Title: Electrical cable and method of making same
Abstract: An electrical cable includes a first layer, a second layer, and a tie layer, disposed between the first layer and the second layer, for bonding the first layer to the second layer. A method of making an electrical cable includes applying a tie layer to an inner layer, the tie layer being miscible with the inner layer, and bonding an outer layer to the tie layer via one of a chemical reaction therebetween and a physical bond therebetween. An electrical cable includes a first layer, a second layer immiscible with the first layer, and a tie layer disposed between the first layer and the second layer, wherein the tie layer is miscible with the first layer and is capable of bonding with the second layer.
Patent Number: 7,005,583 Issued on 02/28/2006 to Varkey, et al.
| Inventors:
|
Varkey; Joseph P. (Missouri City, TX);
Kim; Byong J. (Sugar Land, TX);
Wijnberg; Willem A. (Houston, TX);
Yeh; Chun-Te (Sugar Land, TX)
|
| Assignee:
|
Schlumberger Technology Corporation (Sugar Land, TX)
|
| Appl. No.:
|
423716 |
| Filed:
|
April 25, 2003 |
| Current U.S. Class: |
174/120R |
| Current Intern'l Class: |
H01B 7/00 (20060101) |
| Field of Search: |
174/120 R,120.SR,117.A
|
References Cited [Referenced By]
U.S. Patent Documents
| 4132857 | Jan., 1979 | Scarola et al.
| |
| 4327248 | Apr., 1982 | Campbell.
| |
| 5414217 | May., 1995 | Neuroth et al.
| |
| 5426264 | Jun., 1995 | Livingston et al.
| |
| 5734773 | Mar., 1998 | Teshima et al.
| |
| 5942731 | Aug., 1999 | Rogerson.
| |
| 6262182 | Jul., 2001 | Eagan et al.
| |
| 6359230 | Mar., 2002 | Hildreth.
| |
| 2003/0044606 | Mar., 2003 | Iskander.
| |
| Foreign Patent Documents |
| 2144901 | Mar., 1985 | GB.
| |
Primary Examiner: Nguyen; Chau N.
Attorney, Agent or Firm: Nava; Robin, Echols; Brigitte L.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority from Provisional Application 60/409,563, filed
Sep. 10, 2002, which is incorporated herein by reference.
Claims
What is claimed is:
1. An electrical cable, comprising:
a first layer comprising a methylpentene co-polymer;
a second layer comprising a material selected from the group consisting of an
epoxy-based potting material, a nitrile-based potting material, an ester-based
potting material, and a urethane-based potting material; and
a tie layer, disposed between the first layer and the second layer, for bonding
the first layer to the second layer, the tie layer comprising the methylpentene
co-polymer grafted with one of an unsaturated anhydride or a silane.
2. An electrical cable, comprising:
a first layer comprising a fluoropolymer;
a second layer comprising a material selected from the group consisting of an
epoxy-based potting material, a nitrile-based potting material, an ester-based
potting material, and a urethane-based potting material; and
a tie layer comprising the fluoropolymer grafted with a material selected from
the group consisting of a carboxyl, a carboxyl salt, a carboxyl acid, or an unsaturated
anhydride.
3. An electrical cable comprising:
a first layer comprising methylpentene co-polymer;
a second layer comprising a material selected from the group consisting of a
metal, nylon, a polyphenylene sulfide material, polyurethane, and ethylene vinyl
alcohol co-polymer; and
a tie layer comprising methylpentene co-polymer grafted with an unsaturated anhydride.
4. An electrical cable comprising:
a first layer comprising methylpentene co-polymer;
a second layer comprising one of a metal and ethylene vinyl alcohol co-polymer;
and
a tie layer comprising methylpentene co-polymer grafted with a material selected
from the group consisting of an acrylic acid, a carboxyl acid, and a silane.
5. An electrical cable comprising:
a first layer comprises ethylene tetrafluoroethylene;
a second layer comprises a material selected from the group consisting of a metal,
nylon, a polyphenylene sulfide material, and ethylene vinyl alcohol co-polymer;
and
a tie layer comprises ethylene tetrafluoroethylene grafted with a material selected
from the group consisting of a carboxyl, a carboxyl salt, a carboxyl acid, and
an unsaturated anhydride.
