71
20130101; B29C 66/9161 20130101; B29C 65/1632 20130101; B29C 66/71
20130101; B29C 66/71 20130101; B29K 2023/0641 20130101; B29K
2023/00 20130101; B29K 2023/0616 20130101; B29K 2023/083 20130101;
B29K 2023/12 20130101; B29K 2023/065 20130101; B29K 2023/0633
20130101; B29K 2023/0608 20130101; B29K 2067/00 20130101; B29K
2077/00 20130101; B23K 26/067 20130101; B29C 66/8226 20130101; B29C
66/91212 20130101; B29L 2023/007 20130101; Y10T 428/139 20150115;
B29C 66/0018 20130101; B29C 66/857 20130101; B29C 66/91431
20130101; B29C 66/71 20130101; A61M 1/28 20130101; B29C 65/1674
20130101; B29C 66/82263 20130101; B29C 66/71 20130101; B29K
2105/0088 20130101; Y10T 428/1397 20150115; B23K 26/282 20151001;
B29C 65/7841 20130101; B29C 66/1312 20130101; B29C 66/71 20130101;
B29C 66/91216 20130101; B29C 65/1664 20130101; B29C 66/1222
20130101; B29C 66/1226 20130101; B29C 66/71 20130101; B29K 2009/06
20130101; B29C 66/73921 20130101; B29C 66/9131 20130101; B29C
66/9121 20130101; Y10T 428/1393 20150115; B29C 66/73115 20130101;
B29C 66/723 20130101; B29C 66/1142 20130101; B29C 66/52293
20130101; B29C 66/73322 20130101; B29C 66/961 20130101; B23K
26/0619 20151001; B29C 66/137 20130101; B29C 66/71 20130101; B29C
66/91218 20130101; Y10S 138/07 20130101 |
Class at
Publication: |
428/36.9 ;
156/158 |
International
Class: |
B32B 001/08 |
Claims
We claim:
1. A polymer blend for fabricating a laser-weldable article
comprising: a first component of a material not thermally
responsive to a laser beam and selected from the group consisting
of polyolefins, ethylene and lower alkyl acrylate copolymers,
ethylene and lower alkyl substituted alkyl acrylate copolymers,
ethylene vinyl acetate copolymers, polybutadienes, polyesters,
polyamides, and styrene and hydrocarbon copolymers; a second
component of a laser responsive material having low solubility in
an aqueous medium and present in an amount by weight of from about
20 ppm to about 2000 ppm; and the blend being sufficiently
thermally responsive to exposure to a laser beam having a
wavelength within a range of wavelengths from about 700 nm to about
1500 nm to at melt upon exposure to the laser beam for a short
period of time.
2. The blend of claim 1, wherein the polyolefin is obtained from a
monomer of an .alpha.-olefin having from 2 to 20 carbons.
3. The blend of claim 1, wherein the polyolefin is selected from
the group of propylene containing polymers and ethylene containing
polymers.
4. The blend of claim 1, wherein the polyolefin is selected from
the group consisting of homopolymers of polypropylene and
copolymers of polypropylene.
5. The blend of claim 4, wherein the homopolymer of polypropylene
has a stereochemistry selected from the group consisting of
isotactic, syndiotactic, atactic, hemiisotactic and
stereoblock.
6. The blend of claim 4, wherein the copolymer of polypropylene is
selected from the group consisting of random copolymers and block
copolymers.
7. The blend of claim 4, wherein the copolymer of polypropylene is
obtained by polymerizing a propylene monomer with an .alpha.-olefin
having from 2 to 20 carbons.
8. The blend of claim 4, wherein the copolymer of polypropylene is
selected from the group of random copolymers with ethylene and
block copolymers with ethylene.
9. The blend of claim 1, wherein the polyolefin has a heat of
fusion from about 60 joules/g to about 160 joules/g.
10. The blend of claim 9, wherein the polyolefin has a peak melting
point temperature of less than about 165.degree. C.
11. The blend of claim 1, wherein the first component is a second
blend of a first polypropylene and a styrene and hydrocarbon
copolymer.
12. The blend of claim 11, wherein the styrene and hydrocarbon
copolymer is selected from the group of random copolymers of
styrene and hydrocarbon and block copolymers of styrene and
hydrocarbon.
13. The blend of claim 12, wherein the styrene and hydrocarbon
block copolymer is selected from the group consisting of di-block
copolymers, tri-block copolymers, multi-block copolymers and star
block copolymers.
14. The blend of claim 13, wherein the styrene and hydrocarbon
block copolymer is oil modified.
15. The blend of claim 11, wherein the second blend includes a
second polypropylene, the second polypropylene having a high melt
strength.
16. The blend of claim 15, wherein the second blend has from about
10% to about 50% by weight of the sum of the weights of the first
polypropylene and the second polypropylene and the styrene and
hydrocarbon copolymer constituting the remaining weight portion of
the second blend.
17. The blend of claim 1, wherein the polyolefin is selected from
the group consisting of homopolymers of ethylene and copolymers of
ethylene.
18. The blend of claim 17, wherein the copolymers of ethylene are
obtained by polymerizing ethylene monomers with an .alpha.-olefin
having from 3 to 20 carbons.
19. The blend of claim 17, wherein the copolymers of ethylene are
obtained by polymerizing ethylene monomers with an .alpha.-olefin
having from 4 to 8 carbons.
20. The blend of claim 17, wherein the copolymers of ethylene have
a density of less than about 0.915 g/cc.
21. The blend of claim 17, wherein the copolymers of ethylene have
a density of less than about 0.900 g/cc.
22. The blend of claim 17, wherein the polyolefin is an ultra-low
density polyethylene.
23. The blend of claim 2, wherein the polyolefin is obtained
utilizing a single-site catalyst.
24. The blend of claim 2, wherein the polyolefin is obtained
utilizing a metallocene catalyst.
25. The blend of claim 1, wherein the first component is a
polybutadiene.
26. The blend of claim 1, wherein the laser responsive material has
a functional group selected from the group consisting of:
polymethine, porphine, indanthrene, quinone, di- and
tri-phenylmethane, and metal complexed dithiol dyes.
27. The blend of claim 26, wherein the laser responsive material is
a dye,
28. The blend of claim 27, wherein the dye is thermally stable at
temperatures reached during extrusion processing of the blend.
29. The blend of claim 28, wherein the dye is present in an amount
from about 200 ppm to about 500 ppm.
30. The blend of claim 1, wherein the first component is a third
blend of from about 99% to about 50% by weight of a third component
selected from the group consisting of: (1) ethylene and
.alpha.-olefin copolymers having a density of less than about 0.915
g/cc, (2) ethylene and lower alkyl acrylate copolymers, (3)
ethylene and lower alkyl substituted alkyl acrylate copolymers and
(4) ionic polymers; and from about 50% to about 1% of a fourth
component selected from the group consisting of: (1) propylene
containing polymers, (2) butene containing polymers, (3) polymethyl
pentene containing polymers, (4) cyclic olefin containing polymers
and (5) bridged polycyclic hydrocarbon containing polymers.
31. The blend of claim 30, wherein the laser responsive material is
present in an amount from about 200 ppm to about 2000 ppm.
32. A laser weldable tubing comprising: a sidewall having a layer
from a polymer blend comprising a first component of a material not
thermally responsive to a laser beam and selected from the group
consisting of polyolefins, ethylene and lower alkyl acrylate
copolymers, ethylene and lower alkyl substituted alkyl acrylate
copolymers, ethylene vinyl acetate copolymers, polybutadienes,
polyesters, polyamides, and styrene and hydrocarbon copolymers, a
second component in an amount by weight of from about 20 ppm to
about 500 ppm of a laser responsive material having low solubility
in aqueous medium and the layer being sufficiently thermally
responsive to exposure to a laser beam having a wavelength within a
range of wavelengths from about 700 nm to about 1500 nm to melt a
portion of the sidewall upon exposure to the laser beam for a short
period of time.
33. The tubing of claim 32, wherein the tubing has a monolayer
structure.
34. The tubing of claim 32, wherein the tubing has a multiple layer
structure.
35. The tubing of claim 34, wherein the layer forms a solution
contact layer.
36. The tubing of claim 34, wherein the layer is a core layer.
37. The tubing of claim 34, wherein the layer is a skin layer.
38. The tubing of claim 32, wherein the polyolefin is obtained from
a monomer of an .alpha.-olefin having from 2 to 20 carbons.
39. The tubing of claim 32, wherein the polyolefin is selected from
the group of propylene containing polymers and ethylene containing
polymers.
40. The tubing of claim 32, wherein the polyolefin is selected from
the group consisting of homopolymers of polypropylene and
copolymers of polypropylene.
41. The tubing of claim 40, wherein the homopolymer of
polypropylene has a stereochemistry selected from the group
consisting of isotactic, syndiotactic, atactic, hemiisotactic and
stereoblock.
42. The tubing of claim 40, wherein the copolymer of polypropylene
is selected from the group consisting of random copolymers and
block copolymers.
43. The tubing of claim 40, wherein the copolymer of polypropylene
is obtained by polymerizing a propylene monomer with an
(.alpha.-olefin having from 2 to 20 carbons.
44. The tubing of claim 40, wherein the copolymer of polypropylene
is selected from the group of random copolymers with ethylene and
block copolymers with ethylene.
45. The tubing of claim 32, wherein the polyolefin has a heat of
fusion from about 60 joules/g to about 160 joules/g joules/g.
46. The tubing of claim 45, wherein the polyolefin has a peak
melting point temperature of less than about 165.degree. C.
47. The tubing of claim 32, wherein the first component is a second
blend of a first polypropylene and a styrene and hydrocarbon
copolymer.
48. The tubing of claim 47, wherein the styrene and hydrocarbon
copolymer is selected from the group of random copolymers of
styrene and hydrocarbon and block copolymers of styrene and
hydrocarbon.
49. The tubing of claim 48, wherein the styrene and hydrocarbon
block copolymer is selected from the group consisting of di-block
copolymers, tri-block copolymers, and star block copolymers.
50. The tubing of claim 49, wherein the styrene and hydrocarbon
block copolymer is oil modified.
51. The tubing of claim 47, wherein the second blend includes a
second polypropylene, the second polypropylene having high melt
strength.
52. The tubing of claim 51, wherein the second blend has from about
10% to about 50% by weight of the sum of the weights of the first
polypropylene and the second polypropylene and the styrene and
hydrocarbon copolymer constituting the remaining weight portion of
the second blend.
53. The tubing of claim 32, wherein the polyolefin is selected from
the group consisting of homopolymers of ethylene and copolymers of
ethylene.
54. The tubing of claim 53, wherein the copolymers of ethylene are
obtained by polymerizing ethylene monomers with an .alpha.-olefin
having from 3 to 20 carbons.
55. The tubing of claim 53, wherein the copolymers of ethylene are
obtained by polymerizing ethylene monomers with an .alpha.-olefin
having from 4 to 8 carbons.
56. The tubing of claim 53, wherein the copolymers of ethylene have
a density of less than about 0.915 g/cc.
57. The tubing of claim 53, wherein the copolymers of ethylene have
a density of less than about 0.900 g/cc.
58. The tubing of claim 53, wherein the polyolefin is an ultra-low
density polyethylene.
59. The tubing of claim 58, wherein the ultra-low density
polyethylene is obtained utilizing a single-site catalyst.
60. The tubing of claim 58, wherein the ultra-low density
polyethylene is obtained utilizing a metallocene catalyst.
61. The tubing of claim 32, wherein the laser responsive material
has a functional group selected from the group consisting of:
polymethine, porphine, indanthrene, quinone, di- and
tri-phenylmethane, and metal complexed dithiol dyes.
62. The tubing of claim 61, wherein the laser responsive material
is a dye.
63. The tubing of claim 62, wherein the dye is thermally stable at
temperatures reached during extrusion processing of the tubing.
64. The tubing of claim 63 wherein the dye is present in an amount
from about 200 ppm to about 500 ppm.
