U.S. patent application number 10/976355 was filed with the patent office on 2005-06-02 for barrier materials and containers made therefrom.
Invention is credited to Cox, Richard C., Holicker, James S., Piemonte, Robert B..
Application Number | 20050118366 10/976355 |
Document ID | / |
Family ID | 34623746 |
Filed Date | 2005-06-02 |
United States Patent
Application |
20050118366 |
Kind Code |
A1 |
Piemonte, Robert B. ; et
al. |
June 2, 2005 |
Barrier materials and containers made therefrom
Abstract
A barrier structure comprises: a first membrane substantially
reflective of electromagnetic radiation; a second membrane spaced
apart from the first membrane and bound to the first membrane about
an edge thereof to form a bladder, the second membrane resistant to
vapor transmission; and a fibrous insert disposed between the first
membrane and the second membrane so as to maintain the spaced apart
relationship, the fibrous insert defining a space holding an
insulating medium resistant to the transmission of thermal energy
and interspersed therethough. The first membrane may further
comprise a multilayer composite and may include a polymer resistant
to vapor transmission, for example including at least one of
H.sub.2O, CO.sub.2 and O.sub.2. The polymer may be a polyester. The
multilayer composite may further comprise a structure substantially
reflective of thermal energy. The composite may further comprise
one or both of an outer metallization layer and an inner
metallization layer. The composite may further comprise a sealing
member. The sealing member may be a polyethylene layer. The fibrous
insert may comprise randomly oriented fibers of plural deniers
bonded together in a crush-resistant structure. The plural deniers
may be within a range of 3 to 100 denier. The fibrous insert may
further comprise an acrylic binder, an EVCL binder, a polyvinyl
acetate (PVA) binder or other polymer binder and combinations
thereof. The EVCL binder may be included in the fibrous insert as a
percentage of material comprising the fibrous insert of about
35-75% w/w. The first membrane, the second membrane and the fibrous
insert may all possess substantially similar melt flow indices.
Also shown, a shipping container may comprise plural wall
structures according to the thermal barrier structure described,
disposed on at least two sides of a payload region, such as a box
or envelope. The plural wall structures may be bonded together
along at least one edge, for example to form a shipping envelope
having an interior payload region surrounded by the bladders of the
plural wall structures. The plural structures may further comprise
a third membrane resistant to vapor transmission; and another
fibrous insert disposed between the second membrane and the third
membrane.
Inventors: |
Piemonte, Robert B.;
(Bridgewater, MA) ; Cox, Richard C.; (Duxbury,
MA) ; Holicker, James S.; (Foxboro, MA) |
Correspondence
Address: |
LOWRIE, LANDO & ANASTASI
RIVERFRONT OFFICE
ONE MAIN STREET, ELEVENTH FLOOR
CAMBRIDGE
MA
02142
US
|
Family ID: |
34623746 |
Appl. No.: |
10/976355 |
Filed: |
October 28, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10976355 |
Oct 28, 2004 |
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10877316 |
Jun 25, 2004 |
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60515022 |
Oct 28, 2003 |
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60482415 |
Jun 25, 2003 |
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Current U.S.
Class: |
428/34.1 |
Current CPC
Class: |
H05K 9/009 20130101;
Y10T 428/13 20150115 |
Class at
Publication: |
428/034.1 |
International
Class: |
B65D 001/00 |
Claims
What is claimed is:
1. A barrier structure, comprising: a first membrane substantially
reflective of electromagnetic radiation; a second membrane spaced
apart from the first membrane and bound to the first membrane about
an edge thereof to form a bladder, the second membrane resistant to
vapor transmission; and a fibrous insert disposed between the first
membrane and the second membrane so as to maintain the spaced apart
relationship, the fibrous insert defining a still air space
resistant to the transmission of electromagnetic radiation and
interspersed therethough.
2. The structure of claim 1, wherein the first membrane further
comprises: a multilayer composite.
3. The structure of claim 2, wherein the composite includes a
polymer resistant to vapor transmission.
4. The structure of claim 3, wherein the vapor whose transmission
the polymer resists includes at least one of H.sub.2O, CO.sub.2 and
O.sub.2.
