U.S. patent application number 15/642668 was filed with the patent office on 2017-10-19 for polyurethane-polyethylene delamination resistant tubing with gas barrier properties.
The applicant listed for this patent is Tekni-Plex, Inc.. Invention is credited to Philip Bourgeois, Munish Shah.
Application Number | 20170299089 15/642668 |
Document ID | / |
Family ID | 48797812 |
Filed Date | 2017-10-19 |
United States Patent
Application |
20170299089 |
Kind Code |
A1 |
Bourgeois; Philip ; et
al. |
October 19, 2017 |
POLYURETHANE-POLYETHYLENE DELAMINATION RESISTANT TUBING WITH GAS
BARRIER PROPERTIES
Abstract
A tube comprising an inner layer, an outer layer and a barrier
layer disposed between the inner layer and the outer layer, wherein
the barrier layer is bound to the outer layer by a layer of
adhesive disposed between the outer layer and the barrier layer and
the barrier layer is bound to the inner layer by a layer of
adhesive disposed between the inner layer and the barrier layer,
wherein the inner layer comprises a polyethylene, the outer layer
comprises a thermoplastic polyurethane and the barrier layer
comprises a material that acts as a barrier to gas.
Inventors: |
Bourgeois; Philip;
(Perrysburg, OH) ; Shah; Munish; (Sylvania,
OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Tekni-Plex, Inc. |
Wayne |
PA |
US |
|
|
Family ID: |
48797812 |
Appl. No.: |
15/642668 |
Filed: |
July 6, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13586288 |
Aug 15, 2012 |
9702486 |
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15642668 |
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13354029 |
Jan 19, 2012 |
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13586288 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B32B 2307/412 20130101;
A61L 29/085 20130101; B32B 2250/40 20130101; F16L 9/121 20130101;
B32B 2535/00 20130101; Y10T 137/0318 20150401; F16L 11/04 20130101;
B32B 27/308 20130101; A61L 29/14 20130101; A61L 29/085 20130101;
B32B 2307/51 20130101; A61L 29/085 20130101; B32B 1/08 20130101;
A61L 29/06 20130101; A61L 29/041 20130101; A61L 2420/08 20130101;
A61L 29/041 20130101; B32B 2250/03 20130101; B32B 2250/24 20130101;
B32B 2274/00 20130101; B32B 27/08 20130101; B32B 27/40 20130101;
A61L 29/06 20130101; A61M 39/08 20130101; C08L 33/08 20130101; B32B
2597/00 20130101; B32B 7/12 20130101; C08L 75/04 20130101; C08L
33/08 20130101; C08L 75/04 20130101 |
International
Class: |
F16L 9/12 20060101
F16L009/12; B32B 27/30 20060101 B32B027/30; A61L 29/04 20060101
A61L029/04; A61L 29/06 20060101 A61L029/06; B32B 27/40 20060101
B32B027/40; A61L 29/14 20060101 A61L029/14; A61M 39/08 20060101
A61M039/08; B32B 1/08 20060101 B32B001/08; B32B 7/12 20060101
B32B007/12; B32B 27/08 20060101 B32B027/08; F16L 11/04 20060101
F16L011/04; A61L 29/08 20060101 A61L029/08 |
Claims
1.-25. (canceled)
26. Method of forming a medical tube comprising an outer layer, an
innermost layer and an intermediate layer disposed between the
outer layer and the innermost layer, the method comprising:
selecting a first polymeric material having a selected structural
stability; selecting a second polymeric material that is inert to
aqueous fluids; selecting a third polymeric material that acts as a
barrier to gas; selecting a fourth polymeric material that readily
bonds and adheres to the first and second polymeric materials on
co-extrusion and cooling of the materials; co-extruding the
selected first, second, third and fourth polymeric materials to
form the medical tubing in a configuration that has an outer layer
comprising at least about 90% by weight of the first polymeric
material, an inner layer comprising at least about 90% weight of
the second polymeric material, a layer disposed between the inner
and outer layers that comprises at least about 90% by weight of the
third polymeric material, a layer of the fourth material disposed
between the outer layer and the layer of the third polymeric
material and a layer of the fourth material disposed between the
inner layer and the layer of the third polymeric material.
