U.S. patent application number 12/839902 was filed with the patent office on 2011-02-03 for thermal insulation unit.
This patent application is currently assigned to E.I. DU PONT DE NEMOURS AND COMPANY. Invention is credited to JACQUES ANDRE, LOIC PIERRE ROLLAND.
Application Number | 20110024433 12/839902 |
Document ID | / |
Family ID | 42857190 |
Filed Date | 2011-02-03 |
United States Patent
Application |
20110024433 |
Kind Code |
A1 |
ROLLAND; LOIC PIERRE ; et
al. |
February 3, 2011 |
THERMAL INSULATION UNIT
Abstract
A container has contained therein a phase change material (PCM).
An article or product comprises an insulation unit and the
container, which may be in close proximity to the insulation unit.
The container can be produced from a film or sheet containing a
barrier layer and, optimally, a sealant layer, to prevent the PCM
from leaking out of the container.
Inventors: |
ROLLAND; LOIC PIERRE;
(DIVONNE LES BAINS, FR) ; ANDRE; JACQUES;
(ANNEMASSE, FR) |
Correspondence
Address: |
E I DU PONT DE NEMOURS AND COMPANY;LEGAL PATENT RECORDS CENTER
BARLEY MILL PLAZA 25/1122B, 4417 LANCASTER PIKE
WILMINGTON
DE
19805
US
|
Assignee: |
E.I. DU PONT DE NEMOURS AND
COMPANY
Wilmington
DE
|
Family ID: |
42857190 |
Appl. No.: |
12/839902 |
Filed: |
July 20, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61229800 |
Jul 30, 2009 |
|
|
|
Current U.S.
Class: |
220/592.2 |
Current CPC
Class: |
B32B 2437/02 20130101;
B32B 2419/00 20130101; B32B 2266/0278 20130101; B32B 27/34
20130101; B32B 2262/108 20130101; B32B 7/08 20130101; B32B 13/12
20130101; B32B 2307/514 20130101; F28D 2020/0008 20130101; C09K
5/063 20130101; B32B 27/306 20130101; F28F 2270/00 20130101; B32B
2437/00 20130101; B32B 13/02 20130101; Y02E 60/145 20130101; B32B
2266/0271 20130101; B32B 2439/06 20130101; B32B 1/02 20130101; B32B
7/12 20130101; B32B 2307/30 20130101; B32B 2262/101 20130101; B32B
2266/0228 20130101; Y02E 60/14 20130101; B32B 2307/304 20130101;
B32B 2255/205 20130101; B32B 2439/00 20130101; B32B 27/08 20130101;
B32B 27/20 20130101; B32B 27/18 20130101; B32B 27/32 20130101; B32B
2307/31 20130101; B32B 27/065 20130101; B32B 27/308 20130101; B32B
2255/10 20130101; B32B 2262/06 20130101; F28D 20/02 20130101; B32B
27/12 20130101; B32B 2270/00 20130101; B32B 2307/58 20130101; B32B
2439/46 20130101; B32B 27/304 20130101; B32B 27/22 20130101; B32B
27/365 20130101; B32B 2439/70 20130101; B32B 27/30 20130101; B32B
27/36 20130101 |
Class at
Publication: |
220/592.2 |
International
Class: |
B65D 81/38 20060101
B65D081/38 |
Claims
1. An article comprising a container and a phase change material
wherein the container includes a pouch or a bag; the container has
contained therein at least one phase change material; the container
comprises or is produced from a film or sheet; the film or sheet
includes single layer or multilayer structure comprises at least
one barrier layer; the multilayer structure comprises at least one
sealant layer and at least one barrier layer; the sealant layer
include copolymer of ethylene (meth)acrylic acid, ionomer derived
from copolymer of ethylene (meth)acrylic acid, or combinations
thereof; the barrier layer includes ethylene vinyl alcohol
copolymer, polyamide, polyester, polyvinylidene chloride,
polycarbonate, or combinations of two or more thereof; and
2. The article of claim 1 wherein the film or sheet is permeable to
the phase change material at less than 0.2 g/m.sup.2/24 hr.
3. The article of claim 2 wherein the multilayer structure is
permeable to the phase change material at less than 0.3
g/m.sup.2/24 hr.
4. The article of claim 3 wherein the multilayer structure is
permeable to the phase change material at less than 0.5
g/m.sup.2/24 hr.
5. The article of claim 4 wherein the container is a sealed
pouch.
6. The article of claim 5 wherein the phase change material is the
paraffin; the sealant layer is the ionomer; and the barrier layer
is polyamide.
7. The article of claim 4 wherein the phase change material is a
polymer matrix containing the paraffin.
8. The article of claim 7 wherein the container is a sealed pouch;
the sealant layer is the ionomer; and the barrier layer is
polyamide.
9. The article of claim 6 wherein the (meth)acrylic acid is
partially or completely neutralized with Zn ions and the insulation
layer is the expanded polystyrene foam.
10. The article of claim 8 wherein the (meth)acrylic acid is
partially or completely neutralized with Zn ions and the insulation
layer is the expanded polystyrene foam.
