U.S. patent application number 14/362573 was filed with the patent office on 2015-05-07 for construct comprising metalized dicyclopentadiene polymer and method for producing same.
The applicant listed for this patent is Francesco Nettis, Brian Spencer, Zachary Spencer. Invention is credited to Francesco Nettis, Brian Spencer, Zachary Spencer.
Application Number | 20150125641 14/362573 |
Document ID | / |
Family ID | 45218711 |
Filed Date | 2015-05-07 |
United States Patent
Application |
20150125641 |
Kind Code |
A1 |
Nettis; Francesco ; et
al. |
May 7, 2015 |
CONSTRUCT COMPRISING METALIZED DICYCLOPENTADIENE POLYMER AND METHOD
FOR PRODUCING SAME
Abstract
The present invention comprises a method of forming a thin metal
layer on a dicyclopentadiene polymer surface and to constructs
comprising the metalized layer.
Inventors: |
Nettis; Francesco; (London,
GB) ; Spencer; Brian; (Sacramento, CA) ;
Spencer; Zachary; (Sacramento, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nettis; Francesco
Spencer; Brian
Spencer; Zachary |
London
Sacramento
Sacramento |
CA
CA |
GB
US
US |
|
|
Family ID: |
45218711 |
Appl. No.: |
14/362573 |
Filed: |
December 5, 2011 |
PCT Filed: |
December 5, 2011 |
PCT NO: |
PCT/EP2011/071811 |
371 Date: |
January 8, 2015 |
Current U.S.
Class: |
428/35.8 ;
205/167; 427/322; 428/141; 428/462 |
Current CPC
Class: |
C23C 18/1653 20130101;
C23C 18/20 20130101; C23C 18/1651 20130101; C25D 5/54 20130101;
C23C 18/1658 20130101; Y10T 428/24355 20150115; C23C 18/1641
20130101; C23C 18/2066 20130101; Y10T 428/1355 20150115; C23C 18/31
20130101; Y10T 428/31696 20150401; C25D 5/34 20130101; C23C 18/166
20130101 |
Class at
Publication: |
428/35.8 ;
428/462; 428/141; 205/167; 427/322 |
International
Class: |
C23C 18/31 20060101
C23C018/31; C25D 5/34 20060101 C25D005/34; C23C 18/20 20060101
C23C018/20; C25D 5/54 20060101 C25D005/54 |
Claims
1. A method, comprising: providing a base construct having at least
one surface that comprises a dicyclopentadiene polymer; cleaning
the dicyclopentadiene polymer surface with solvent but not
otherwise activating the surface; providing a first aqueous
solution comprising a salt of a first metal and a complexing agent
that forms a complex with the first metal; and contacting the first
aqueous solution at or near the dicyclopentadiene polymer surface
with a second aqueous solution comprising a reducing agent whereby
a layer of the first metal is deposited onto the dicyclopentadiene
surface.
2. The method of claim 1, wherein the base construct is fabricated
of a dicyclopentadiene polymer such that the at least one surface
is a surface of the base construct itself.
3. The method of claim 1, wherein the base construct is fabricated
of a material other than a dicyclopentadiene polymer such that the
at least one surface comprises a layer of a dicyclopentadiene
polymer disposed over a surface of the base construct.
4. The method of claim 1, wherein contacting the first aqueous
solution with the second aqueous solution at or near the
dicyclopentadiene polymer surface comprises simultaneously spraying
the two aqueous solutions at the dicyclopentadiene polymer surface
such that the sprays mix on or near the surface.
5. The method of claim 1, wherein a second metal layer is disposed
over the first metal layer electrolytically or electrolessly.
6. The method of claim 5, wherein depositing the second metal
electrolessly on the first metal comprises contacting, at or near
the first metal layer surface, a third aqueous solution comprising
a salt of the second metal and a complexing agent with a fourth
aqueous solution comprising a reducing agent.
7. The method of claim 6, wherein contacting the third and fourth
solutions comprises spraying the two aqueous solutions at the
dicyclopentadiene polymer surface such that the sprays mix on or
near the surface.
8. The method of claim 5, wherein electrolytically depositing the
second metal onto the first metal comprises: contacting a negative
terminal of a direct current power supply with the first metal
layer; providing an aqueous solution comprising a salt of the
second metal, an electrode made of the second metal immersed in the
aqueous solution or a combination thereof; contacting a positive
terminal of the direct current power supply with the aqueous
solution; contacting the first metal layer with the aqueous
solution; and turning on the power supply.