5. The structure of claim 4, wherein the polymer is a
polyester.
6. The structure of claim 2, wherein the multilayer composite
further comprises: a structure substantially reflective of thermal
energy.
7. The structure of claim 6, wherein the composite further
comprises: one of an outer metallization layer and an inner
metallization layer.
8. The structure of claim 7, wherein the composite further
comprises: another one of an outer metallization layer and an inner
metallization layer.
9. The structure of claim 8, wherein the composite further
comprises: a sealing member.
10. The structure of claim 9, wherein the sealing member further
comprises: a polyethylene layer.
11. The structure of claim 10, wherein the fibrous insert
comprises: randomly oriented fibers of plural deniers bonded
together in a crush-resistant structure.
12. The structure of claim 11, wherein the plural deniers are
within a range of 3 to 100 denier.
13. The structure of claim 12, wherein the fibrous insert further
comprises: at least one of an EVCL binder, an acrylic binder and a
PVA binder.
14. The structure of claim 13, wherein the fibrous insert further
comprises: an EVCL binder.
15. The structure of claim 14, wherein the EVCL binder is included
in the fibrous insert as a percentage of material comprising the
fibrous insert of about 35-75% w/w.
16. The structure of claim 1, wherein the first membrane, the
second membrane and the fibrous insert all possess substantially
similar melt flow indices.
17. The structure of claim 1, wherein the second membrane
comprises: a corrosive inhibiting film.
18. The structure of claim 17, wherein the corrosive inhibiting
film comprises: a reactive intercept barrier film.
19. A shipping container comprising: plural wall structures
according to the thermal barrier structure of claim 1, disposed on
at least two sides of a payload region.
20. The shipping container according to claim 19, wherein the
plural wall structures are bonded together along at least one
edge.
21. The shipping container according to claim 20, wherein the
plural structures are bonded together to form a shipping envelope
having an interior payload region surrounded by the bladders of the
plural wall structures.
22. The shipping container according to claim 21, wherein each of
the plural structures further comprises: a third membrane resistant
to vapor transmission; and another fibrous insert disposed between
the second membrane and the third membrane.
23. The shipping container according to claim 19, wherein the
plural structures are incorporated in walls of a box structure.
24. The structure of claim 19, wherein the one of the outer
metallization layer and the inner metallization layer is capable of
receiving a static electric discharge to the structure without
damage to items carried therein.
25. The structure of claim 19, wherein the second membranes of the
plural barrier structures are adjacent a payload region, and the
second membranes comprise: a corrosive inhibiting film.
26. The structure of claim 25, wherein the corrosive inhibiting
film comprises: a reactive intercept barrier film.
27. An insert for a shipping container, the shipping container
defined by an outer wall, the inset comprising: an inner wall
membrane resistant to vapor transmission and defining a payload
space; a fibrous insert disposed between the inner wall and the
outer wall, so as to maintain the outer wall and the inner wall in
a spaced-apart relationship, the fibrous insert defining a still
air space resistant to the transmission of electromagnetic
radiation and interspersed therethrough; wherein closing the
shipping container forms a bladder defined by the fibrous insert
and the still air space which together surround the payload
space.
28. The insert of claim 27, wherein the fibrous insert further
comprises: randomly oriented fibers having plural denier within a
range of 3 to 100 denier and the insert has a surface resistivity
less than about 10.sup.11 .OMEGA./.quadrature..
29. The insert of claim 28, wherein the fibers are at least one of
polyethylene, polypropylene and polyester.
30. The insert of claim 29, wherein the fibers are hollow.
31. The insert of claim 27, wherein the fibrous insert further
comprises: a binder having at least one of anti-bacterial,
anti-fungal and anti-static properties.
32. The insert of claim 31, wherein the binder comprises EVCL.
33. The insert of claim 27, wherein the inner wall membrane further
comprises: a corrosion inhibiting film.
34. The insert of claim 33, wherein the corrosion inhibiting film
comprises: a reactive intercept barrier film.
35. The insert of claim 34, wherein the reactive intercept barrier
film comprises: a reactive layer, reactive with inorganic ions; and
an absorber layer, absorptive of organic ions.