11. The article of claim 2 wherein the container is a component of
a thermal insulation unit comprising at least one insulation layer
and at least one container wherein the insulation layer includes
expanded polystyrene foam, mineral wool, foamed polyurethane,
vermiculite, fiber-cement board, plaster walls, compressed wheat
straw, foamed epoxy, drywall, wood based insulting materials,
blankets, loose-fill, or rigid systems with materials such as rock
wool, fiber glass, cellulose, polyurethane foam, extruded
polystyrene foam, polyurethane foam, polyisocyanurate foam, or
combinations of two or more thereof.
12. The article of claim 11 wherein the multilayer structure is
permeable to the phase change material at less than 0.3
g/m.sup.2/24 hr.
13. The article of claim 12 wherein the multilayer structure is
permeable to the phase change material at less than 0.5
g/m.sup.2/24 hr.
14. The article of claim 13 wherein the container is a sealed
pouch; the phase change material is paraffin; the sealant layer is
the ionomer; and the barrier layer is polyamide.
15. The article of claim 13 wherein the phase change material is a
polymer matrix containing the paraffin; the sealant layer is the
ionomer; and the barrier layer is polyamide.
16. The article of claim 14 wherein the (meth)acrylic acid is
partially or completely neutralized with Zn ions and the insulation
layer is the expanded polystyrene foam.
17. The article of claim 15 wherein the (meth)acrylic acid is
partially or completely neutralized with Zn ions and the insulation
layer is the expanded polystyrene foam.
18. The article of claim 11 wherein the article comprises at least
one additional insulating layer positioned adjacent to the
container or to the insulation layer.
19. The article of claim 11 wherein the article is a component of
cloth, shoe, glove, sock, sleeping bag, tent, food container,
beverage container, or combinations of two or more thereof; and the
article is thermal insulation unit comprising at least one
insulation layer and at least one container wherein the insulation
layer includes expanded polystyrene foam, mineral wool, foamed
polyurethane, vermiculite, fiber-cement board, plaster walls,
compressed wheat straw, foamed epoxy, drywall, wood based insulting
materials, blankets, loose-fill, or rigid systems with materials
such as rock wool, fiber glass, cellulose, polyurethane foam,
extruded polystyrene foam, polyurethane foam, polyisocyanurate
foam, or combinations of two or more thereof.
20. The article of claim 11 wherein the article is a personal
protection.
Description
[0001] This application claims priority to U.S. provisional
application 61/229,800, filed Jul. 30, 2009; the entire disclosure
of which is incorporated herein by reference.
[0002] The invention relates to thermal insulation units comprising
phase change materials.
BACKGROUND OF THE INVENTION
[0003] There is a general desire in all technical fields to be
energy efficient. In the building industry, for example, there is a
permanent need to decrease the energy costs related to heating and
cooling indoor rooms. The same applies also to the textile
industry, for instance, for protective clothing, and sportswear,
where it is often necessary to conduct excess heat away from a
person's body in order to increase the overall comfort.
Phase change materials (PCMs) are latent thermal storage materials
that are capable of absorbing and releasing high amounts of latent
heat during melting and crystallization, respectively. The thermal
energy transfer occurs when a material is transformed from a solid
to a liquid phase or from a liquid to a solid phase. During such
phase changes, the temperature of the PCM material remains nearly
constant as does the space surrounding the PCM material, the heat
flowing through the PCM being "entrapped" within the PCM itself.
Among other well-known PCMs, paraffin is frequently used as PCM
because of its low cost and low toxicity.
[0004] PCMs can be introduced into matrices composed of different
materials or they can be applied to coatings. See, e.g., U.S. Pat.
No. 4,003,426, U.S. Pat. No. 4,528,328, U.S. Pat. No. 5,053,446,
US20060124892 (WO2006/062610), WO98/04644, and WO2004/044345.
[0005] PCM can be incorporated into construction materials such as
gypsum wallboards and other aggregate construction panels (see,
.e.g, U.S. Pat. No. 4,797,160, U.S. Pat. No. 4,988,543, U.S. Pat.
No. 5,349,798, and WO96/039473). When used in modern building
applications, PCM-containing panels can also be incorporated into
the panels or walls together with more traditional building
materials, such as, for example, mineral wool, foamed styrene,
gypsum boards, bricks, and the like. When PCM-containing panels are
utilized within walls, an insulating layer comprising, for example,
mineral wool or expanded polystyrene can be placed on the external
side of the PCM-containing panels. This insulating layer thermally
isolates the PCM-containing panels and diminishes the quantity of
heat the panels absorb, thereby improving the overall thermal
performance of the insulated wall.
[0006] In building applications, PCMs may perform well in small
containers, usually divided into cells. See, e.g., U.S. Pat. No.
6,412,545 and U.S. Pat. No. 6,482,332. The cells are shallow to
reduce static head--based on the principle of shallow container
geometry. PCM in containers of different sizes can be mounted
inside the walls. However, after absorbing enough heat to undergo
phase transition, the PCMs liquefy and flow to the bottom of the
containers. After the temperature decreases, they solidify and
remain in the altered position. This leads to an inhomogeneous
distribution of PCM in the container itself that results in a
decrease in insulation performance.