9. The method of claim 8, wherein contacting the first metal layer
with the aqueous solution comprises spraying the aqueous solution
onto the first metal layer.
10. The method of claim 8, wherein contacting the first metal layer
with the aqueous solution comprises dipping the first metal layer
into the aqueous solution.
11. The method of claim 8, wherein the negative and positive
terminals of a direct current power supply comprise a battery or a
rectifier.
12. The method of claim 5, wherein the second metal is selected
from the group consisting of nickel, zinc, chromium, tin and
copper.
13. The method of claim 5, wherein the second metal is selected
from the group consisting of nickel and zinc.
14. The method of claim 1, wherein the first metal is selected from
the group consisting of silver, copper, nickel, tin, chromium,
cadmium, zinc, cobalt and mixtures or alloys thereof.
15. The method of claim 14, wherein the first metal is silver.
16. A metalized construct made using the method of claim 1.
17. The metalized construct of claim 16, comprising a metalized
polymeric liner for a pressure vessel.
18. The construct of claims 17, wherein the metal layer on the
polymeric liner is smooth textured or rough-textured.
19.-21. (canceled)
22. A pressure vessel comprising a construct according to claim
16.
23. A pressure vessel according to claim 22, wherein the pressure
vessel is suitable for containing CNG.
24. A pressure vessel according to claim 23, having a length in
excess of 6 m.
25. A pressure vessel according to claim 23, having a diameter in
excess of 1 m.
26. A ship comprising one of more pressure vessels as defined in
claim 22.
Description
FIELD
[0001] This invention relates to constructs comprising a metalized
dicyclopentadiene polymer surface and to methods of preparing
such.
BACKGROUND
[0002] Metalized films are a well-established presence in the
modern world. They are used for decorative purposes such as
balloons, holographic images, light-reflecting decals, mirrored
surfaces, sport cards and the like. They also are useful in
packaging of processed fruits and vegetables, beverages, snack
food, coffee and tobacco products due to their resistance to
permeation by oxygen and moisture. They also can serve as
insulators to keep heat and cold in, as in thermos applications,
and to keep heat in and cold and radiation out as in space suit
applications. In the electronics industry, metalized films find use
in capacitors, resistors and other components.
[0003] With regard to pressure vessels, metalized polymeric
surfaces could have substantial utility due to the above-mentioned
barrier-enhancing properties. That is, metallization of a pressure
vessel's polymeric liner could greatly improve the impermeability
of the liner to fluids contained in the pressure vessel. This would
be of particular value when dealing with modern lightweight
pressure vessels comprised almost entirely of polymeric
material.
[0004] As a non-limiting example, a so-called Type IV pressure
vessel comprises a polymeric liner that is fully wrapped with a
filamentous composite, which composite wrap provides the entire
strength of the vessel. Type IV vessels are the lightest of the
four currently approved classes of pressure vessel but are also the
most expensive.
[0005] It is for obvious reasons preferable that the liner of a
Type IV pressure vessel be as impermeable as possible to the fluid
contained therein. While current polymers suitable for use as
pressure vessel liners have differing degrees of impermeability,
some of which are very good, metalizing the inner surface of the
liner would be expected to further enhance impermeability.
[0006] Ancillary benefits that would flow from metallization of
polymeric pressure vessel liners include increased inertness, i.e.
lack of chemical reactivity, of the liner to contained pressurized
fluids and improved insulating properties.
[0007] These benefits would, of course, inure to any type of
pressure vessel that comprises a polymeric liner.
[0008] The problem with metalizing polymeric liners of pressure
vessels is the current method of preparing them.
[0009] The virtually universal method of creating metalized polymer
constructs is vacuum metallization. Vacuum metallization comprises
placing the construct to be metalized into a vacuum chamber along
with a hot ingot of the metal to be coated on the construct. An
electromagnetic field in the chamber directs ions that are
thermally released from the metal surface onto the construct. This
process is, obviously, adequate for preparing metalized polymeric
constructs in which the construct to be metalized is relatively
small such that an appropriately sized vacuum chamber can be
reasonably made. A problem arises, however, when applying this
technique to pressure vessels, in particular to those vessels
intended for the marine transport of compressed fluids, is
contemplated. This is because those vessels are much larger.