65. A film comprising: a layer comprising a first blend of a
polymeric component and a laser responsive component, wherein the
polymeric component is a second blend of from about 99% to about
50% by weight of a first component selected from the group
consisting of: (1) ethylene and .alpha.-olefin copolymers having a
density of less than about 0.915 g/cc, (2) ethylene and lower alkyl
acrylate copolymers, (3) ethylene and lower alkyl substituted alkyl
acrylate copolymers and (4) ionic polymers; and from about 50% to
about 1% of a second component selected from the group consisting
of: (1) propylene containing polymers, (2) butene containing
polymers, (3) polymethyl pentene containing polymers, (4) cyclic
olefin containing polymers and (5) bridged polycyclic hydrocarbon
containing polymers; and wherein the film is sufficiently thermally
responsive to exposure to a laser beam having a wavelength within a
range of wavelengths from about 700 nm to about 1500 nm to at melt
upon exposure to the laser beam for a short period of time.
66. The film of claim 65, wherein the .alpha.-olefin has from 4 to
8 carbons.
67. The film of claim 66, wherein the ethylene and .alpha.-olefin
copolymer is obtained using a single-site catalyst.
68. The film of claim 66, wherein the second component is a
propylene containing polymer.
69. The film of claim 68, wherein the propylene containing polymer
is a homopolymer.
70. The film of claim 68, wherein the propylene containing polymer
is a copolymer of propylene and ethylene.
71. The film of claim 70, wherein the second blend includes a third
component of a second ethylene and .alpha.-olefin copolymer.
72. The film of claim 71, wherein the second ethylene and
.alpha.-olefin copolymer is obtained using a single-site
catalyst.
73. The film of claim 72, wherein the first ethylene and
.alpha.-olefin copolymer has a density of less than about 0.900
g/cc, and the second ethylene and .alpha.-olefin copolymer has a
density of higher than about 0.900 g/cc but less than about 0.910
g/cc.
74. The film of claim 65 further comprising a laser responsive
material in the first blend and wherein the laser responsive
material is a dye having a functional group selected from the group
polymethine, porphine, indanthrene, quinone, di- and
tri-phenylmethane, and metal complexed dithiol dyes.
75. The film of claim 65, wherein the film is a monolayer
structure.
76. The film of claim 65, wherein the film is a multiple layer
structure.
77. The film of claim 76, wherein the layer is a seal layer.
78. A film comprising: a layer of a first blend of a polymeric
component and a laser responsive component wherein the polymeric
component is a second blend comprising by weight of from about 35%
to about 45% of a first ethylene and .alpha.-olefin copolymer
having a density of less than about 0.900 g/cc, from about 20% to
about 30% of a second ethylene and .alpha.-olefin copolymer having
a density of higher than about 0.900 g/cc but less than about 0.910
g/cc, and from about 30% to about 40% of a polypropylene and
wherein the film is sufficiently thermally responsive to exposure
to a laser beam having a wavelength within a range of wavelengths
from about 700 nm to about 1500 nm to at melt upon exposure to the
laser beam for a short period of time.
79. The film of claim 78, wherein the first ethylene and
.alpha.-olefin copolymer is obtained using a single-site
catalyst.
80. The film of claim 79, wherein the second ethylene and
.alpha.-olefin copolymer is obtained using a single-site
catalyst.
81. The film of claim 80, wherein the polypropylene is a random
copolymer of propylene with ethylene.
82. The film of claim 78 further comprising a laser responsive
material in the first blend and wherein the laser responsive
material is a dye having a functional group selected from the group
polymethine, porphine, indanthrene, quinone, di- and
tri-phenylmethane, and metal complexed dithiol dyes.
83. A film comprising: a layer of a blend of an ethylene and
.alpha.-olefin copolymer and a dye having a functional group
selected from the group polymethine, porphine, indanthrene,
quinone, di- and tri-phenylmethane, and metal complexed dithiol
dyes.
84. The film of claim 83, wherein the ethylene and .alpha.-olefin
copolymer is obtained using a single-site catalyst.
85. The film of claim 84, wherein ethylene and .alpha.-olefin
copolymer has a density of less than about 0.915 g/cc.
86. The film of claim 84, wherein ethylene and .alpha.-olefin
copolymer has a density of less than about 0.900 g/cc.
87. A laser weldable multiple lumen tubing comprising: a first
lumen and a second lumen each having a layer from a polymer blend
comprising a first component of a material not thermally responsive
to a laser beam and selected from the group consisting of
polyolefins, ethylene and lower alkyl acrylate copolymers, ethylene
and lower alkyl substituted alkyl acrylate copolymers, ethylene
vinyl acetate copolymers, polybutadienes, polyesters, polyamides,
and styrene and hydrocarbon copolymers, a second component in an
amount by weight of from about 20 ppm to about 2,000 ppm of a laser
responsive material having low solubility in aqueous medium and the
layer being sufficiently thermally responsive to exposure to a
laser beam having a wavelength within a range of wavelengths from
about 700 nm to about 1500 nm to melt a portion of the sidewall
upon exposure to the laser beam for a short period of time.
88. The multiple lumen tubing of claim 87 wherein the first lumen
and the second lumen are connected together along peripheral
edges.
89. The multiple lumen tubing of claim 88 wherein the first lumen
and the second lumen extend in a parallel direction with respect to
one another.
90. The multiple lumen tubing of claim 88 wherein the first lumen
and the second lumen are helically disposed with respect to one
another.
91. The multiple lumen tubing of claim 87 wherein the first lumen
and the second lumen are concentrically disposed with respect to
one another.
92. The multiple lumen tubing of claim 87 wherein the first lumen
defines a passageway and further comprising a third lumen wherein
the second lumen and third lumen are disposed in the passageway.
Description
RELATED APPLICATIONS
[0001] This is a continuation in part of U.S. patent application
Ser. No. 10/061,835 filed on Jan. 31, 2002, which is currently
pending, and which is hereby incorporated herein by reference and
made a part hereof.
FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable.
BACKGROUND OF THE INVENTION
[0003] The present invention relates to laser-weldable flexible
tubing that is particularly well suited for use in the delivery of
therapeutic solutions such as peritoneal dialysis solutions.
[0004] It is known to use medical containers with tubing for
various medical procedures such as kidney dialysis, intravenous
delivery of therapeutic fluids, delivery of nutritional fluids;
delivery of blood., blood components, and blood substitutes. Fluid
containers and tubing are also widely used in other industries such
as the food industry and the chemical industries.
[0005] For example, flexible medical tubings are used in systems
for treating renal disease. In renal failure of any cause, there
are several physiological derangements. The balance of water,
minerals and the excretion of daily metabolic load is no longer
possible in renal failure. During renal failure, toxic end products
of nitrogen metabolism (urea, creatinine, uric acid and others) can
accumulate in blood and tissues.
[0006] Kidney failure and reduced kidney function have been treated
with dialysis. Dialysis removes waste, toxins and excess water from
the body that would otherwise have been removed by normal
functioning kidneys. Dialysis treatment for replacement of kidney
functions is critical to many people because the treatment is life
saving. One who has failed kidneys could not continue to live
without replacing at least the filtration functions of the kidneys.
Hemodialysis and peritoneal dialysis are two types of dialysis
therapies commonly used to treat loss of kidney function.
[0007] In general, hemodialysis treatment removes waste, toxins,
and excess water from the patient's blood. The patient is connected
to a hemodialysis machine and the patient's blood is pumped through
the machine. Catheters are inserted into the patient's veins and
arteries to connect the blood flow to and from the hemodialysis
machine. As blood passes through a dialyzer in the hemodialysis
machine, waste, toxins, and excess water are removed from the
patient's blood and the blood is infused back into the patient.
Many tubes are used in the process that must be connected or
disconnected. Hemodialysis treatment lasts several hours and is
generally performed in a treatment center about three or four times
per week.
[0008] Peritoneal dialysis, typically, utilizes a dialysis
solution, or dialysate, which is infused into a patient's
peritoneal cavity. The dialysate contacts the patient's peritoneal
membrane in the peritoneal cavity. Waste, toxins and excess water
pass from the patient's bloodstream through the peritoneal membrane
and into the dialysate. The transfer of waste, toxins and water
from the bloodstream into the dialysate occurs due to diffusion and
osmosis, i.e., there is an osmotic gradient across the membrane.
The spent dialysate is drained from the patient's peritoneal cavity
to remove the waste, toxins and water from the patient. After the
spent dialysis is drained, it is replaced with a fresh dialysate
solution.
[0009] While the present invention has application in connecting or
disconnecting tubes for medical procedures, the following
discussion focuses, as an example, on a particular tube connection
and disconnection processes performed during peritoneal dialysis.
Numerous tubes are used in the process that must be connected or
disconnected. In peritoneal dialysis, patients have a catheter
implanted in their peritoneal cavity with an end protruding from
the patient. The protruding end of the catheter terminates with a
section of tubing known as a transfer set. The transfer set is
typically made from a silicone material and must be periodically
replaced say every several months. The transfer set is provided to
connect the patient to dialysate fluid bags or discharge bags. The
transfer set typically has a spike that connects to an access port
positioned in a tube associated with the drain bag or dialysate
solution bag (dialysate set). In general, the patient manually
stabs the port with the spike to connect the transfer set to the
dialysate set. The patient connects the tube in the transfer set to
a drain to allow spent dialysate fluid to drain from the peritoneal
cavity. Next, the patient is connected to a bag of fresh dialysate
and manually infuses the fresh dialysate through the catheter and
into the patient's peritoneal cavity. When the patient completes
treatment, the port is pulled off the spike and a cap is placed on
the spike until the patient is ready for the next treatment. When
the patient disconnects the catheter from the fresh dialysate bag,
the dialysate dwells within the peritoneal cavity to draw waste,
toxins and excess water from the patient's bloodstream to the
dialysate solution. After the dwell period, the patient repeats the
manual dialysis procedure and drains the spent dialysate from the
peritoneal cavity.
[0010] Accordingly, during dialysis treatments such as those
described above, the patient is required to connect and disconnect
the catheter and transfer set from the fill or drain line (or tube)
a number of times. Some devices are available today to assist the
patient during the process when using specialized sterilization
equipment. However, by and large, these connections and
disconnections are performed manually.
[0011] One such device, incorporates a heated wafer or hot knife
that physically contacts the tubing to cut it by melting the tube
and joining two tubes together or melt-sealing the tube ends.
Typically, heated wafer applications involve a "melt and wipe"
process. In peritoneal dialysis, for example, a patient must drain
spent dialysate or replenish his/her peritoneal cavity with fresh
dialysate. To this end, the patient must connect the transfer set
tubing to a tube extending from either a drain bag or a bag
containing fresh dialysate. In one "melt and wipe" process, the
transfer set tubing is bent in a U or V-shape to fit into a U or
V-shaped tube holder. Similarly, the bag-side tube is bent in a U
or V-shape to fit into another U or V-shaped tube holder adjacent
the first tube holder. A heated wafer moves across the space
between the two tube holders and physically contacts the tubing at
the bend junction of the U-shape or V-shape. As the heated wafer
contacts the tubing, it melts the tube at the bend junction of the
U-shape or V-shape. The wafer then wipes the melted tubing material
and removes the material from the area between the tube holders.
The two holders are brought together and two connections are made.
In the first connection, the transfer set tubing is connected to
the bag-side tube and the dialysis process is ready to begin. In
the second connection, the wasted tube material from the transfer
set tubing and the bag-side tube is connected together and
discarded.
[0012] In order to disconnect the patient from the bag, hot knives
are used to cut the tube. An example of a known disconnecting
process with the hot knife involves two tubes that are placed side
by side across two tube holders. One of the tubes is a short tube
having two sealed ends. Generally, the tube holders include a ridge
at one end of the tube holder to flatten a portion of the tube to
stop fluid flow. The hot knife severs each tube into two pieces.
After the hot knife cuts the tube, one of the tube holders moves in
relation to the other tube holder. The tubing is "swapped,"
realigned with one of the cut portions of the short tube, and
connected to it--thus, a disconnection is made between the patient
and the bag.
[0013] These devices have a relatively low level of reliability due
to the inconsistency in melting and cutting processes. This
inconsistency can result in imperfect seals, leading to leaks,
bacterial infiltration and, ultimately, the patient may well
experience, among other things, infection or peritonitis. Also,
none of these known methods inspect the integrity of the weld
formed between the two tube ends during the connection process.
Thus, users must rely on their own visual inspection of the
weld.
[0014] Moreover, these devices are not user friendly. Often times,
patients that need dialysis treatment are visually or otherwise
impaired. For example, some dialysis patients experience manual
dexterity problems. Many of the known processes involve a great
deal of human interaction with loading the tubes into the tube
holders. Also, the equipment should be cleaned and the heated wafer
replaced after each use to avoid contamination. Thus, this is a
difficult process for visually impaired patients and those with
poor manual dexterity.
