U.S. patent application number 15/610666 was filed with the patent office on 2017-09-21 for method for obtaining a cooking vessel having a colored hard-anodized outer face.
The applicant listed for this patent is SEB S.A.. Invention is credited to Martin Rubio, Stephane Tuffe.
Application Number | 20170268121 15/610666 |
Document ID | / |
Family ID | 47997568 |
Filed Date | 2017-09-21 |
United States Patent
Application |
20170268121 |
Kind Code |
A1 |
Rubio; Martin ; et
al. |
September 21, 2017 |
Method for Obtaining a Cooking Vessel Having a Colored
Hard-Anodized Outer Face
Abstract
Provided is a method for obtaining a cooking vessel comprising
the following steps: producing a container having an aluminium
outer face and an inner face, carrying out hard anodization of at
least the outer face of the container. At least one colouring step
is carried out on the anodized outer face following hard
anodization, said colouring step employing at least one
water-soluble anthraquinone organic dye. Also provided is a
culinary article or an electric cooking appliance comprising a
cooking vessel obtained by the above method.
Inventors: |
Rubio; Martin; (Rumilly,
FR) ; Tuffe; Stephane; (Cognin, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SEB S.A. |
Ecully |
|
FR |
|
|
Family ID: |
47997568 |
Appl. No.: |
15/610666 |
Filed: |
June 1, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14382699 |
Sep 3, 2014 |
9714475 |
|
|
PCT/FR2013/050460 |
Mar 4, 2013 |
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15610666 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A47J 37/105 20130101;
A47J 27/002 20130101; B21C 37/06 20130101; B65D 25/02 20130101;
A47J 37/10 20130101; C25D 11/243 20130101; C25D 11/16 20130101;
A47J 36/02 20130101; C23C 2/00 20130101; A47J 36/025 20130101; B65D
25/34 20130101; C23C 2/02 20130101 |
International
Class: |
C25D 11/24 20060101
C25D011/24; A47J 27/00 20060101 A47J027/00; C25D 11/16 20060101
C25D011/16; B65D 25/02 20060101 B65D025/02; B65D 25/34 20060101
B65D025/34; C23C 2/02 20060101 C23C002/02; B21C 37/06 20060101
B21C037/06; C23C 2/00 20060101 C23C002/00; A47J 36/02 20060101
A47J036/02; A47J 37/10 20060101 A47J037/10 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 7, 2012 |
FR |
1252086 |
Claims
1. A process of obtaining a cooking vessel, consisting of the
following steps: producing a container with an exterior surface
made of aluminum and an interior surface, performing a hard
anodization on at least the exterior surface of the container to
obtain a hard anodized layer, wherein at least one coloring step is
performed on the anodized exterior surface after the hard
anodization is performed, said coloring step uses at least one
water-soluble anthraquinone organic dye, and said coloring step
uses a coloring bath containing anthraquinone organic compounds
which will precipitate and be trapped inside pores of the hard
anodized layer to obtain coloring on the exterior anodized
surface.
2. The process of obtaining a cooking vessel described in claim 1,
wherein the coloring step uses an immersion in an aqueous solution
of one or more water-soluble anthraquinone organic compound(s).
3. The process of obtaining a cooking vessel described in claim 1,
including a step in which a PTFE coating is applied to the interior
surface of the container, and wherein the step in which hard
anodization is performed on the exterior surface of the container
occurs after the step in which a PTFE coating is applied to the
interior surface of the container.
4. The process of obtaining a cooking vessel described in claim 3,
including a step in which preliminary hard anodization is performed
on the exterior surface and on the interior surface of the
container prior to the step in which the PTFE coating is applied to
the interior surface of the container, and wherein the step in
which hard anodization is performed on the exterior surface of the
container occurs after an etching step on the exterior surface of
the container, following the PTFE coating step on the interior
surface of the container.
5. The process of obtaining a cooking vessel described in claim 1,
wherein the hard anodization step and the coloring step are
performed on the interior surface and the exterior surface of the
container.
6. The process of obtaining a cooking vessel described in claim 1,
wherein the hard anodization is performed at a temperature of
greater than or equal to 0.degree. C.
