Note: Descriptions are shown in the official language in which they were submitted.
PLASTIC FTLM METAL FOIL MULTZ-LAM:LNAT'SS
BACKGROUND OF THE IN"~IENTION
The preaent invention relates ~to film/ foil lami-
nates; and in particular film/foil laminates wherein a plural-
ity of metal sheets and polymeric films are bonded together.
In the past, various combinations of metallic
sheets with non-metallic coatings, substrates and the like
have been employed to provide a packaging material, or to
alter the inherent properties of metallic sheets.
t1. S. Patent No. 4,211,822 (Kurfman et all disclos-
es a layer of polystyrene or polycarbonate film metallized
with indium or tin/cadmium alloy. This results in reflective
and decorative parts for automobiles and. other vehicles. The
polymer may be pretreated including the use of corona dis-
charge. Materials such as polyvinyl halide or polyvinylidene
halide are disclosed as polymers of the polymer layer. The
metal layer may be applied to both sides of the polymer lay-
er.
U. S. Patent No. 4,241,129 (Morton et al) discloses
a multilayer metal/organic polymer like that of the Iturfman
patent, and. including a soft adhesive polymer such as
ethylene vinyl acetate copolymer.
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U.. S, Patent No, 4,257,536 (Hilmar et a1) discloses
a laminate structure for dispensing containers having an
almninum layer bonded to a corona treated polyester barrier
layer by a polyester. or other suitable adhesive layer.
U. S. Patent No. 4,291,085 (Ito et al) discloses a
polyprapylene layer which has been corona treated, bonded to
a layer of aluminum foil.
U. S. Patent No. 4,528,234 (Kaiho et a1) discloses
an aluminum layer bonded to a corona bonded plastic sub-
strate.
U. S. Patent No. 4,597,818 (Aoyama et al) discloses
an aluminum substrate bonded to a corona treated ultra-high
molecular weight polyethylene.
U. S. Patent No. 4,749,625 (Obayashi et al) disclos-
es an amorphous metal with a polymeric coating layer laminat-
ed to one surface of the amorphous metal.
U. S. Patent No. 4,766,035 (Lancaster et al) dis-
closes a metal s'ubstra'te with a halopolymer adhered thereto.
U. S. Patent No. 4,855,186 (Grolig et al) discloses
a plastic carrier film, a first dielectric layer adhered to
the carrier film, and a heat reflection metallic :Layer ad.
hered to the first dielectric layer.
WO 82/00020 (Nelson-Ashley et al) discloses adher-
ing a linear low density polyethylene film to a sheet metal
or f oil by engaging the film and sheet metal, heating at
least the sheet metal, and applying pressure to the opposed
free surfaces: This article may be folded to a pouch.
French Patent Abstract No. FR 2618382-A discloses a
packaging material comprising a heat shrinkable plastics
material layer adhered to a layer of metallic, preferably
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aluminum foil. The preferred heat shrinkable layer is
polyethylene.
Japanese Patent No. J01027923-A (Mitsui) discloses
coextrusion-laminating a resin layer to an oriented film or
an aluminum foil through an adhesive layer. The resin may be
a polyolefin.
UK Patent Specification 1295132 discloses the pre-
treatment of one surface of a plastic film by corona
discharge; bringing the treated film into contact with a
steel sheet at a temperature sufficient to soften the plastic
film; and annealing the plastic/metal laminate at or above
the melting point of the plastic.
A problem associated with some conventional
film/foil laminate is that it is subject to pin holes and
flex cracks. When this occurs, the gas barrier properties of
the laminate is degraded, sometimes to such an extent that
the laminate loses its utility for the intended end use.
It has now been discovered that by providing a
multiplicity of polymeric films and foils laminated together,
a laminate is produced which approaches an absolute barrier.
This laminate can be made into for example a vacuum
insulating panel by making a pouch, filling it with a
separating material (such as a non-woven material or silica),
evacuating the pouch and sealing it.
An additional advantage of the present invention is
that different metal foils can be combined into a coherent
stampable sheet. Therefore metal such as aluminum and steel
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can be used and built up in thickness to achieve a laminate
sheet capable of being stamped or shaped as desired, e.g.
beverage cans.
