U.S. patent application number 10/687083 was filed with the patent office on 2004-04-29 for protective packaging comprised of shape memory foam.
Invention is credited to Sendijarevic, Ibrahim, Sendijarevic, Vahid.
Application Number | 20040079670 10/687083 |
Document ID | / |
Family ID | 32110197 |
Filed Date | 2004-04-29 |
United States Patent
Application |
20040079670 |
Kind Code |
A1 |
Sendijarevic, Ibrahim ; et
al. |
April 29, 2004 |
Protective packaging comprised of shape memory foam
Abstract
In one embodiment of the present invention, a protective
packaging for protecting an at least one article is disclosed. The
protective packaging is comprised of a shape memory foam (SMF)
structure conforming to at least a portion of to at least one
article for protecting the at least one article. The SMF has a
glass transition temperature (T.sub.g).
Inventors: |
Sendijarevic, Ibrahim;
(Hoboken, NJ) ; Sendijarevic, Vahid; (Troy,
MI) |
Correspondence
Address: |
BROOKS KUSHMAN P.C.
1000 TOWN CENTER
TWENTY-SECOND FLOOR
SOUTHFIELD
MI
48075
US
|
Family ID: |
32110197 |
Appl. No.: |
10/687083 |
Filed: |
October 16, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60418928 |
Oct 16, 2002 |
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Current U.S.
Class: |
206/523 |
Current CPC
Class: |
B29C 44/5627 20130101;
B65D 81/107 20130101; B29C 44/3484 20130101 |
Class at
Publication: |
206/523 |
International
Class: |
B65D 085/30 |
Claims
What is claimed:
1. A protective packaging for protecting an at least one article,
the protective packaging comprised of a shape memory foam (SMF)
structure conforming to at least a portion of the at least one
article for protecting the at least one article wherein the SMF has
a glass transition temperature (T.sub.g).
2. The protective packaging of claim 1, wherein the SMF structure
has a T.sub.g of at or above about 21.degree. C., the SMF structure
being rigid below the T.sub.g and elastic above the T.sub.g, the
SMF structure having a shape memory characteristic such that when
the SMF structure in an original shape is deformed or compressed
above the T.sub.g to produce a compressed shape and cooled in the
compressed shape below the T.sub.g, the SMF structure retains the
compressed shape without the need of external forces and when the
temperature is raised above the T.sub.g, the SMF structure returns
substantially to the original shape.
3. The protective packaging of claim 2, wherein the SMF structure
is comprised of a thermoset or thermoplastic SMF.
4. The protective packaging of claim 2, wherein the SMF structure
is comprised of a structure of polyurethane foam produced by
reacting an isocycate and a polyol.
5. The protective packaging of claim 4, wherein the polyurethane
foam is prepared using a polyol selected from the group comprised
of an aromatic polyester polyol, a polycarbonate polyol, a
polyether polyol, and mixtures thereof.
6. The protective packaging of claim 5, wherein the polyol has an
average functionality between about 2 and about 4.
7. The protective packaging of claim 4, wherein the isocyanate is
an aromatic isocyanate having a functionality between about 2 and
about 3.
8. The protective packaging of claim 4, wherein the polyurethane
foam is produced by reacting the isocyanate with the polyol and a
chain extender.
9. The protective packaging of claim 2, wherein the SMF has a
substantially open cell structure.
10. The protective packaging of claim 2, wherein the T.sub.g is
less than about 21.degree. C.
11. The protective packaging of claim 2, wherein the SMF is
compressible to less than about 50% of the original volume.
12. The protective packaging of claim 2, wherein the SMF further
includes a natural or synthetic additive.
13. The protective packaging of claim 1, wherein the SMF structure
is at least partially wrapped, coated, laminated, or encased in a
film.
14. The protective packaging of claim 2, wherein the SMF is
hydrophobic.
15. The protective packaging of claim 2, wherein the SMF is
resistant to moderate levels of ionizing or non-ionizing
radiation.
16. A method for producing a protective packaging for protecting an
at least one article, the method comprising placing a shape memory
foam (SMF) structure having a glass transition temperature
(T.sub.g) and an at least one article in a container, whereby the
SMF conforms to at least a portion of the at least one article to
protect the at least one article.
17. The method of claim 16 wherein the SMF is at a temperature of
about below or about above the T.sub.g.
18. The method of claim 16 further comprising: deforming or
compressing the SMF structure in an original shape to produce a
compressed shape; cooling the compressed shape to below the T.sub.g
to retain the compressed shape; and raising the temperature of the
compressed shape to above about the T.sub.g to substantially regain
the original shape, whereby the original shape or the compressed
shape conforms to at least a portion of the at least one article to
protect the at least one article.
19. The method of claim 18 wherein the raising of the temperature
of the SMF is accomplished by a process selected from the group
consisting of convection heating, conductive heating, microwave
heating, or chemical reaction.
20. The method of claim 18 wherein the cooling of the SMF is
accomplished by a process selected from the group consisting of
free convection, forced convection, refrigeration, conductive
cooling, cooling baths, and liquid gas or nitrogen.
21. The method of claim 18 further comprising providing a plurality
of SMF structures and a plurality of articles.