7. The process of obtaining a cooking vessel described in claim 6,
wherein the hard anodization is performed at a temperature of less
than or equal to 17.degree. C.
8. The process of obtaining a cooking vessel described in claim 1,
wherein the hard anodization is performed at a temperature of
between 5.degree. C. and 12.degree. C.
9. A cooking vessel comprising a container with an exterior surface
made of aluminium and an interior surface, wherein at least the
exterior surface is anodized, wherein the exterior surface is hard
anodized to obtain a hard anodized layer and the hard anodized
exterior surface is colored with at least one water-soluble
anthraquinone organic dye, using anthraquinone organic compounds
trapped inside pores of the hard anodized layer, to obtain coloring
on the anodized external surface.
10. The cooking vessel according to claim 9, wherein the anodized
layer is at least equal to 25 .mu.m in thickness.
11. The cooking vessel described in claim 10, wherein the container
is obtained by stamping a substrate with at least one surface made
of aluminum.
12. The cooking vessel described in claim 11, wherein the substrate
has two aluminum surfaces.
13. The cooking vessel described claim 11, wherein the substrate is
made of solid aluminum.
14. The cooking vessel described in claim 11, wherein the substrate
is formed by a laminate with one aluminum surface and one stainless
steel surface.
15. The cooking vessel described in claim 10, wherein the container
is made of cast aluminum.
16. The cooking vessel described in claim 10, wherein the exterior
surface of the container has one of a brushed or microbead-blasted
surface.
17. The cooking vessel described in claim 10, wherein the container
has at least one insert made of ferromagnetic material.
18. Culinary item consisting of a cooking vessel and a handling
instrument attached to said cooking vessel by at least one rivet or
by welding, wherein said cooking vessel conforms to claim 10.
19. Electric cooking appliance, consisting of a cooking vessel
combined with a heat source, wherein said cooking vessel conforms
to claim 10.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 14/382,699 which is the United States national
phase of International Application No. PCT/FR2013/050460 filed Mar.
4, 2013, and claims priority to French Patent Application No.
1252086 filed Mar. 7, 2012, the disclosures of which are hereby
incorporated in their entirety by reference.
FIELD OF THE INVENTION
[0002] This invention pertains to the technical field of cooking
appliances and utensils with a cooking vessel.
[0003] This invention pertains more specifically, but not
exclusively, to culinary items such as saucepans, frying pans and
woks, as well as electric cooking appliances with a container for
holding food.
DESCRIPTION OF RELATED ART
[0004] There is a known method, as described in Document GB 1 099
486, of producing cooking vessels made of aluminum with a
hard-anodized layer on the surface. This surface layer may, if
desired, be colored. The surface thus obtained is easier to clean
than a non-anodized surface. However, the surface thus obtained is
not as easy to clean as a surface with a non-stick layer.
[0005] Document EP 0 424 072 and Document EP 0 902 105 describe the
creation of cooking vessels with a non-stick coating such as PTFE
on an aluminum frame with hard anodization. The hard anodization is
therefore done prior to the PTFE coating. This arrangement improves
the PTFE coating's resistance to wear and tear and to scratching.
Ordinarily, the PTFE coating is used primarily to coat the interior
surface of cooking vessels, due to the limited mechanical
durability of this type of coating.
[0006] There is a known method, described in Document EP 1 894 502,
of producing a sol-gel coating on at least one surface of a
culinary item consisting of an aluminum or aluminum-alloy frame,
and this frame can be made of anodized aluminum. That document
describes an anodized layer thickness of between 5 and 100 .mu.m.
The other surface may, if desired, be coated in PTFE. The sol-gel
coating improves the cooking vessel's resistance to the dishwasher,
as well as the cooking vessel's flame resistance.
[0007] There is a known method, described in Patent Application FR
10 59522, of producing a cooking vessel with a colored
hard-anodized exterior surface, for which a sol-gel coating is
applied to the hard-anodized exterior surface. This procedure
produces cooking vessels for which the coloring on the exterior
surface is of a durable nature, and that are resistant to the
washing agents used in dishwashers and to flame. One disadvantage
of the production method described resides in the complexity of the
process implemented, which requires many steps.