[0010] With regard to the marine transport of fluids such as
compressed natural gas (CNG), the economics of the manufacturing
method, an ultimately the transportation method, is critical.
Ocean-going vessels can carry just so much laden weight and the
cost of shipping by sea reflects this fact, the cost being
calculated on the total weight being shipped, that is, the weight
of the product plus the weight of the container vessel in which the
product is being shipped. If the net weight of the product is low
compared to the tare weight of the shipping container, the cost of
shipping per unit mass of product becomes prohibitive. This is
particularly true of the transport of compressed fluids, which
conventionally are transported in steel cylinders that are
extremely heavy compared to weight of contained fluid.
[0011] This problem has been ameliorated somewhat by the advent of
Type III and Type IV pressure vessels. Type III pressure vessels
are comprised of a relatively thin metal liner that is wound with a
filamentous composite wrap, which results in a vessel with the
strength of a steel vessel at a substantial saving in overall
vessel weight. Type IV pressure vessels, as mentioned previously,
comprise a polymeric liner that is likewise wrapped with a
composite filamentous material.
[0012] The use of Type III and Type IV vessels coupled with the
trend to make these vessels very large--cylindrical vessels 18
meters in length and 2.5-3.0 meters in diameter are currently being
fabricated and vessels 30 or more meters in length and 6 or more
meters in diameter are contemplated--has resulted in a major step
forward in optimizing the economics of ocean transport of
compressed fluids.
[0013] As should be readily apparent, the difficulty and expense of
creating vacuum chambers capable of enclosing pressure vessels of
such enormous dimensions would be, to say the least,
prohibitive.
[0014] What would be desirable, then, would be a method of
metalizing polymeric surfaces that does not involve vacuum
metallization. The instant invention provides such method and
constructs prepared using the method.
SUMMARY
[0015] Thus, in one aspect, the instant invention relates to a
construct, comprising:
[0016] at least one exposed surface that comprises a
cyclopentadiene polymer; and
[0017] a thin layer of a first metal contiguous to and in contact
with the cyclopentadiene polymer.
[0018] The construct may also comprise a thin layer of a second
metal contiguous to and in contact with the thin layer of the first
metal.
[0019] In an aspect of this invention the cyclopentadiene polymer
comprises poly(cyclopentadiene) homopolymer.
[0020] In an aspect of this invention, the poly(cyclopentadiene)
homopolymer is formed by ring-opening metathesis polymerization
(ROMP) of cyclopentadiene.
[0021] In an aspect of this invention, the cyclopentadiene polymer
is a copolymer of cyclopentadiene and one or more reactive ethylene
monomers, wherein the mol % of cyclopentadiene in the copolymer is
sufficient to maintain adhesion of the first metal to the
cyclopentadiene polymer.
[0022] In an aspect of this invention, the first metal is selected
from the group consisting of silver, gold, copper, nickel, tin,
chromium, cadmium, zinc, cobalt and alloys thereof.
[0023] In an aspect of this invention, the first metal is
silver.
[0024] In an aspect of this invention, the second metal is selected
from the group consisting of aluminum, nickel, zinc, chromium, tin,
copper and alloys thereof.
[0025] In an aspect of this invention, the second metal is selected
from the group consisting of nickel and zinc.
[0026] In an aspect of this invention, the entire construct
comprises a polycyclopentadiene polymer.
[0027] In an aspect of this invention, the cyclopentadiene polymer
comprises a layer disposed over a construct body made of a material
other than cyclopentadiene polymer but that is capable of adhering
to cyclopentadiene polymer.
[0028] The construct may be a liner of a pressure vessel.
[0029] The construct may be a component of a pressure vessel.
[0030] The pressure vessel may be for containing CNG. CNG may be
contained at a pressure of up to, or in excess of, 250 bar.
[0031] The pressure vessel may have a length in excess of 6 m.
[0032] The pressure vessel may have a diameter in excess of 1
m.
[0033] An aspect of this invention is a method comprising
[0034] providing a construct comprising at least one exposed
surface comprising a dicyclopentadiene polymer;
[0035] cleaning the cyclopentadiene polymer surface with solvent
but not otherwise activating the surface;
[0036] contacting the cyclopentadiene polymer surface with an
aqueous solution comprising a salt of a first metal and a
complexing agent;
[0037] contacting the aqueous solution of the complexed first metal
at the cyclopentadiene polymer surface with an aqueous solution of
a reducing agent wherein a layer of the first metal is deposited on
surface.