22. The method of claim 21 whereby the plurality of SMF structures
are stackable for protecting the plurality of articles.
23. A method for producing a protective packaging, the method
comprising: providing a shape memory foam (SMF) structure having a
glass transition temperature (T.sub.g); providing a transportation
or storage container; deforming or compressing the SMF structure to
produce a compressed shape; and placing he compressed shape in the
transportation or storage container.
24. The method of claim 23 wherein the compressed shape is
substantially flat.
25. The method of claim 23 further comprising providing a plurality
of SMF structures suitable for deforming or compressing into
deformed shapes for storing in the transportation or storage
container.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. provisional
application Serial No. 60/418,928, filed Oct. 16, 2002, and
entitled "Protective Packaging Comprised Of Shape Memory Foam".
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] One aspect of the present invention relates to protective
packaging comprised of shape memory polymeric foam and methods of
using shape memory polymeric foam in protective packaging
applications.
[0004] 2. Background Art
[0005] Protective packaging structures are often used to protect an
article from physical shock during storage and transport. As an
example, to protect valuable or fragile articles from physical
shock or other external forces during shipping, storage, loading,
or unloading, it is desirable to place articles that are being
shipped in a box or a container. However, in order to provide
adequate levels of protection, it is often necessary to place
additional protective packaging structures between an article that
is being shipped and the walls of an outside box or a
container.
[0006] Polymeric foams are commonly utilized in packaging
applications as protective packaging structures. These foams are
usually inserted between an article that is being shipped and the
walls of a container or a box. Foams most frequently utilized in
protective packaging are polyurethane foams, however, polyolefin,
polystyrene, and other polymeric foams are utilized as well. These
polymeric foams are generally cellular, low-density materials. As a
result, polymeric foams are bulky materials that are therefore
expensive to transport and store. Consequently, the main drawbacks
of polymeric foams are high costs of storage and transportation
from the manufacturers to the end-users of the polymeric foams.
[0007] As a result, large-volume users, otherwise referred to as
customers, of polymeric foams used in protective packaging often
purchase the reagents and produce polyurethane foams on-site. The
reagents used in production of polyurethane foams are isocyanate
compounds and polyol compounds, which are usually in the liquid
form making them less bulky and therefore less costly to transport
and store than the solid polyurethane foams.
[0008] Most common packaging applications involve wrapping of an
article that is to be protected and shipped with a layer of
protective material (such as a plastic sheet or a film) and placing
it into a container or a box. Subsequently, isocyanate compounds
and polyol compounds are co-injected into a container, where they
react to form polyurethane foam. If done properly, polyurethane
foam rises and fills the spaces between a wrapped article and the
walls of a container, providing a custom-fit protective packaging.
Alternatively, isocyanate compounds and polyols compounds can be
co-injected into a bag. These bags have a vent that allows some
CO.sub.2 to escape. These bags (while the reagents are reacting and
foaming) are simply placed in a container around an article being
protected and shipped, and the container is closed. As the reagents
react, the polyurethane foam in the bags rises, filling the voids
in the container, creating a custom-fit protective packaging. See
U.S. Pat. Nos. 4,800,708, 4,854,109, and 4,938,007.
[0009] The main drawback of customers synthesizing polyurethane
foams is that handling of the reactive chemicals (reagents) can be
extremely messy, and if not properly controlled, the foam
characteristics can vary from the desired properties. For instance,
inadequate foaming can result in compromised protective packaging
properties. On the other hand, excess foaming can result in
spillage. Furthermore, the foaming reagents (reactive chemicals)
are very sensitive to atmospheric conditions. Therefore, special
care is required in handling and storage of these reagents, which
can require a significant capital investment for proper storage
containers for isocyanate compounds and polyol compounds.
Furthermore, the end-users are required to purchase the systems for
pumping and co-injection of the reactive reagents, which can be
costly and difficult to maintain.
[0010] To circumvent these problems, manufacturers of protective
packaging materials have developed a deployable foam-in-a-bag
system that contains the reactive reagents. In these deployable
foam-in-a-bag systems isocyanate compounds and polyols compounds
are stored in separate pouches within a single bag. Prior to
application, pouches are ruptured and the reagents mix and react in
a bag to form foam. While the reagents are reacting to form a
polyurethane foam, the bags are simply placed in a container around
an article being shipped, and the container is closed. As the
reagents in the bag react, the polyurethane foam in the bag rises,
filling the voids in the container, and creating a custom-fit
protective packaging. See U.S. Pat. Nos. 6,398,029, 4,854,109,
5,027,583, 5,139,151, 5,699,902, and 5,873,221.
[0011] However, these deployable foam-in-a-bag systems have several
notable disadvantages. Most commonly the reactive reagents do not
completely mix which can result in foams that are structurally
inappropriate or in some cases no foam at all. Incomplete reaction
also results in unreacted isocyanate compounds, which are
environmentally undesirable and subject to regulations as such. On
the other hand, fully reacted polyurethane foams are much more
environmentally friendly. In addition, isocyanate residue can be
hazardous to an article being packaged. Furthermore, the foaming
reagents are very sensitive to atmospheric conditions. Therefore,
special care is required in sealing of the pouches and bags. In
addition, the foam-in-a-bag systems are limited in a variety of
shapes and sizes that they can deploy to. Also, the foam-in-a-bag
systems are difficult to produce in a large variety of shapes and
sizes. For these reasons, in packaging applications, the deployable
foam-in-a-bag reactive systems have had a limited success in
replacing the polymeric foam materials made from more conventional
methods.