SUMMARY OF THE INVENTION
[0015] The present invention provides a polymer blend for
fabricating a laser-weldable article having a first component of a
material not thermally responsive to a laser beam and selected from
the group consisting of polyolefins, ethylene and lower alkyl
acrylate copolymers, ethylene and lower alkyl substituted alkyl
acrylate copolymers, ethylene vinyl acetate copolymers,
polybutadienes, polyesters, polyamides, and styrene and hydrocarbon
copolymers; a second component of a laser responsive material
having low solubility in an aqueous medium and present in an amount
by weight of from about 20 ppm to about 2000 ppm; and the blend
being sufficiently thermally responsive to exposure to a laser beam
having a wavelength within a range of wavelengths from about 700 nm
to about 1500 nm to at melt upon exposure to the laser beam for a
short period of time.
[0016] The present invention further provides a laser weldable
tubing having a sidewall having a layer from a polymer blend having
a first component of a material not thermally responsive to a laser
beam and selected from the group consisting of polyolefins,
ethylene and lower alkyl acrylate copolymers, ethylene and lower
alkyl substituted alkyl acrylate copolymers, ethylene vinyl acetate
copolymers, polybutadienes, polyesters, polyamides, and styrene and
hydrocarbon copolymers. The blend has a second component in an
amount by weight of from about 20 ppm to about 500 ppm of a laser
responsive material having low solubility in aqueous medium and the
layer being sufficiently thermally responsive to exposure to a
laser beam having a wavelength within a range of wavelengths from
about 700 nm to about 1500 nm to melt a portion of the sidewall
upon exposure to the laser beam for a short period of time.
[0017] The present invention further provides a film having a layer
of a first blend. The blend has a polymeric component and a laser
responsive component. The polymeric component is a second blend of
from about 99% to about 50% by weight of a first component selected
from the group consisting of: (1) ethylene and .alpha.-olefin
copolymers having a density of less than about 0.915 g/cc, (2)
ethylene and lower alkyl acrylate copolymers, (3) ethylene and
lower alkyl substituted alkyl acrylate copolymers and (4) ionic
polymers. The blend has a second component from about 50% to about
1%. The second component is selected from the group consisting of:
(1) propylene containing polymers, (2) butene containing polymers,
(3) polymethyl pentene containing polymers, (4) cyclic olefin
containing polymers and (5) bridged polycyclic hydrocarbon
containing polymers. The film is sufficiently thermally responsive
to exposure to a laser beam having a wavelength within a range of
wavelengths from about 700 nm to about 1500 nm to at melt upon
exposure to the laser beam for a short period of time.
[0018] The present invention further provides a film having a layer
of a first blend of a polymeric component and a laser responsive
component. The polymeric component is a second blend comprising by
weight of from about 35% to about 45% of a first ethylene and
.alpha.-olefin copolymer having a density of less than about 0.900
g/cc, from about 20% to about 30% of a second ethylene and
.alpha.-olefin copolymer having a density of higher than about
0.900 g/cc but less than about 0.910 g/cc, and from about 30% to
about 40% of a polypropylene. The film is sufficiently thermally
responsive to exposure to a laser beam having a wavelength within a
range of wavelengths from about 700 nm to about 1500 nm to at melt
upon exposure to the laser beam for a short period of time.
[0019] The present invention further provides a laser weldable
multiple lumen tubing having a first lumen and a second lumen each
having a layer from a polymer blend. The layer has a first
component of a material not thermally responsive to a laser beam
and selected from the group consisting of polyolefins, ethylene and
lower alkyl acrylate copolymers, ethylene and lower alkyl
substituted alkyl acrylate copolymers, ethylene vinyl acetate
copolymers, polybutadienes, polyesters, polyamides, and styrene and
hydrocarbon copolymers, a second component in an amount by weight
of from about 20 ppm to about 2,000 ppm of a laser responsive
material having low solubility in aqueous medium and the layer
being sufficiently thermally responsive to exposure to a laser beam
having a wavelength within a range of wavelengths from about 700 nm
to about 1500 nm to melt a portion of the sidewall upon exposure to
the laser beam for a short period of time.
BRIEF DESCRIPTION OF THE FIGURES
[0020] FIG. 1 is a perspective view of a housing of an embodiment
of the present invention.
[0021] FIGS. 2A through 2D are perspective views of a connection
and disconnection device according to principles of the present
invention.
[0022] FIGS. 3A and 3B are perspective views of another tube holder
of an embodiment of the present invention.
[0023] FIGS. 4A through 4H are schematic plan views of the device
embodiment in FIGS. 2A through 2D.
[0024] FIGS. 5A through 5C are schematic cross-sectional views of
an embodiment of a sealed end tube of the present invention.
[0025] FIG. 6 is a schematic plan view of a protective film
according to principles of the present invention.
[0026] FIG. 7 is a schematic plan view of another embodiment of the
present invention.
[0027] FIG. 8 is a perspective view of an optical assembly of
another embodiment of the present invention.
[0028] FIGS. 9A and 9B are schematic plan views of another
embodiment of the present invention.
[0029] FIGS. 10A and 10B are perspective views of another
embodiment of the present invention.
[0030] FIGS. 11a, 11b and 11c are respectively cross-sectional
views of a monolayer, non-PVC, laser weldable tubing and a multiple
layer tubing having the monolayer tubing as a layer therein and a
multilumen tubing.
[0031] FIG. 12 is a cross-sectional view of a capped tubing
assembly.
[0032] FIG. 13 is a cross-sectional view of a coupler.
[0033] FIG. 14 is a cross-sectional view of a tubing and coupler
assembly.
[0034] FIG. 15 is a plan view of a medical fluids container
connected to a non-PVC laser-weldable tubing.
[0035] FIG. 16 is a cross-sectional view of a laser-weldable tubing
connected through a coupler device to a tubing from a transfer
set.
[0036] FIG. 17 is a cross-sectional view of a dual lumen
tubing.
[0037] FIG. 18 is a cross-sectional view of a dual lumen tubing
with the individual lumen concentrically disposed with respect to
one another.
[0038] FIG. 19 is a cross-sectional view of a multiple lumen
tubing.
DETAILED DESCRIPTION OF THE INVENTION
[0039] Although the present invention can be made in many different
forms, the presently preferred embodiments are described in this
disclosure and shown in the attached drawings. This disclosure
exemplifies the principles of the present invention and does not
limit the broad aspects of the invention only to the illustrated
embodiments.
[0040] Generally, the present invention relates to the aseptic
connection and disconnection of tubing. Such tubing can be
advantageously used to transfer fluid or blood to and from the
human body. In a preferred embodiment, the present invention
pertains to a device that opens sealed tube ends and connects the
opened tube ends together. Moreover, the device disconnects a tube
and reseals the tubing. All of these processes use laser generated
heat and provide a connection or disconnection that is aseptic or
sterile.
[0041] The Device
[0042] FIG. 1 shows a device 10 according to an embodiment of the
present invention. The device 10 includes a housing 12 that has a
front 14, a back 16, and two sides 18, 20 there between. The
housing 12 also includes a bottom 22 and a lid or door 24. The four
sides 14, 16, 18, 20 and bottom 22 define an interior area A. Two
slots or openings 30, 32 are located at upper ends 34, 36 of two
sides 18, 20 of the housing 12. The door 24 is hinged to the back
16 of the housing 12. The door 24 may be hinged in any number of
ways to allow it to be easily opened and shut. The door includes a
locking mechanism (not shown) to lock the door closed when the
device is in operation. In an embodiment, the door 24 also has two
slots 38, 40 that align with the slots 30, 32 to create an area
(not shown) for loading and unloading tubing 50 which will be
described in further detail below.
[0043] FIGS. 2A through 2D show the inside of the device 10
according to an embodiment of the present invention. Inside the
housing 12 are two passageways 52, 54. In an embodiment, the
passageways 52, 54 are funneled. Each passageway leads to a guide
56, 58. The guides 56, 58 receive the tubing 50 and advance the
tubing 50 within the housing 12. The guides are, preferably, pinch
rollers, however, various types of guides or threading devices, may
be used. In a preferred embodiment, the guides 56, 58 crimp the
tubing 50 as it is fed into the device 10. (See FIG. 2A, Ref. No.
58). This crimping purges fluid from a portion 60 of the tube 50
that progresses past the guides 56, 58 into the device.
[0044] FIGS. 2A through 2D also show a pair of tube holders 70, 72
aligned with guides 56, 58 in the housing 12. FIGS. 3A and 3B show
an enlarged view of another tube holder 70 of the present
invention. As shown in FIGS. 2A through 2D and 3A and 3B, each tube
holder 70, 72 has a first part 74, 76 and a second part 78, 80,
respectively. Each first and second part 74, 76 and 78, 80 has a
recess or groove 82, 84 that corresponds with an outer diameter B
of the tubing 50. The first part 74, 78 is movably attached to the
second part 76, 80 via a hinge 85 or similar mechanism. When the
tube holders 70, 72 are in the closed position, an aperture 90 is
formed extending through the holder 70, 72. A diameter C of this
aperture 90 is slightly smaller than the outer diameter B of the
tube 50. In this way, the tubing 50 is fed through the guides 56,
58 and received in the tube holders 70, 72. In an embodiment, an
inside surface of the tube holders 70, 72 is tapered (not shown).
The aperture 90 may be slightly tapered toward the center of the
device 10. In this example, the diameter C of the aperture 90
facing the inside of the device is smaller than a diameter of the
aperture facing the guides 70, 72. When in the closed position, the
tube holders 70, 72 close with sufficient force to grip, but not
flatten, the tubing. In addition, if necessary, the aperture 90
uniformly compresses the tubing 50 and forces the tubing to
maintain a cylindrical shape. This may be necessary if, for
example, the tubing 50 is not cylindrical due to storage conditions
of the tubing or prior sterilization methods, e.g., steam
sterilization or ETO sterilization, which may cause the tubing 50
to coil and not be perfectly round.
[0045] In an embodiment, the tube holders 70, 72 are mounted on a
bar 100. Each tube holder has a guide arm 102, 104 associated with
it. The guide arms 102, 104 extend below the bar 100 to a track 105
in a plate 106. As described in more detail below in conjunction
with FIGS. 4A through 4H, the plate 106 moves back and forth within
the housing 12. As the plate 106 moves to the back 16, the tube
holders 70, 72 move in a straight line toward each other to the
center of the device 10 (See FIGS. 4D and 4E). The guide arms 102,
104 may be, for example, a lead screw or lever/cam/slot mechanism
or a combination of any of these. With the assistance of the guide
arms 102, 104, the tube holders 70, 72 pull or push the tube 50
within the housing 12; thus, manipulating the tubing 50 to a
desired position, e.g., sterilizing and opening two sealed ends of
tubing, and connecting the two ends together, or disconnecting,
sterilizing and sealing the ends of a single tube.
[0046] As will be described in detail below, the device 10 also
includes a hammer 110 and an anvil 112. The hammer 110 and anvil
112 are used during the disconnecting process of the tubing 50. The
hammer 110 is movably mounted to a motor 114 via a shaft 116. In an
embodiment, the hammer 110 moves forward and backward along the
shaft 116 in the housing. As the hammer moves forward, a front part
111 of the hammer contacts a surface 113 of the anvil 112. The
hammer 110 may be made from a metal, ceramic, or even rigid plastic
material.
[0047] Laser Optics
[0048] The device also includes a laser unit 200. In a preferred
embodiment, the laser unit 200 is a semiconductor diode laser which
can be a single laser diode or a laser array of diodes. However,
other types of lasers can be used in the invention. For example,
Argon, CO.sub.2 or YAG lasers may be used. The laser
characteristics, e.g., wavelength of the laser, should be evaluated
to determine the corresponding characteristics of the tubing 50 to
be used in the application. In an embodiment, the laser unit 200
may have an optical assembly to direct a controlled laser beam to
the desired location for the connecting or disconnecting
processes.
[0049] FIGS. 2A through 2D and 4A through 4H show an optical
assembly 202 according to an embodiment of the invention. In this
example, the optical assembly 202 includes a collimator 204, and a
reflective prism 206. Depending on the characteristics of the laser
unit 200, a laser beam may begin to diverge as soon as it leaves
the unit 200. In this scenario, the collimator 204 limits the
divergence of the laser beam. Specifically, the collimator 204 has
a generally flat back surface 207 that faces the laser 200. The
collimator 204 also has slightly convex front surface 208. As the
laser energy travels through the collimator 204, the collimator
refocuses the laser beam to the prism 206. Other applications, for
example CO.sub.2, may have a small laser beam that can be expanded
by using a beam expander. The collimator 204 is, preferably, made
from an acrylic material, however, other transparent or translucent
materials may be used.