[0038] The method may additionally comprise contacting the layer of
first metal with an aqueous solution of a salt of a second metal;
wherein
[0039] the second metal is deposited onto the first metal layer
electrolytically or electrolessly.
[0040] In an aspect of the method of this invention, depositing the
second metal electrolessly comprises contacting an aqueous solution
of the second metal salt and a second complexing agent with an
aqueous solution of a reducing agent at the surface of the first
metal layer.
[0041] In an aspect of the method of this invention,
electrolytically depositing the second metal onto the first metal
comprises applying a negative electrical potential to the first
metal layer; contacting the negatively-charged first metal layer
with a positively-charged aqueous solution of the salt of the
second metal, an electrode made of the second metal or a
combination thereof.
[0042] In an aspect of the method of this invention, contacting the
cyclopentadiene polymer with an aqueous solution comprising a
complexed salt of the first metal comprises spraying the aqueous
solution onto the cyclopentadiene polymer surface.
[0043] In as aspect of method of this invention, contacting the
aqueous solution of the complexed salt of a first metal at the
dicyclopentadiene polymer surface with an aqueous solution of a
reducing agent comprises simultaneously spraying the two aqueous
solutions onto the surface of the cyclopentadiene polymer
surface.
[0044] In an aspect of the method of this invention, applying a
negative electrical charge to the first metal layer and a positive
electrical charge to the aqueous solution of the salt of the second
metal comprises using a battery or a rectifier.
[0045] In an aspect of the method of this invention, contacting the
negatively-charged first metal layer with the positively-charged
aqueous solution of the salt of the second metal comprises spraying
the positively-charged aqueous solution of the salt of the second
metal onto the negatively-charged first metal surface.
[0046] In an aspect of the method of this invention, the first
metal is selected from the group consisting of silver, copper,
nickel, tin, chromium, cadmium, zinc, cobalt and mixtures or alloys
thereof.
[0047] In an aspect of the method of this invention, the first
metal is silver.
[0048] In an aspect of the method of this invention, the second
metal is selected from the group consisting of nickel, zinc,
chromium, tin and copper.
[0049] In an aspect of the method of this invention , the second
metal is selected from the group consisting of nickel and zinc.
[0050] In an aspect of the method of this invention, the exposed
surface that comprises a cyclopentadiene polymer is a liner of a
pressure vessel.
[0051] In an aspect of the method of this invention, the liner has
a rough-textured surface.
[0052] In an aspect of the method of this invention, the liner has
a smooth-textured surface.
[0053] The method may be used to produce the construct previously
described.
DETAILED DESCRIPTION
Discussion
[0054] It is understood that, with regard to this description and
the appended claims, any reference to any aspect of this invention
made in the singular includes the plural and vice versa unless it
is expressly stated or unambiguously clear from the context that
such is not intended.
[0055] As used herein, any term of approximation such as, without
limitation, near, about, approximately, substantially, essentially
and the like, means that the word or phrase modified by the term of
approximation need not be exactly that which is written but may
vary from that written description to some extent. The extent to
which the description may vary will depend on how great a change
can be instituted and have one of ordinary skill in the art
recognize the modified version as still having the properties,
characteristics and capabilities of the word or phrase unmodified
by the term of approximation. In general, but with the preceding
discussion in mind, a numerical value herein that is modified by a
word of approximation may vary from the stated value by .+-.10%,
unless expressly stated otherwise.
[0056] As used herein, the term "optional," "optionally" and the
like refers to a feature of a construct or a step in a method that
may, but need not necessarily, be present to achieve the objective
of the construct design or of the method.
[0057] As used herein, "contiguous" refers to two surfaces that are
adjacent and that are in direct contact or that would be in direct
contact were it not for an intervening layer of another
material.
[0058] As used herein, "impermeable" or "impervious" refers to the
property of a substance that renders it substantially impossible
for a fluid to penetrate to any significant degree into a surface
formed of the first substance.
[0059] As used herein, "inert" refers to the property of a
substance that renders a surface formed of the substance chemically
unreactive toward any components of a fluid that may be contacted
with the surface.