[0012] Therefore, there is a need for polymeric foam materials that
are inexpensive to transport and store, however, that provide
adequate levels of protection for protective packaging
applications, and eliminate the need for customers to synthesize
their own polymeric foams or use reactive deployable systems.
SUMMARY OF THE INVENTION
[0013] A first embodiment of the present invention is a protective
packaging for protecting an at least one article. The protective
packaging includes a shape memory foam (SMF) structure conforming
to at least a portion of the at least one article for protecting
the at least one article. The SMF has a glass transition
temperature (T.sub.g). The SMF structure can have a T.sub.g of at
or above about 21.degree. C. The SMF structure can be rigid below
the T.sub.g and elastic above the T.sub.g. The SMF structure can
have a shape memory characteristic such that when the SMF structure
in an original shape is deformed or compressed above the T.sub.g to
produce a compressed shape and cooled in the compressed shape below
the T.sub.g, the SMF structure retains the compressed shape without
the need of external forces and when the temperature is raised
above the T.sub.g, the SMF structure returns substantially to the
original shape.
[0014] According to the first embodiment, the SMF structure can be
a thermoset or thermoplastic SMF. The SMF structure can be composed
of a structure of polyurethane foam produced by reacting an
isocycate and a polyol. The polyurethane foam can be prepared using
a polyol selected from the group comprised of an aromatic polyester
polyol, a polycarbonate polyol, a polyether polyol, and mixtures
thereof. The polyol can have an average functionality between about
2 and about 4. Further, the isocyanate can be an aromatic
isocyanate having a functionality between about 2 and about 3. The
polyurethane foam can be produced by reacting the isocyanate with
the polyol and a chain extender. Additionally, the SMF can have a
substantially open cell structure. In certain applications of the
first embodiment, the SMF is compressible to less than about 50% of
the original volume. The SMF can further include a natural or
synthetic additive. Further, the SMF structure can be at least
partially wrapped, coated, laminated, or encased in a film. The SMF
can also be hydrophobic and/or resistant to moderate levels of
ionizing or non-ionizing radiation.
[0015] According to a second embodiment of the present invention, a
method for producing a protective packaging for protecting an at
least one article is disclosed. The method includes placing a shape
memory foam (SMF) structure having a glass transition temperature
(T.sub.g) and an at least one article in a container, whereby the
SMF conforms to at least a portion of the at least one article to
protect the at least one article. The SMF can be at a temperature
of about below or about above the T.sub.g.
[0016] The second embodiment can also include the following steps:
deforming or compressing the SMF structure in an original shape to
produce a compressed shape, cooling the compressed shape to below
the T.sub.g to retain the compressed shape, raising the temperature
of the compressed shape to above about the T.sub.g to substantially
regain the original shape, whereby the original shape or the
compressed shape conforms to at least a portion of the at least one
article to protect the at least one article. The raising of the
temperature of the SMF can be accomplished by a process selected
from the group consisting of convection heating, conductive
heating, microwave heating, or chemical reaction. The cooling of
the SMF can be accomplished by a process selected from the group
consisting of free convection, forced convection, refrigeration,
conductive cooling, cooling baths, and liquid gas or nitrogen.
[0017] Additionally, the second embodiment can include the step of
providing a plurality of SMF structures and a plurality of
articles. In certain applications, the plurality of SMF structures
are stackable for protecting the plurality of articles.
[0018] According to a third embodiment of the present invention, a
method for producing a protective packaging is comprised. The
method includes providing a shape memory foam (SMF) structure
having a glass transition temperature (T.sub.g), providing a
transportation or storage container, deforming or compressing the
SMF structure to produce a compressed shape, and placing he
compressed shape in the transportation or storage container. The
compressed shape can be substantially flat. The method of the third
embodiment can further include providing a plurality of SMF
structures suitable for deforming or compressing into deformed
shapes for storing in the transportation or storage container.
[0019] The above embodiments and other embodiments and features of
the present invention are readily apparent from the following
detailed description of the best mode for carrying out the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The features of the present invention which are believed to
be novel are set forth with particularity in the pending claims.