36. The insert of claim 35, wherein the reactive intercept barrier
film further comprises: a composite including a substrate resistant
to transmission of H.sub.2O or O.sub.2, an outer layer of
conductive carbon, forming the absorber layer, and an inner layer
of a material to which free ions are attracted, forming the
reactive layer.
37. The insert of claim 36, wherein the reactive intercept barrier
film further comprises: a metallized film on the outer layer of
conductive carbon.
38. The insert of claim 36, wherein the substrate further
comprises: polyethylene teraphthalate.
Description
RELATED APPLICATIONS
[0001] This application claims the benefit under 35 U.S.C. .sctn.
120 of U.S. patent application Ser. No. 10/877,316, entitled
"Barrier Materials And Containers Made Therefrom" filed on Jun. 25,
2004 (pending), which claims priority under 35 U.S.C. .sctn. 119(e)
to U.S. Provisional Application Ser. No. 60/482,415, entitled
"THERMAL INSULATION CONTAINER," filed on Jun. 25, 2003 (expired),
both of which are herein incorporated by reference in their
entirety. This application also claims the benefit under 35 U.S.C.
.sctn. 119(e) to U.S. Provisional Application Ser. No. 60/515,022,
entitled "THERMAL INSULATION CONTAINER," filed on Oct. 28, 2003
(pending), herein incorporated by reference in its entirety.
BACKGROUND
[0002] The present invention relates to barrier materials,
including those that shield against electromagnetic radiation and
fields, electric discharge, chemical infiltration and the like,
particularly thermal, chemical and electrostatic barrier insulation
materials, especially including thermal, chemical and electrostatic
barrier insulation materials incorporated in or formed into
shipping containers, including envelopes, bags, boxes, cases and
the like.
[0003] Insulating packaging and materials, especially various
barrier materials find many uses in storing and transporting
sensitive payloads. Sensitive payloads may include pharmaceuticals,
medical products such as blood products, food products and others
that are preferably stored and shipped at temperatures below the
usual ambient temperature. They may also include electronics and
precision mechanics sensitive to electric discharge or shock,
mechanical damage or chemical contamination.
[0004] An example of the use of thermally insulating materials is
in a so-called "cold chain" of transportation. A pharmaceutical
product might be prepared under chilled conditions or chilled after
preparation in order to maintain certain desired properties. The
pharmaceutical then needs to be shipped to an end user. In order to
control costs, the shipping preferably takes place through
conventional channels such as ordinary truck or air freight
systems, which generally have little or no temperature control
provisions for the payloads shipped. In order to preserve the
pharmaceutical product for effective use by the end user, the
manufacturer might place the pharmaceutical as a payload in a "cold
chain" shipping container, which is then shipped conventionally by
a next day freight or courier service.
[0005] Conventional "cold chain" shipping containers include
multiple layers of insulating, conducting and reflecting layers
that combine to allow a chilled payload to remain below a threshold
temperature for the duration of shipping the payload. The ability
of conventional systems to maintain the desired temperature is
enhanced by including with the payload a cold sink that absorbs
some of the heat energy that penetrates the shipping container,
such as a block of dry ice, a cold gel pack, ice or the like.
[0006] Conventional shipping containers maintain proper cold
temperatures for longer than up to about 24 hours. They do so using
metal foils or unmetallized films that partly reflect thermal
energy and partly absorb thermal energy, spreading it over the
surface of the container, combined with various paper and plastic
substrates and EPS, foam or masticated paper insulating layers.
Also used are bubble wrap materials combined with foils.
[0007] The foam and masticated paper insulating layers are only
partially effective due to excessive conduction of heat energy and
due to absorption of moisture. Once a foam or masticated paper
layer begins to absorb moisture, it conducts heat energy through
that moisture ever more readily. Moreover, they provide little or
no mechanical protection for the payload due to their density.
[0008] Similar examples abound in fields sensitive to electric
shock, mechanical shock, damage and chemical contamination. Often,
the varied requirements, such as protection against mechanical
shock compete against other requirements, such as protection
against electrical shock, due to the materials and space
available.