27. The method of claim 26 wherein the first polymeric material is
selected to be a polyurethane, the second polymeric material is
selected to be a polyethylene, the third polymeric material is
selected from the group consisting of an ethylene vinyl alcohol
copolymer and a polyamide and the fourth polymeric material is one
or more ethylene acrylic copolymers.
28. The method of claim 26 wherein the first polymeric material is
selected to be a polyurethane, the second polymeric material is
selected to be a polyethylene, the third polymeric material is
selected from the group consisting of an ethylene vinyl alcohol
copolymer and a polyamide and the fourth polymeric material is
selected such that the medical tubing does not visually delaminate
after being submersed in water at 60.degree. C. for 36 hours.
29. The method of claim 28 wherein the fourth polymeric material
comprises one or more anhydride grafted ethylene acrylate
copolymers.
30.-34. (canceled)
35. The method of claim 29 wherein the fourth polymeric material
comprises one or more anhydride grafted ethylene methyl acrylate
copolymers.
36. The method of claim 26 wherein the first polymeric material
comprises an aromatic or aliphatic polyether based polyurethane and
the second polymeric material comprises polyethylene.
37. The method of claim 36, wherein the polyethylene comprises one
or more of a low density polyethylene, a linear low density
polyethylene and a high density polyethylene and wherein the
aromatic polyether based polyurethane comprises a
polytetramethyleneglycol-based polyurethane.
38. The method of claim 36, wherein the polyethylene comprises a
low density polyethylene (LDPE), and the first polymeric material
comprises a polytetramethyleneglycol-based polyurethane.
39. The method of claim 27, where the thickness of the polyurethane
outer layer is between 0.001 inches and 0.025 inches, the thickness
of the inner polyethylene layer is between 0.001 inches and 0.025
inches and the thickness of the barrier layer is between 0.001
inches and 0.025 inches.
40. The method of claim 26, wherein the inner and outer layers do
not visually delaminate when subjected to a stress and strain up to
the tube's elastic yield point as measured in a mechanical tester
at a pull rate of about 12 inches per minute at ambient conditions
of 72 degrees F. and 50% relative humidity.
41. The method of claim 26, wherein the tube has a central axial
fluid flow passage, the inner layer having a radially inner wall
surface that defines the passage, the outer and inner layers
resisting delamination when subjected to a stress and strain up to
the tube's elastic yield point as measured in a mechanical tester
at a pull rate of about 12 inches per minute at ambient conditions
of 72 degrees F. and 50% relative humidity.
42. The method of claim 26, wherein the thickness of the layer of
the fourth material disposed between the barrier layer and the
outer layer is between 0.0001 inches and 0.025 inches and wherein
the thickness of the layer of the fourth material disposed between
the barrier layer and the inner layer is between 0.001 inches and
0.025 inches.
43. The method of claim 26, wherein the tube does not visually
delaminate when submersed in water at 60.degree. C. for 36 hours.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of and claims the benefit
of priority to U.S. application Ser. No. 13/586,288 filed Aug. 15,
2012 which is continuation-in-part of and claims the benefit of
priority of U.S. application Ser. No. 13/354,029 filed Jan. 19,
2012, the disclosures of which are incorporated by reference as if
fully set forth herein.
FIELD OF THE INVENTION
[0002] The present invention relates to polymeric tubing typically
formed by a co-extrusion process, the tubing having multiple layers
of the same or different polymeric materials, each layer
successively adhered to each other.
BACKGROUND
[0003] Tubing comprised of polymeric material is used in many
industrial and commercial applications including in the medical
field. Various FDA compliant plastics are used, depending upon
properties desired and the intended applications. Where the tubing
is used to transport fluids for in vivo treatment of human
patients, selection of the polymeric materials can be a factor.