[0007] Solutions to this problem that have been proposed include
employing a polymer matrix that absorbs and binds the PCM, even in
its liquid state. For example, WO2006/062610 discloses blends of
polymer matrix and PCM which retain their shape even above the
melting point of the PCM itself. Such blends are processed into
thermal insulation panels, for example, by sandwiching them between
metal foil layers whereby the exposed flanges of the panels are
covered with adhesive tape, for example. Despite good retention of
the PCM material within the polymer matrix and a good degree of
tightness of the panel itself, some leakage may nevertheless occur
through unwanted creases that are formed by folding the adhesive
metal tape around the flanges of the panel. The leakage leads to a
decrease in the amount of PCM material in the thermal insulation
panels and therefore negatively affects their performance.
Furthermore, the released PCM can permeate into adjacent porous
building material such as drywall or gypsum boards and causes
irremovable stains which may become visible on the exterior of the
building walls. This problem is exacerbated when the shapes of the
PCM panels become more complex, such as for example polygons and
circular shapes, because the number of potential leakage sites
increases with increasing number of flanges.
[0008] In order to simplify production routine, it is desirable to
provide a sealing solution that is unaffected by the aforementioned
formation of unwanted creases.
[0009] The metal sheets used as barrier layers are easily punctured
because their thickness is in the range of 100 .mu.m. Increasing
the thickness of the metal sheet results in an undesirable
augmentation of rigidity, weight, and cost.
[0010] It would be desirable to provide a PCM-containing article
overcoming the problems mentioned above.
SUMMARY OF THE INVENTION
[0011] A container comprises, consists essentially of, consists of,
or is produced from, a film or sheet wherein the container includes
a pouch or a bag; the film or sheet may be a single layer or
multilayer structure; the film or sheet comprises, consists
essentially of, consists of, or is produced from, at least one
barrier layer and optionally a sealant layer; and the film or sheet
can have barrier properties to PCM.
[0012] A container comprises at least one phase change material in
the container, which can be the same as that disclosed above.
[0013] A thermal insulation unit comprises, consists essentially
of, consists of, or is produced from, at least one thermal
insulation layer and at least one container wherein the insulation
layer or a portion thereof can be in close proximity with one or
more containers and the container has contained therein at least
one phase change material.
[0014] A panel comprises, consists essentially of, consists of, or
is produced from the above-described insulation unit
DETAILED DESCRIPTION
[0015] Trademarks are shown in capital letters.
[0016] The term "produced from" is an open-ended term indicating
that it does not exclude any elements that are not disclosed or
recited. For example, when a multilayer structure is produced from
a sealant layer and a barrier layer, the structure may comprise
additional layer(s).
[0017] All references disclosed are incorporated herein by
reference.
[0018] A container can include a bag or pouch having a size that
can be fixed in placed inside a construction panel or wall material
as discussed above in the Background. For example, a container can
have an area of about 1 to about 500, 2 to 200, 3 to 100, 4 to 50,
or 5 to 10 cm.sup.2 or any other convenient size that fits within
the construction panels.
[0019] The container can have any shape such as rectangular,
square, round, triangle, etc.
[0020] The container or a portion of the container can contain one
or more PCMs that can be of organic nature, such as hydrocarbons,
salt hydrates (e.g., M.sub.nH.sub.2O), or eutectic (e.g.,
organic-organic, organic-inorganic, inorganic-inorganic compounds).
Hydrocarbon includes alkanes. Alkanes having the formula
C.sub.nH.sub.2n+2 or paraffins are preferred PCMs. Such PCMs can be
used in building applications, as they are non-toxic, readily
available and have melting points within the temperature range used
for human habitation. The crystallization of the aliphatic chain
releases a large amount of the latent heat. Both the melting point
and the heat of fusion increase with increasing chain length.
Therefore, it is possible to select the paraffin, or mixtures
thereof, in such a way that the phase change temperature (melting
point) matches with the temperature range of the system in which
they are applied.
[0021] The PCM can be blended with a polymer matrix as described in
WO2006/062610 (or US20060124892) the disclosure of which is
incorporated herein by reference. The blend of PCM and polymer
matrix can comprise, based on the total weight of the blend, 5 to
90, 10 to 90, or to 80% of a PCM and the balance one or more
polymers including polyethylene (e.g., very low density
polyethylene or low density polyethylene), ethylene propylene
rubber (such as ethylene propylene diene methylene or ethylene
propylene methylene), styrenic copolymers (e.g., styrene ethylene
butadiene styrene copolymer or styrene butadiene styrene
copolymer), or combiations of two or more thereof. The polyethylene
and ethylene propylene rubber may have any density known to one
skilled in the art such as about 0.88 to about 0.92 g/cm.sup.3.
[0022] The matrix may be of low polarity and crystallinity.
[0023] The blend of PCM and polymer can be produced by any means
known to one skilled in the art. For example, a blend of PCM and
polymer matrix can be produced by soaking different component(s)
all together at temperatures which are slightly above the melting
point of the PCM but below the melting point of one or more
polymers. Soaking is a natural absorption of the molten PCM by the
polymer(s). The components can be mixed together in a tumble
blender for a certain period of time such as 1 to 10 hours or about
8 hours.