[0008] One objective of this invention is to offer coloring of the
anodized exterior surface of a cooking vessel, which is durable,
without requiring a protective coating.
[0009] Another objective of this invention is to provide coloring
for the anodized exterior surface of a cooking vessel, which is
resistant to the flames used for cooking or to any other source of
heat used for cooking, without requiring a protective coating.
[0010] An additional objective of this invention is to provide
coloring for the anodized exterior surface of a cooking vessel,
which is compatible with a PTFE coating on the interior surface of
said cooking vessel, without requiring a protective coating.
SUMMARY OF THE INVENTION
[0011] These objectives are met through a process for obtaining a
cooking vessel consisting of the following steps: [0012] Production
of a container with an aluminum exterior surface and an interior
surface, [0013] Performance of hard anodization on at least the
exterior surface of the container, in which at least one coloring
step is performed on the anodized exterior surface after hard
anodization has been performed, said coloring step using at least
one water-soluble anthraquinone organic dye. Surprisingly, testing
has shown that coloring the anodized exterior surface of a cooking
vessel, when done in this way, results in durability, even when the
cooking vessel is exposed to flame, without requiring a protective
layer such as a sol-gel, varnish, lacquer or PTFE coating.
[0014] According to one advantageous method of implementation, the
coloring step uses an immersion in an aqueous solution of one or
more water-soluble anthraquinone organic compound(s). The use of
organic solvents can thus be avoided.
[0015] According to one preferred method of implementation, said
process includes a step in which a PTFE coating is applied to the
interior surface of the container. If desired, the PTFE coating
step may include a surface preparation, as well as the application
of one or more intermediate layers. The PTFE may be applied by
coating, for example.
[0016] Thus, according to one method of implementation, the process
includes a step in which a PTFE coating is applied to the interior
surface of the container, and the step in which the exterior
surface of the container is hard anodized occurs after the step in
which the PTFE coating is applied to the interior surface of the
container. The anodization performed after the PTFE coating offers
the advantage of anodizing only the exterior surface of the
container, which shortens the processing time, and decreases the
consumption of electricity and acid as compared to the anodization
of the exterior surface and the interior surface of the container.
Moreover, PTFE supports the sulfuric acid bath usually used in
anodization quite well.
[0017] If desired, the process may include a step in which
preliminary hard anodization is performed on the exterior surface
and the interior surface of the container prior to the step in
which the PTFE coating is applied to the interior surface of the
container, the hard anodization of the exterior surface of the
container occurring after an etching step on the exterior surface
of the container, following the step in which a PTFE coating is
applied to the interior surface of the container. This preliminary
hard anodization treatment pertains to the interior surface and the
exterior surface of the container and produces a hard base prior to
the application of the PTFE coating.
[0018] Without a PTFE coating, ideally the hard anodization step
and the coloring step are performed on the interior surface and the
exterior surface of the container.
[0019] According to one advantageous characteristic of the
invention, the hard anodization is performed at a temperature of
greater than or equal to 0.degree. C. For lower anodization
temperatures, the pores formed during anodization are indeed very
dense and very small, and the anodized surface cannot be dyed.
[0020] According to another advantageous characteristic of the
invention, the hard anodization is performed at a temperature of
less than or equal to 17.degree. C. For higher anodization
temperatures, the pores formed during anodization are too large and
the anodization is not hard enough, even if the dyeing is very
effective.
[0021] According to one preferred characteristic of the invention,
the hard anodization is performed at a temperature of between
5.degree. C. and 12.degree. C. For this range of temperatures, the
pores formed during anodization are small enough for the anodized
surface to be hard, and large enough for the anthraquinone dyes to
be able to penetrate into the pores and color the hard-anodized
surface.
[0022] These objectives are also reached with a cooking vessel
obtained according to a process that possesses at least one of the
aforementioned characteristics.
[0023] According to one advantageous method of implementation, the
container is obtained by stamping a substrate with at least one
surface made of aluminum, in which case said surface forms the
exterior surface of the container.
[0024] Thus, according to one method of implementation, the
substrate has two aluminum surfaces. For example, the substrate can
be made of solid aluminum, or as a laminate with two aluminum
surfaces and a steel core. If desired, the steel may be chosen from
among the stainless steels.