[0004] Polyvinyl chloride (PVC) is one of the most widely used
plastics. While structurally stable and easily formable into
desired shapes, PVC is typically manufactured using plasticizers
which can migrate out of the PVC matrix into bodily fluids and has
other properties not ideally suited for medical treatment
applications. Likewise, due to the inherent nature of plasticized
PVC tubing, there arises the potential absorption of medicines and
other components of aqueous fluids used in medical treatments into
the sidewall of the PVC tube. Polyurethane is potentially a
substitute for PVC. However, dual layer tubing comprised of
polyurethane and polyethylene suffers from the inability of the two
layers to remain adhered to each other under low to moderate
stress, strain or mechanical manipulation conditions as well as the
inability to sufficiently impede migration of oxygen through the
layers. U.S. Pat. No. 4,627,844 to Schmitt ("Schmitt"), the
disclosure of which is incorporated herein by reference as if fully
set forth, discloses a tri-layer tube which is embodied in a
commercial product sold under the trademark "SUREPATH 151" by the
Natvar Division of Tekni-Plex, Inc. As disclosed in Schmitt, an
outer layer of PVC and an inner fluid-contact layer of low density
polyethylene (LDPE) are co-extruded with an intermediate tie layer
of ethylene vinyl acetate copolymer (EVA). However, while Schmitt
greatly reduces the possibility for the migration of additives from
the PVC to the fluid and absorption of components from the fluid to
the PVC tubing by providing a LDPE fluid-contact layer, elimination
of the PVC is preferred. Other tubing configurations are disclosed
in U.S. Pat. No. 7,647,949, U.S. Pat. No. 4,211,741 and U.S. Patent
Publication No. 2007/0119511, the disclosures of which are
incorporated by reference as if fully set forth herein. Where
medical tubing is concerned, preservation of the integrity of
reagents contained in fluids being routed through the tubing can be
a concern. Similarly, prevention of migration of components out of
the fluids through the tubing can be an issue. In such
applications, incorporation into the tubing of a layer of material
comprised of a gas barrier material can be implemented for purposes
of preventing migration of gases such as oxygen into the fluid thus
preserving oxygen sensitive reagents in the fluid.
SUMMARY OF THE INVENTION
[0005] In accordance with the invention there is provided a tube
comprising an inner layer, an outer layer and a barrier layer
disposed between the inner layer and the outer layer, wherein the
barrier layer is bound to the outer layer by a layer of adhesive
disposed between the outer layer and the barrier layer and the
barrier layer is bound to the inner layer by a layer of adhesive
disposed between the inner layer and the barrier layer, wherein the
inner layer comprises a polyethylene, the outer layer comprises a
thermoplastic polyurethane and the barrier layer comprises a
material that acts as a barrier to gas.
[0006] The barrier layer preferably comprises more than about 90%
by weight of an ethylene vinyl alcohol copolymer or a polyamide or
blends thereof.
The adhesive typically comprises one or more ethylene acrylic
copolymers, more typically one or more anhydride grafted ethylene
acrylate copolymers and preferably one or more anhydride grafted
ethylene methyl acrylate copolymers.
[0007] The inner layer typically comprises more than about 90% by
weight of a polyethylene and the outer layer comprises more than
about 90% by weight of an aromatic or aliphatic polyether based
polyurethane.
[0008] The barrier layer typically comprises more than about 90% by
weight of an ethylene vinyl alcohol copolymer or a polyamide or
blends thereof and the adhesive comprises more than about 90% by
weight of one or more ethylene acrylic copolymers,
[0009] The barrier layer can comprise more than about 90% by weight
of an ethylene vinyl alcohol copolymer or a polyamide or blends
thereof and the inner layer can comprise more than about 90% by
weight of a polyethylene and the outer layer can comprise more than
about 90% by weight of an aromatic or aliphatic polyether based
polyurethane.
[0010] The adhesive can comprise more than about 90% by weight of
one or more ethylene acrylic copolymers and the inner layer can
comprise more than about 90% by weight of a polyethylene and the
outer layer can comprises more than about 90% by weight of an
aromatic or aliphatic polyether based polyurethane.