[0024] The blend of PCM and polymer can also be produced by melt
blend extrusion whereby the components are blended at temperatures
above the melting point of both the one or more polymers and the
PCM, the thus obtained mixture being subsequently extruded into
granules or directly into sheets or any other suitable form.
[0025] The film or sheet can comprise one or more barrier layers
that have barrier properties to PCM which can prevent the
permeation of PCM though the film or sheet.
[0026] The film or sheet may be substantially impermeable to a PCM
and may have a permeability of less than 0.5 g per square meter per
day (0.5 g/m.sup.2/24 hr), less than 0.3 g/m.sup.2/24 hr, less than
0.25 g/m.sup.2/24 hr, or less than 0.2 g/m.sup.2/24 hr, to one or
more PCMs.
[0027] A barrier layer can comprise or be produced from one or more
ethylene vinyl alcohol copolymers (EVOH), polyamides (nylons),
polyester, polyvinylidene chloride, polycarbonate, or combinations
of two or more thereof.
[0028] EVOH includes saponified or hydrolyzed ethylene/vinyl
acetate copolymer having about 27 to 44 mole % ethylene. EVOH can
be produced by, e.g., hydrolysis of vinyl acetate copolymers. The
degree of hydrolysis is preferably from about 50 to 100 mole %, or
about 85 to 100 mole %. EVOH is available as EVAL.RTM. from Kuraray
(EVALCA) and NOLTEX.RTM. from Nippon Goshei.
[0029] The polyamide includes polyamide 6, polyamide 9, polyamide
10, polyamide 11, polyamide 12, polyamide 6,6, polyamide 6,10,
polyamide 6,12, polyamide 6I, polyamide 6T, polyamide 6I 6T,
polyamide MXD6 (i.e., polymetaxylene adipate homo- and/or
co-polyamides), polyamide 6,9, a copolymer thereof, polyamides
prepared from terephthalic acid and/or isophthalic acid and
trimethylhexamethylenediamine; from adipic acid, azelaic acid,
2,2-bis-(p-aminocyclohexyl)propane; from adipic acid and m-xylene
diamine; and from terephthalic acid and
4,4'-diaminocyclohexyl-methane, or combinations of two or more
thereof including polyamide nanocomposites such as those available
commercially as AEGIS from Honeywell or IMPERM from Mitsubishi Gas
Chemicals/Nanocor.
[0030] Preferably, the polyamide is a polyamide 6,6, polyamide 6,12
or polyamide 6.
[0031] More preferably, the polyamide is a polyamide 6,6.
[0032] Polyamides may be made by any method known to one skilled in
the art. The polyamide used may also be one or more of those
referred to as "toughened nylons," which are often prepared by
blending one or more polyamides with one or more polymeric or
copolymer elastomeric toughening agents. See, e.g., U.S. Pat. No.
4,174,358, U.S. Pat. No. 4,474,927, U.S. Pat. No. 4,732,938, and
U.S. Pat. No. 4,755,566, each is incorporated herein by reference.
Because such methods are well known, the description of which is
omitted herein for the interest of brevity.
[0033] Polyester is well known to one skilled in the art. It can
include polyethylene terephthalate, polypropylene terephthalate,
polybutylene terephthalate, polyethylene naphthalate,
isophthalate-containing polyester, or combinations of two or more
thereof. Because such methods are well known, the description of
which is omitted herein for the interest of brevity.
[0034] The barrier layers may have thickness in the range of 5 to
150 .mu.m, 10 to 100 .mu.m, 30 to 75 .mu.m, or 50 .mu.m.
[0035] Barrier layers can also be metallized film such as oriented
polypropylene or oriented polyethylene terephthalate, ethylene
vinyl alcohol, aluminum foil, nylon or biaxial oriented nylon,
blends or composites of the same as well as related copolymers
thereof. Metallized film comprises a polymer film having its
surface or portion thereof deposited with metal or metal
powder.
[0036] The film or sheet can also be a multilayer structure that
comprises or is produced from at least one sealant layer and at
least one barrier layer.
[0037] The sealant layer can comprise or be a resin that can be
bonded to itself (sealed) at temperatures lower than, or
substantially below, the melting temperature of other layer(s) so
that the other layer's appearance may not be affected by the
sealing process and may not stick to the jaws of the sealing bar.
Sealant layer used in multilayer container can include copolymer of
ethylene (meth)acrylic acid, ionomer derived from the copolymer of
ethylene (meth)acrylic acid, or combinations thereof.
[0038] The ethylene acid copolymers can be direct acid copolymers
such as those comprising repeat units derived from an
.alpha.-olefin, such as ethylene, at least one monomer derived from
a C.sub.3-8.alpha.,.beta.-ethylenically unsaturated carboxylic
acid, and optionally a softening monomer. Softening refers to the
crystallinity being disrupted (the polymer is made less
crystalline).
[0039] The C.sub.3-8.alpha.,.beta.-ethylenically unsaturated
carboxylic acid can be a (meth)acrylic acid (acrylic acid or
methacrylic acid), maleic acid, fumaric acid, itaconic acid, or
combinations of two or more thereof; fumaric acid monoester,
itaconic acid monoester, maleic acid monoester, or combinations of
two or more thereof where the ester is derived from C.sub.1 to
C.sub.4 alcohols.