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SUMMARY OF THE INVENTION
In one aspect of the invention, a method of making
a film/foil laminate comprises passing a plurality of metal
sheets and polymeric films toward a pair of press rolls, the
metal sheets and polymeric films being arranged in alternat-
ing sequence so that each metal sheet is positioned between
'two films; corona treating each surface of each polymeric
film that will subsequently band to a respective metal sheet;
and passing the plurality of metal sheets and treated films
between the pair of press rolls.
In another aspect of 'the invention, a film/foil
laminate comprises a plurality of metal sheets and polymeric
films arranged in alternating sequence, with polymeric films
forming the outermost surfaces of the laminate.
In still another aspect of the invention, a method
of making a filmlfoil laminate comprises passing a plurality
of metal sheets and polymeric films toward a pair of press
rolls, the metal sheets and polymeric films being arranged in
alternating sequence so that each polymeric film is posi-
tioned between two metal sheets; corona treating both surfac-
es of each polymeric film; and passing the plurality of metal
sheets and treated films between the pair of press rolls.
In still another aspect of the invention, a
film/foil laminate comprises a plurality of metal sheets and
polymeric films arranged in alternating sequence, with metal
sheets forming the outermost surfaces of the laminate.
In an additional aspect of the invention, a method
of making a vacuum insulating panel comprises passing a plu-
rality of metal sheets and polymeric films toward a pair of
press rolls, the metal sheets and polymeric films being ar-
ranged in alternating sequence so that each metal sheet is
positioned between two films; corona treating each surface of
each polymeric film that faces a metal sheet; and passing the
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plurality of the metal sheets and treated films between the
pair of press rolls to form a film/foil laminate; making a
pouch from the film/foil laminate; placing an insulating
material inside the pouch; evacuating the pouch; and sealing
the pouch.
In another aspect of the invention, the invention
comprises a pouch made from the film/foil laminate with
polymeric films forming the outermost surface of the
laminate. This pouch may optionally have an insulating
material inside the pouch.
In still another aspect of the invention, a method
of making a film/foil laminate comprises passing a plurality
of metal sheets and polymeric films toward a pair of press
rolls, the metal sheets and polymeric films being arranged in
alternating sequence so that a polymeric film forms one of
the outermost surfaces of the laminate, and a metal sheet
forms another of the outermost surfaces of the laminate;
corona treating each surface of each polymeric film that will
subsequently bond to a respective metal sheet; and passing
the plurality of metal sheets and treated films between the
pair of press rolls.
In still another aspect of the invention, a
film/foil laminate comprises a plurality of metal sheets and
polymeric films arranged in alternating sequence, so that a
polymeric film forms one of the outermost surfaces of the
laminate, and a metal sheet forms another of the outermost
surfaces of the laminate.
In still another aspect of the invention, the
invention comprises a pouch made from the film/foil laminate
comprising a plurality of metal sheets and polymeric films
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arranged in alternating sequence, so that a polymeric film
forms one of the outermost surfaces of the laminate, and a
metal sheet forms another of the outermost surfaces of the
laminate.
In an additional aspect of the invention, a method
of making a vacuum insulating panel comprises: passing a
plurality of metal sheets and polymeric films toward a pair
of press rolls, the metal sheets and polymeric films being
arranged in alternating sequence so that a polymeric film
forms an innermost surface of a resulting laminate, and a
metal sheet forms an outermost surface of the laminate;
corona treating each surface of each polymeric film that will
subsequently bond to a respective metal sheet; and passing
the plurality of metal sheets and treated films between a
pair of press rolls to form a film/foil laminate; making a
pouch from the film/foil laminate; placing an insulating
material inside the pouch evacuating the pouch; and sealing
the pouch at respective innermost surfaces of the pouch.
The terms "metal foil" and the like, and "metal
sheet" and the like, are used herein interchangeably.
BRIEF DESCRIPTION OF THE DRAWING
Referring to the sole drawing figure, Figure 1 is a
schematic diagram of an apparatus for producing the inventive
film/foil multi-laminate.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the sole drawing figure, several
polymeric films and metallic foils are passed through a
series of pull rolls and gathered together between a pair of
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press rolls to form a film/foil mufti-laminate of the present
invention.