The present invention, together with the further objects and
advantages thereof, may be best understood with reference to the
following description, taking in connection with the accompanying
drawings:
[0021] FIG. 1 is a diagram illustrating a shape memory cycle of a
shape memory foam used in accordance with an embodiment of the
present invention;
[0022] FIG. 2 is a photograph of a shape memory foam used in
accordance with an embodiment of the present invention as a
compressed sheet and in its original block shape;
[0023] FIG. 3 is a schematic of the deployment of a shape memory
foam used in accordance with an embodiment of the present invention
from a compressed shape to its original shape that is induced by
heating above the T.sub.g;
[0024] FIG. 4 describes an application in which an article (A) is
packaged in between two pieces of protective packaging made of
shape memory foams, which in elastic state, conform around an
article and the walls of a container;
[0025] FIG. 5 describes an application in which an article (A) is
packaged in between several pieces of protective packaging made of
shape memory foam, which in elastic state deform around an article
and the walls of a container;
[0026] FIG. 6 describes an application in which protective
packaging made of shape memory foam is deployed from a compressed
shape (shape II) to its original custom-made shape (shape I) at a
temperature above the T.sub.g;
[0027] FIG. 7 describes an application in which protective
packaging made of shape memory foam is deployed from a compressed
shape to its original custom-made shape at a temperature above the
T.sub.g;
[0028] FIG. 8 describes an application in which protective
packaging made of shape memory foam is deployed from a compressed
shape to its original custom-made shape at a temperature above the
T.sub.g;
[0029] FIG. 9 shows how protective packaging made of shape memory
foam can be used to protect and package two or more articles;
[0030] FIG. 10 describes an application in which a sheet of
protective packaging made of shape memory foam is applied (wrapped)
around an article while the shape-memory foam is elastic (its
temperature above the T.sub.g); and
[0031] FIG. 11 describes how protective packaging made of shape
memory foam(s) can be deformed in a die (D) at a temperature above
the T.sub.g, and then cooled in a die to a temperature below the
T.sub.g to produce a shape that custom-fit and protective one or
more articles (A).
DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION
[0032] As required, the detailed embodiments of the present
invention are disclosed herein. However, it is to be understood
that the disclosed embodiments are merely exemplary of the
invention that may be embodied in various and alternative forms.
Therefore, specific functional details disclosed herein are not to
be interpreted as limiting, but merely as a representative basis
for teaching one skilled in the art to variously employ the present
invention.
[0033] The invention will be described in more detail with
reference to the following examples, which are not intended to
restrict the scope of the invention. The protective packagings of
the present invention have a shape memory foam (SMF) as at least
one of its components.
[0034] The shortcomings in protective packaging applications of
conventional foams and the reactive systems that require customers
to synthesize polyurethane foams can be eliminated by the
protective packaging made of "shape memory foams," which above
their glass transition temperature are elastic and can regain their
original shape, and below their glass transition temperature are
rigid and can retain their original shapes or take on compressed
shapes. In other words, protective packaging made of shape memory
foams can take a compressed shape that is desirable for transport
and storage, and can take other shapes which are required for
protective packaging applications. The following references
disclose examples of shape memory foams: U.S. Pat. Nos. 5,049,591,
5,093,384, 5,418,261, and Tey et al., Smart Materials and
Structures, 2001, 10, 321-325. The present invention meets this
objective with the protective packaging that has for at least one
of its components a shape memory foam, which has shape memory
characteristics.
[0035] Therefore, one aspect of the present invention is to provide
the protective packaging that has for at least one of its
components a polymeric foam that has shape memory characteristics.
The protective packaging that can be easily compressed (deformed)
into a shape that is convenient for storage and transportation, and
that can substantially regain its original shape or take on other
shapes needed in the protective packaging applications.
[0036] In certain embodiments, the shape memory foam can be a
thermoset or thermoplastic polyurethane foam, having a glass
transition temperature, T.sub.g, which can be above about room
temperature, which is commonly referenced at about 21.degree. C.,
in certain embodiments, above about 35.degree. C., and in other
embodiments above 50.degree. C. The foam is rigid below the T.sub.g
and elastic above the T.sub.g. The foam has shape memory
characteristics such that when it is compressed (deformed) at a
temperature above the T.sub.g and cooled in that compressed
(deformed) shape to a temperature that is below the T.sub.g, the
foam remains in that compressed shape without any aid from an
outside force, and when the temperature is then raised above the
T.sub.g the foam returns substantially to its original shape and
size. In other words, the foam possesses hibernated elastic memory
of its original shape in the rigid state and is called "shape
memory foam."
[0037] For the purpose of this invention, the T.sub.g refers to a
temperature at which the polymer undergoes a transition from
elastic to rigid, as determined by differential scanning
calorimetry or dynamic mechanical analysis. In certain embodiments,
the shape memory foams used in this invention have a single
T.sub.g. In certain embodiments, if the shape memory foam has a
broad glass transition or multiple glass transitions, the lowest
temperature at which the glass transition occurs can be above about
room temperature. In other embodiments, the glass transition
temperature can be below about room temperature.
[0038] The protective packaging of the present invention is heated
above the T.sub.g of shape memory foam until it becomes elastic, at
which point it is compressed (deformed) from its original shape
(which can be of any size and shape) into a shape that occupies
less volume, and it is cooled in that compressed shape to a
temperature below the T.sub.g until rigid. The protective packaging
remains in that compressed shape without any aid of an outside
force as long as it is kept at a temperature below the T.sub.g. The
protective packaging in a compressed shape can be packed, stored,
and transported.
[0039] Prior to packaging applications, the protective packaging of
the present invention is heated above the T.sub.g until it regains
its original shape. At this point, when the protective packaging
has substantially regained its original shape and while still
elastic (its temperature above the T.sub.g), it can be placed in
between an article that is being protected and packaged and the
walls of a box (or a container). Since the shape memory foam is
elastic while above the T.sub.g, the protective packaging will
conform around at least a portion of an article and once the shape
memory foam cools below its T.sub.g, it rigidizes and provides a
custom-fit protective cushion.