[0060] As used herein, the use of "preferred," "preferably," or
"more preferred," and the like refers to preferences as they
existed at the time of filing of this patent application.
[0061] As used herein, a "fluid" refers to a gas, a liquid or a
mixture of gas and liquid. For example, without limitation, natural
gas as it is extracted from the ground and transported to a
processing center is often a mixture of the gas with liquid
contaminants. Such mixture would constitute a fluid for the
purposes of this invention.
[0062] As used herein, a "construct" refers to any object of any
design or physical form that can be fabricated from a
dicyclopentadiene polymer or any material to which a
dicyclopentadiene polymer can be adhered as a coating layer, either
directly or by means of an intervening primer layer. A "base
construct" refers to a construct to which the metallization method
of this invention is to be applied. A base construct may itself
comprise primarily dicyclopentadiene polymer or it may comprise
some other material entirely, such as, without limitation, another
polymer, a metal, a composite or a ceramic material.
[0063] As used herein, a "dicyclopentadiene polymer" refers to a
polymer prepared by polymerization or curing (the terms are used
interchangeably herein) of DCPD to yield a DCPD homopolymer
(poly(dicyclopentadiene), pDCPD) or curing of a prepolymer
formulation comprising dicyclopentadiene (DCPD) that is at least
92% pure.
[0064] As used herein a "prepolymer formulation" refers a blend of
at least 92% pure DCPD, with one or more reactive ethylene
monomer(s), a polymerization initiator or curing agent plus any
other desirable additives prior to curing.
[0065] As used herein, a reactive ethylene monomer refers to a
molecule that contains at least one ethylenic, i.e., --C.dbd.C--,
bond that is capable of reacting with DCPD under the polymerization
conditions selected. Preferred at present are cyclic ethylenic
monomer such as the norbornenes.
[0066] As used herein, a "thin layer" of a metal refers to a layer
that ranges from essentially an atomic monolayer to a layer that is
about 0.5 .mu.m thick.
[0067] As used herein, a "cleaning solvent" refers to any liquid
that will not dissolve or substantially swell the particular DCPD
polymer used in a surface to be metalized but which can be used to
remove unwanted substances from that surface. Such liquids include,
without limitation, water, alcohols such as, without limitation,
methanol, ethanol and isopropanol; ketones such as acetone and
methyl ethyl ketone; hydrocarbons such as hexane, cyclohexane,
benzene, toluene, etc. Since the scope of DCPD polymers useful for
the fabrication of a construct is quite broad, it is not possible
to list every conceivable solvent that may be used with the polymer
without deleteriously affecting its surface but those skilled in
the art will very easily be able to determine which solvents do and
which solvents do not meet the criteria herein without undue
experimentation.
[0068] "Not otherwise activating the surface" refers to the fact
that a dicyclopentadiene polymer surface of this invention need not
be treated in any manner other than simple solvent cleaning to
remove physical and chemical contaminants. That is, such procedures
as "tinning," which is often used when mirroring of polymeric
surfaces, and plasma activation need not be used with the
dicyclopentadiene polymers of this invention when applying the
first metal layer to the polymer.
[0069] Thus, in an aspect of this invention, a construct is
fabricated of a DCPD polymer or any material that a DCPD polymer
can be adhered to or can be made to adhere to using an intervening
primer layer. A primer layer refers to a layer of material
interspersed between two other materials where the primer is
capable of adhering to both materials, thus binding the two
materials together. In the context of this invention, a primer
would have to be able to adhere to whatever material a construct is
made of and to the DCPD polymer that will eventually be metalized.
Thus, if a base construct is other than a DCPD polymer, the DCPD
polymer is applied to the construct as a coating to form a layer of
the polymer on the exposed surface(s) of the construct wherein the
exposed surfaces may have to be primed for the DCPD polymer to
adhere.
[0070] If the base construct material is a dicyclopentadiene
polymer or other polymeric material, the construct can be
fabricated by any means available to those skilled in the art for
such fabrications including, without limitation, casting, molding
or carving from a solid block of the polymer.
[0071] Other materials of which the base construct can be
fabricated include, without limitation, metals, composites,
ceramics and the like.
[0072] The DCPD will be applied to the base construct as a layer,
either directly or, as mentioned above, with the intervention of a
primer layer.