[0009] Electronic circuits and circuit modules are increasingly
sensitive to electrical and mechanical shock due to ever decreasing
feature sizes. As feature sizes decrease, less electrical energy in
the form of a static discharge is required to break down a
particular circuit feature and burn it out. Mechanical shock can
induce a feature to delaminate, thus becoming defective.
[0010] Conventional electrostatic discharge (ESD) protection bags
provide either no mechanical shock resistance or provide such
protection using one of the materials discussed above. Those
materials are to one degree or another unsuitable because they
provide insufficient protection, cost too much or themselves
contribute to the problem of static discharge either by
triboelectric charge build-up or by their ability to carry a large
charge without a corresponding ability to dissipating it.
[0011] Electronic circuits, circuit modules and mechanical devices,
especially nano-mechanics, are also increasingly sensitive to
microscopic chemical and particulate contamination. Contamination
includes water vapor, airborne bacteria and spores, dust and
particulates, gases and various surface contaminates and oils
already present on payloads. Conventional materials, especially
when treated in ESD protections capability, not only do not prevent
or reduce such contamination, but often contribute to it because
coatings have a tendency to "crumb" off and thus introduce
particulate contamination into a container.
SUMMARY OF INVENTION
[0012] What are desired are barrier materials, packaging materials
and packages made therefrom that maintain the condition,
cleanliness, stability and freshness of a payload protected thereby
or carried therein, extends the shelf life of the payload, reduces
growth of bacteria, retards decay or decomposition of the payload,
prevents melting or shrinking of payloads susceptible to such, and
maintains the flavor and/or aroma of certain payloads. Barrier
materials and packaging made therefrom according to various aspects
of the invention may provide one or more of these advantages, or
other advantages as will be apparent to the skilled artisan upon
reading the following Summary of Invention, as well as reading the
following Detailed Description together with the Drawings.
[0013] According to aspects of embodiments of the invention, a
barrier structure comprises: a first membrane substantially
reflective of electromagnetic radiation, for example, "Pewter"
polyethylene a second membrane spaced apart from the first membrane
and bound to the first membrane about an edge thereof to form a
bladder, the second membrane resistant to vapor transmission; and a
fibrous insert disposed between the first membrane and the second
membrane so as to maintain the spaced apart relationship, the
fibrous insert defining a space holding an insulating medium
resistant to the transmission of thermal energy and interspersed
therethough. The first membrane may further comprise a multilayer
composite and may include a polymer resistant to vapor
transmission, for example including at least one of H.sub.2O,
CO.sub.2 and O.sub.2. The polymer may be a polyester. The
multilayer composite may further comprise a structure substantially
reflective of thermal energy. The composite may further comprise
one or both of an outer metallization layer and an inner
metallization layer. The composite may further comprise a sealing
member. The sealing member may be a polyethylene layer. The fibrous
insert may comprise randomly oriented fibers of plural deniers
bonded together in a crush-resistant structure. The plural deniers
may be within a range of 3 to 100 denier. The fibrous insert may
further comprise an acrylic binder, an EVCL binder, a polyvinyl
acetate (PVA) binder or other polymer binder and combinations
thereof. The EVCL binder may be included in the fibrous insert as a
percentage of material comprising the fibrous insert of about
35-75% w/w. The first membrane, the second membrane and the fibrous
insert may all possess substantially similar melt flow indices. The
second membrane may further comprise a corrosion preventive, oxygen
scavenging and/or anti-static material.
[0014] According to other aspects of embodiments of the invention,
a shipping container may comprise plural wall structures according
to the thermal barrier structure described, disposed on at least
two sides of a payload region, such as a box or envelope. The
plural wall structures may be bonded together along at least one
edge, for example to form a shipping envelope having an interior
payload region surrounded by the bladders of the plural wall
structures. The plural structures may further comprise a third
membrane resistant to vapor transmission; and another fibrous
insert disposed between the second membrane and the third
membrane.