[0040] While elastic, the protective packaging of the present
invention can be wrapped around one or more articles, once it is
cooled below its T.sub.g, it rigidizes around the article(s). At
this point, the wrapped article(s) can be placed into a container,
however, that may not always be necessary.
[0041] On the other hand, prior to application in packaging, the
protective packaging of the present invention in a compressed shape
is heated above the T.sub.g until it becomes elastic and regains
its original shape. At this point, the protective packaging is
cooled in its original shape to a temperature below the T.sub.g to
rigidize. The original shape of the protective packaging can be
designed to provide a custom-fit to a specific article (or several
articles), which provides a custom-fit protective packaging. In
certain embodiments, the article in the protective packaging is
placed in a box (or a container).
[0042] Alternatively, the shape needed to custom-fit one or more
articles can be achieved by pressing the protective packaging of
the present invention in its original shape, into a die at any
temperature, but in certain embodiments at a temperature above the
T.sub.g, followed by cooling below the T.sub.g at which point the
protective packaging will remain in a deformed (compressed) shape
that is a negative of the topology of a die.
[0043] SMFs are polymeric foams that have shape memory
characteristics. An example of shape memory characteristics is
illustrated in FIG. 1. The illustration shows a SMF that is a block
in its original shape (shape I). SMFs are rigid below the glass
transition temperature (T.sub.g) and elastic above the T.sub.g. For
most packaging applications, the T.sub.g of a SMF needs to be above
room temperature, which is commonly referenced at about 21.degree.
C. When heated to a temperature above the T.sub.g, the flexibility
of a SMF allows it to be compressed (deformed) from its original
shape (shape I) into a compressed shape (shape II). When the
temperature of a SMF, which is in its compressed shape (shape II),
is brought to a temperature below the T.sub.g, it becomes rigid and
no external forces are required to keep it in a compressed shape,
i.e. the foam is "frozen" in that shape. Subsequently, when the
temperature of a SMF is brought to a temperature above the T.sub.g,
it becomes flexible again and it expands to restore its original
size and shape of a block (shape I). At this point, when cooled to
a temperature below the T.sub.g, the foam rigidizes in its original
shape (shape I). The cycle illustrated in FIG. 1 can be
repeated.
[0044] In certain embodiments, SMFs used in the protective
packaging of the present invention should have a T.sub.g greater
than about 21.degree. C. so that the foam is rigid at room
temperature. In other embodiments, SMFs can have a T.sub.g of at
least about 35.degree. C., and in other embodiments of at least
about 50.degree. C. In certain embodiments, SMFs used in the
protective packaging of the present invention could have a T.sub.g
lower than about 21.degree. C.
[0045] In certain embodiments, SMFs used in the protective
packaging of the present invention have an open cell structure. The
open cell structure can be achieved in various ways, for example by
appropriate selection of cell openers and/or surfactants, or by
standard reticulation (elimination of cell windows) methods applied
on foams at flexible (elastic) state above the T.sub.g. The open
cell structure of the foam allows it to be compressed to less than
its original volume. In certain embodiments, SMFs are compressible,
without significant damage to its structure and its properties, to
less than about 20% of its original volume, in other embodiments,
less than about 10%, and in yet other embodiments, about 5%. The
foam can substantially recover its original volume and shape when
its temperature is raised above the T.sub.g.
[0046] In certain embodiments, SMFs used in the protective
packaging of the present invention can have good heat resistance so
that they can go through multiple cycles of shape changes without
significant damage to its structure and properties. In certain
embodiments, SMFs are substantially undamaged at a temperature of
about 120.degree. C. In certain embodiments, the SMFs used in the
protective packaging of the present invention have good resistance
to water. In certain embodiments, the SMFs used in the protective
packaging of the present invention can be resistant to moderate
levels of ionizing (alpha, beta, gamma, x-ray) and non-ionizing
(ELF, VLF, RF, Microwave) radiation.
[0047] As non-limiting examples of composition and for preparation
of polyurethane SMF, an isocyanate component and a polyol component
can be mixed in the ratios presented in Tables 1-2, corresponding
to Examples 1-6 and 7-12. Surfactants, cell openers, blowing
agents, and catalysts were also added as indicated in Examples
1-12. The mixture is poured into a mold and the reaction occurs at
room temperature. Post curing of resulting foam at higher
temperatures followed, but is not always necessary. After curing,
the foams were crushed at a temperature above the T.sub.g to
produce an open cell structure. The foam is then cut into a desired
shape as required for a protective packaging application.
[0048] Some non-limiting examples of suitable aromatic polyester
polyols are ortophthalic diethylene glycol polyester polyols with
functionality of 2, such as Stepanol PS-2002 (equivalent weight of
288) and Stepanol PS-1752 (equivalent weight 316) sold by Stepan
Company. Other non-limiting types of aromatic based polyester
polyols can also be used for preparation of SMFs, including
terephthalate based polyols manufactured utilizing dimethyl
terephthalate (such as Terate polyols, KOSA) or polyethylene
terephthalate (such as Terol polyols, OXIDE).