[0011] The barrier layer can comprises more than about 90% by
weight of an ethylene vinyl alcohol copolymer or a polyamide or
blends thereof, the adhesive can comprise more than about 90% by
weight of one or more ethylene acrylic copolymers, the inner layer
can comprises more than about 90% by weight of a polyethylene and
the outer layer can comprise more than about 90% by weight of an
aromatic or aliphatic polyether based polyurethane.
[0012] The polyethylene typically comprises one or more of a low
density polyethylene, a linear low density polyethylene and a high
density polyethylene and the aromatic polyether based polyurethane
can comprise a polytetramethyleneglycol-based polyurethane.
[0013] The adhesive can comprise more than about 90% by weight of
one or more ethylene acrylic copolymers, the inner layer can
comprise more than about 90% by weight of low density polyethylene
(LDPE), the outer layer can comprise more than about 90% by weight
of a polytetramethyleneglycol-based polyurethane and the middle
layer can comprise more than about 90% of a material that acts as a
barrier to gas.
[0014] The adhesive typically comprises more than about 90% by
weight of one or more ethylene acrylic copolymers.
[0015] The thickness of the polyurethane outer layer is typically
between about 0.001 inches (0.0254 mm) and about 0.025 inches
(0.635 mm), the thickness of the inner polyethylene layer is
typically between about 0.001 inches (0.0254 mm) and about 0.025
inches (0.635 mm) and the thickness of the barrier layer is
typically between about 0.001 inches (0.0254 mm) and about 0.025
inches (0.635 mm).
[0016] The inner and outer layers preferably do not visually
delaminate when subjected to a stress and strain up to the tube's
elastic yield point as measured in a mechanical tester at a pull
rate of about 12 inches per minute at ambient conditions of 72
degrees F. (22.degree. C.) and 50% relative humidity.
[0017] Preferably, the tube does not visually delaminate when
submersed in water at 60.degree. C. for 36 hours.
[0018] The tube preferably has a central axial fluid flow passage
through which aqueous fluid is routed, the inner layer having a
radially inner wall surface that contacts the aqueous fluid the
outer and inner layers resisting delamination when subjected to a
stress and strain up to the tube's elastic yield point as measured
in a mechanical tester at a pull rate of about 12 inches per minute
at ambient conditions of 72 degrees F. (22.degree. C.) and 50%
relative humidity. Such a tube preferably does not visually
delaminate after being submersed in water at 60.degree. C. for 36
hours.
[0019] In such a tube, the thickness of the adhesive disposed
between the barrier layer and the outer layer is preferably between
about 0.001 inches (0.0254 mm) and about 0.025 inches (0.635 mm)
and the thickness of the adhesive disposed between the barrier
layer and the inner layer is preferably between about 0.001 inches
(0.0254 mm) and about 0.025 inches (0.635 mm)
[0020] In another aspect of the invention there is provided a
medical tube for transport of aqueous fluid comprising:
an inner layer comprising more than about 90% by weight of a
polyethylene, an outer layer comprising more than about 90% by
weight of a an aromatic polyether-based polyurethane, a barrier
layer disposed between the outer and inner layers comprising more
than about 90% by weight of a material that acts as a barrier to
gas, and, an adhesive disposed between the barrier layer and the
outer layer and disposed between the barrier layer and the inner
layer, the adhesive comprising one or more ethylene acrylic
copolymers,
[0021] In such an embodiment, the inner and outer layers preferably
do not visually delaminate when subjected to a stress and strain up
to the tube's elastic yield point as measured in a mechanical
tester at a pull rate of about 12 inches per minute at ambient
conditions of 72 degrees F. (22.degree. C.) and 50% relative
humidity.
[0022] In such an embodiment, the tube preferably does not visually
delaminate after being submersed in water at 60.degree. C. for 36
hours.
[0023] In such an embodiment, the adhesive comprises one or more
anhydride grafted ethylene acrylate copolymers.