BRIEF DESCRIPTION OF DRAWINGS
[0015] The accompanying drawings are not intended to be drawn to
scale. In the drawings, each identical or nearly identical
component that is illustrated in various figures is represented by
a like numeral. For purposes of clarity, not every component may be
labeled in every drawing. In the drawings:
[0016] FIG. 1 is a cross-section view of the three main components
of a barrier material according to aspects of an embodiment of the
invention;
[0017] FIG. 2 is a cross-section view of the components of FIG. 1,
assembled into a barrier bladder with side seams;
[0018] FIG. 3 is a cross-section top view of a shipping envelope
constructed of two barrier bladders as shown in FIG. 2;
[0019] FIG. 4 is a plan view of the top edge of the shipping
envelope of FIG. 3, showing some closure details;
[0020] FIG. 5 is a cross-section side view of the shipping envelope
of FIG. 4 showing further closure details;
[0021] FIG. 6 is a perspective view of a shipping container
including barrier material in the walls according to aspects of an
embodiment of the invention; and
[0022] FIG. 7 is a perspective view of an insert for a shipping
envelope according to aspects of an embodiment of the
invention.
DETAILED DESCRIPTION
[0023] This invention is not limited in its application to the
details of construction and the arrangement of components set forth
in the following description or illustrated in the drawings. The
invention is capable of other embodiments and of being practiced or
of being carried out in various ways. Also, the phraseology and
terminology used herein is for the purpose of description and
should not be regarded as limiting. The use of "including,"
"comprising," or "having," "containing", "involving", and
variations thereof herein, is meant to encompass the items listed
thereafter and equivalents thereof as well as additional items.
[0024] Aspects of embodiments of the present invention provide a
low cost, effective, light-weight structure for protecting and/or
insulating a payload; for example, for thermally insulating
temperature sensitive payloads for an extended period of time, for
protecting against mechanical or electrical shocks , for cushioning
a payload and for scrubbing harmful molecules out of the immediate
surroundings of the payload.
[0025] Comparisons under matched conditions of conventional
shipping containers and containers according to aspects of
embodiments of the invention have shown conventional containers to
maintain proper temperatures for up to about 24 hours, whereas our
containers can maintain proper temperatures for example, but not
limited to, a period of 24-48 hrs. Aspects of embodiments of the
present invention also provide a cushioned, aseptic, tamper
resistant package. Other aspects of embodiments of the invention
also provide for prevention of freezing when the package is exposed
to sub-freezing temperatures. Yet other aspects of embodiments of
the invention convert conventional packaging into thermally,
mechanically and/or electrically protected packaging. Even other
aspects of embodiments of the invention protect the payload from
harmful molecules in the immediate environment of the payload,
including protecting the payload from sources of corrosion.
[0026] The barrier material according to some aspects of
embodiments of the present invention is a bladder comprised of
three main elements, as shown in the cross-section of FIG. 1.
[0027] The three elements comprising the bladder are an
electromagnetic radiation reflecting layer 101, a vapor barrier 102
and a fibrous insert 103. As shown in the cross-section of FIG. 2,
the three elements are sealed at the edges 201 and 202. Each
barrier wall structure according to some aspects of embodiments of
the invention is sealed at the edges around the entire periphery of
the bladder comprising the barrier wall. The bladder can have any
suitable shape when viewed in plan view. For example, the bladder
may be circular to cover the bottom of a cylindrical container, or
may be rectangular when used as one wall of a shipping
envelope.
[0028] Now, the three main elements of the bladder of FIGS. 1 and 2
are described in more detail. First, the reflecting layer 101 is
described, followed by the vapor barrier 102 and the fibrous insert
103.
[0029] The reflecting layer 101 is itself a multi-layered composite
material according to aspects of some embodiments of the invention.
The composite may have a polymer substrate, for example
polyethylene teraphthalate (PET). Any suitable substrate may be
used, although some preferable properties of the substrate material
include vacuum formability, low porosity and low vapor transmission
relative to oxygen (O.sub.2), water (H.sub.2O) and carbon dioxide
(CO.sub.2), high burst strength, puncture resistance, flexibility,
environmental compatibility for disposal or recycling and
compatibility with the other materials to be used for purposes of
sealing the edges. The sealing method to be described below
includes use of heat and pressure to form bonded edge seals.