6. An electrical cable, comprising:
a first layer comprising a mixture of ethylene propylene co-polymer and an ethylene
propylene co-polymer grafted with an unsaturated anhydride and a second layer bonded
to the first layer, the second layer comprises nylon.
7. An electrical cable, comprising:
a first layer comprising a material selected from the group consisting of polyethylene
and ethylene propylene co-polymer; and
a second layer bonded to the first layer, the second layer comprising a mixture
of nylon and a material selected from the group consisting of a polyethylene grafted
with an unsaturated anhydride and an ethylene propylene co-polymer grafted with
an unsaturated anhydride.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to electrical cabling and, more particularly, to an electrical
cable having a tie layer disposed between a first layer and a second layer and
a method for manufacturing same.
2. Description of Related Art
Many electrical cables, such as seismic, oceanographic, and wireline cables,
are sometimes used in corrosive environments at pressures that may range from atmospheric
to very high and at temperatures that may range from arctic to very high. Accordingly,
the insulating and jacketing materials used in such cables must be able to withstand
these harsh environments, as well as have the dielectric and capacitive properties
desirable for the cables. Polymers belonging to the polyolefin family, such as
polyethylene, polypropylene, and polyethylene propylene co-polymer, and polymers
belonging to the fluoropolymer family, such as ethylene tetrafluoroethylene, fluorinated
ethylene propylene, polytetrafluoroethylene/perfluoromethylvinylether co-polymer,
and perfluoroalkoxy polymer, are commonly used as insulating materials in these cables.
It is often desirable to have multiple layers of insulating and jacketing materials
surrounding the conductors in seismic, oceanographic, and other electrical cables
so that the cable will have the desired electrical properties and be able to withstand
the environment in which it is used. Generally, it is also desirable to bond or
"pot" the insulating layers to a connector or the like within a cable termination
to inhibit moisture or other contaminants from penetrating between the insulating
layers and/or from entering the connector. Polyolefin and fluoropolymer materials,
however, may not bond well to conventional epoxy, nitrile, ester, or urethane-based
potting compounds. In general, only cyanoacrylate adhesives are effective in bonding
these materials in electrical cable applications. Cyanoacrylate adhesives, however,
may be brittle and may be unable to withstand the pressure and/or temperature cycling
encountered by such cables.
Primers have been used to enhance the bonding, but they are not as effective
on polyolefin and fluoropolymer materials as on other polymeric materials. Surface
treatments, such as flame treatment, corona discharge, and solvent etching, have
been used to enhance the bonding characteristics of polyolefin and fluoropolymer
materials. These techniques, however, may be time consuming and impractical in
certain situations. For example, it may be difficult to apply these treatments
to large numbers of small, insulated conductors that are bundled together. As a
result, such surface treatments may provide results that are less than optimal.
Multiple layers of different potting materials have also been used to overcome
the bonding problems of polyolefin and fluoropolymer materials. However, this process
has proven to be difficult and time consuming. In some situations the layers of
potting material may not effectively bond together, which provides the potential
for moisture ingression. Further, a longer length cable termination results from
this process, which is generally undesirable.
When the insulating layer and the jacketing layer are not properly bonded together,
such as in a cable having a polyvinylchloride insulating layer with a nylon jacketing
layer, a small, often microscopic void or voids may exist between the insulating
layer and the jacketing layer, which may allow wicking of fluids therein. Moreover,
mechanical flexing of such layers having a void or voids therebetween may cause
wrinkling and separation of the layers, inhibiting the usefulness of the cable.
Some conventional electrical cables have utilized insulating and jacketing materials
that have better bonding characteristics than polyolefin and fluoropolymer materials,
such as nylon and thermoplastic polyester elastomers (e.g., Hytrel®, manufactured
by E. I. du Pont de Nemours and Company of Wilmington, Del., U.S.A.). However,
such materials generally have electrical properties that are inferior to polyolefin materials.
The present invention is directed to overcoming, or at least reducing, the effects
of one or more of the problems set forth above.
BRIEF SUMMARY OF THE INVENTION
In one aspect of the present invention, an electrical cable is provided. The
electrical
cable includes a first layer, a second layer, and a tie layer, disposed between
the first layer and the second layer, for bonding the first layer to the second layer.
In another aspect of the present invention, a method of making an electrical
cable
is provided. The method includes applying a tie layer to an inner layer, the tie
layer being miscible with the inner layer, and bonding an outer layer to the tie
layer via one of a chemical reaction therebetween and a physical bond therebetween.