[0040] Softening comonomers can include alkyl acrylate, alkyl
methacrylate, or combinations of two or more thereof wherein the
alkyl group has from 1 to 8 or 1 to 4 carbon atoms. The carboxylic
acid can be present from about 3 to about 30, 4 to 25, or 5 to 20,
wt % of the acid copolymer, and the softening comonomer, if
present, can be from 0 to about 35, 0.1 to 35, or 5 to 30, wt % of
the acid copolymer.
[0041] Acid copolymers are well known to one skilled in the art
such as NUCREL.RTM. available from E. I. du Pont de Nemours and
Company, Wilmington, Del., USA (DuPont).
[0042] The acid copolymer can be treated with a basic compound to
nominally neutralized to any level from 0 to about 99%, about 15 to
about 90%, about 15 to about 75%, 20 to 25%, or even 100% of the
acid moieties of the acid copolymer by an alkaline earth metal
cation, an alkali metal cation, or a transition metal cation. For
example, an ionomer can be produced from an acid copolymer by
partially or fully neutralized with metal ions such as Na, Zn, Mg,
Li, or combinations of two or more thereof.
[0043] Preferably, the ionomer is partially or fully neutralised
with zinc or sodium metal ions.
[0044] Preferably, the ionomer is partially or fully neutralised
with sodium metal ions.
[0045] A sealant layers can have a thickness of about 10 to about
100 .mu.m, 25 .mu.m to 35 .mu.m, or about 30 .mu.m.
[0046] lonomers and their methods of manufacture are disclosed in
U.S. Pat. No. 3,264,272 and are commercially available as
SURLYN.RTM. from DuPont.
[0047] The film or sheet may have a permeability of less than 5 g
per square meter per day (5 g/m.sup.2/24 hr), less than 2
g/m.sup.2/24 hr, less than 1 g/m.sup.2/24 hr, or less than 0.5
g/m.sup.2/24 hr, to one or more PCMs.
[0048] The barrier layer can be the same as that disclosed
above.
[0049] The multilayer structure can also comprise at least one tie
layer (adhesive layer), which is any interior layer having the
primary purpose of adhering two layers to one another. Tie layers
can comprise any polymer having a polar group thereon, or any other
polymer that provides sufficient interlayer adhesion to adjacent
layers comprising otherwise non-adhering polymers.
[0050] The tie layer may be any suitable polymer such as an
ethylene copolymer comprises repeat units derived from ethylene and
an alkyl (meth)acrylate or an ionomer disclosed above such as
zinc-neutralized ionomer. An ethylene alkyl(meth)acrylate copolymer
such as ethylene methyl acrylate copolymer or ethylene butyl
acrylate copolymer is well known to one skilled in the art such as
the commercially available ELVALOY.RTM. from DuPont.
[0051] Other tie layer may include ethylene polymer (e.g., low
density polyethylene, linear low density polyethylene, metallocene
catalyst-produced polyethylene), an ionomer disclosed above,
ethylene vinyl acetate copolymer, polyester, or combinations of two
or more thereof.
[0052] The thickness of the at least one tie layer may have a
thickness varying from 2 to 50 .mu.m, 5 up to 50 .mu.m, 15 to 25
.mu.m, or about 20 .mu.m.
[0053] The adhesive layer may be adjacent to the barrier layer or
adhere the multilayer film to an at least one layer of insulating
material, building material, or combinations thereof.
[0054] Preferably, the film or sheet forming the container is
obtained by blown (co)extrusion, cast film mono/co-extrusion or
extrusion coating.
[0055] Most preferably, the film or sheet forming the container is
obtained by blown film mono/co-extrusion.
[0056] The film or sheet can be further processed into articles
disclosed below with uniaxial or biaxial stretching, axial heat
sealing, thermoforming, vacuum forming, sheet folding, heat
sealing, compression molding, or combinations of two or more
thereof.
[0057] For example, a multilayer structure can be produced by a
process including extrusion coating or lamination, blown
mono/co-extrusion, cast film mono/co-extrusion or sheet
mono/co-extrusion and mono/co-extrusion coating, lamination or any
suitable method known in the art. A blown film can be prepared by
extruding a polymeric composition through an annular die and
expanding the resulting tubular film with an air current to provide
a blown film. Cast flat films can be prepared by extruding the
composition through a flat die. The film leaving the die is cooled
by at least one roll containing internally circulating fluid (a
chill roll) or by a water bath to provide a cast film. Extrusion
coating or lamination can involve laying down a molten curtain of a
sealant composition on a moving barrier layer (e.g., 50 to 1000
feet per minute) in which the melt curtain can be formed by
extruding the sealant composition through a flat die. Because such
film making methods are well known to one skilled in the art, the
description of which is omitted for the interest of brevity.
[0058] Various additives can be present in the respective film
layers including a tie layer. The additives can be one or more
antioxidants, thermal stabilizers, ultraviolet (UV) light
stabilizers, pigments and dyes, fillers, delustrants, anti-slip
agents, plasticizers, anti-block agents, other processing aids, and
the like.