Therefore, compatibility with the other materials to be used for
purposes of sealing the edges can include material compatibility
and melt flow index compatibility between the substrate of the
reflecting layer 101, the other components of the reflecting layer
composite, the vapor barrier layer 102 and the fibrous insert
103.
[0030] To provide the reflecting layer 101 with suitable reflecting
qualities, it includes one or more metallization layers. For
example, a polymer substrate having two layers of aluminum (Al)
metallization of about 280 .ANG. thickness each initially reflects
about 97% of light from ultraviolet (UV) through infrared (IR) at
the first layer, with much of the balance (approximately only 3%)
reflected at the second layer. Other thicknesses of metallization
may be suitable to achieve other results as may be desired. A
greater thickness of Al may result in greater than 97% reflectivity
at the first metallization layer, for example. The level of
performance described would be suitable for many pharmaceutical
products, foods and other medical products that could be damaged by
UV radiation or excessive heat or cold. Other suitable
metallization layers include copper (Cu) and other suitable metals.
Different metallization layers provide different reflective or
attenuating characteristics. A metallization material may be chosen
to provide any suitable reflective or attenuating
characteristic.
[0031] The composite may have a layer provided to aid in sealing
the edges of the bladder, for example a layer of another polymer.
Providing such an additional layer may permit the use of materials
in the vapor barrier 102 and the fibrous insert 103 that would be
otherwise incompatible for sealing purposes with the substrate
material of the reflecting layer 101, for example PET.
[0032] The vapor barrier layer 102 should preferably be a moisture
vapor transmission (MVT) barrier that resists transmission of
O.sub.2, H.sub.2O and CO.sub.2, or any other vapor desired to be
blocked. The vapor barrier layer 102 can be simply a layer of any
suitable polymer. The vapor barrier should also be environmentally
compatible for disposal, as well as suitable for placement adjacent
the payload when used in packaging. For example, for foodstuff
payloads, the vapor barrier should be an FDA-approved, food storage
and shipment material. As with the reflecting layer 101, the vapor
barrier layer 102 should be compatible for heat sealing with the
other components of the barrier material.
[0033] One suitable material for the vapor barrier is polyethylene
sheeting. Polyethylene sheeting possesses all of the
characteristics discussed above. It also remains flexible at low
temperatures, and is resistant to many chemical and biological
materials that are desired to be shipped as payloads in containers
made using aspects of embodiments of the invention. Other suitable
materials for the vapor barrier include an electrostatically
dissipative material such as described by Ray et al. in U.S. Pat.
No. 4,875,581, incorporated herein in its entirety by reference,
and the material described by Neal et al. in U.S. Pat. No.
4,648,508, also incorporated herein in its entirety by reference.
Suitable materials also include anti-static and corrosion
preventive materials currently sold under the trademarks RIBS
Media.TM., RIBS Shielding.TM. and RIBS MVTR.TM. (Pure-Stat
Technologies, Inc., Lewiston, Me.). Also suitable are various
corrosion inhibiting films made by Cromwell-Phoenix, Inc., Alsip,
Ill. and others.
[0034] RIBS Media.TM. is a two-layer structure. One layer includes
a polymer and copper membrane to be located adjacent to a payload
space. The copper scavenges inorganic ions from the payload space.
A second layer includes a polymer matrix containing conductive
carbon. Organic ions are scavenged from the payload space by the
carbon.
[0035] RIBS Shielding.TM. adds layers of polyester, aluminum and an
abrasion resistant coating, as does RIBS MVTR.TM.. RIBS MVTR uses a
heavier aluminum layer to achieve better moisture barrier
characteristics.