[0073] The technique of metalizing certain materials has, of
course, long been known. For example the silvering of glass to
create mirrors has been used for over a century. The process
involves the formation of an aqueous silver-ammonia complex from
silver nitrate and ammonium hydroxide. The complex is contacted
with a glass surface and with a second solution of a reducing agent
that reduces the silver complex to elemental silver, which is
deposited on the glass. The ancient technique, however, has
consistently been found not to work with organic polymers.
Therefore, as mentioned previously, the technique of metalizing
organic polymeric surfaces using vacuum metallization has become
the de facto standard.
[0074] It has now been unexpectedly and surprisingly found that the
age-old, simple, inexpensive metallization technique works
extremely well with dicyclopentadiene polymers.
[0075] Since the technique for metallization of glass and other
non-organic polymer surfaces is well-known, it need only be
described in brief.
[0076] As is readily gleaned from the above description of glass
metallization to form mirrors, electroless deposition of a metal
generally requires (1) a source of metal ions; (2) a complexing
agent to keep the metal ions in stable solution; and (3) a reducing
agent. The most well-known example is, of course, the
above-mentioned glass silvering process in which silver nitrate
provides the metal ions, ammonium hydroxide provides the complexing
agent and a variety of substances such as, without limitation, the
so-called "reducing sugars," i.e., without limitation, glucose,
fructose, glyceraldehydes and galactose and other aldehydes such
as, without limitation, formaldehyde, provide the reducing agent.
The choice of reducing agent depends on the metal salt being
reduced; such selection is well within the knowledge of those
skilled in the art and all such substances are within the scope of
this invention.
[0077] pH adjustment of the solution(s) may be required but such is
likewise well within the knowledge of those skilled in the art.
[0078] Many metals other than silver may be deposited using the
above electroless process including, without limitation, gold,
copper, nickel, chrome, cobalt, cadmium, iron, rhodium and tin.
Alloys such as, without limitation, nickel-phosphorus,
nickel-cobalt and nickel-X-phosphorus, where X is a third metal,
can also be deposited.
[0079] Each may require its own complexing agent and, in
particular, its own reducing agent. Complexing agents in addition
to ammonium hydroxide include, without limitation, tetraaza
compounds, ethylenediaminetetraacetic acid, citrates, tartrates,
nitrilotriacetic acid and its alkali salts, gluconates and
triethylamine.
[0080] Reducing agents, in addition to those mentioned above with
regard to silver, include, without limitation, tartrates,
dimethylamineborane, potassium borohydrides, sodium hypophosphite,
thiosulfates, hydrazines, hydroxyamines and glyoxylic acid.
[0081] The selection of a suitable complexing agent and suitable
reducing agent is well within the ability of those skilled in the
art based on the disclosure herein and any such combination of
complexing agent and reducing agent is within the scope of this
invention.
[0082] In the practice of an embodiment of this invention, a DCPD
polymer construct or a construct of another material which has been
coated with a layer of DCPD polymer is first washed with one or
more solvents to remove extraneous contaminants, such as dirt,
oils, moisture and the like. No further treatment of the
dicyclopentadiene polymer surface is required.
[0083] The cleaned DCPD polymer surface is then contacted with a
solution of a salt of a first metal in the presence of a complexing
agent to keep the metal ions in solution and to stabilize the
solution generally. For the purpose of this invention, a metal salt
and complexing agent solution may be referred to simply as the
"complexed (first or second) metal salt" or "complex of the (first
or second) metal salt."
[0084] The surface with the complexed metal salt in contact with it
or at least near the surface is simultaneously or consecutively
contacted with an aqueous solution of a reducing agent. The metal
complex is reduced to afford the zero valence metal which adheres
to the DCPD polymer; i.e., an electrolessly deposited layer of
metal on the surface results.
[0085] In an embodiment of this invention, the metal complex
solution and the reducing solution can be concurrently sprayed onto
the DCPD polymer surface either from separate spray units, the
spray streams being directed so as to intersect at or near the DCPD
polymer surface, or from a single spray unit having separate
reservoirs and spray tip orifices, the two streams being mixed as
they emerge from the spray tip and impinge on the polymer
surface.
[0086] The surface that results from the deposition of the first
metal may be rough-textured or smooth-textured depending on the
texture of the construct, for instance, the interior surface of a
pressure vessel liner may be smooth, which will result in an
essentially mirrored surface, or rough, which will result in a
rough-textured metalized surface.