[0049] In addition to the aromatic polyester polyols, polycarbonate
polyols can also be used to prepare the foams of SMFs, such as
poly(cycloaliphatic carbonate) polyol PC 1667 (Stahl USA). These
polyols are also characterized with great rigidity. Advantageously,
aromatic polyester polyols and polycarbonate polyols produce a foam
having good heat resistance, good moisture (water) resistance, and
good radiation resistance.
[0050] A combination of aromatic polyester polyols and
polycarbonate-based polyols, as well as mixtures of these polyols
with other polyols such as polyether-based polyols, and mixtures of
these polyols with chain extenders (e.g., short chain aromatic or
aliphatic diols or diamines) can be used to prepare SMFs. In
certain embodiments, the average functionality of polyol mixtures
is between about 2 and 4, in other embodiments, between about 2 and
3, and in yet other embodiments, between about 2 and 2.3.
[0051] The polyol is reacted with an isocyanate in the preparation
of polyurethane SMF. In certain embodiments, the isocyanate is an
aromatic isocyanate having a functionality between 2 and 3, in
other embodiments, between 2 and 2.7, and in yet other embodiments,
between 2 and 2.4. Two examples of suitable aromatic isocyanates
include Lupranate M10 (polymeric diphenylmethane diisocyanate
having a functionality of 2.2 and an equivalent weight of 132) sold
by BASF, and Isonate 50 O,P" (2,4-/4,4'-diphenylmethane
diisocyanate having a functionality of 2.0 and an equivalent weight
of 125) sold by Dow. Some examples of chain extenders are ethylene
glycol, 1,4-butanediol, hydroquinone (2-hydroxyethyl)ether, and
aromatic secondary diamines such as Unilink 4200 (UOP).
[0052] In addition to the polyol and the isocyanate, the
polyurethane SMF can also include other components typically used
in foams, such as blowing agents, cell openers, catalysts and
surfactants. Some examples of suitable blowing agents include water
(reaction with isocyanate gives CO.sub.2), low-boiling organic
compounds (e.g., hydrocarbons and halogenated hydrocarbons such as
methylene chloride, dichlorofluoroethane, pentane, hexane, and
various refrigerants), acetone, "azo" compounds which generate
nitrogen, and the like. An example of a suitable cell opener is
Ortegol 501 (Goldschmidt). Some examples of suitable catalysts
include stannus octoate, tertiary amine compounds such as
triethylene diamine, bis(dimethylaminoethyl)ether, and
organometallic compounds. Some examples of suitable surfactants
include silicone surfactants and alkali metal salts of fatty
acids.
EXAMPLES 1-6
[0053] Table 1 discloses polyurethane foam formulations and their
properties in Examples 1-6 that can be used in the protective
packaging of the present invention. The component values are in
grams.
1 TABLE 1 1 2 3 4 5 6 Component Polyol A -- 50 50 50 50 50 Polyol B
50 -- -- -- -- -- Polyol C -- -- -- -- -- -- Surfactant -- 0.17
0.17 0.25 0.25 0.25 Cell Opener -- 0.5 0.15 0.11 0.10 0.10 Water
2.0 0.8 0.8 0.4 0.1 -- Blowing Agent -- 14.0 14.0 14.0 14.0 14.0
Catalyst A 0.3 0.15 0.15 0.15 0.10 0.05 Catalyst B -- 0.05 0.06
0.10 0.10 0.10 Isocyanate A 50.2 34.7 34.7 28.9 24.4 23.0
Isocyanate B -- -- -- -- -- -- Properties Isocyanate Index 100 100
100 100 100 100 Density (Pcf) 2.7 1.4 1.6 1.5 1.8 1.7 T.sub.g (DSC)
-- 42.degree. C. -- 41.degree. C. 40.degree. C. 41.degree. C.
T.sub.g (DMA) -- 54.degree. C. -- 57.degree. C. 54.degree. C.
49.degree. C. Polyol A: Stepanpol PS-2002, Stepan
[ortophtalate-diethylene glycol polyester polyol (eq. wt. 288;
functionality 2)] Polyol B: Stepanpol PS-1752, Stepan
[ortophtalate-diethylene glycol polyester polyol (eq. wt. 316;
functionality 2)] Polyol C: Terate 203, KOSA [terephthalate based
polyol manufactured utilizing dimethyl terephthalate (eq. wt. 180;
functionality 2.3)] Surfactant: Dabco DC 193, Air Products
(non-hydrolyzable silicone surfactant) Cell Opener: Ortegol 501,
Goldschmidt Blowing Agent: Genetron 141-b, Allied Signal
[dichlorofluoroethane] Catalyst A: Dabco 33LV, Air products [33%
triethylene diamine in dipropylene glycol] Catalyst B: Niax A-1,
Urethane Additives [70% bis(dimethylaminoethyl)ether and 30%
dipropylene glycol] Isocyanate A: Lupranate M10, BASF [polymeric
diphenylmethane diisocyanate (eq. wt. = 132; functionality 2.2)]
Isocyanate B: Isonate 50 O, P", Dow [2,4-/4,4'-diphenylmethane
diisocyanate (eq. wt. = 125; functionality 2.0)] DSC: differential
scanning calorimetry. DMA: dynamic mechanical analysis.