[0050] The prism 206 splits the laser beam and directs the split
beam to the desired location, e.g., the tube ends 51, for the
connection process. In order to obtain optimal laser concentration
during the connection process, the design of the prism 206 is
directly related to the prism location in the device 10. In a
preferred embodiment, the prism 206 is between the two tube holders
70, 72. In this example, the prism 206 is constructed from two
plano convex lenses 210, 212 juxtaposed to each other.
[0051] As is further described below, the prism 206 may also
include a light pipe 220 that intersects a center 222 of the prism
206. The light pipe 220 directs the laser beam during both the
connecting and disconnecting processes. In addition, the anvil 112
is along a back 224 of the prism lens 206 and, specifically, near
an end 230 of the light pipe 220.
[0052] Tubing
[0053] In general, the material of the tubing 50 is a flexible
plastic. The tubing and assemblies thereof are discussed in greater
detail below. In a preferred embodiment, the material is a
thermoplastic, kraton polypropylene blend, or the like. In one
preferred form of the invention a chemical additive is added that
is responsive to the laser to generate heat. One particularly
suitable additive can be selected from dyes. The dye is selected to
absorb energy at or near the wavelength of the laser diode to
promote absorption of the energy of the laser, thereby heating the
tubing. Thus, the frequency of the laser selected, e.g.,
semiconductor diode or YAG laser, should match the specific
characteristics of the dye that is added to the tube material. In
some applications, e.g., CO.sub.2 laser applications, no dye may be
required because the absorption wavelength of the tube is the same
as the wavelength generated by the laser.
[0054] Moreover, a second dye may be added to color code each of
the tubes. Such color coding creates a machine detectable and
patient detectable distinction between the tubing that is connected
to the patient and the new tubing to be connected. For example, the
catheter tubing that is implanted in the patient, or the transfer
set connected to the catheter, may be dyed one color and the tubing
that is attached to the bag of fluid may be dyed a different color.
This color distinction is especially helpful for patients that are
visually impaired. Other methods of distinction may be employed
without departing from the spirit of the invention.
[0055] Sensors
[0056] A number of sensors 300, 302, 304, . . . are positioned
within the housing 12. It should be understood that the location of
the sensors identified in the drawings is just one example. Other
acceptable locations for the sensors may be accomplished depending
on the layout of the components within the device 10. These sensors
detect and confirm different stages of the process, whether it is
during the connection or the disconnection processes. For example,
during the connection process, a sensor 300 may be employed to
identify an object at the funneled pathway 52, 54. If the object is
acceptable, e.g. the tubing 50, the sensor 300 will activate the
guides 56, 58. If the object is not acceptable, the guides are not
activated. Thus, these sensors help to keep out foreign objects,
and even fingers. This sensor 300 may be, for example, an
absorption sensor. An absorption sensor identifies tubing 50 that
has a dye. In this way, not only will the sensor keep out foreign
objects but also it will identify if improper tubing is attempting
to be loaded. As mentioned above, the patient's catheter (or
transfer set connected to the catheter) may be a different color
than the tube connected to the fluid or blood to be administered to
the patient. In this way, the absorption sensor checks to make sure
the patient-side and disposable (or bag-side) sealed end tubes are
loaded in the pathways 52, 54. If the user attempts to improperly
load two bag-side tubes, the sensor 300 alerts the user and the
user must retry the loading procedure. Depending on the
application, the sensor may be set to allow certain combinations of
tubing to enter the apparatus. Thus, the sensor 300 provides a
safety measure to guard against improper loading.
[0057] Another sensor that may be used in the device 10 is an edge
sensor 302. The edge sensor 302 identifies when tube ends 51 extend
beyond the tube holders 70, 72 during loading of the tube ends 51
into the device. Specifically, as the tube end 51 crosses the light
beam path, the signal from the photo detector 302 is fed into a
comparator. The sensor 302 subsequently switches the output state
at the desired threshold level, e.g., when sufficient tube length
extends beyond the tube holder 70, 72. The sensor 302 may be, for
example, a precision edge sensor such as a Cartesian Ovoid LED and
a die mounted aperture photo detector. However, other sensing
devices capable of identifying the edge of the tube 50 may be
used.
[0058] Moreover, during the disconnection process, the single tube
is loaded into the device for sealing and separation. A color
sensor 300 or 304 checks to make sure that not all the tubing in
the device is the same color. If the entire tube 50 is the same
color, the device will not be able to locate the prior weld. The
sensor 304 alerts the user and the patient must reload the tube 50
and try again. This occurs because the sensor 304 also determines
where to disconnect the tube 50 based on the position of an
existing weld W in the tube. Therefore, when two tubes of different
color are present at the sensors 304 the existing weld W is
somewhere in between.
[0059] After the sensors confirm the tubing 50 is loaded properly,
the same or different sensor 304 determines the location of the
existing weld W in the tube. This may be accomplished, for example,
using a digital camera--like mechanism that searches for the flange
in the weld. In a preferred embodiment, the sensor 304 is a CMOS
Image Detector. Once the existing weld W is located, the sensor
identifies the position for crimping, sealing and separating the
tube. The sensor then activates the guides and moves the tube a
predetermined distance, on the catheter side, toward the patient.
For example, the existing weld may be located at position X. The
sensor locates the weld and moves the tube X+1/8" toward the
patient side for the location of the cut. In this way, the sensor
ensures that the section of tube containing the existing weld W is
discarded. This maintains the integrity of the remaining tube in
the transfer set that leads to the catheter tube implanted in the
patient. In addition, the sensor provides a safety measure since
making a new weld on top of an existing weld may not be
sufficiently durable.
[0060] Alternatively, the sensor 304 may detect a distinction in
color between the tubing based on a color coding scheme like that
described above. Accordingly, the sensor identifies a color change
at the area surrounding the weld.
[0061] As described in further detail below, the device 10 also
includes a number of temperature or heat sensors (320) to maintain
consistency throughout the operation of the device. These sensors
320 may be infrared sensors, such as thermopile infrared sensors.
However, other sensors such as thermal couplers or thermistors may
be employed. The sensors 320 are used, for example, during the
connection and disconnection processes. The sensors verify the
tubing is heating properly and may be calibrated to indicate a
level of heat is reached for a "good weld" or "bad weld." For
example, in applications where the tubing includes a dye, the heat
is absorbed by the dye and, in turn, the tubing begins to melt and
flow. In this way, the sensors are non-contact temperature sensors
that correspond to the infrared output of the tubing as the tubing
absorbs the energy from the laser.
[0062] Thus, sensors may be employed to compensate the
effectiveness of the system based on efficiency of the dye
concentration of the tubing, power variation, or laser optic
variations.
[0063] The Method
[0064] FIGS. 2A through 2D illustrate the connecting and
disconnecting process as follows. Specifically, FIGS. 2A and 2B
show the inventive process that connects two tube ends together.
FIGS. 2C and 2D show the inventive process that disconnects the
tubing. Additionally, FIGS. 4A through 4H show a simplified
schematic of the connecting process.
[0065] Method of Connecting Two Tube Ends
[0066] The method of connecting two tube ends will now be
described. During the connection process, the lid 24 is closed. As
shown in FIGS. 2A and 4A, the user inserts two tubes 50, each
having a sealed end 51, into the device 10 via the loading area
openings 30, 32, 38, 40. However, it is within the scope of the
invention to use at least one tube end 51 that is not sealed, but,
open. In applications involving an open tube end, several types of
end caps may be used to maintain the necessary sanitation levels at
the inside of the tube. One type of end cap may be a sealed "drum
head" that covers the end of the tube. The sealed "drum head" may
be a piece of film placed over the open end of the tube and sealed
around the entire face of the tube. Another example may include an
open end with a vented seal over the face of the tube. A vented
seal may be, for example, a perforated membrane. In this example,
an end cap would be added to cover the vented end for sanitation
purposes. The tubing and cap assembly will be discussed in greater
detail below.
[0067] As each tube end 51 enters a respective passageway 52, 54
the sensor 300 identifies the tubing 50 and checks to make sure
that one tube end 51 is the patient's tube and the other tube end
51 is the bag tube. It should be noted that it does not matter
which tube is loaded into which loading area. Advantageously, the
sensors 300 at the passageway 52, 54 communicate with each other to
determine that one of each tubing type is loaded. When the tubing
is properly loaded, the guides 56, 58 are activated. (FIG. 4B). The
guides 56, 58 crimp or squish the tubing and advance each tube end
51 into the device 10 to the tube holders 70, 72. This crimping or
squishing creates a vacuum effect in the tubing and purges fluid
from the portion 60 of tubing that enters the device 10. The
precision edge sensor 302 identifies when the tube 51 extends the
predetermined length beyond the holder 70, 72 and stops the guides
56, 58.
[0068] In FIGS. 4C, the reflective prism 206 is between the tube
holders 70, 72. After each tube end 51 is loaded into its
respective tube holder 70, 72, the laser unit 200 is activated and
energy diverges from the laser source. The collimator 204 refocuses
the diverging energy toward the prism lens 206. As the energy/light
strikes the reflective prism 206 it reflects into two bundles of
energy. In this embodiment, the prism lenses 210, 212 re-direct
each bundle of energy at approximately a 90.degree. angle to focus
the energy around the tube ends 51. More particularly, a "spot" of
energy strikes the tube ends 51 and preferably, slightly exceeds
the diameter B of the tube 50 to ensure the tube is covered with
adequate radiant energy.
[0069] Heat sensors 320 positioned in the housing 12 detect the
temperature near the sealed ends 51. Such heat sensors 320 may be,
for example, thermopile infrared sensors. As the laser beam strikes
the sealed tube ends 51, the heating, melting and aseptic (and/or
sterilization) process begins. Depending on the application, the
sensors can be used to detect the desired temperature levels for
melting and welding. For example, some applications require aseptic
conditions be generated. Typically, aseptic, high level
disinfection, or germicidal conditions include a less than 6 log
reduction of heat resistant spores. Other applications may require
sterile conditions be generated. Sterile conditions generally
include an operating mode of equal to or greater than a 6 log
reduction of heat resistant spores.
[0070] As the temperature of the tubing material at the tube ends
51 increases, the tube ends 51 begin to melt, flow and reopen. The
tubing material has a certain level of "memory"--as the sealed end
of the tube reopens, the tube is predisposed to returning to its
symmetrical, circular form. FIGS. 5A and 5B illustrate an example
of the laser beam striking the sealed tube end 51. As the laser
beam strikes the tube end the rise in temperature at the tube end
causes the sealed end to peel open and flare. Once the heat sensors
320 detect that the required aseptic or sterilization temperature
level is obtained and sufficient melting of the tube ends 51 has
occurred the laser 200 shuts off.
[0071] FIGS. 4D through 4F show the next step of the connecting
process. After the laser 200 shuts off, the plate 106 moves to the
back 16 of the housing 12. As the plate 106 moves, the collimator
204 moves to the side 18 along track 107. At the same time, the
prism 206 moves toward the laser unit 200, and the tube holders 70,
72 come together via track 105. At this point, the now melted and
aseptically heated or sterilized tube ends 51 contact each other. A
weld-seal W is formed. Typically, the weld W is in the form of a
ring as shown in FIG. 5C. The tube holders 70, 72 remain in this
position until the weld W has sufficiently cooled. In another
embodiment, the laser unit 200 may be energized again (FIG. 4F). As
shown in FIG. 4F, the laser beam is directed down the light pipe
220 to the tube ends. In this example, the weld-seal W forms and
the laser unit 200 is shut off. In an embodiment, the weld-seal W
is a hermetic seal.