[0087] The DCPD polymer surface metalized with the first metal may
be used as such or it may be subjected to further deposition of a
second metal.
[0088] The second metal may be disposed on the first metal by the
same electroless process describe above or it may be deposited in
an electrochemical process since the first metal provides the
necessary conductivity for electrodeposition.
[0089] The electrodeposition process contemplated herein is
well-known in the art and need not be extensively described. In
brief, the metalized surface of the previously electrolessly plated
DCPD construct is connected to the negative terminal (cathode) of a
direct current power source, which may simply be a battery but,
more commonly, is a rectifier. The anode, which constitutes the
second metal to be deposited onto the first metal layer, is
connected to the positive terminal (anode) of the power source. The
anode and cathode are electrically connected by means of an
electrolyte solution in which the surface to be metalized a second
time is submersed or bathed as by contact with a spray of the
solution.
[0090] The electrolyte solution contains dissolved metal salts of
the metal to be plated as well as other ions that render the
electrolyte conductive.
[0091] When power is applied to the system, the metallic anode is
oxidized to produce cations of the metal to be deposited and the
positively charged cations migrate to the cathode, i.e., the
metallized surface of the DCPD polymer construct, where they are
reduced to the zero valence state metal and are deposited on the
construct.
[0092] In an embodiment of this invention, a solution of cations of
the metal to be deposited can be prepared and the solution can be
sprayed onto the metalized construct.
[0093] A presently preferred use of the method of this invention is
the metallization of the interior surface of a DCPD polymer liner
of a pressure vessel. The metallization of the DCPD polymer liner
enhances the impermeability of the liner to a fluid that may be
contained in the vessel as well as improving the inertness of the
liner to reaction with any components of the fluid.
[0094] As a non-limiting example, a pressure vessel with a
metalized DCPD liner can be used for the containment and transport
of compressed natural gas, CNG. While pure CNG is a relatively
unreactive fluid, it is most often transported from its source as
raw natural gas. Raw gas refers to natural gas as it comes,
unprocessed, from a well. This fluid contains, of course, natural
gas (methane) itself but also often contains liquids such as
condensate, natural gasoline and liquefied petroleum gas. Water may
also be present. Other gases, either as such or dissolved in the
water may also be present. These other gasses include nitrogen,
carbon dioxide, hydrogen sulfide and helium. Some of these may be
reactive in their own right or may be reactive when dissolved in
water, such as carbon dioxide which produces an acid when dissolved
in water.
[0095] While DCPD liners exhibit a fairly high degree of
imperviousness and inertness to the components of raw gas,
metalizing the surface of the PDCD can greatly enhance these
properties. A method of metalizing the inside of a pressure vessel
is therefore highly beneficial in that the enhanced performance is
achieved with minimal change in the mass of the pressure
vessel--the thickness of the metalized surface will be minimal.
[0096] In the present example, the pressure vessels described
herein can carry a variety of gases, such as raw gas straight from
a bore well, including raw natural gas, e.g. when compressed--raw
CNG or RCNG, or H.sub.2, or CO.sub.2 or processed natural gas
(methane), or raw or part processed natural gas, e.g. with CO.sub.2
allowances of up to 14% molar, H.sub.2S allowances of up to 1,000
ppm, or H.sub.2 and CO.sub.2 gas impurities, or other impurities or
corrosive species. The preferred use, however, is CNG
transportation, be that raw CNG, part processed CNG or clean
CNG--processed to a standard deliverable to the end user, e.g.
commercial, industrial or residential.
[0097] CNG can include various potential component parts in a
variable mixture of ratios, some in their gas phase and others in a
liquid phase, or a mix of both. Those component parts will
typically comprise one or more of the following compounds:
C.sub.2H.sub.6, C.sub.3H.sub.8, C.sub.4H.sub.10, C.sub.5H.sub.12,
C.sub.7H.sub.16, C.sub.8H.sub.18C.sub.9+ hydrocarbons, CO.sub.2 and
H.sub.2S, plus potentially toluene, diesel and octane in a liquid
state, and other impurities/species.
[0098] These and other features of the present invention may be
used independently or in combination, within the scope of the
claims and/or the present disclosure.
[0099] The present invention has therefore been described above
purely by way of example. Modifications in detail may be made to
the invention within the scope of the claims appended hereto.
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