In yet another aspect of the present invention, an electrical cable is provided.
The electrical cable includes a first layer, a second layer immiscible with the
first layer, and a tie layer disposed between the first layer and the second layer,
wherein the tie layer is miscible with the first layer and is capable of bonding
with the second layer.
In another aspect of the present invention, an electrical cable is provided.
The
electrical cable includes a first layer and a second layer bonded to the first
layer comprising a polymer and at least one of an unsaturated anhydride, an acrylic
acid, a carboxyl acid, a silane, and a vinyl acetate.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention may be understood by reference to the following description taken
in conjunction with the accompanying drawings, in which the leftmost significant
digit in the reference numerals denotes the first figure in which the respective
reference numerals appear, and in which:
FIG. 1 is a cross-sectional view of a first illustrative embodiment of an electrical
cable according to the present invention;
FIG. 2 is a cross-sectional view of the electrical cable of FIG. 1 potted to
a connector;
FIG. 3 is a cross-sectional view of the electrical cable of FIG. 1 having a
polymeric jacketing layer;
FIG. 4 is a cross-sectional view of the electrical cable of FIG. 1 having a
metallic jacketing layer;
FIG. 5 is a cross-sectional view of the electrical cable of FIG. 3 potted to
a connector; and
FIG. 6 is a cross-sectional view of a second illustrative embodiment of a cable
according to the present invention.
While the invention is susceptible to various modifications and alternative
forms, specific embodiments thereof have been shown by way of example in the drawings
and are herein described in detail. It should be understood, however, that the
description herein of specific embodiments is not intended to limit the invention
to the particular forms disclosed, but, on the contrary, the intention is to cover
all modifications, equivalents, and alternatives falling within the spirit and
scope of the invention as defined by the appended claims.
DETAILED DESCRIPTION OF THE INVENTION
Illustrative embodiments of the invention are described below. In the
interest of clarity, not all features of an actual implementation are described
in this specification. It will of course be appreciated that in the development
of any such actual embodiment, numerous implementation-specific decisions must
be made to achieve the developer's specific goals, such as compliance with system-related
and business-related constraints, which will vary from one implementation to another.
Moreover, it will be appreciated that such a development effort might be complex
and time-consuming, but would nevertheless be a routine undertaking for those of
ordinary skill in the art having the benefit of this disclosure.
FIG. 1 depicts, in cross-section, a first illustrative embodiment of an electrical
cable according to the present invention. In the illustrated embodiment, an electrical
cable
100 includes a plurality of electrical conductors
102, an insulating
layer
104, and a tie layer
106. The plurality of electrical conductors
102 may be individually-insulated conductors (e.g., a plurality of twisted
pairs), strands of an electrical conductor, or a combination of both. The insulating
layer
104 electrically isolates the plurality of electrical conductors
102
and is disposed between the plurality of electrical conductors
102 and the
tie layer
106. The insulating layer
104 may be made of any chosen
polyolefin, polyolefin co-polymer, or fluoropolymer material suitable for electrically
isolating the plurality of electrical conductors
102, e.g., polyethylene,
polypropylene, ethylene propylene co-polymer, ethylene vinyl acetate, methylpentene
co-polymer, e.g., TPX® from Mitsui Chemicals America, Inc. of Purchase, New
York, U.S.A., polytetrafluoroethylene/perfluoromethylvinylether co-polymer, ethylene
tetrafluoroethylene, perfluoroalkoxy polymer, or fluorinated ethylene propylene.
It is often desirable to bond potting material layers to insulating layers in
electrical cable terminations or to bond jacketing layers to insulating layers.
However, polyolefin and fluoropolymer materials are not readily bonded, except
with cyanoacrylate adhesives, and such adhesives are often brittle and are not
capable of withstanding the temperature and/or pressure cycling requirements of
some electrical cables, such as seismic, oceanographic, and wireline cables. Accordingly,
the illustrated embodiment shown in FIG. 1 includes the tie layer
106, which
is miscible with the insulating layer
104 and readily bonds to potting materials
and jacketing layer materials. In various embodiments, the tie layer
106
may comprise a material in the same polymer family as the insulating layer
104
that has been modified to include a functional group capable of interacting physically
(e.g., via polar bonds) or chemically (e.g., via a chemical reaction) with the
potting material or jacketing layer materials.