[0072] In applications that use at least one "drum head" end, this
type of end responds to the laser in a similar manner as that
described above regarding the opening of a sealed end tube. One
example of the "drum head" end is as follows. The film of the "drum
head" may have a higher concentration of dye than the tubing
material. Thus, the film heats faster than the tubing material. The
film melts and flows outward to the perimeter of the tube and
combines with the tube. The film material may be made from a
variety of polymer materials such as polyolefins, polyamides,
polyesters, styrene and hydrocarbon copolymers and particularly
block copolymers of styrene and dienes and their hydrogenated
derivatives, ethylene and vinyl acetate copolymers, ethylene and
methacrylic acid copolymers and their ester derivatives. The film
may be made from a blend of these materials and can be a monolayer
or multiple layer structure. For example, polypropylene,
polypropylene-Kraton blend, polypropylene polyethylene blend, or
other compatible material.
[0073] Other embodiments may include one tube holder that is
stationary and one tube holder that moves within the apparatus.
[0074] Weld Inspection Process
[0075] FIGS. 4G and 4H show the weld inspection process. Upon
cooling, the first part 74, 78 of the tube holders 70, 72 open and
the guides 56, 58 move weld W to the weld detecting sensor 304 for
the post process inspection. The inspection process analyzes, for
example, the weld thickness and weld height. This data is compared
to the profile data for an acceptable or "good" weld. In a
preferred embodiment, this sensor 304 is a CMOS image sensor.
However, other similar image sensors may be employed. If the post
process inspection indicates that the weld is a "good" weld, the
lid 24 is unlocked and the guides 56, 58 open. The user is free to
open the lid 24 and remove the connected tubing.
[0076] On the other hand, if the post inspection process indicates
a "bad" weld, the device automatically pinch seals the patient-side
of the tubing. The automatic pinch seal process reduces the
possibility of contaminants entering the tubing. During this
situation, the user is notified of the "bad" weld. The user can
then obtain another bag-side tube and start the connection process
again. This unique inspection process provides a safety feature to
ensure the patient uses "good" welds only. This is especially
helpful for visually impaired patients who may have difficulty
visually inspecting a weld after the connection process.
[0077] Method of Disconnecting a Tube
[0078] FIGS. 2C and 2D generally illustrate the inventive method
for disconnecting and sealing the tube 50. When the user desires to
disconnect from the dialysate solution bag, drainage bag, blood
bag, or the like, he/she opens the lid 24 of the device 10. When
the lid 24 opens, the guides 56, 58 automatically move to the open
position. (FIG. 2C, Ref. No. 56). The user places the tube 50 in
the groove of the second part 78, 80 of the tube holders 70, 72. In
this way, the tube 50 extends along the funneled passageway 52, 54.
In this application, it is not necessary for the first part 74, 78
of the tube holders 70, 72 to close. The user closes the lid 24,
thus, closing the guides 56, 58 which, in turn, crimp the tubing
50.
[0079] It is preferable to place the tube 50 so that the
preexisting weld W is approximately centered between the tube
holders 70, 72. Similar to the connecting process, the sensor 300
identifies the tubing 50 and confirms that a patient-side tube is
at one of the passageways 52, 54 and the bag-side tube is at the
other passageway 52, 54. Thus, the sensor 300 confirms that a
preexisting weld exists somewhere there between, e.g., within the
device.
[0080] After the sensors 300 accept the tubing, the same or
different sensor 300 or 304 determines the location of the
pre-existing weld W in the tube. This may be accomplished, for
example, with a digital camera or similar device. The sensor
searches for a flange in the weld W. Alternatively, the sensor 304
may detect a distinction in color between the tubing based on the
color coding scheme such as that described above. Accordingly, the
sensor 304 could identify a color change at the area surrounding
the weld, indicating a weld W exists between the two different
colors.
[0081] Once the pre-existing weld W is located, the sensor 304
identifies the position for the cut in the tube 50. The guides 56,
58 are activated and the tube 50 moves a predetermined distance, on
the catheter side, toward the patient. For example, the existing
weld may be located at position X. The sensor 304 locates the weld
and moves the tube X+1/8" away from the patient side for the
location of the crimping and separation of the tube. In this way,
the position for the disconnection is a minimal distance from the
existing weld. Therefore, waste of tube material of the patient
catheter (or transfer set) is minimized. Alternatively, a patient
extension line may be used between the transfer set and the
disposable (or bag-side). The use of an extension line will prolong
the life of the transfer set because the transfer set will not need
to be replaced as often. Instead, the patient extension line is
easily replaced by disconnecting the old extension line from the
transfer set and connecting a new extension to the transfer set by
the methods disclosed herein. Moreover, the sensor 304 ensures that
the section of tube containing the existing weld is discarded. This
improves the integrity of the remaining catheter tube. In addition,
the sensor 304 provides a safety measure since making a weld on top
of an existing weld may not be sufficiently durable.
[0082] At the start of the disconnecting process the laser unit 200
is off. As shown in FIG. 2D, the hammer 110 moves (via shaft 116)
into contact with the tube 50. It should be noted that the hammer
110 is not heated prior to contacting the tube 50. As the hammer
110 contacts the tube 50 it compresses the tube so that the inner
surface of the tube is touching. To this extent, the hammer 110
pushes the liquid existing in the tube 50 out of the area to be
disconnected.
[0083] The laser unit 200 is subsequently activated. The light pipe
220 directs the majority of the laser energy down it onto the
tubing 50. The tubing 50 continues to be pinched between the anvil
112 and the hammer 110. In this example, the light pipe 220 is a
part of the anvil 112. As the heated tubing is pinched it begins to
seal. The heat sensors 320 monitor the temperature near the pinched
tubing. The laser unit 200 is shut off. In an embodiment, a sensor
320 is mounted on the hammer 110 near the front 111. In general,
the sensor verifies the laser is operating properly. The pinch
hammer 110 remains in contact with the tubing while the tube cools.
After the cooling of the tubes, the hammer 110 moves back to its
original position. The guides 56, 58 are then activated and reverse
movement a predetermined distance. This predetermined distance is
dependent on the size and material of the flexible tube 50. As the
guides 56, 58 reverse, the tubing 50 is pulled apart resulting in
two sealed ends. Thus, the combination of the guides 56, 58 and the
hammer 110 act as a separator to separate the tubing into two
sealed end tubes. The device 10 notifies the user that the lid 24
is unlocked and ready to be opened. The two newly sealed ends of
tubing are subsequently unloaded from the device 10. Other
applications may include a laser that stays on for the duration or
is pulsed on and off while the hammer moves in to pinch the
tubing.
[0084] Protective Film
[0085] FIG. 6 shows a protective film 400 according to an
embodiment of the invention. The protective film 400 covers the
plano convex lenses 210, 212, the anvil 112, and the light pipe
220. The protective film 400 is a thin clear material, preferably,
a Mylar.RTM. or polyethylene material. The film 400 is provided on,
for example, a roll 402 that advances after each disconnection
application. When the film 400 advances it is stored in another
roll 404. After the roll 402 is used both rolls 402 and 404 can be
easily discarded. The laser energy does not have any heating effect
on the film. The film 400 does not alter the laser beam
characteristics. In this way, the film 400 protects the optics
assembly 202 and eliminates cleaning of same. It will be
appreciated that one could also achieve this purpose by providing a
system of advancing disposable lenses. For example, if the optical
assembly includes the light pipe 220 as the anvil 112, the optical
assembly could be a number of disposable lenses on a cartridge that
rotates after each use. Thus, the used optical assembly is
discarded and a new optical assembly is used in each
application.
[0086] Further Embodiments
[0087] FIG. 7 illustrates another embodiment of the invention in
which the prism 206 and light pipe 220 are not between the tube
holders 70, 72 but located near the front 14 of the housing 12. For
simplification purposes, FIG. 6 shows the anvil 112 between the
collimator 204 and the prism 206. However, during the connection
process, the anvil 112 is generally not employed. Instead, the
anvil 112 is off to one side 18 or 20 in the housing 12. During the
disconnection process, the anvil 112 moves in front of the laser
200. Thus, the anvil 112 may be mounted on a tracking system
similar to that described above with respect to the collimator
204.
[0088] During the connection process, the prism lens 206 diffuses
the laser beam and spreads the energy over a slightly larger area
than that described above in FIGS. 4A through 4H. In this example,
the lenses 210, 212 are shown with flat reflecting surfaces 210a,
212a. However, it should be understood that the lenses 210, 212 may
be concave or some other configuration depending on the laser type
and the need to redirect and focus the beam. Also, the prism 206
may be rough edged lenses 210, 212 to spread the energy at the
surface of the sealed tube ends 51. Moreover, another lens (now
shown) may be positioned at the surfaces 210a, 212a between the
surface and the tubing to further focus the laser beam. As
described above with respect to the embodiment in FIGS. 2A and 2B,
the tube ends are brought together after the tube ends are
sufficiently heated and a weld is formed. However, the embodiment
of FIG. 6 is less complex because it is not necessary to move the
prism 206 from in between the tube ends prior to bringing the tube
ends together.
[0089] During the disconnecting process, the anvil 112 moves in
front of the laser 200. The hammer 110 moves through a passageway
250 between the two lenses 210, 212 in the direction of the anvil
112. The hammer 110 compresses the tubing 50 against the anvil 112.
In this regard, the remaining steps of the disconnection process
are substantially the same as that described above.
[0090] FIG. 8 shows another embodiment of the invention. In this
embodiment, the laser optics assembly incorporates a fiber optics
assembly 410. The fiber optics assembly can include a large
cylinder rod or multiple optical fibers to transmit the
electromagnetic energy to the tube and provide the necessary
heating and distribution of the energy. In this embodiment, the
fiber optics assembly 410 includes a fixed lens 412 with first and
second sides 414, 416 and a front and back end 420, 422. A recess
or access slot 430 extends from the front end 420 into the assembly
410. The recess 430 ends at wall 431 within the assembly 410. The
wall 431 acts as the anvil during the disconnection process. The
fiber optics assembly 410 has a parting line 411 in which the
assembly may be opened while the tube is loaded for the
disconnection process. After the tube 50 is loaded, the recess 430
receives the hammer 110 and the hammer compresses the tube 50 at
wall 431. The laser unit 200 is energized and the laser beam is
directed down the fixed lens 412 in a similar manner as the light
pipe 220 described above. In this way, the crimping and separation
process begins.
[0091] In addition, a fiber optic member 432, 434 extends
perpendicular from each side 414, 416 of the lens 412. During the
connection process, the laser unit 200 is energized and the laser
beam is directed down the fixed lens 412 to the fiber optic members
432, 434. The fiber optic members 432, 434 emit the laser energy at
the tube ends 50. Similar to the embodiment described in FIGS. 2A
and 2B above, the assembly 410 moves out from between the tube
holders 70, 72 and the tube holders bring the tube ends together to
form a weld. If necessary, the laser unit 200 can be energized
again and the laser beam is directed down the fixed lens 412 to the
area where the tube ends are joined to form a weld.
[0092] FIGS. 9A and 9B show another embodiment of the invention. In
FIG. 9A, an optical assembly 450 is used with the laser unit 200.
The optical assembly 450 is adjacent to the laser unit 200 between
the laser unit and a plane X that intersects the tubing 50. The
optical assembly 450 includes a generally "Y"-shaped optical
splitter 452, in which a base 454 of the "Y" is near the output of
the laser unit 200. The "Y"-shaped optical splitter extends from
the laser unit 200 toward the plane X. The "Y"-shaped optics may be
solid fiber optics or individual fibers.
[0093] The optical assembly 450 remains stationary during the
connection and disconnection operation of the apparatus. During the
connection of two tube ends 51, the laser beam is split down the
"Y" to each tube end. The tube ends are subsequently brought
together for welding. During the disconnection process, the laser
beam is directed down a center optical component of the assembly or
light pipe 456. Similar to the applications described above, the
anvil 110 moves toward the light pipe 456 to compress and pinch the
tubing. It is also within the scope of the invention to have the
optics assembly 450 as two separate components. In this example,
the "Y"-shaped optical splitter 452 and the light pipe 456 are
discrete components (not shown). Each component 452, 456 is mounted
on a movable plane that moves the required component in front of
the laser unit depending on the process to be performed by the
apparatus.
[0094] FIGS. 10A and 10B show another embodiment of the invention.
In this example, the laser unit 200 is used without the optics
assembly. The tube holders 70, 72 are mounted on a track system
500. During the connection process, the track system 500 moves the
tube holders 70, 72 along a predetermined path toward the laser
unit 200. (FIG. 8B). In this way, the tube holders 70, 72
manipulate the tubes 50 so that the tube ends 51 are, preferably,
parallel to each other and face the laser unit 200. Thus, the tube
holders 70, 72 rotate approximately 90 degrees from when they
receive the tube ends to the point at which the tube ends 51 face
the laser unit 200. However, the tube holders may rotate in the
range of 70 to 110 degrees and achieve the same results.