[0036] Preferred materials omit aluminum, although it may
optionally be used, because aluminum composites are more difficult
to recycle. The fibrous insert layer 103 helps maintain the air
pocket in the bladder by supporting the reflective layer 101 and
the vapor barrier layer 102 away from each other, as well as
providing some mechanical protection for the payload of a container
made using aspects of embodiments of the invention. Thus, the
fibrous insert layer 103 should be crush resistant, under repeated
crush insult or if vapor or payload material should penetrate a
breached vapor barrier layer 102, contain a large volume of air or
other suitable insulating medium and should be compatible for heat
sealing with the other components of the barrier material. The
fibrous insert layer 103 should further be non-absorbent and
resistant to decomposition due to biologic action. Alternatively,
the fibrous insert layer 103 could be of a material that decomposes
on exposure to biologic or aqueous media. As with the other
materials used, the fibrous insert layer 103 should be
environmentally compatible for disposal.
[0037] Materials and structures suitable for the fibrous insert
layer 103 are now described.
[0038] Preferably, the fibrous insert layer 103 is a batting or
non-woven matrix of PET fibers having multiple deniers. Deniers in
a range of about 3 to 100 are suitable, with a mixture of fibers
having deniers of 3, 6, 15, 25 and 45 having been found to be
particularly suitable. The mixture of fibers from which the fibrous
insert layer 103 is formed is further mixed with about 35% to 75%
w/w of a binder to retain the fibers in the form of a batting or
non-woven matrix. Suitable binders include 38% to 48% w/w of
ethylene vinyl chloride (EVCL), an acrylic or a PVA. The binder
should possess similar environmental compatibility and sealing
properties to the other materials, or at least not interfere with
those properties. The fibers of PET on other materials can be
treated with carbon, a copper matrix or other coating, to achieve
better anti-static, cleanliness properties, anti-fungal,
anti-bacterial, etc.
[0039] As mentioned above, each bladder wall is sealed at the edges
(see FIG. 2, 201 and 202). Conventional heat and pressure sealing
techniques can be used, if the materials selected all have similar
melt flow indices. As is known in the art, sealing processes
operate successfully over ranges of temperatures and pressures.
According to some aspects of some embodiments of the invention, the
sealing temperature and pressure should be selected or adjusted so
as to provide a well-bonded but porous seal. The degree of porosity
can be adjusted, for example, by adjusting the pressure or dwell
time, while holding the sealing temperature at a level to provide a
well-bonded seal. By allowing the seam to be porous, the bladder
can adjust to changes in external pressure without bursting. For
example, if the external pressure on a bladder incorporated into a
shipping container drops due to the container being carried at high
altitude by an aircraft, the internal pressure of the bladder
bleeds out through the seam. However, when the package returns to a
higher pressure zone, such as ground level, air can bleed back in
through the seam. The bladder volume is maintained by the fibrous
insert 103, so the bladder becomes a low pressure zone, and the
pressure differential between ambient and the interior of the
bladder, across the seam, results in the bleeding back in of some
air. Thus, the insulating properties of a bladder having relatively
still air inside are maintained over a range of pressures, without
the need for a valve and without concern for bursting of the
bladder.
[0040] A sealed seam has been described for the circumstance in
which adjustment to external pressure changes is required.
Alternatively, if adjustment to external pressure changes is not a
requirement, then the seam can be formed between only the
reflective layer 101 and the vapor barrier layer 103 with the
batting having a size small enough that it does not extend into the
seam. This construction has at least an advantage of lower
manufacturing cost.
[0041] Barrier material as described above can be supplied in many
forms.
[0042] One form in which the barrier material can be provided, is
pre-assembled into a shipping envelope, as shown in FIGS. 3, 4 and
5.
[0043] A shipping envelope according to aspects of embodiments of
the invention includes two walls (FIG. 3, 301 and 302), each formed
of the barrier material described above. Each wall (FIG. 3, 301 and
302) includes the three layers described above, a reflecting layer
101, a vapor barrier layer 102 and a fibrous insert 103. The edges
of the shipping envelope are sealed as described above to form a
six-layer seam (FIG. 3, 303) around the periphery of the envelope,
leaving one edge open (FIGS. 4 and 5, 401) to receive the payload
into an interior space (FIGS. 3 and 5, 304).
[0044] The open edge (FIGS. 4 and 5, 401) may be sealed after
loading the payload into the envelope, for example using a plastic
zipper-type seal (FIGS. 4 and 5, 402) and/or a flap with a tape
seal (FIG. 5, 501 and 502). Prior to use, each tape seal (FIG. 5,
501 and 502) is covered by a release paper strip (not shown) that
is removed in order to make the seal.