[0059] A film can be further oriented beyond the immediate
quenching or casting of the film. Orientation and stretching
apparatus to uniaxially or biaxially stretch film are known in the
art and may be adapted by those skilled in the art to produce films
of the present invention. Examples of such apparatus and processes
include, for example, those disclosed in U.S. Pat. Nos. 3,278,663,
3,337,665, 3,456,044, 4,590,106, 4,760,116, 4,769,421, 4,797,235,
and 4,886,634.
[0060] The multilayer structure may be different in structure
(e.g., one layer can be clear and the other can be opaque).
[0061] The container can be produced from the film or sheet, for
example, by folding back the film or sheet on itself, where the
sealant layer is against itself (if the film or sheet is a
multilayer structure containing a sealant layer), along essentially
the superimposed edges directly (or indirectly through an
intervening tie layer or adhesive layer) thereby defining a sealed
perimeter and forming a container such as a pouch. One side of the
container can be left open and sealed only after one or more PCMs
are enclosed in the container thereby forming a sealed container
containing PCM(s) or a matrix containing the PCM(s). The seal
strength of the sealed perimeter is sufficient to withstand manual
compression of the PCM.
[0062] Because the sealant layer is made from heat-sealable
polymer(s), the container can be self-sealed under the heat without
an intervening tie layer.
[0063] Sheet can also be made with the PCM or PCM blend where such
sheet can have a thickness of 0.5 and 10 mm and can be manufactured
either directly by melt blend extrusion as known to one skilled in
the art or by preparing the PCM (or blend) which is subsequently
processed by means of any conventional technology such as
extrusion, calendering and hot lamination. The sheet can also be a
multilayer structure.
[0064] A PCM can also be shaped into sheets and laminated on both
sides with the film or sheet, the heat-sealable copolymer side
being in direct contact with the PCM. The lateral edges of the
multilayer film can be sealed to each other. The edges may comprise
or consist of multilayer film overhanging the lateral sides of the
PCM sheet in the case where the dimensions of the multilayer film
exceed the ones of the PCM sheet. In the case where the multilayer
film and PCM sheet have the same dimensions, the edges consist of a
multilayer film and PCM.
[0065] Heat sealing of the lateral edges can be achieved through
heated pliers or rolls pinching down from both sides of the
laminated PCM sheet, thereby contacting the at least one
heat-sealable copolymer of both multilayer films under heat and
pressure.
[0066] After sealing the lateral edges, the laminated PCM sheet can
subsequently be sealed and cut transversally to yield rectangular
laminated PCM sheets that are now completely encapsulated within
the multilayer film.
[0067] The container can also be produced from different films or
sheets, for example, by sealing the sealant layer of the films or
sheets or indirectly through another intervening tie layer or
adhesive layer thereby defining a sealed perimeter and forming a
container such as a pouch.
[0068] Alternatively, manufacturing a film or sheet where the
heat-sealable copolymer is not a continuous layer of copolymer, but
where instead the heat-sealable copolymer may be only a strip or
closed outline defining the parts of the film where a seal is to be
formed. For example, two different films or sheet can be sealed
together using any one of the adhesives disclosed herein. Using two
polyamide films or sheets as example, they can be made into a pouch
by using a heat sealable adhesive such as an ionomer disclosed
above or an ethylene alkyl(meth)acrylate copolymer along the edges
and then heat-sealed.
[0069] Other adhesives can be used. The invention may enable the
manufacture of thermal insulation units, even when the
heat-sealable copolymers of the multilayer film are contaminated
with PCM. In addition to lamination, the PCM sheets can be
co-extruded together with the multilayer films forming the
pouch.
[0070] The shape of the PCM sheets and, concordantly, the shape of
the thermal insulation unit, are completely adjustable to the
geometric constraints of the desired application, and can be even
complex shapes otherwise unrealizable using conventional
techniques. Examples include, but are not limited to, polygons,
ovals and circles, depending on the shape needed and depending on
where pressure and heat are applied.
[0071] The PCM sheet can also be placed on a single multilayer
film, which can be folded over the PCM sheet such that only three
of the edges of the multilayer film need to be heat sealed to form
the thermal insulation unit.
[0072] The thermal insulation unit can further comprise at least
one additional layer of insulating and/or construction material
layer. The thermal insulation unit may be adhered to the at least
one additional insulating and/or construction material layer by at
least one layer of adhesive.
[0073] The at least one additional insulating layer may be any
suitable insulating material layer used in construction, textile or
automotive application. Examples include, but are not restricted
to, expanded polystyrene foam (EPS), mineral wool, foamed
polyurethane, vermiculite, fiber-cement board, plaster walls,
compressed wheat straw, foamed epoxy, drywall, wood based insulting
materials, blankets, loose-fill, or rigid systems with materials
such as rock wool, fiber glass, cellulose, polyurethane foam,
extruded polystyrene foam, polyurethane foam, polyisocyanurate
foam, or combinations of two or more thereof.
[0074] In the case where the additional insulating layer is
expanded polystyrene foam, an adhesive layer may be either an
anhydride-modified ethylene vinyl acetate or ionomer such as an
anhydride modified ethylene vinyl acetate having a vinyl acetate
content of about 25.5 wt % and a maleic anhydride content of about
0.11 wt %; or a sodium ionomer having a neutralization level of
54%, a methacrylic acid content of 10 wt %.