[0095] The laser unit 200 turns on and melts and sterilizes the
tube ends. As discussed above, the tube ends 51 enter the device 10
as sealed tube ends. As such, the tube ends 51 begin to reopen as
the laser energy melts this area. The laser unit 200 shuts off once
the sensors determine that sufficient heating of the tube ends
occurred. At this time, the tube holders 70, 72 retract to their
starting position (near guides 56, 58) and then move forward toward
each other. The two tube ends 51 come into contact with each other
and a weld seal is formed.
[0096] Non-PVC, Laser-Weldable Tubing
[0097] FIGS. 11a and 11b show a monolayer tubing 600 and a multiple
layer tubing 600 respectively that are suitable for use with the
present invention. FIG. 11c shows a multiple lumen tubing which can
have two or more fluid passageways. Like the single lumen tubing of
FIGS. 11a and 11b, the multiple lumen tubing of FIG. 11c can be a
monolayer structure or a multiple layer structure, and, therefore,
it should be understood the following description shall apply to
single lumen tubings or multiple lumen tubings.
[0098] The monolayer tubing 600 has a sidewall 602 made from a
polymeric material and more preferably from a non-PVC containing
polymer and most preferably from a non-PVC containing polymer that
is capable of heating upon exposure to a laser beam ("laser
responsive"). The multiple layer tubing 600 has a first layer or
solution contact layer 604 and a second layer 606. At least one of
the layers 604 or 606 is composed of a non-PVC containing polymer
that is laser responsive. In a preferred form of the invention, the
other layer 604 or 606 will also be a non-PVC containing polymer,
and more preferably a non-PVC containing polymer that heats upon
exposure to a laser beam. However, it may also be desirable to have
a solution contact layer 604 that is not laser responsive or does
not contain any components that may leach into solution or react
with the solution. Of course, it is contemplated that tubing having
more than two-layers can be used without departing from the scope
of the present invention. The tubing sidewalls define a fluid
pathway 608 therethrough.
[0099] Suitable non-PVC containing polymers include polyolefins,
ethylene and lower alkyl acrylate copolymers, ethylene and lower
alkyl substituted alkyl acrylate copolymers, ethylene vinyl acetate
copolymers, polybutadienes, polyesters, polyamides, and styrene and
hydrocarbon copolymers.
[0100] Suitable polyolefins include homopolymers and copolymers
obtained by polymerizing alpha-olefins containing from 2 to 20
carbon atoms, and more preferably from 2 to 10 carbons. Therefore,
suitable polyolefins include polymers and copolymers of propylene,
ethylene, butene-1, pentene-1, 4-methyl-1-pentene, hexene-1,
heptene-1, octene-1, nonene-1 and decene-1. Most preferably the
polyolefin is a homopolymer or copolymer of propylene or a
homopolymer or copolymer of polyethylene.
[0101] Suitable homopolymers of polypropylene can have a
stereochemistry of amorphous, isotactic, syndiotactic, atactic,
hemiisotactic or stereoblock. In a more preferred form of the
invention the polypropylene will have a low heat of fusion from
about 20 joules/gram to about 220 joules/gram, more preferably from
about 60 joules/gram to about 160 joules/gram and most preferably
from about 80 joules/gram to about 130 joules/gram. It is also
desirable, in a preferred form of the invention, for the
polypropylene homopolymer to have a melting point temperature of
less than about 165.degree. C. and more preferably from about
130.degree. C. to about 160.degree. C., more preferably from about
140.degree. C. to about 150.degree. C. In one preferred form of the
invention the homopolymer of polypropylene is obtained using a
single site catalyst.
[0102] Suitable copolymers of propylene are obtained by
polymerizing a propylene monomer with an .alpha.-olefin having from
2 to 20 carbons. In a more preferred form of the invention the
propylene is copolymerized with ethylene in an amount by weight
from about 1% to about 20%, more preferably from about 1% to about
10% and most preferably from 2% to about 5% by weight of the
copolymer. The propylene and ethylene copolymers may be random or
block copolymers. The propylene copolymer should have a low heat of
fusion of from about 40 joules/gram to about 140 joules/gram, more
preferable from about 60 joules/gram to about 90 joules/gram. In a
preferred form of the invention, the propylene copolymer is
obtained using a single-site catalyst.
[0103] It is also possible to use a blend of polypropylene and
.alpha.-olefin copolymers wherein the propylene copolymers can vary
by the number of carbons in the .alpha.-olefin. For example, the
present invention contemplates blends of propylene and
.alpha.-olefin copolymers wherein one copolymer has a 2 carbon
.alpha.-olefin and another copolymer has a 4 carbon .alpha.-olefin.
It is also possible to use any combination of .alpha.-olefins from
2 to 20 carbons and more preferably from 2 to 8 carbons.
Accordingly, the present invention contemplates blends of propylene
and .alpha.-olefin copolymers wherein a first and second
.alpha.-olefins have the following combination of carbon numbers: 2
and 6, 2 and 8, 4 and 6, 4 and 8. It is also contemplated using
more than 2 polypropylene and .alpha.-olefin copolymers in the
blend. Suitable polymers can be obtained using a catalloy
procedure.
[0104] It may also be desirable to use a high melt strength
polypropylene. High melt strength polypropylenes can be a
homopolymer or copolymer of polypropylene having a melt flow index
within the range of 10 grams/10 min. to 800 grams/10 min., more
preferably 30 grams/10 min. to 200 grams/10 min, or any range or
combination of ranges therein. High melt strength polypropylenes
are known to have free-end long chain branches of propylene units.
Methods of preparing polypropylenes which exhibit a high melt
strength characteristic have been described in U.S. Pat. Nos.
4,916,198; 5,047,485; and 5,605,936 which are incorporated herein
by reference and made a part hereof. One such method includes
irradiating a linear propylene polymer in an environment in which
the active oxygen concentration is about 15% by volume with high
energy ionization energy radiation at a dose of 1 to 10.sup.4
megarads per minute for a period of time sufficient for a
substantial amount of chain scission of the linear propylene
polymer to occur but insufficient to cause the material to become
gelatinous. The irradiation results in chain scission. The
subsequent recombination of chain fragments results in the
formation of new chains, as well as joining chain fragments to
chains to form branches. This further results in the desired
free-end long chain branched, high molecular weight, non-linear,
propylene polymer material. Radiation is maintained until a
significant amount of long chain branches form. The material is
then treated to deactivate substantially all the free radicals
present in the irradiated material.
[0105] High melt strength polypropylenes can also be obtained as
described in U.S. Pat. No. 5,416,169, which is incorporated in its
entirety herein by reference and made a part hereof, when a
specified organic peroxide (di-2-ethylhexyl peroxydicarbonate) is
reacted with a polypropylene under specified conditions, followed
by melt-kneading. Such polypropylenes are linear, crystalline
polypropylenes having a branching coefficient of substantially 1,
and, therefore, has no free end long-chain branching and will have
a intrinsic viscosity of from about 2.5 dl/g to 10 dl/g.
[0106] Suitable homopolymers of ethylene include those having a
density of greater than 0.915 g/cc and includes low density
polyethylene (LDPE), medium density polyethylene (MDPE) and high
density polyethylene (HDPE).
[0107] Suitable copolymers of ethylene are obtained by polymerizing
ethylene monomers with an .alpha.-olefin having from 3 to 20
carbons, more preferably 3-10 carbons and most preferably from 4 to
8 carbons. It is also desirable for the copolymers of ethylene to
have a density as measured by ASTM D-792 of less than about 0.915
g/cc and more preferably less than about 0.910 g/cc and even more
preferably less than about 0.900 g/cc. Such polymers are oftentimes
referred to as VLDPE (very low density polyethylene) or ULDPE
(ultra low density polyethylene). Preferably the ethylene
.alpha.-olefin copolymers are produced using a single site catalyst
and even more preferably a metallocene catalyst systems. Single
site catalysts are believed to have a single, sterically and
electronically equivalent catalyst position as opposed to the
Ziegler-Natta type catalysts which are known to have a mixture of
catalysts sites. Such single-site catalyzed ethylene
.alpha.-olefins are sold by Dow under the trade name AFFINITY,
DuPont Dow under the trademark ENGAGE.RTM. and by Exxon under the
trade name EXACT. These copolymers shall sometimes be referred to
herein as m-ULDPE.
[0108] Suitable copolymers of ethylene also include ethylene and
lower alkyl acrylate copolymers, ethylene and lower alkyl
substituted alkyl acrylate copolymers and ethylene vinyl acetate
copolymers having a vinyl acetate content of from about 8% to about
40% by weight of the copolymer. The term "lower alkyl acrylates"
refers to comonomers having the formula set forth in Diagram 1:
1
[0109] The R group refers to alkyls having from 1 to 17 carbons.
Thus, the term "lower alkyl acrylates" includes but is not limited
to methyl acrylate, ethyl acrylate, butyl acrylate and the
like.
[0110] The term "alkyl substituted alkyl acrylates" refers to
comonomers having the formula set forth in Diagram 2: 2
[0111] R.sub.1 and R.sub.2 are alkyls having 1-17 carbons and can
have the same number of carbons or have a different number of
carbons. Thus, the term "alkyl substituted alkyl acrylates"
includes but is not limited to methyl methacrylate, ethyl
methacrylate, methyl ethacrylate, ethyl ethacrylate, butyl
methacrylate, butyl ethacrylate and the like.
[0112] Suitable polybutadienes include the 1,2- and 1,4-addition
products of 1,3-butadiene (these shall collectively be referred to
as polybutadienes). In a more preferred form of the invention the
polymer is a 1,2-addition product of 1,3 butadiene (these shall be
referred to as 1,2 polybutadienes). In an even more preferred form
of the invention the polymer of interest is a syndiotactic
1,2-polybutadiene and even more preferably a low crystallinity,
syndiotactic 1,2 polybutadiene. In a preferred form of the
invention the low crystallinity, syndiotactic 1,2 polybutadiene
will have a crystallinity less than 50%, more preferably less than
about 45%, even more preferably less than about 40%, even more
preferably the crystallinity will be from about 13% to about 40%,
and most preferably from about 15% to about 30%. In a preferred
form of the invention the low crystallinity, syndiotactic 1,2
polybutadiene will have a melting point temperature measured in
accordance with ASTM D 3418 from about 70.degree. C. to about
120.degree. C. Suitable resins include those sold by JSR (Japan
Synthetic Rubber) under the grade designations: JSR RB 810, JSR RB
820, and JSR RB 830.
[0113] Suitable polyesters include polycondensation products of
di-or polycarboxylic acids and di or poly hydroxy alcohols or
alkylene oxides. In a preferred form of the invention the polyester
is a polyester ether. Suitable polyester ethers are obtained from
reacting 1,4 cyclohexane dimethanol, 1,4 cyclohexane dicarboxylic
acid and polytetramethylene glycol ether and shall be referred to
generally as PCCE. Suitable PCCE's are sold by Eastman under the
trade name ECDEL. Suitable polyesters further include polyester
elastomers which are block copolymers of a hard crystalline segment
of polybutylene terephthalate and a second segment of a soft
(amorphous) polyether glycols. Such polyester elastomers are sold
by Du Pont Chemical Company under the trade name HYTREL.RTM..
[0114] Suitable polyamides include those that result from a
ring-opening reaction of lactams having from 4-12 carbons. This
group of polyamides therefore includes nylon 6, nylon 10 and nylon
12. Acceptable polyamides also include aliphatic polyamides
resulting from the condensation reaction of di-amines having a
carbon number within a range of 2-13, aliphatic polyamides
resulting from a condensation reaction of di-acids having a carbon
number within a range of 2-13, polyamides resulting from the
condensation reaction of dimer fatty acids, and amide containing
copolymers. Thus, suitable aliphatic polyamides include, for
example, nylon 66, nylon 6,10 and dimer fatty acid polyamides.
[0115] The styrene of the styrene and hydrocarbon copolymer
includes styrene and the various substituted styrenes including
alkyl substituted styrene and halogen substituted styrene. The
alkyl group can contain from 1 to about 6 carbon atoms. Specific
examples of substituted styrenes include alpha-methylstyrene,
beta-methylstyrene, vinyltoluene, 3-methylstyrene, 4-methylstyrene,
4-isopropylstyrene, 2,4-dimethylstyrene, o-chlorostyrene,
p-chlorostyrene, o-bromostyrene, 2-chloro-4-methylstyrene, etc.