More specifically, film feed rolls 12, 14, 16, and
18 feed respective first film 22, second film 24, third film
26, and fourth film 28 toward press rolls 54 and 58.
These films have previously been corona treated at
a conventional corona treating station (not shown) such that
first film 22 and fourth film 28 have been corona treated on
one interior surface thereof, while second film 24 and third
film 26 have been corona treated on both surfaces thereof.
By "interior surface" of first film 22 and fourth film 28 is
meant that surface of the film which will subsequently come
into bonding contact with a metallic foil as described more
fully below.
Foil feed rolls 32, 34 and 36 feed respectively
first foil 42, second foil 44 and third foil 46 toward press
rolls 54 and 58.
The films and foils are gathered together by means
of a pull roll array 50 comprising a series of rolls arranged
so that, in cooperation with press rolls 54 and 58, the films
and foils are brought into communication with each other as
shown in the diagram.
The corona treated surfaces of the films come in
contact with adjacent foils to help insure an adequate bond
within the mufti-laminate.
Heating means 52 employs a heating medium such as
hot air to preheat the films and foils prior to pressing
between press roll 54 and press roll 58. Conventional
heating means can be used for this purpose. Preferably,
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heating roll 56 and press roll 58 are also heated to optimize
the bond strength between individual layers of the final
multi-laminate. Conventional heating means can be used for
this purpose.
Roll 60 conveys the final multi-laminate to a wind
up roll (not shown).
Polymeric films useful in the present invention are
typically thermoplastic and can themselves be of monolayer or
multilayer construction, formed by conventional lamination,
coextrusion, extrusion coating or other techniques well known
in the art. Compositionally, these films may be made up of
polyolefinic or other polymeric materials, and may also
include polyvinylidene chloride or vinylidene chloride
copolymer materials commonly known as saran. Polyethylene
and copolymers of ethylene such as ethylene vinyl acetate
copolymer, ethylene alpha-olefin copolymer (linear low
density polyethylene and very low density polyethylene), and
ethylene vinyl acetate copolymer are particularly preferred
materials for films 22, 24, 26 and 28.
The foils of the present invention are metallic
foils and preferably aluminum. Other materials such as steel
can also be used.
Each of the films used in the present invention can
be identical, or can differ in composition or construction.
Likewise, different metals can be used for the various foils
used in producing the multi-laminate.
One advantage of the present invention is that the
process and apparatus is flexible enough to accommodate
differing metallic foils and differing films.
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The invention may be further understood by
reference to the following examples.
EXAMPLE 1
A polymeric, multilayer film was prelaminated to an
aluminum foil. This lamination was accomplished by corona
treating one surface of the polymeric film, and using a metal
nip roll at a temperature of about 160°F, and a line speed of
about 50 feet per minute, to bond the film to the foil.
This procedure was repeated to produce two rolls of
the prelaminated film/foil.
These two rolls of prelaminate film/foil were
positioned approximately as shown at rolls 32 and 36 in
Figure 1.
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A central feed roll of aluminum foil was pasitianed
between the two rolls of prelaminated film/foil. The rela-
tive position of the feed roll of aluminum foil was that
represented by feed roll 34 of Figure 1.
A feed roll of polymeric multilayer film was posi-
tioned respectively between the central aluminum feed roll
layer and each prelaminated film/foil feed roll. Thus., the
two feed rolls of the polymeric multilayer film were posi-
tioned as represented by feed rolls 14 and 16 in Figure 1.
The film from the two film feed rolls was corona
'treated on both surfaces thereof.
Both of the prelaminated film/foil, the central
aluminum foil, and the two multilayer films were drawn
through a pull roll array and gathered at press rolls to
produce a multi-laminate. A heating roll represented by roll
56 of Figure 1 was run at a temperature of about 160°F, as
was the press roll represented by roll 58 of Figure 1.