[0025] Thus, according to another method of implementation, the
substrate is formed by a laminate with one aluminum surface and one
stainless steel surface, this stainless steel surface being
advantageously intended to receive a PTFE coating.
[0026] According to another advantageous method of implementation,
the container is made of aluminum casting.
[0027] According to one advantageous method of implementation, the
exterior surface of the container has a brushed or
microbead-blasted surface. The anodization treatment is a surface
treatment in which the surface material is modified, and not a
surface coating, in which one or more layers are added to an
existing surface. Hard anodization treatment is not limited to
smooth or polished surface conditions, and so anodization may be
considered, for example, on a brushed or microbead-blasted
surface.
[0028] Ideally, in order to obtain an induction-compatible cooking
vessel, the container has at least one insert made of a
ferromagnetic material.
[0029] These objectives are also met with a culinary item
consisting of a cooking vessel and a handling instrument attached
to said cooking vessel by at least one rivet or by welding, said
cooking vessel possessing at least one of the aforementioned
characteristics.
[0030] These objectives are also met with an electric cooking
appliance, consisting of a cooking vessel combined with a heat
source, said cooking vessel possessing at least one of the
aforementioned characteristics.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] The invention will be better understood upon examining
examples of implementation, which should in no way be taken as
limiting, and which are illustrated in the attached drawings, in
which:
[0032] FIG. 1 depicts a cooking vessel (1) described in the
invention,
[0033] FIG. 2 depicts a culinary item (100) containing a cooking
vessel (1) described in the invention
[0034] FIG. 3 is an illustration of an electric cooking appliance
(200) containing a cooking vessel (1) described in the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0035] The cooking vessel (1) depicted in FIGS. 1 and 2 has a
container (10) with an exterior surface (11) made of aluminum as
well as an interior surface (12).
[0036] According to one method of implementation, the container
(10) is obtained by stamping a substrate (13) with at least one
surface made of aluminum that is intended to form the exterior
surface (11) of the container (10).
[0037] According to one method of implementation, the substrate
(13) has two aluminum surfaces intended to form the exterior
surface (11) and the interior surface (12), respectively, of the
container (10).
[0038] If desired, the substrate (13) may be made of solid
aluminum. An aluminum alloy (3003), for example, may also be used
for this purpose. The substrate (13) used to form the container
(10) is thus cut out of an aluminum sheet.
[0039] According to another method of implementation, the substrate
(13) is formed by a laminate with one aluminum surface and one
stainless steel surface, the aluminum surface being intended to
form the exterior surface (11) of the container, and the stainless
steel surface being intended to form the interior surface (12) of
the container (10).
[0040] According to another method of implementation, the container
(10) is made of cast aluminum, for example with an aluminum alloy
AlSi12.
[0041] If desired, the exterior surface (11) of the container (10)
is not necessarily smooth or polished, but may, for example, have a
brushed or microbead-blasted surface.
[0042] If desired, the container (10) may have at least one insert
made of ferromagnetic material, such as, for example, ferritic
steel, to make a cooking vessel (1) that can be heated by
induction. Preferably, the ferromagnetic material is a ferritic
stainless steel. If desired, the insert made of ferromagnetic
material may be formed by a plate with one or more perforations.
The insert is ideally assembled by hot or cold heading with the
aluminum in the substrate (13) or is covered in cast aluminum, the
perforation(s) preferably being filled by the aluminum. The insert
made of ferromagnetic material may have at least one part showing,
which can be protected by masking in acid chemical baths, such as
the anodization bath(s).
[0043] The cooking vessel (1) described in the invention is
obtained according to a process consisting of the following steps:
[0044] Production of a container (10) with an exterior surface (11)
made of aluminum and an interior surface (12), [0045] Performance
of hard anodization on at least the exterior surface (11) of the
container (10),
[0046] in which at least one coloring step is performed on the
anodized exterior surface following the hard anodization, said
coloring step using at least one water-soluble anthraquinone
organic dye.
[0047] The coloring step preferably uses an immersion in an aqueous
solution of one or more water-soluble anthraquinone organic
compound(s).
[0048] The anthraquinone dyes offer good resistance to temperatures
that can exceed 300.degree. C., this temperature being higher than
the maximum temperatures stated for other organic dyes.