For example, as shown in FIG. 2, a potting material layer
202 is disposed
between the tie layer
106 and, for example, a connector
204 for bonding
the cable
100 to the connector
204. In various embodiments, the potting
material
202 may comprise epoxy-, nitrile-, ester-, or urethane-based potting
materials. In on embodiment, the insulating layer
104 comprises polyethylene
and the tie layer
106 comprises a modified polyethylene material grafted
with an unsaturated anhydride (e.g., maleic anhydride or norbornene-2, 3-dicarboxylic
anhydride), an acrylic acid, a carboxyl acid, or a silane. In another embodiment,
the insulating layer
104 comprises polypropylene and the tie layer
106
comprises a modified polypropylene material grafted with an unsaturated anhydride,
an acrylic acid, a carboxyl acid, or a silane.
In yet another embodiment, the insulating layer
104 comprises ethylene-propylene
co-polymer and the tie layer
106 comprises a modified ethylene propylene
co-polymer material grafted with an unsaturated anhydride, an acrylic acid, a carboxyl
acid, or a silane. In still another embodiment, the insulating layer
104
comprises ethylene vinyl acetate and the tie layer
106 comprises an ethylene
vinyl acetate material modified with, for example, a carboxyl acid or an acrylic
acid. In yet another embodiment, the insulating layer
104 comprises methylpentene
co-polymer and the tie layer
106 comprises a modified methylpentene co-polymer
material grafted with an unsaturated anhydride or a silane.
Still referring to FIG. 2, it may be desirable for the insulating layer
104
to comprise a fluoropolymer. In one embodiment, the insulating layer
104
comprises ethylene tetrafluoroethylene and the tie layer
106 comprises a
modified ethylene tetrafluoroethylene material grafted with a carboxyl, a carboxyl
salt, a carboxyl acid, or an unsaturated anhydride.
Alternatively, it may be desirable to bond the insulating layer
104
to a polymeric jacketing layer
302, comprising a material such as, for example,
nylon, polyphenylene sulfide, polyurethane, or ethylene vinyl alcohol co-polymer,
as shown in FIG.
3. Such jacketing materials are advantageous in that they
are resistant to attack by many chemicals and, thus, are capable of protecting
the insulating layer
104 from degradation. In various embodiments, the insulating
layer
104 comprises polyethylene and the jacketing layer
302 comprises
nylon, polyphenylene sulfide modified with a functionalized polyethylene group
(e.g., Fortron SKX-382®, provided by Ticona of Summit, N.J. U.S.A.), polyurethane,
or ethylene vinyl alcohol co-polymer. In such embodiments, the tie layer
106
may comprise materials as shown in Table 1.
| TABLE 1 |
|
| Tie layer 106 materials for an insulating |
| layer 104 comprising polyethylene. |
| |
Jacketing layer 302 |
Tie layer 106 |
| |
|
| |
Nylon |
Polyethylene grafted with an unsaturated |
| |
|
anhydride, an acrylic acid, a carboxyl |
| |
|
acid, or a silane. Ethylene vinyl acetate |
| |
|
grafted with an unsaturated anhydride. |
| |
Polyethylene modified |
Polyethylene grafted with an unsaturated |
| |
polyphenylene sulfide |
anhydride, an acrylic acid, a carboxyl |
| |
|
acid, or a silane. |
| |
Polyurethane |
Polyethylene or ethylene vinyl acetate |
| |
|
grafted with an unsaturated anhydride. |
| |
Ethylene vinyl alcohol |
Polyethylene grafted with an unsaturated |
| |
co-polymer |
anhydride, an acrylic acid, a carboxyl |
| |
|
acid, or a silane. Ethylene vinyl acetate |
| |
|
grafted with an unsaturated anhydride. |
| |
|
In other embodiments, the insulating layer
104 comprises polypropylene
and the jacketing layer
302 comprises nylon, polyphenylene sulfide modified
with a polyethylene functional group, polyurethane, or ethylene vinyl alcohol co-polymer.