The polymeric film used in 'the prelaminated
film/foil comprised a four layer construction having one
outer layer of a linear law density polyethylene (Dowlex
2035) available from Dow. Chemical; a second. layer of linear
low- density polyethylene (Dowlex 2045) available from Dow; a
third layer of an ethylene vinyl acetate copolymer (Elvax
:PE-3508) available from du Pont; and a fourth, bonding layer
comprising a mixture of 800 of an ethylene vinyl acetate
copolymer (Alathon 3180) available from du Pont, blended with
20o antiblocking agent having 900 low density polyethylene
and 10a colloidal silica, where 'the low density polyethylene
is Dow PE 722 and the colloidal silica is Syloid 378. The
fourth, bonding layer was the layer which was corona treated
and bonded to the aluminum foil to produce the prelaminate.
The total thickness of each film was about one (1) mil.
All of the foils used in Example 1 were aluminum.
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Each foil had a thickness of about .35 mil.
The polymeric multilayer film fed from intermediate
rolls represented by feed rolls 14 and 16 in Figure 1
comprised a five layer film having outer layers of a blend of
80% of an ethylene vinyl acetate copolymer (Elvax 3182)
available from du Pont, blended with 20% of the antiblock
agent described above. The central layer of the five layer
film was linear low density polyethylene (Dowlex 2045). The
intermediate (second and fourth) layers of the multilayer
polymeric film were ethylene vinyl acetate copolymer (Elvax
PE-3508). The total thickness of each multilayer film was
about .65 mil.
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A film/foil multilaminate is produced having four
discrete polymeric films, and three separate aluminum foil
layers disposed between the films in alternating fashion.
These polymeric films are corona treated on both sides in the
case of films forming an interior layer of the final
multilaminate, and on one side in the case of films forming
an outer layer of the final multi-laminate, the corona
treated side of these latter films being that side which will
ultimately be bonded to an aluminum foil surface.
These polymeric films and aluminum foils are drawn
through a pull roll array, preheated, and pressed between
respective press rolls which are heated. Heating procedures
are like those described in Example 1.
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EXAMPLE 3
A film/foil multi-laminate is produced
substantially as described in Example 1, but having foils of
differing metals.
9a
EXAMPLE
A film/foil mufti-laminate is produced substantial-
7.y as described in Example 2, but having foils comprising
different metals.
EXAMPLES
A film/foil laminate is produced substantially as
described in Examples. 1 or 2, but having a polymeric film as
one of the outermost surfaces of the mufti-laminate, and a
metal foil as the other outermost surface of the mufti-lami-
nate.
EXAMPLE 6
A film/foil laminate is produced substantially as
described in Examples l or 2, but having metal foils as
both outermost surfaces of the mufti-laminate.
nvarrtrT ~ '7
A pouch is made from any one of the laminates of
Examples 1 through 6.
EXAMPLE 8
Any of the pouches of Example 7 is made into an
insulating panel by placing an insulating material, such as a
non-woven separating material or silica, inside the pouch;
evacuating the pouch; and sealing the pouch.
The invention has been described with reference to
preferred embodiments and specific examples, but one skilled
in the art will appreciate that modifications can be made
within the spirit and scope of the claims which follow. For
example, any number of polymeric films and metallic foils or
sheets can be brought together to produce the film/foil lami-
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nate of the present invention. Likewise, the choice of
polymeric resins is to a great extent limited only by
cosiderations of cost, desired end use, and the composition
of the surfaces) to be corona treated. The surface
composition should be such that an adequate bond to an
adjacent metallic foil will result, following the method of
the present invention. Many metals are suitable for the
metallic foil, especially aluminum and steel. The
thicknesses of the various films and foils or sheets used in
the present invention can differ within a single multi-
laminate, and can also differ from one mufti-laminate to the
next. As an example, film gauges can be as low as .1 mil or
as high as 10 mil. Foil thicknesses can also range from .l
mil. to 10 mil. Films used in the present invention can
optionally be cross-linked by e.g. irradiation or chemical
cross-linking. Irradiation can be done by the use of high
energy electrons, ultra violet radiation, X-rays, gamma rays,
beta particles, etc.
Many apparatus for irradiating films are known to
those of skill in the art. Irradiation is typically carried
out at a dosage between about 1 MR and 20 MR.
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