[0024] In another aspect of the invention there is provided, a
medical tube for transport of an aqueous fluid comprising:
an inner layer comprised of at least about 90% by weight of a
polyethylene. an outer layer comprised of at least about 90% by
weight of an aromatic polyether-based polyurethane, a barrier layer
disposed between the outer and inner layers comprising more than
about 90% by weight of a material that acts as a barrier to gas,
and, an adhesive disposed between the barrier layer and the outer
layer and disposed between the barrier layer and the inner layer,
the adhesive comprising more than about 90% by weight of one or
more ethylene acrylic copolymers, wherein the tubing does not
visually delaminate after being submersed in water at 60.degree. C.
for 36 hours.
[0025] In another aspect of the invention, there is provided a
medical tube for transport of an aqueous fluid comprising:
an inner layer comprised of at least about 90% by weight of a low
density polyethylene, an outer layer comprised of at least about
90% by weight of a polytetramethyleneglycol-based polyurethane, a
barrier layer disposed between the outer and inner layers
comprising more than about 90% by weight of a material that acts as
a barrier to gas, and, an adhesive disposed between the barrier
layer and the outer layer and disposed between the barrier layer
and the inner layer, the adhesive comprising one or more ethylene
acrylic copolymers, wherein the tubing does not visually delaminate
when subjected to a stress and strain up to the tube's elastic
yield point as measured in a mechanical tester at a pull rate of
about 12 inches per minute at ambient conditions of 72 degrees F.
(22.degree. C.) and 50% relative humidity, and, wherein the tubing
does not visually delaminate after being submersed in water at
60.degree. C. for 36 hours.
[0026] In another aspect of the invention there is provided, a
method of forming a medical tube comprising an outer layer, an
innermost layer and an intermediate layer disposed between the
outer layer and the innermost layer, the method comprising:
[0027] selecting a first polymeric material having a selected
structural stability;
[0028] selecting a second polymeric material that is inert to
aqueous fluids;
[0029] selecting a third polymeric material that acts as a barrier
to gas;
[0030] selecting a fourth polymeric material that readily bonds and
adheres to the first and second polymeric materials on co-extrusion
and cooling of the materials;
[0031] co-extruding the selected first, second, third and fourth
polymeric materials to form the medical tubing in a configuration
that has an outer layer comprising at least about 90% by weight of
the first polymeric material, an inner layer comprising at least
about 90% weight of the second polymeric material, a layer disposed
between the inner and outer layers that comprises at least about
90% by weight of the third polymeric material, a layer of the
fourth material disposed between the outer layer and the layer of
the third polymeric material and a layer of the fourth material
disposed between the inner layer and the layer of the third
polymeric material.
[0032] In such a method, the first polymeric material is typically
selected to be a polyurethane, the second polymeric material is
selected to be a polyethylene, the third polymeric material is
selected from the group consisting of an ethylene vinyl alcohol
copolymer and a polyamide and the fourth polymeric material is one
or more ethylene acrylic copolymers,
[0033] In such a method, the first polymeric material is preferably
selected to be a polyurethane, the second polymeric material is
selected to be a polyethylene, the third polymeric material is
selected from the group consisting of an ethylene vinyl alcohol
copolymer and a polyamide and the fourth polymeric material is
selected such that the medical tubing does not visually delaminate
after being submersed in water at 60.degree. C. for 36 hours.
[0034] In such a method, the adhesive typically comprises one or
more anhydride grafted ethylene acrylate copolymers.
[0035] In another aspect of the invention there is provided, a
method of delivering an aqueous fluid to a subject comprising;
selecting a tube comprising an inner layer, an outer layer and a
barrier layer disposed between the inner and outer layers, wherein
the inner layer comprises a polyethylene, the outer layer comprises
a thermoplastic polyurethane and the barrier layer comprises one or
more of an ethylene vinyl alcohol copolymer and a polyamide;
wherein the tube has a central fluid flow passage surrounded by the
layers; routing an aqueous fluid through the central fluid flow
passage of the tube, and, delivering the aqueous fluid routed
through the central fluid flow passage into a blood vessel of the
subject.