In such embodiments, the tie layer
106 may comprise materials as shown in
Table 2.
| TABLE 2 |
|
| Tie layer 106 materials for an insulating |
| layer 104 comprising polypropylene. |
| Jacketing layer 302 |
Tie layer 106 |
|
| Nylon |
Polypropylene grafted with an unsaturated |
| |
anhydride, an acrylic acid, a carboxyl acid, |
| |
or a silane. |
| Polyethylene modified |
Polypropylene grafted with an unsaturated |
| polyphenylene sulfide |
anhydride, an acrylic acid, a carboxyl acid, |
| |
or a silane. |
| Polyurethane |
Polypropylene grafted with an unsaturated |
| |
anhydride. |
| Ethylene vinyl alcohol |
Polypropylene grafted with an unsaturated |
| co-polymer |
anhydride, an acrylic acid, a carboxyl acid, |
| |
or a silane. |
|
Alternatively, the insulating layer
104 may comprise ethylene
propylene co-polymer and the jacketing layer
302 may comprise nylon, polyphenylene
sulfide modified with a polyethylene functional group, polyurethane, or ethylene
vinyl alcohol co-polymer. In such embodiments, the tie layer
106 may comprise
materials as shown in Table 3.
| TABLE 3 |
|
| Tie layer 106 materials for an insulating |
| layer 104 comprising ethylene propylene co-polymer. |
| Jacketing layer 302 |
Tie layer 106 |
|
| Nylon |
Ethylene propylene co-polymer grafted with |
| |
an unsaturated anhydride, an acrylic acid, |
| |
a carboxyl acid, or a silane. |
| Polyethylene modified |
Ethylene propylene co-polymer grafted with |
| polyphenylene sulfide |
an unsaturated anhydride, an acrylic acid, |
| |
a carboxyl acid, or a silane. |
| Polyurethane |
Ethylene propylene co-polymer grafted with |
| |
an unsaturated anhydride. |
| Ethylene vinyl alcohol |
Ethylene propylene co-polymer grafted with |
| co-polymer |
an unsaturated anhydride, an acrylic acid, |
| |
a carboxyl acid, or a silane. |
|
In other embodiments, the insulating layer
104 comprises ethylene vinyl
acetate and the jacketing layer
302 comprises nylon, polyphenylene sulfide
modified with a polyethylene functional group, polyurethane, or ethylene vinyl
alcohol co-polymer. In such embodiments, the tie layer
106 may comprise
materials as shown in Table 4.
| TABLE 4 |
|
| Tie layer 106 materials for an insulating |
| layer 104 comprising ethylene vinyl acetate. |
| Jacketing layer 302 |
Tie layer 106 |
|
| Nylon |
Ethylene vinyl acetate grafted with an unsaturated |
| |
anhydride, an acrylic acid, or a carboxyl acid. |
| Polyethylene modified |
Ethylene vinyl acetate grafted with an unsaturated |
| polyphenylene sulfide |
anhydride, an acrylic acid, a carboxyl acid, or a |
| |
silane. |
| Polyurethane |
Ethylene vinyl acetate grafted with an unsaturated |
| |
anhydride. |
| Ethylene vinyl alcohol |
Ethylene vinyl acetate grafted with an unsaturated |
| co-polymer |
anhydride, an acrylic acid, a carboxyl acid, or a |
| |
silane. |
|
In yet other embodiments, the insulating layer
104 comprises methylpentene
co-polymer and the jacketing layer
302 comprises nylon, polyphenylene sulfide
modified with a polyethylene functional group, polyurethane, or ethylene vinyl
alcohol co-polymer. In such embodiments, the tie layer
106 may comprise
materials as shown in Table 5.
| TABLE 5 |
|
| Tie layer 106 materials for an insulating |
| layer 104 comprising methylpentene co-polymer. |
| |
Jacketing layer 302 |
Tie layer 106 |
| |
|
| |
Nylon |
Methylpentene co-polymer grafted with an |
| |
|
unsaturated anhydride. |
| |
Polyethylene modified |
Methylpentene co-polymer grafted with an |
| |
polyphenylene sulfide |
unsaturated anhydride. |
| |
Polyurethane |
Methylpentene co-polymer grafted with an |
| |
|
unsaturated anhydride. |
| |
Ethylene vinyl alcohol |
Methylpentene co-polymer grafted with an |
| |
co-polymer |
unsaturated anhydride, an acrylic acid, |
| |
|
a carboxyl acid, or a silane. |
| |
|
In other embodiments, the insulating layer
104 comprises ethylene tetrafluoroethylene
and the jacketing layer
302 comprises nylon, polyphenylene sulfide modified
with a polyethylene functional group, or ethylene vinyl alcohol co-polymer. In
such embodiments, the tie layer
106 may comprise ethylene tetrafluoroethylene
grafted with a carboxyl, a carboxyl salt, a carboxyl acid, or an unsaturated anhydride,
e.g., Tefzel HT-2202, provided by E. I. du Pont de Nemours and Company.