[0045] Tape seals are useful for enhancing the bladder structure by
restricting airflow in or out of the closed envelope, as well as
providing a more secure closure and for providing a tamper-evident
closure. An aggressive tape seal is tamper-evident because of the
distortion to the envelope caused when it is unsealed. In order to
provide some degree of re-usability to the shipping envelope, two
tape seals (FIG. 5, 501 and 502) are shown. The space between them
can be perforated or otherwise weakened (FIG. 5, 503) for
permitting the opening of the envelope sealed using the first tape
seal (FIG. 5, 501), which can then be resealed using the second
tape seal (FIG. 5, 502). Thus, a payload can be shipped from a
supplier to a consumer, operated upon by that consumer and finally
shipped back to the supplier, as is sometimes done in
pharmaceutical and medical testing scenarios.
[0046] Alternatively, a less aggressive adhesive tape seal can be
re-used without damage to the envelope. Another form in which the
barrier material can be supplied is as rolls of sheet material, or
as individual bladder walls, i.e. pre-divided and pre-sealed sheets
of material.
[0047] For example, rolls of material, sealed along the side edges
can be supplied with or without cross seals. A roll of material
with cross seals is, of course, pre-divided into sheets, each sheet
being one bladder. The cross seals can be provided with
perforations, for example, to allow each bladder to be separated
from the roll and placed in a shipping container as an insulating
wall. Without cross seals, the user would need sealing equipment to
seal and separate bladders of arbitrary desired dimensions from the
roll.
[0048] Sheets of material, i.e., individual bladders, can be
inserted into suitable shipping boxes arranged and sized to receive
them, as shown in FIG. 6. Each bladder 601, 602, 603 and 604 is
particularly sized to fit the wall of the box into which it is
inserted. In a conventional, six-sided box, six closely-fitting
wall bladders would be employed. The shipping container could also
be substantially cylindrical, in which case a floor bladder, a
ceiling bladder and a single, wrap-around wall bladder could be
inserted.
[0049] Barrier material can also be supplied without reflecting
layer (FIG. 1, 101), for example pre-assembled into a payload
protection inserts (FIG. 7) to be inserted in conventional, e.g.
polymer or Kraft paper or other shipping envelopes. In that form,
the reflecting layer (FIG. 1, 101) may simply be the user-supplied
shipping envelope, even though that reflecting layer may not be as
effective as some other embodiments described herein.
[0050] An insert such as just described is shown in FIG. 7. The
insert has two inner membrane layers 701 that define a payload
space 702. Adjacent to the inner membrane layers 701 are fibrous
layers 703. The insert is sealed on three sides 704, as previously
described. The open end 705 may include a tape or zipper seal, also
as previously described.
[0051] Many variations to the foregoing are possible. Although the
invention has been illustrated with respect to keeping a payload
cold, the invention can also be used to keep a payload hot or any
other desired temperature. Aspects of the embodiments of the
invention illustrated also possess other useful properties. For
example, the shipping envelope or shipping container, having a
metallization layer substantially completely surrounding the
payload, forms a Faraday cage protecting the payload from
electrical shock. The barrier material itself has superior
mechanical shock absorbing properties, and so could be used to
protect fragile payloads, or as a cushion or pad to protect a
payload, even when insulation properties are not required. In the
shipping envelope described in connection with FIGS. 3, 4, and/or
5, each wall 301 and 302 may include two layers of barrier
material. In any of the shipping containers or other uses of the
barrier material, the reflective layer may be the exterior layer or
an interior layer. This choice will usually, although not
exclusively, depend on which side of the barrier will be exposed to
heat and which to cold. Preferably, the reflective layer faces the
heat source.
[0052] Having thus described several aspects of at least one
embodiment of this invention, it is to be appreciated various
alterations, modifications, and improvements will readily occur to
those skilled in the art. Such alterations, modifications, and
improvements are intended to be part of this disclosure, and are
intended to be within the spirit and scope of the invention.
Accordingly, the foregoing description and drawings are by way of
example only.
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