Styrene is the most preferred.
[0116] The hydrocarbon portion of the styrene and hydrocarbon
copolymer includes conjugated dienes. Conjugated dienes which may
be utilized are those containing from 4 to about 10 carbon atoms
and more generally, from 4 to 6 carbon atoms. Examples include
1,3-butadiene, 2-methyl-1,3-butadiene (isoprene),
2,3-dimethyl-1,3-butadiene, chloroprene, 1,3-pentadiene,
1,3-hexadiene, etc. Mixtures of these conjugated dienes also may be
used such as mixtures of butadiene and isoprene. The preferred
conjugated dienes are isoprene and 1,3-butadiene.
[0117] The styrene and hydrocarbon copolymers can be block
copolymers including di-block, tri-block, multi-block, and star
block. Specific examples of diblock copolymers include
styrene-butadiene, styrene-isoprene, and the hydrogenated
derivatives thereof. Examples of triblock polymers include
styrene-butadiene-styrene, styrene-isoprene-styrene,
alpha-methylstyrene-butadiene-alpha-methylstyre- ne, and
alpha-methylstyrene-isoprene-alpha-methylstyrene and hydrogenated
derivatives thereof.
[0118] The selective hydrogenation of the above block copolymers
may be carried out by a variety of well known processes including
hydrogenation in the presence of such catalysts as Raney nickel,
noble metals such as platinum, palladium, etc., and soluble
transition metal catalysts. Suitable hydrogenation processes which
can be used are those wherein the diene-containing polymer or
copolymer is dissolved in an inert hydrocarbon diluent such as
cyclohexane and hydrogenated by reaction with hydrogen in the
presence of a soluble hydrogenation catalyst. Such procedures are
described in U.S. Pat. Nos. 3,113,986 and 4,226,952, the
disclosures of which are incorporated herein by reference and made
a part hereof.
[0119] Particularly useful hydrogenated block copolymers are the
hydrogenated block copolymers of styrene-isoprene-styrene, such as
a styrene-(ethylene/propylene)-styrene block polymer. When a
polystyrene-polybutadiene-polystyrene block copolymer is
hydrogenated, the resulting product resembles a regular copolymer
block of ethylene and 1-butene (EB). As noted above, when the
conjugated diene employed is isoprene, the resulting hydrogenated
product resembles a regular copolymer block of ethylene and
propylene (EP). One example of a commercially available selectively
hydrogenated is KRATON G-1652 which is a hydrogenated SBS triblock
comprising 30% styrene end blocks and a midblock equivalent is a
copolymer of ethylene and 1-butene (EB). This hydrogenated block
copolymer is often referred to as SEBS. Other suitable SEBS or SIS
copolymers are sold by Kurrarry under the tradename SEPTON.RTM. and
HYBRAR.RTM..
[0120] It may also be desirable to use graft modified styrene and
hydrocarbon block copolymers by grafting an alpha,beta-unsaturated
monocarboxylic or dicarboxylic acid reagent onto the selectively
hydrogenated block copolymers described above.
[0121] The block copolymers of the conjugated diene and the vinyl
aromatic compound are grafted with an alpha,beta-unsaturated
monocarboxylic or dicarboxylic acid reagent. The carboxylic acid
reagents include carboxylic acids per se and their functional
derivatives such as anhydrides, imides, metal salts, esters, etc.,
which are capable of being grafted onto the selectively
hydrogenated block copolymer. The grafted polymer will usually
contain from about 0.1 to about 20%, and preferably from about 0.1
to about 10% by weight based on the total weight of the block
copolymer and the carboxylic acid reagent of the grafted carboxylic
acid. Specific examples of useful monobasic carboxylic acids
include acrylic acid, methacrylic acid, cinnamic acid, crotonic
acid, acrylic anhydride, sodium acrylate, calcium acrylate and
magnesium acrylate, etc. Examples of dicarboxylic acids and useful
derivatives thereof include maleic acid, maleic anhydride, fumaric
acid, mesaconic acid, itaconic acid, citraconic acid, itaconic
anhydride, citraconic anhydride, monomethyl maleate, monosodium
maleate, etc.
[0122] The styrene and hydrocarbon block copolymer can be modified
with an oil such as the oil modified SEBS sold by the Shell
Chemical Company under the product designation KRATON G2705.
[0123] In one preferred form of the invention, the tubing is
composed of a multiple component polymer blend. The present
invention contemplates blending two or more of any of the polymers
set forth above. In a preferred form of the invention, the polymer
blend includes a polyolefin blended with a styrene and hydrocarbon
copolymer. In a preferred form of the invention, the polyolefin is
a propylene containing polymer and can be selected from the
homopolymers and copolymers of propylene described above including
high melt strength polypropylenes. It may also be desirable to have
three or more components including a styrene and hydrocarbon
copolymer with a blend of various types of polypropylenes. The
polypropylene, either alone or in sum, can be present in an amount
by weight of the blend from about 10% to about 50%, more preferably
from about 15% to about 45% and most preferably from about 20% to
about 40% with the balance of the blend being the styrene and
hydrocarbon block copolymer.
[0124] When using oil modified SEBS it may be desirable, though not
critical, to use a high melt strength polypropylene as a blend
component. Suitable polypropylene and SEBS containing blends
include: (1) precompounded blends of PP and SEBS sold by Wittenburg
under the trade name CAWITON and particularly grades PR 3670E and
PR4977; (2) from 90-98% by weight KRATON G2705 with 2-10% Basell
PROFAX PF 611 high melt strength polypropylene; (3) 75% KRATON
G2705 with 23% Basell PROFAX SA 861random copolymer of propylene
and ethylene with 2% Basell PROFAX PF-611 which is high melt
strength PP; and (4) precompounded blend of PP/SEBS sold by J-Von
under grade 70585 E.
[0125] In another preferred form of the invention, the tubing will
be fabricated from a single m-ULDPE resin or a blend of m-ULDPE
resins. One particularly suitable m-ULDPE resin is sold by
DuPont-Dow under the trademark ENGAGE.RTM. and even more
particularly ENGAGE.RTM. 8003 (density 0.885 g/cc). It is also
contemplated blending more than one m-ULDPE resins. Such resins and
tubings and film made therefrom are more fully set forth in U.S.
Pat. No. 6,372,848 which is incorporated in its entirety herein by
reference and made a part hereof.
[0126] It is also contemplated fabricating tubing from
polybutadienes or blends of polybutadiene resins described
above.
[0127] Because the suitable non-PVC containing polymers and polymer
blends are typically not laser responsive one must incorporate into
the polymer or polymer blend a laser responsive component. Suitable
laser-responsive components include dyes, colorants and/or
pigments. In a more preferred form of the invention, the laser
responsive material is a dye and more preferably an organic dye
having a functional group that is responsive to a laser beam at a
wavelength, or a narrow range of wavelengths, within a range of
wavelengths in the near infrared spectrum and more preferably from
about 700 nm to about 1500 nm. Representative functional groups
include polymethine, porphine, indanthrene, quinone, di- and
tri-phenylmethane, and metal complexed dithiol dyes. In a preferred
form of the invention, the dye will have an absorptivity of higher
than about 50 (optical density/gram) when exposed to a laser beam
providing light in the frequency range in which the dye is
responsive. In a preferred form of the invention, the dye is
responsive to a laser beam at peak wavelengths from about 780 nm to
about 810 nm and generates sufficient heat over a short period of
time to allow for melting of the non-PVC polymer or polymer blend.
What is meant by short period of time is less than 15 seconds.
[0128] The dyes are preferably sparingly soluble or insoluble in an
aqueous medium including water, saline solutions, dextrose
solutions, lipid containing solutions and protein containing
solutions so if they form a part of the solution contact layer they
will not readily leach into the solution in a significant or
deleterious amount. The dyes are also preferably thermally stable
at temperatures reached during extrusion processing of the polymer
or polymer blend. Suitable dyes are sold by Epolin Inc. under the
trade name EPOLIGHT 4121 and 4149. When using a laser responsive
material with an absorption of higher than about 50, only low
quantities of such dye material is required and typically is added
to the tubing blend in an amount from about 20 ppm to about 500
ppm, more preferably from about 100 ppm to about 400 ppm and most
preferably from about 200 ppm to about 300 ppm. It is contemplated
using a laser responsive material having an absorptivity of less
than 50 but one would have to use higher concentrations of the
laser responsive material. It is also contemplated using other dyes
that are not responsive to the laser but are used for color coding
purposes described above.
[0129] In another preferred form of the invention, the laser
responsive material will be applied to a surface of materials to be
joined instead of incorporating the laser responsive material into
the blend. To this end, the laser responsive material is dissolved
or suspended in a suitable carrier or solvent, and, in this form
can be applied specifically to selected portions of the surfaces to
be joined. The laser responsive material can be applied by dipping
the surfaces to be joined into the laser responsive material, or
the laser responsive material can be brushed on, sprayed on,
printed on or the like.
[0130] The tubings of the present invention can be manufactured by
any known polymer processing technique, but, in a preferred form of
the invention, is formed by extrusion, coextrusion or injection
molding. Such tubings are soft, flexible, kink resistant, have a
good touch feeling (haptics), and are capable of being sterilized
by steam sterilization, radiation or by ethylene oxide (EtO)
exposure.
[0131] Non-PVC, Laser Weldable End Cap Film
[0132] FIG. 12 shows the tubing 600 with an end cap 610
hermetically sealed thereto. The end cap film 610 is a monolayer or
multiple layer polymeric film that has a tubing contacting surface
611 that is adhesively compatible with the tubing 600. The end cap
film can be formed by any suitable polymer processing technique
including extrusion, coextrusion, extrusion lamination, lamination,
injection molding and the like. The end cap film 610, in a
preferred form of the invention, is attached with sufficient
strength to an end surface of tubing to withstand a burst strength
of 30 psi. Burst strength is measured by applying pressurized air
through a tubing flowpath 613 to pressurize the tubing until the
tubing or end cap ruptures or leaks. The end cap 610 can be
dimensioned to exceed the dimension of the end of the tubing and
excess material is wrapped around the tubing end where it is
attached to the tubing sidewalls 602 to form the drum embodiment
referred to above. It is also possible to dimension the cap 610 as
shown in FIG. 12 to match the dimension of the end of the tubing
and be attached only to the end portion of the tubing without any
significant amount of excess material.
[0133] The end cap 610 can be fabricated from single polymers such
as the m-ULDPE resins described above. Such and end cap made from
m-ULDPE are particularly well suited for use with m-ULDPE tubing
containing blends. The end cap 610 can also be fabricated from
polymer blends having at least a first component and a second
component. The first component is selected from: (1) ethylene and
.alpha.-olefin copolymers having a density of less than about 0.915
g/cc, (2) ethylene and lower alkyl acrylate copolymers, (3)
ethylene and lower alkyl substituted alkyl acrylate copolymers and
(4) ionic polymers, commonly referred to as ionomers. The term
"ionomer" is used herein to refer to metal salts of the acrylic
acid copolymers having pendent carboxylate groups associated with
monovalent or divalent cations such as zinc or sodium. The first
component is present in an amount from about 99% to about 50% by
weight of the blend, more preferably from about 85%-50% and most
preferably from about 70%-50%.
[0134] The second component is selected from the group consisting
of: (1) propylene containing polymers, (2) butene containing
polymers, (3) polymethyl pentene containing polymers, (4) cyclic
olefin containing polymers and (5) bridged polycyclic hydrocarbon
containing polymers. The second component is present in an amount
by weight of the blend from about 50% to about 1%, more preferably
from about 50%-15% and most preferably from about 30%-50%. These
polymer blends for the end cap are particularly well suited for use
with the tubings made from blends of polyolefin and styrene and
hydrocarbon copolymers.
[0135] Suitable homopolymer and copolymers of cyclic olefins and
bridged polycyclic hydrocarbons and blends thereof can be found in
U.S. Pat. Nos. 4,874,808; 5,003,019; 5,008,356; 5,288,560;
5,218,049; 5,854,349; 5,863,986; 5,795,945; and 5,792,824, which
are incorporated in their entirety herein by reference and made a
part hereof.