[0075] The at least one layer of adhesive is then heated by heated
pliers or rolls while being pressed against the at least one
additional insulating and/or construction material layer.
[0076] Alternatively, the thermal insulation unit can be affixed by
any other suitable means to the at least one additional insulating
and/or construction material layer, such as for example, nailing,
stapling, adhesive taping and gluing.
[0077] The at least one additional layer may be any suitable
material for interior or exterior application, prefabricated or
non-prefabricated. This includes gypsum fiberboards, cement
fiberboards, cement wallboards, plasterboards, bricks, concrete,
drywall, wood, metal, glass, polymer-based materials, and the like.
Drywall is typically made of a gypsum or plaster core sandwiched or
faced in paper or cardboard and is produced as sheets which may be
fastened to wall frames with nails or screws.
[0078] Also provided is an article for sport and/or outdoor
activities where the article includes a thermal insulation unit.
The article may be chosen among clothes, shoes, gloves, socks,
sleeping bags, tents, food containers, beverage containers, others,
or combinations of two or more thereof.
[0079] The thickness and the shape of the thermal insulation unit
comprised in the article may be adjusted according to the needs of
the sport and/or outdoor application. For example, a thermal
insulation layer can be 0.0001 to 10 cm thick and up to many meters
long.
[0080] The article may be used for personal protection such as
ballistic vests, firefighter equipment, insulating garments, and
others. The thickness and the shape of the thermal insulation unit
comprised in the article may be adjusted according to the needs of
the personal protection application.
EXAMPLES
Example 1
PCM-Polymer Blend
[0081] 60 g of paraffin commercially available from Rubitherm under
the trade name RUBITHERM.RTM. RT21 (melting point 21.degree. C.)
and 40 g of granules of VLDPE (density 0.863 g/cm.sup.3) grafted
with 0.5 wt % of maleic anhydride, were simultaneously introduced
into a 1-liter tumble blender. Blending was carried out during
eight (8) hours at 25.degree. C. to enable sufficient time for
maximal incorporation of the liquid paraffin into the polymer
matrix (soaking).
[0082] The granules soaked with the paraffin were taken out of the
blender.
[0083] The difference in the granules weight before and after
soaking was measured, thus allowing to calculate the weight
percentage of paraffin absorbed by the polymer matrix.
Example 2
Multilayer Film M1 for Forming a Pouch
[0084] A tubular multilayer film M1 was manufactured by blown film
extrusion, having, from inside to outside, (1) a 20 .mu.m layer of
an anhydride-modified ethylene vinyl acetate having a vinyl acetate
content of 25.5 wt % and a maleic anhydride content of 0.11 wt %,
(2) a 50 .mu.m layer of nylon 6,12, (3) a 20 .mu.m layer zinc
ionomer derived from ethylene methacrylic acid copolymer having a
neutralization level of 38% and 12 wt % methacrylic acid, and (4) a
30 .mu.m layer of sodium ionomer derived from ethylene methacrylic
acid copolymer having a neutralization level of 54% and 10 wt %
methacrylic acid. The expansion ratio between die and blown tube of
film was 3.28.
Multilayer Film M2 for Forming a Pouch
[0085] A tubular multilayer film M2 was manufactured by blown film
extrusion, having, from inside to outside, (1) a 30 .mu.m layer of
sodium ionomer derived from ethylene methacrylic acid copolymer
having a neutralization level of 54% and 10 wt % methacrylic acid,
(2) a 20 .mu.m layer of zinc ionomer derived from ethylene
methacrylic acid copolymer having a neutralization level of 58% and
15 wt % methacrylic acid, and (3) a 50 .mu.m layer of nylon 6,12.
The expansion ratio between die and blown tube of film was
3.28.
Example 3
[0086] A first metal board (steel) having dimensions of
200.times.200.times.3 mm was inserted into the bottom part of a
heat press. A sheet of PTFE (polytetrafluoroethylene) having 200
.mu.m in thickness was laid on top of the first metal board (to
prevent it from sticking to the metal). A second metal board
(steel) having the dimensions 200.times.200.times.5 mm and having a
central window the size of 150.times.150 mm was laid on top of the
PTFE sheet. The cavity created by the window of the metal board was
filled with PCM-polymer blend and a second sheet of PTFE (200
.mu.m) was laid on top of the second metal board. Subsequently, a
third metal board (steel) was laid on top of the PTFE sheet. The
resulting multilayered stack was then heat pressed by pre-heating
for 1 minute at a temperature of 110.degree. C., no pressure;
heating for 1 minute at a temperature of 110.degree. C. at a
pressure of 5 bars; heating for 2 minutes at a temperature of
110.degree. C. at a pressure of 50 bars; and cooling to a
temperature of 10.degree. C. at a pressure of 50 bars.
[0087] PTFE was used to prevent the PCM polymer blend from sticking
to the metal and was removed from the slab afterwards.
[0088] The resulting PCM polymer blend slab having the size of
150.times.150.times.5 mm was then placed between two multilayer
films manufactured according to the above description (M1 and M2),
the ionomer layer of both multilayer films being in direct contact
with the PCM polymer slab.