[0036] The step of selecting preferably comprises:
[0037] selecting the tube such that a layer of an adhesive is
disposed between the outer layer and the barrier layer and between
the inner layer and the barrier layer.
[0038] The step of selecting typically comprises:
co-extruding the outer, inner and barrier layers and adhesive
layers to form the tube and selecting the adhesive to comprise more
than about 90% by weight of one or more ethylene acrylic
copolymers.
[0039] The adhesive typically comprises one or more anhydride
grafted ethylene acrylate copolymers.
[0040] The adhesive can comprise one or more anhydride grafted
ethylene methyl acrylate copolymers.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] The drawings depict one or more embodiments of the invention
that are shown by way of examples of the invention wherein:
[0042] FIG. 1 is a schematic perspective view of a five-layered
tube showing the outer and middle or intermediate layers broken
away in order to better illustrate the construction and arrangement
of the tubing;
[0043] FIG. 2 is a cross-sectional view taken along lines 2-2 of
the tube 10 shown in FIG. 1.
DETAILED DESCRIPTION
[0044] There is shown in FIG. 1 an embodiment of a co-extruded
five-layer tubing 10 according to the invention which comprises an
outer layer 1 comprised of at least about 90% by weight of a
polyurethane material, typically a polytetramethyleneglycol-based
polyurethane one example of which is Lubrizol TPU Pellethane
2363-90AE, an inner fluid-contact layer 3 comprised of at least
about 90% by weight of a polyethylene material, typically a low
density polyethylene, one example of which is Westlake LDPE
EM808AA, an intermediate gas barrier layer 5 comprised of at least
about 90% by weight of an ethylene vinyl alcohol copolymer (EVOH),
a polyamide or a mixture or blend of two or more thereof and
bonding layers 7, 9 comprised of an adhesive material that bonds
the barrier layer 5 to the outer 1 and inner 3 layers. The gas
barrier layer 5 acts as a barrier to gases generally such as
oxygen, nitrogen, hydrogen, chlorine, nitrous oxide and the like.
The adhesive layers 7, 9 preferably comprise a material that
renders the tubing 10 subsequent to extrusion resistant to
delamination where the tubing does not visually delaminate after
being subjected to submersion in water at 60.degree. C. for 36
hours and subsequently mechanically flattened by manual squeezing
of the tube from its normal round in cross-sectional condition to a
flattened or oval shape cross-sectional shape or condition. The
adhesive material is most preferably selected to comprise one or
more ethylene acrylic copolymers, an example of which is an
anhydride grafted ethylene methyl acrylate copolymer, a specific
example of which is an anhydride grafted ethylene methyl acrylate
copolymer such as commercially available Westlake Tymax GA 7001
(Anhydride grafted Ethylene Methyl Acrylate Copolymer).
[0045] As shown in FIG. 1 the outer layer of polyurethane 1 has a
radially inner facing surface S1 that binds and adheres to a
radially outer facing surface S2 of the anhydride modified acrylate
adhesive layer 7. The adhesive layer 7 has a radially inner facing
surface S3 that binds to the radially outer facing surface S4 of
the barrier layer 5. The barrier layer 5 has a radially inner
facing surface S5 that binds to the radially outer facing surface
S6 of another layer 9 of adhesive. The adhesive layer 9 has a
radially inner facing surface S7 that binds to the radially outer
facing surface S8 of the inner polyethylene layer 3. The
intermediate barrier layer 5 adheres to the outer 1 and inner 3
layers such that the three layers 1, 3 and 5 remain adhered to
layers 7, 9 and to each other when the tube 10 is subjected to a
stress and strain up to the tube's elastic yield point as measured
in a mechanical tester at a pull rate of about 12 inches per minute
at ambient conditions of 72 degrees F. (22.degree. C.) and 50%
relative humidity. Mechanical testers for measuring such stress and
strain are knowing in the art, an example of which is a Lloyd LRSK
Plus mechanical tester. Elastic yield point is the highest point at
which one or more of the layers of the tubing permanently deforms
or as otherwise defined in "Introduction to Physical Polymer
Science, 4.sup.th Edition," L. H. Sperling (author), John Wiley
& Sons (publisher), 2006, the disclosure of which is
incorporated by reference in its entirety as if fully set forth
herein.