[0136] In a preferred form of the invention, suitable cyclic olefin
monomers are monocyclic compounds having from 5 to about 10 carbons
in the ring. The cyclic olefins can be selected from the group
consisting of substituted and unsubstituted cyclopentene,
cyclopentadiene, cyclohexene, cyclohexadiene, cycloheptene,
cycloheptadiene, cyclooctene, and cyclooctadiene.
[0137] In a preferred form of the invention, suitable bridged
polycyclic hydrocarbon monomers have two or more rings and more
preferably contain at least 7 carbons. The rings can be substituted
or unsubstituted. Suitable substitutes include lower alkyl, aryl,
aralkyl, vinyl, allyloxy, (meth) acryloxy and the like. The bridged
polycyclic hydrocarbons are selected from the group consisting of
those disclosed in the above incorporated patents. Suitable bridged
polycyclic hydrocarbon containing polymers are sold by Ticona under
the tradename TOPAS, by Nippon Zeon under the tradename ZEONEX and
ZEONOR, by Daikyo Gomu Seiko under the tradename CZ resin, and by
Mitsui Petrochemical Company under the tradename APEL.
[0138] In a preferred form of the invention, the end cap will be a
monolayer film from a blend by weight of from about 35% to about
45% of a ethylene and .alpha.-olefin copolymer having a density of
less than about 0.900 g/cc, from about 20% to about 30% of an
ethylene and .alpha.-olefin copolymer having a density of higher
than about 0.900 g/cc but less than about 0.910 g/cc, and from
about 30% to about 40% polypropylene, and more preferably a random
copolymer of propylene with approximately 3% by weight of an
ethylene comomoner. The end cap should have a thickness from about
3 mils to about 10 mils.
[0139] Because these end cap materials are not laser responsive,
one of the laser responsive dyes must be incorporated into the
single polymer or polymer blends for the end cap. For the end cap
material, the dye should be incorporated in an amount from about
200 ppm to about 2000 ppm, more preferably from about 400 ppm to
about 1800 ppm and most preferably from about 500 ppm to about 1000
ppm.
[0140] Coupler
[0141] FIG. 13 shows a coupler 620 having opposed tubing mounting
portions 622, a tubing stop 624 and a fluid pathway 626
therethrough. As shown in FIG. 14, the coupler can be used to
connect a first tubing to a second tubing even when the first and
second tubings are incompatible with one another. The assembly
shown in FIG. 14 will be discussed in greater detail below. The
tubing mounting portions 622 can have a tapered portion at its
distal end for ease of mounting a tubing thereto. The surface of
the coupler 620 can be textured or have a matte finish for ease of
mounting of the tubing. The tubing mounting portions 622 are shown
to have relatively the same length but could have different lengths
without departing from the scope of the present invention. It is
also contemplated the tubing mounting portions 622 can have ridges
or other protuberances for heat concentrating or enhancing an
interference fit between the tubing and the tubing mounting
portions 622.
[0142] The tubing mounting portions 622 are shown to be
concentrically mounted with respect to one another and with respect
to the fluid pathway 626. It is contemplated the coupler can have
numerous shapes where the tubing portions 622 are not
concentrically disposed with respect to one another. It is
contemplated one tubing mounting portion can have a first axis and
the other tubing mounting portion will have a second axis
transverse to the first axis. What is meant by transverse is one
axis extends in a direction to intersect the second axis even if
the axis will not intersect it. It is also contemplated the coupler
can have more than two tubing mounting portions, more than one
tubing stop and more than one fluid pathway. It is desirable the
tubing when attached to the coupler have a bond strength in excess
of 15 lbf when tested by a pull test. An assembly fails the pull
test if the tubing breaks or become detached from the coupler at a
pull force below 15 lbf.
[0143] The coupler is composed of a non-PVC polymeric material
selected from the materials set forth above for the tubing and
preferably is composed of a polymer blend. In one preferred form of
the invention the tubing has two components of from about 40% to
about 60% EVA and a second component of from about 60% to about 40%
of a polyester, polyester elastomer, or a polyurethane. The EVA,
preferably, has a modifier group associated therewith and selected
from the group consisting of: aromatic hydrocarbons, carbon
dioxide, monoethylenically unsaturated hydrocarbons,
acrylonitriles, vinyl ethers, vinyl esters, vinylamides, vinyl
ketones, vinyl halides, epoxides, carboxylic acids and anhydride
derivatives thereof (including fused ring carboxylic acid
anhydrides). Most preferably, the modifier group is maleic acid or
maleic anhydride.
[0144] In another preferred form of the invention the polymer blend
has three components. The first component is a polyolefin and more
preferably a propylene containing polymer in an amount by weight of
from about 25% to about 35% such as those sold by Solvay under the
trade name FORTILENE and most particularly FORTILENE grade KS 490.
The second component is a polyester and more preferably a polyester
elastomer such as those sold by DuPont under the tradename
HYTREL.RTM. and in an amount by weight of the blend of from about
35% to about 45%. The second component can also be a polyurethane.
The third component is an ethylene vinyl acetate copolymer having a
vinyl acetate content of from about 8% VA to about 40% vinyl
acetate, and more preferably a carboxylic acid modified EVA or a
carboxylic acid anhydride modified EVA. The EVA is present in an
amount by weight of the blend of from about 25% to about 35%. The
present invention further contemplates acid modifying or carboxylic
acid anhydride modifying the propylene first component instead of
or in addition to such modification to the EVA. The coupler 620 can
be made by polymer processing techniques such as injection
molding.
[0145] Suitable polyurethanes include both aromatic and aliphatic
type polyurethanes. Suitable polyurethanes are formed by reacting
diisocyanate with a chain extender. Diisocyanates include:
Diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI),
hexylene diisocyanate (HDI), and isophorone diisocyanate (IPDI).
Chain Extenders include diol type, diamine type, polyester
containing polyols and polyether containing polyols. The diol type
include: 1,4-butane diol, ethylene glycol, 1,6-hexane diol and
1,4-bis-beta-hydroxyethoxybenzene. The diamine type include
aliphatic and aromatic type. Aliphatic type includes ethylene
diamine. Aromatic type includes: toluylene diamine and
diaminodiphenylmethane.
[0146] Laser-Weldable Tubing Assemblies and Therapeutic Fluid
Delivery Sets
[0147] FIG. 14 shows a tubing assembly 628 having a first laser
weldable tubing 600 and a second tubing 630 which are connected
together and placed in fluid communication by the coupler 620. The
second tubing 630 is made from a material incompatible with the
material of tubing 600. What is meant by incompatible is the
materials are not capable of being directly joined together in a
secure fashion utilizing conductive or inductive heat sealing
techniques. This assembly 628 is particularly well suited for
joining a PVC tubing 630 from a fluid delivery set or peritoneal
dialysis set with the laser weldable, non-PVC tubing 600 described
above. The laser weldable tubing 600 can be connected to a transfer
set of a patient using the laser welding device 10 discussed
above.
[0148] The first and second tubing 600, 630 can be connected to the
coupler by sliding the fluid pathway 608 of the tubings over the
tubing mounting portions 622 until an end portion of the tubing
contacts the tubing stop 624. The tubings 600 and 630 are then
fixedly attached to the coupler by heat sealing such as with a
ring-shaped die, radio frequency heat sealing, solvent bonding,
adhesive bonding, or by heating the tubing and coupler in an
autoclave during a steam sterilization process (i.e., 121.degree.
C. for 1 hour) or other suitable techniques. When heat sealing a
mandrel may be employed to maintain the shape of the coupler and
tubing assembly.
[0149] FIG. 15 shows a fluid container 640 such as a therapeutic
fluid container for storing a dialysate solution, a drain bag of a
peritoneal dialysis set, an I.V. container, a blood container, a
blood component container a blood substitute container or the like,
in fluid communication with a laser weldable tubing 600.
[0150] FIG. 16 shows the laser-weldable tubing 600 connected to a
tubing 650 from a peritoneal dialysis transfer set. The tubing
connection is made with the device 10 as described in detail
above.
[0151] FIG. 17 shows a laser-weldable dual lumen tubing 660 having
first and second fluid passageways 662 and 664 and first and second
lumen 666 and 668 attached together. It is contemplated that more
than two lumen, such as three, four or five or more, could be
attached together without departing from the scope of the present
invention. The first and second lumen are connected along
peripheral edges and can extend parallel with respect to one
another along a length of the tubing or the first and second lumen
can be helically disposed with respect to one another or otherwise
braided.
[0152] FIG. 18 shows another embodiment of a laser-weldable dual
lumen tubing 670 having a first and second lumen 672 and 674
having, respectively, first and second fluid passageways 676 and
678. The first and second lumen 672 and 674 are concentrically
disposed with respect to one another. It is contemplated that more
than two lumen could be concentrically mounted without departing
from the present invention.
[0153] FIG. 19 shows yet another embodiment of a laser-weldable,
multiple lumen tubing 680 having a primary lumen 682 and four
secondary lumen 684 each having a fluid passageway 686. The term
"multiple" is meant to include 2 or more so a dual lumen tubing is
a multiple lumen tubing. The area 688 between the secondary lumen
684 can be a fluid passageway or can be material such as packing
material to hold the secondary lumen in position. While four
secondary lumen are shown it is contemplated that two or more
secondary lumen could be provided without departing from the
present invention. Also, while the secondary lumen 684 are shown
spaced apart from one another one or more of these secondary lumen
can be attached together. The secondary lumen 684 can extend in a
direction parallel to one another or be helically disposed with
respect to one another or otherwise braided together.
EXAMPLES
Example 1
[0154] A membrane film was extruded from a polymer blend of 40% by
weight of a first m-ULDPE resin (density 0.885 g/cc, Dow VP 8770),
25% by weight of a second m-ULDPE resin (density of 0.902 g/cc, Dow
PL 1880), 35% polypropylene (Basell SR-549M) and 600 ppm dye
(Epolin 4121). The components were blended in a David Standard twin
screw extruder and extruded through a die to a thickness of 0.005
inches. The film was exposed to a diode laser (810 nm), 30 amp for
a period of 10 seconds where the film melted.
Example 2
[0155] A tubing was extruded from a polymer blend of Cawiton PR
3670 with 200 ppm dye (Epolin 4121). The components were blended in
a David Standard twin screw extruder and extruded through a die to
a wall thickness 0.039 inches, ID of 0.157 inches, OD of 0.235
inches. The tubing was exposed to a diode laser (810 nm), 30 amp
for a period of 10 seconds where the tubing melted.
Example 3
[0156] A tubing was extruded in the same manner as in Example 2
except the blend contained 250 ppm of the dye. The tubing was
exposed to a diode laser (810 nm), 30 amp for a period of 10
seconds where the tubing melted.
Example 4
[0157] A coupler was injection molded from a two component polymer
blend of 50% HYTREL.RTM. 5556 WITH 50% BYNEL 1123. The blend
components were pellitized with a 11/2 inch David Standard twin
screw extruder and injected molded with a 25 ton Arburg injection
molding machine. A first tubing of PVC was slid over a first tubing
mounting portion and attached to the coupler by radio frequency
sealing. A second tubing was fabricated as set forth in Example 2.
The second tubing was slid over a second tubing mounting portion of
the coupler and then autoclaved at 121.degree. C. for one hour. The
assembly was allowed to cool and the first tubing and the second
tubing were pulled until the tubing broke or until it became
detached from the coupler and the force required to do so was
measured respectively at 29.3 lbf and 29.4 lbf.
Example 5
[0158] A coupler was injection molded as set forth in Example 4
from a three-component polymer blend of 30% polypropylene (Solvay
KS 490), 40% polyester elastomer (HYTREL.RTM. 5556) and 30%
anhydride modified EVA (BYNEL 3810). As in example 4, a first
tubing of PVC was slid over a first tubing mounting portion and
sealed thereto using radio frequency sealing. A second tubing was
fabricated as set forth in Example 2 and was slid over a second
tubing mounting portion. The assembly was autoclaved at 121.degree.
C. for one hour. The assembly was allowed to cool and the first
tubing and the second tubing were pulled until the tubing broke or
until it became detached from the coupler and the force required to
do so was measured respectively at 48.2 lbf and 34.3 lbf.
[0159] It should be understood that various changes and
modifications to the presently preferred embodiments described
herein will be apparent to those skilled in the art. Such changes
and modifications can be made without departing from the spirit and
scope of the present invention and without diminishing its intended
advantages. It is therefore intended that such changes and
modifications be covered by the appended claims.
* * * * *