[0049] Anthraquinone dyes can be used to obtain colorings on the
anodized exterior surface of a cooking vessel, which offer
durability. The coloring step(s) use(s) a coloring bath containing
anthraquinone organic compounds that will precipitate and be
trapped inside the pores of the hard anodized layer. The addition
of a protective coating no longer appears to be necessary to
protect the coloring of the anodized exterior surface of the
cooking vessel resting on a hotplate, or even exposed to a flame
from a burner such as a gas burner.
[0050] According to one advantageous method of implementation, the
coloring step uses an immersion in an aqueous solution of
water-soluble anthraquinone organic compounds.
[0051] Testing conducted with "Sanodye Violet MRB New," "Sanodye
Blue 2LW" and "Sanodye Blue G" dyes from OMYA showed surprisingly
satisfactory durability of the coloring obtained at the
temperatures at which cooking utensils are used, with thermal
stability of the color up to 300.degree. C. in a furnace, as well
as after cooking to browning for 20 minutes over a gas burner.
[0052] Prior to coloring, the surfaces being colored are subjected
to etching in an alkaline product followed by rinses and
neutralization in an acid medium. If desired, a prior mechanical
preparation may be performed, depending on the surface appearance
sought, such as a polishing, brushing, sandblasting or
shot-blasting mechanical preparation, for example. After
neutralization, a brightening treatment may be performed by
immersion in a phosphoric acid bath. The anodization step in a
sulfuric acid solution is performed with an acid concentration of
between 10 and 500 g/I, at a temperature of between -10.degree. C.
and +30.degree. C., with a continuous current having a current
density of between 0.1 and 5 A/dm.sup.2. Testing has shown that in
order to obtain anodization of sufficient hardness, the temperature
of the anodization bath must be less than or equal to 17.degree.
C., and preferably less than or equal to 12.degree. C.; to obtain
coloring of the hard anodized surface, the temperature of the
anodization bath must be greater than or equal to 0.degree. C., and
preferably greater than or equal to 5.degree. C. The anodization
process is followed by multiple rinses, the last of which is
performed with demineralized water. This treatment range results in
the formation of an anodized layer of variable thickness, depending
on the treatment time, of 5 to 100 .mu.m, and a hardness ranging
from 100 to 600 Vickers.
[0053] Ideally, the coloring bath is composed of an aqueous
solution containing between 0.1 and 10 g/1 of anthraquinone dye.
The aqueous solution is prepared with demineralized water. The pH
obtained is between 4 and 6. The temperature of the coloring bath
is between 20 and 80.degree. C. The coloring time depends on the
color sought and is typically between 1 and 60 minutes.
[0054] Preferably, the coloring step is followed by a rinsing step.
The rinsing step may be followed by a sealing step. The sealing
step may, for example, use boiling water, or saturated steam, or
even a bath containing metal salts of nickel and/or lithium and/or
silicon. However, the use of a sealing step does not seem to
appreciably modify the durability of the coloring obtained.
[0055] The process ideally includes a step in which a PTFE coating
is applied to the interior surface of the container. The PTFE
coating step may, for example, be performed by a coating process.
If desired, the PTFE coating step may use a filled PTFE, to improve
the resistance of the interior surface (12) of the PTFE-coated
container (10). Mineral particles may be used, for example, as
reinforcement filling. To obtain the PTFE cooking surface, the PTFE
coating is heated to a temperature of over 400.degree. C. (usually
on the order of 420.degree. C.). Thus, the PTFE coating step is
performed prior to the coloring step.
[0056] According to one method of implementation, the hard
anodization step performed on the exterior surface (11) of the
container (10) takes place after the PTFE coating step performed on
the interior surface (12) of the container (10).
[0057] If desired, a preliminary hard anodization step performed on
the exterior surface (11) and the interior surface (12) of the
container (10) may be considered prior to the PTFE coating step
performed on the interior surface (12) of the container (10). This
prior hard anodization treatment can be done to obtain a hard base
beneath the PTFE coating. The presence of a hard base beneath the
PTFE coating improves the mechanical durability of the PTFE
coating. Applying a PTFE coating after hard anodization is
described, for example, in Document EP 0 902 105. However, etching
of the exterior surface (11) of the container (10) is then
necessary to re-anodize said exterior surface (11) before
performing a coloring step. The hard anodization step performed on
the exterior surface (11) of the container (10) then occurs after
an etching step on the exterior surface (11) of the container (10),
following the PTFE coating step performed on the interior surface
(12) of the container (10).