Alternatively, it may be desirable to bond the insulating layer
104
to a metallic jacketing layer
402, comprising a material such as, for example,
aluminum, stainless steel, and tin-plated steel, as shown in FIG.
4. Such
jacketing materials are advantageous in that they are capable of protecting the
insulating layer
104 from mechanical damage. In various embodiments having
a metallic jacketing layer
402, the insulating layer
104 may comprise
polyethylene, polypropylene, ethylene propylene co-polymer, methylpentene co-polymer,
or ethylene tetrafluoroethylene. In such embodiments, the tie layer
106
may comprise the material of the insulating layer
104 (e.g., polyethylene,
polypropylene, ethylene propylene co-polymer, methylpentene co-polymer, or ethylene
tetrafluoroethylene) grafted with an unsaturated anhydride, an acrylic acid, a
carboxyl acid, or a silane.
It may be desirable in certain applications to pot or attach the cable
100
of FIG. 3 or FIG. 4 to a connector. Accordingly, FIG. 5 illustrates a potting layer
502 disposed between the jacketing layer
302 and a connector
504.
While the jacketing layer
302 is illustrated in FIG. 5 as comprising a polymeric
material, the present invention is not so limited. Rather, the connector
504
may be attached via the potting layer
502 to a metallic jacketing layer,
such as the metallic jacketing layer
402 of FIG.
4. The potting layer
502 may comprise a material corresponding to the potting layer
202
of FIG. 2, or another material.
It may also be desirable in certain situations to incorporate a tie layer material,
such as that of the tie layer
106, into the insulating layer
104
(shown in FIGS. 1-5) and/or the jacketing layer
302 (shown in FIGS.
3
and
5). Accordingly, FIG. 6 depicts a second illustrative embodiment of
a cable
600 according to the present invention. The cable
600 comprises
a plurality of conductors
602, which may correspond to the conductors
102
of FIGS. 1-5. The cable
600 further comprises an insulating layer
604
disposed around the conductors
602 and a jacketing layer
606 disposed
on the insulating layer
604.
Still referring to FIG. 6, in one embodiment, a tie layer material is included
in one of the insulating layer
604 and the jacketing layer
606 as
a mixture. In various embodiments, one of the insulating layer
604 and the
jacketing layer
606 may comprise a polymer and at least one of an unsaturated
anhydride, an acrylic acid, a carboxyl acid, a silane, and a vinyl acetate. In
one embodiment, one of the insulating layer
604 and the jacketing layer
606 comprises nylon and the other layer comprises a mixture of polyethylene
and a polyethylene grafted with an unsaturated anhydride. In another embodiment,
one of the insulating layer
604 and the jacketing layer
606 comprises
nylon and the other layer comprises a mixture of ethylene propylene co-polymer
and an ethylene propylene co-polymer grafted with an unsaturated anhydride.
In yet another embodiment, one of the insulating layer
604 and the jacketing
layer
606 comprises polyethylene and the other layer comprises a mixture
of nylon and a polyethylene grafted with an unsaturated anhydride. In another embodiment,
one of the insulating layer
604 and the jacketing layer
606 comprises
ethylene propylene co-polymer and the second layer comprises a mixture of nylon
and an ethylene propylene co-polymer grafted with an unsaturated anhydride. In
each of the embodiments relating to FIG. 6, the insulating layer
604 or
the jacketing layer
606 may comprise a polymer grafted with an unsaturated
anhydride within a range of about 20 weight percent of the layer to about 80 weight
percent of the layer containing the mixture.
The particular embodiments disclosed above are illustrative only, as the invention
may be modified and practiced in different but equivalent manners apparent to those
skilled in the art having the benefit of the teachings herein. Furthermore, no
limitations are intended to the details of construction or design herein shown,
other than as described in the claims below. It is therefore evident that the particular
embodiments disclosed above may be altered or modified and all such variations
are considered within the scope and spirit of the invention. Accordingly, the protection
sought herein is as set forth in the claims below.
*