EXAMPLES 7-12
[0054] Table 2 discloses foam formulations and their properties in
Examples 7-12 that can be used in the protective packaging of the
present invention. The component values are in grams. The specific
components are the same as disclosed in Examples 1-6.
2 TABLE 2 7 8 9 10 11 12 Component Polyol A -- -- -- -- -- --
Polyol B -- -- -- -- -- -- Polyol C 50 50 50 50 50 50 Surfactant
0.2 0.25 0.25 0.25 0.25 0.25 Cell Opener 0.5 0.5 0.5 0.2 0.1 0.2
Water 1.0 0.8 0.1 0.05 -- 0.05 Blowing Agent 12 13 12 14 14 14
Catalyst A 0.4 0.25 0.2 0.05 0.05 0.05 Catalyst B 0.1 0.01 0.01 0.1
0.1 0.1 Isocyanate A 51.3 48.4 38.1 37.4 36.7 -- Isocyanate B -- --
-- -- -- 35.4 Properties Isocyanate Index 100 100 100 100 100 100
Density (Pcf) 2.0 1.8 1.9 1.7 1.8 2.0 T.sub.g (Dsc) -- 73.degree.
C. -- -- -- 69.degree. C. T.sub.g (DMA) -- -- -- -- -- --
[0055] Besides the foams described in Examples 1-12, any thermoset
or thermoplastic foam exhibiting the shape memory characteristics,
and the blends thereof, can be used in protective packaging of the
present invention, that include but are not limited to foams based
on polyurethane chemistry, polyurea chemistry, or any other
chemistries or methods that produce foams which exhibit shape
memory characteristics.
[0056] In addition, blends of SMFs with other thermoplastic and
thermoset polymers can be used in the protective packaging of the
present invention, as well as composites of SMFs with other
polymeric materials, organic or inorganic fibers, glass fibers,
carbon black, substrates made of natural fibers, or woven and
non-woven substrates. Also, in the protective packaging of the
present invention, additives can be added to SMF to change its
mechanical, thermal, and surface properties, resistance to
biological agents, resistance to ionizing and non-ionizing
radiation, as well as its affinity to water.
[0057] In the protective packaging of the present invention, SMFs
can be wrapped, laminated, coated, or enclosed with polymeric
sheets or thin films, which can be thermoplastic or thermosetting,
which may not have shape-memory characteristics, but can have
shape-memory characteristics. SMFs used in the protective packaging
of the present invention can also be wrapped, laminated, or
enclosed with sheets or thin film made of natural fibers. SMFs used
in the protective packaging of the present invention can be
laminated, coated, wrapped or enclosed with sheets or thin films at
any point before application in protective packaging. In addition,
articles to be packaged can be wrapped, laminated, or enclosed with
sheets or thin films, made of thermoplastic or thermosetting
polymers, woven or non-woven materials, or natural fibers.
[0058] Heating of the protective packaging of the present invention
can be achieved by several methods that include, but are not
limited to, convection ovens of any type, microwave ovens of any
type, free or forced convective heating, conductive heating,
radiation, light, electric field, magnetic field, ultrasound, or
chemical reaction. Cooling of the protective packaging of the
present invention can be achieved by several methods that include,
but are not limited to: free convection, forced convection,
refrigeration, conductive cooling, cooling baths, liquid or gas
nitrogen, or any other cooling gas or liquid. The heating and/or
cooling source can be imbedded to be a part of the protective
packaging of the present invention.
[0059] FIG. 1 shows that the SMF used in the protective packaging
of the present invention in shape I can be compressed into shape II
at a temperature above its T.sub.g, and once cooled in that
compressed shape to a temperature below its T.sub.g, it rigidizes
and remains in shape II without any aid from an outside force. In
compressed shape II, at temperatures below its T.sub.g, the
protective packaging made of SMFs can be packaged, transported, and
stored.
[0060] FIG. 2 shows an example of a polyurethane SMF, prepared
according to Example 2, at a temperature below its T.sub.g, in its
original block shape and compressed sheet shape. The SMF can be
produced in a variety of shapes and sizes and compressed (deformed)
to a variety of shapes and sizes.
[0061] As depicted in FIG. 3, prior to protective packaging
applications, a compressed sheet of the protective packaging made
of SMFs is heated to a temperature above the T.sub.g until it
substantially regains its original shape (shape I).
[0062] In its original shape, at a temperature above its T.sub.g,
the protective packaging made of SMFs can be used in the packaging
applications as described in FIGS. 4 and 5. Two or more pieces of
the protective packaging, which are above the T.sub.g in their
original shape, can be placed between an article and the walls of a
container, after which point a container is closed. Since the SMFs
are elastic while above the T.sub.g the protective packaging will
conform to the shape of an article and substantially fill the voids
in a closed container. Once the SMF cools below the T.sub.g, the
foam rigidizes and provides a custom-fit protective packaging for
the article being protected.
[0063] FIGS. 6, 7, and 8 show how SMFs used in the protective
packaging of the present invention can be pre-molded or cut into
original shapes that custom-fit articles that are being shipped and
protected, and snugly fit in a container (or a box). The SMFs can
be compressed at a temperature above the T.sub.g, and when cooled
in compressed shapes to a temperature below their T.sub.g they
remain in those shapes without the need of an outside force. In
compressed shapes, at temperatures below its T.sub.g, the packaging
made of SMFs can be packaged, transported, and stored. Prior to
protective packaging application, a custom-made shape of the SMF is
regained after heating to a temperature above their T.sub.g. The
SMF can be cooled below the T.sub.g in custom-made original shapes
to rigidize before application in protective packaging. In certain
embodiments, articles encased in the protective packaging made of
shape memory foams are placed into a container or a box.