[0058] According to another method of implementation, the hard
anodization step may be performed on the interior surface (12) and
the exterior surface (11) of the container (10), in order to obtain
a hard base. The hard anodization step is then a dual-surface hard
anodization step.
[0059] If desired, a surface preparation prior to hard anodization
may include an acid- or base-type degreasing and/or an acid- or
base-type etching, and/or HNO.sub.3 neutralization. A few minutes
of degreasing in a NaOH bath with a concentration of 50 g/I at a
temperature on the order of 50.degree. C. produces satisfactory
results.
[0060] The hard anodization treatment can be applied by soaking in
a bath. The preliminary anodization treatment may also be performed
by soaking in a bath. Hard anodization offers the advantage of good
scratch and impact resistance. A wider range of materials may also
be considered for making the container (10), with respect to
enameling, while retaining the cleaning properties conferred by the
PTFE coating on the interior surface (12) of the container
(10).
[0061] Hard anodization may, for example, be obtained with a
H.sub.2SO.sub.4 bath at a concentration of 130 g/I for 90 minutes
at a temperature on the order of 10.degree. C. with a current
density on the order of 1.8 A/dm.sup.2. Lower temperatures of
around 0.degree. C. with a greater current density can shorten the
treatment time.
[0062] An anodized layer with a thickness of between 10 .mu.m and
100 .mu.m produces satisfactory results for coloring options.
Preferably, in order to obtain a hard anodized layer with
sufficient mechanical durability, the anodized layer has a
thickness of at least 25 .mu.m. The hardness of the hard anodized
layer thus obtained is greater than 350 Hv.
[0063] According to one preferred characteristic, the anodized
exterior surface (11) has pores that are less than 30 nm in size,
and preferably less than 20 nm.
[0064] The process described in the invention may include the
following examples of implementation:
Example 1
[0065] PTFE coating of the interior surface (12), hard anodization
of the exterior surface (11), coloring of the hard anodized
exterior surface (11).
Example 2
[0066] Preliminary dual-surface hard anodization of the container
(10) to obtain a hard base, PTFE coating of the interior surface
(12), hard anodization of the exterior surface (11), coloring of
the hard anodized exterior surface (11).
Example 3
[0067] Dual-surface hard anodization of the container (10) to
obtain a hard base, coloring of the hard anodized exterior surface
(11) and the hard anodized interior surface (12).
[0068] FIG. 2 depicts a culinary item (100) consisting of a cooking
vessel (1) and a handling instrument (2) attached to said cooking
vessel (1) by at least one rivet (3). To this end, the rivet (3) is
assembled in a hole in the container (10) of the cooking vessel
(1). If desired, multiple rivets (3) may be used to attach the
handling instrument (2) to the cooking vessel (1). Preferably
between two and four rivets (3) are used to attach the handling
instrument (2) to the cooking vessel (1). Alternatively, the
handling instrument (2) may be welded to said cooking vessel (1).
If desired, another handling instrument (4) may be attached to said
cooking vessel (1) by at least one other rivet (5) or by
welding.
[0069] FIG. 3 depicts an electric cooking appliance (200),
consisting of a cooking vessel (1) combined with a heat source
(250). The cooking vessel (1) forms a container positioned in a
heating base (210) containing a heat source (250). The exterior
surface (11) of the container (10) rests on the heat source (250).
If desired, the exterior surface (11) may be attached to the heat
source (250).
[0070] As a variation, the interior surface (12) of the container
(10) is not necessarily coated in PTFE; other coating types may be
considered, if desired.
[0071] As a variation, the interior surface (12) of the container
(10) is not necessarily coated. If desired, the interior surface
(12) of the container (10) may be polished, for example.
[0072] This invention is in no way limited to the described
examples of implementation, but encompasses many modifications
within the context of the claims.
* * * * *