U.S. patent application number 10/121777 was filed with the patent office on 2002-08-15 for metallized sheeting, composites, and methods for their formation.
This patent application is currently assigned to Textron Systems Corporation. Invention is credited to Murano, Adam.
Application Number | 20020108708 10/121777 |
Document ID | / |
Family ID | 22093554 |
Filed Date | 2002-08-15 |
United States Patent
Application |
20020108708 |
Kind Code |
A1 |
Murano, Adam |
August 15, 2002 |
Metallized sheeting, composites, and methods for their
formation
Abstract
A metallized composite includes a thermoplastic sheet and at
least one discontinuous layer of metal within the thermoplastic
sheet. The discontinuous metal layer can be disposed between two
thermoplastic layers that are bound together, such as by melting
the layers together, pressing, or by use of an adhesive. The
metallized composites of the invention can be employed as
reflective surfaces, such as are used as mirrors or substitutes for
chrome trim on automobiles. A particularly preferred metal as a
component of the discontinuous layer of the composite is
indium.
Inventors: |
Murano, Adam; (West
Chesterfield, NH) |
Correspondence
Address: |
HAMILTON, BROOK, SMITH & REYNOLDS, P.C.
530 VIRGINIA ROAD
P.O. BOX 9133
CONCORD
MA
01742-9133
US
|
Assignee: |
Textron Systems Corporation
Wilmington
MA
|
Family ID: |
22093554 |
Appl. No.: |
10/121777 |
Filed: |
April 11, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10121777 |
Apr 11, 2002 |
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09223545 |
Dec 30, 1998 |
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60070166 |
Dec 31, 1997 |
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Current U.S.
Class: |
156/307.3 ;
156/276; 156/298; 156/324 |
Current CPC
Class: |
B32B 2255/28 20130101;
Y10T 428/31699 20150401; Y10T 428/3158 20150401; Y10T 428/31605
20150401; B32B 2250/02 20130101; B32B 3/30 20130101; B32B 2274/00
20130101; Y10T 428/31696 20150401; Y10T 428/31913 20150401; Y10T
428/24851 20150115; Y10T 428/31935 20150401; Y10T 156/109 20150115;
Y10T 428/3154 20150401; Y10T 428/31797 20150401; B32B 27/08
20130101; B32B 27/36 20130101; B32B 2255/10 20130101; Y10T
428/24909 20150115; B32B 2307/412 20130101; Y10T 428/31678
20150401; B32B 7/12 20130101; B32B 2255/205 20130101; Y10T
428/31663 20150401; Y10T 428/24893 20150115; Y10T 428/31681
20150401; Y10T 428/3192 20150401; B32B 15/08 20130101; Y10T
428/31725 20150401; B32B 2398/20 20130101; B32B 2038/0092 20130101;
Y10T 428/31609 20150401; Y10T 428/31544 20150401; Y10T 428/31692
20150401; Y10T 428/31786 20150401; B32B 3/14 20130101; Y10T
428/24826 20150115; C08J 5/124 20130101; B32B 2307/41 20130101;
Y10T 428/24917 20150115; B32B 27/304 20130101; Y10T 428/31938
20150401; B32B 27/40 20130101; Y10T 428/31909 20150401; B32B 37/12
20130101; Y10T 428/24802 20150115; B32B 2307/416 20130101; Y10T
428/31928 20150401; B32B 15/02 20130101; B32B 2307/738 20130101;
B32B 7/14 20130101 |
Class at
Publication: |
156/307.3 ;
156/298; 156/324; 156/276 |
International
Class: |
B29B 007/00; C09J
001/00 |
Claims
What is claimed is:
1. A method for forming an metallized composite, comprising the
steps of: a) depositing a metal on a first thermoplastic layer to
from a discontinuous layer of said metal; and b) laminating a
second thermoplastic layer onto said discontinuous layer to form
said metallized composite, thereby forming the metallized
composite.
2. The method of claim 1, further including the step of injection
molding a thermoplastic polymer at a surface of the metallized
composite.