[0064] FIG. 6 describes an application in which the protective
packaging of the present invention made of shape memory foam is
deployed from a compressed shape (II) to its original custom-made
shape (I) at a temperature above the T.sub.g. Once cooled below the
T.sub.g in its original custom-made shape, the protective packaging
made of shape memory foams can be used to custom-fit an article
that is being packaged. In certain embodiments, the protective
packaging is designed to snugly fit into a box or a container.
However, in certain applications it may not be necessary to place
an article in the protective packaging in a box or a container. The
protective packaging can be designed to custom-fit one or more
articles that can have same or different topologies.
[0065] FIG. 7 describes an application in which the protective
packaging of the present invention made of shape memory foam is
deployed from a compressed shape to its original custom-made shape
at a temperature above the T.sub.g. Once cooled below the T.sub.g
in its original custom-made shape(s), several pieces of the
protective packaging can be used to custom-fit one or more
articles, that can have same or different topologies. In certain
embodiments, an article in the protective packaging can be placed
in a box or a container and the protective packaging can be
designed to snugly fit into a box or a container.
[0066] FIG. 8 describes an application in which the protective
packaging of the present invention made of shape memory foam is
deployed from a compressed shape to its original custom-made shape
at a temperature above the T.sub.g. Once cooled below the T.sub.g
in its original custom-made shape(s), one or more pieces of the
protective packaging can be used to custom-fit one or more
articles, and to snugly fit into a box or a container, without
having to completely fill the void in a container or a box.
[0067] FIG. 9 illustrates how several articles can be packaged in a
container by using several pieces of the protective packaging of
the present invention. In certain embodiments, the shape of the
protective packaging can be specially designed for the purpose of
stacking and to custom-fit articles. However, the packaging as
described in FIGS. 4 and 5 might be adequate for certain types of
packaging.
[0068] FIG. 10 depicts the protective packaging of the present
invention used to wrap or encase an object. FIG. 10 illustrates
using a sheet of the protective packaging made of SMFs at a
temperature above the T.sub.g to encase a cylinder. Once cooled
below the T.sub.g, the protective packaging remains around a
cylinder. Similarly, articles of different shapes and sizes can be
wrapped or encased with one or more pieces of the protective
packaging. Furthermore, articles of different shapes and sizes can
be partially or fully wrapped or covered with the protective
packaging of the present invention. Articles encased in the
protective packaging do not have to be placed into a container or a
box, but can be placed into a container or a box.
[0069] FIG. 11 describes how the protective packaging of the
present invention made of shape memory foam(s) can be deformed in a
die (D) at any temperature, but in some embodiments at a
temperature above the T.sub.g, and then cooled in a die to a
temperature below the T.sub.g to produce a shape that is a negative
of the topology of a die. By using this method a shape can be
produced to custom-fit and protective one or more articles (A) as
was described in FIGS. 6-9.
[0070] SMFs can also be used as loose-fill packing particles. SMF
particles used in this application can vary in size and shape. The
particles can be transported and stored in compressed shapes. Prior
to applications in packaging, the particles can substantially
regain its original shape and volume by heating above the T.sub.g,
at which point they can be applied as loose-fill packing material.
These loose-fill packing materials can be made by cutting larger
pieces of SMF into smaller particles at temperatures below or above
the T.sub.g. In certain embodiments, when the loose-fill particles
are being cut out of large pieces of SMF, these large pieces of SMF
are in compressed (compacted) shape at a temperature below the
T.sub.g.
[0071] For added levels of protection, articles to be packaged can
be wrapped, encased, or laminated with sheets or thin films
composed of polymeric materials, woven and non-woven materials, and
natural fiber materials, before they are packaged with the
protective packaging of the present invention. In addition, in the
protective packaging of the present invention, SMF, or the blends
there of, can be laminated, coated, wrapped, or encased in other
materials, such as polymeric materials, woven and non-woven
materials, and natural fiber materials. In addition, SMFs can be
laminated, wrapped, encased, or coated with flexible,
semi-flexible, or viscoelastic materials that are made of synthetic
polymers or natural materials. SMFs can be laminated, coated,
wrapped, or encased during or right after manufacture of SMFs,
before, during, or after transport, or immediately before
application in protective packaging applications.
[0072] Protective packaging comprised of shape memory polymeric
foam and methods of using shape memory polymeric foam in protective
packaging applications as disclosed in this patent can be applied
to, but are not limited to, packaging of electronics, such as
computers, monitors, printers, cameras, electronic components, food
items, glass items, furniture, and any other article that require
protective packaging.
[0073] While embodiments of the invention have been illustrated and
described, it is not intended that these embodiments illustrate and
describe all possible forms of the invention. Rather, the words
used in the specification are words of description rather than
limitation, and it is understood that various changes may be made
without departing from the spirit and scope of the invention.
* * * * *