[0089] The two multilayer films were then pressed into close
contact with the PCM polymer blend slab to prevent air cavities
between multilayer film and PCM polymer blend slab by applying
pressure on the external side of the multilayer films with a
metallic roll or board.
[0090] The edges of the two multilayer films were then sealed to
each other by thermal impulse sealing for 2 seconds at a
temperature of 160.degree. C. followed by cooling to 60.degree. C.
to form a pouch.
Example 4
Seal Strength Measurements
[0091] The sample film strips for seal strength testing were film
strips of 15 mm width, cut from prepared blown films in machine
direction.
[0092] Sample 1 was a film strip made of a zinc ionomer derived
from ethylene methacrylic acid copolymer having a neutralization
level of 23% and 15 wt % methacrylic acid.
[0093] Sample 2 was a film strip made of a random polypropylene
copolymer.
[0094] Sample 3 was a film strip made of a LLDPE.
[0095] Sample 4 was a film strip made of a LDPE.
[0096] The samples were then heat-sealed on a Kopp Heat Sealer,
with two flat PTFE-coated, internally heated heating bars using
cartridge-type electric heaters. Each sample was sealed on itself
at a pressure of 0.3 MPa, a temperature of 160.degree. C. and a
dwell time of 1 second (s). To avoid sticking of polymer to the
heated bar, a polyester film covered each sample. To compare the
effect of paraffin contamination on seal strength, each sample was
also sealed to itself according to the above description, but with
50 g/m.sup.2 of paraffin (RUBITHERM.RTM. RT21), spread evenly
across the surface to be sealed.
[0097] Peel strength test. Strength of the prepared seals was
measured after conditioning at 23.degree. C. and 50% relative
humidity for 24 h. The samples were then placed in the Zwick jaw
clamps. The peel strength was measured on a Zwick 1435 Tensile
Tester at a pulling speed set to 100 mm/min and having a peel angle
of 90.degree.. The values presented are given in N/15 mm and are an
average of at least three measurements.
[0098] Table 1 shows seal strength values for different polymer
films sealed to themselves. For each polymer film, the table shows
the seal strength value for a paraffin contaminated seal and an
uncontaminated seal. Sample 2, 3, and 4 were comparative
examples.
TABLE-US-00001 TABLE 1 Seal strength values of samples 1, 2, 3, and
4 Sample 1 2 3 4 Seal 22.75.sup.A 22.sup.B 20.2.sup.A 10.1.sup.B
11.2.sup.A 9.8.sup.B 13.5.sup.A 7.4.sup.B Strength (N/15 mm)
.sup.AUncontaminated; .sup.BContaminated with paraffin.
[0099] Table 1 shows that the seal strength values of comparative
examples 2, 3, and 4 decreased by up to 50% when contaminated with
paraffin. In contrast, the seal strength value of sample 1 was
nearly constant, irrespective of paraffin contamination. For this
reason, ionomers, which were unaffected by paraffin contamination,
are suitable to be used as sealant layers in the multilayer films
for forming pouches.
Example 5
Barrier Measurements
[0100] Sample 1 was a 50 .mu.m thick film made of a zinc ionomer
having a neutralization level of 23%, a methacrylic acid content of
15 wt %. Sample 2 was a 25 .mu.m thick aluminum metalized film made
of a zinc ionomer having a neutralization level of 23%, a
methacrylic acid content of 15 wt % where the metallization
thickness is about 1 .mu.m.
[0101] Sample 3 was an 18 .mu.m thick film made of biaxially
oriented met-polypropylene.
[0102] Sample 4 was a 50 .mu.m thick film made of nylon 6,12
copolyamide.
[0103] Sample 5 was a 50 .mu.m thick film made of nylon 6.
[0104] Sample 6 was a 24 .mu.m thick film made of biaxially
oriented PET.
[0105] Sample 7 was a 25 .mu.m thick film made of oriented nylon
6,6.
[0106] Film samples 1-7 were cut into circular pads having a
diameter of about 7.5 cm. Each circular pad was then fixed to the
open end of a cylindrical Albert cup (Model 68 by Thwing-Albert,
diameter 63.5 mm) containing 75 g of paraffin (RUBITHERM.RTM.
RT21).
[0107] The cylindrical Albert cups were then weighted and the
weights recorded for later comparison.
[0108] The cylindrical Albert cups were then placed upside-down, so
that the sample film was at the lower end and the paraffin rested
on top of it.
[0109] The cylindrical Albert cups were then placed in an oven at
60.degree. C. for 1 month. The cylindrical Albert cups were then
weighted and the weight recorded. The loss of paraffin corresponds
to the difference in weight between the beginning of measurements
and after removal from the oven and is expressed in grams/square
meter.times.day. Results are normalized to a film thickness of 50
.mu.m to be comparable directly to each other. Results are shown in
Table 2.
TABLE-US-00002 TABLE 2 Paraffin permeability of samples 1-7 1 2 3 4
5 6 7 Loss of paraffin (in gr/m2 .times. day) 17 11 6.7 0.47 0.22
0.2 0.11
[0110] Table 2 shows the paraffin permeability values of samples
1-7. Films having a paraffin permeability value of less than 1
g/m.sup.2.times.day were suitable as barrier layers for the
multilayer forming pouch.
* * * * *