[0046] The layers 1, 3, 5, 7, 9 of such tubing 10 remain adhered to
each other such that the layers do not visually delaminate after
being subjected to submersion in water at 60.degree. C. for 36
hours and subsequently mechanically flattened by manual squeezing
of the tube from its normal round in cross-sectional condition to a
flattened or oval shape cross-sectional shape or condition.
[0047] As shown in FIGS. 1 and 2, the layers 1, 3, 5 are formed
into structurally stable walls that surround and enclose a central
hollow fluid passage 20 through which an aqueous solution is routed
and flows along an axial A direction contacting the radially inner
facing surface S9 of the inner layer 3. The adhesive layers 7, 9
bind and hold the structural layers, inner 3, intermediate 5 and
outer 1 together.
[0048] The inner layer 3 provides a radially inner fluid-contact
surface S9, the thickness, of the inner layer 3 typically ranging
in cross-sectional thickness T1 of between about 0.001 inches
(0.0254 mm) and about 0.025 inches (0.635 mm). The intermediate
layer 5 typically ranges in cross-sectional thickness T3 of between
about 0.001 inches (0.0254 mm) and about 0.025 inches (0.635 mm).
The outer layer 1 typically ranges in cross-sectional thickness T5
of between about 0.001 inches (0.0254 mm) and about 0.025 inches
(0.635 mm). The adhesive layers 7, 9 typically range in
cross-sectional thickness T2, T4 of between about 0.001 inches
(0.0254 mm) and about 0.025 inches (0.635 mm).
[0049] The polyethylene material is preferably a branched
low-density polyethylene (LDPE), such as Westlake EM808, available
from Westlake Chemical Corporation. The polyethylene material can
be a linear low density polyethylene (LLDPE) such as Dowlex 2035G,
available from the Dow Chemical Company. The polyethylene material
can also be a high-density polyethylene (HDPE), such as Chevron
9506 HDPE, Chevron 9406 HDPE, and Chevron 9503 HDPE, available from
Chevron Corporation. The polyethylene material can be a mixture or
blend of two or more of the aforementioned polyethylene
materials.
[0050] The polyurethane elastomer (TPU) is typically the reaction
product of a polyol and isocyanate and usually includes a
combination of hard and soft segment domains. An aromatic
polyether-based TPU or an aliphatic polyether-based TPU can be used
such as a polytetramethyleneglycol-based polyurethane. Such
examples of these TPU's include the Pellethane 2363-90 AE series
available from the Lubrizol Corporation.
[0051] The respective thickness of each layer of tubing 10 can be
controlled by conventional multi-layer extrusion tooling and
equipment and typically includes a die set configured for producing
multi-layer tubing such as a five-layer tube as shown in FIG. 1.
Such a suitable extrusion apparatus is selected so as to provide a
uniform thickness of the layers 1, 3, 5, 7, 9 along the substantial
entirety of the axial length L of all of the layers 1, 3, 5, 7,
9.
[0052] The polymeric materials of which the layers 1, 3, 5, 7, 9
are comprised are preferably selected so as to be manually flexible
along and around the axis A of the tubing. The polymeric materials
are also selected so as to maintain the integrity of the tubing 10
(namely delamination does not occur) and its transparency or
clarity after being subjected to ethylene oxide (EtO) and gamma
irradiation sterilization processes.
[0053] The foregoing description is intended to illustrate and not
limit the scope of the invention, those skilled in the art will
realize that equivalents thereof are contemplated by the
description above and that changes and modifications may be made
thereto without departing from the spirit of the invention, all
such equivalents, changes and modifications falling within the
scope of the claims hereof.
* * * * *