3. The method of claim 1, further including the step of blow
molding a thermoplastic polymer at a surface of the metallized
composite.
4. The method of claim 1, further including the step of
thermoforming a thermoplastic polymer at a surface of the
metallized composite.
5. The method of claim 1, further including the step of
vacuum-forming a thermoplastic polymer at a surface of the
metallized composite.
6. The method of claim 1, further including the step of adhering
the metallized composite to a substrate.
7. The method of claim 1, wherein said metal is deposited on the
first thermoplastic layer by electron beam evaporation.
8. The method of claim 7, wherein indium is deposited on the first
thermoplastic layer.
9. The method of claim 1, wherein said metal is deposited on the
first thermoplastic layer by sputtering.
10. The method of claim 1, wherein said metal is deposited in the
first thermoplastic layer by ion plating.
11. The method of claim 1, wherein said metal is deposited in the
first thermoplastic layer by induction heating.
12. The method of claim 1, wherein said metal is deposited in the
first thermoplastic layer by thermal evaporation.
13. The method of claim 1, further including the step of bonding
said first thermoplastic layer to said second thermoplastic
layer.
14. The method of claim 13, wherein said first thermoplastic layer
is bonded to said second thermoplastic layer by heating said first
and second thermoplastic layers.
15. The method of claim 14, wherein said first and second
thermoplastic layers bond by at least partially melting said
layers, whereby said layers become a continuous thermoplastic
sheet.
16. The method of claim 15, wherein said first thermoplastic layer
is bonded to said second thermoplastic layer by pressing said first
and second layers together.
17. The method of claim 15, wherein said first thermoplastic layer
is bonded to said second thermoplastic layer by depositing an
adhesive on said discontinuous layer of metal and said first
thermoplastic layer prior to laminating said second thermoplastic
layer onto the discontinuous layer.
18. The method of claim 17, further including the step of curing
said adhesive by exposure to ultraviolet light.
19. The method of claim 15, wherein said first thermoplastic layer
is bonded to said second thermoplastic layer by depositing an
adhesive on said second thermoplastic layer prior to laminating the
second layer onto the discontinuous layer, whereby said adhesive is
trapped between said first and second thermoplastic layers of the
metallized sheeting.
20. The method of claim 19, further including the step of curing
the adhesive by exposing to ultraviolet light.
21. The method of claim 1, wherein said metal is deposited on said
first thermoplastic layer by transferring said metal from a
substrate applied to said first layer.
22. The method of claim 1, further including the step of embossing
said metallized composite.
23. The method of claim 1, further including the step of folding
said metallized composite.
24. The method of claim 1, further including the step of applying
said metallized composite to a support.
25. The method of claim 24, further including the step of bonding
said metallized composite to said support.
26. The method of claim 1, further including the steps of: a)
depositing a metal onto the metallized composite to form a second
discontinuous layer of metal; and b) laminating a third
thermoplastic layer onto said second discontinuous layer.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of U.S. Ser. No.
09/223,545, which was filed on Dec. 30, 1998, which claims priority
to U.S. Provisional Application No. 60/070,166, filed Dec. 31,
1997. The entire teachings of the above applications are
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] Metallized polymer sheeting is now commonly employed as a
substitute for decorative chrome parts, especially in the
automotive industry. Typically, such metallized polymer sheeting
includes a layer of metal disposed between two polymer sheets.
[0003] There are several problems, however, with many types of
known metallized polymer sheets. For example, laminates typically
include an electrically continuous metal layer sandwiched between
two polymer sheets. Such materials are often subject to
delamination consequent to poor binding between the metal layer and
the polymer layers on either side. Further, corrosion of the metal
layer, which is usually aluminum can spread between the polymer
layers, thereby causing significant diminution in appearance.
[0004] One attempt to reduce the likelihood of delamination and
loss of appearance resulting from corrosion of the metal layer has
been to form a discontinuous metal layer on a polymer basecoat,
such as a resinous urethane. A monomer top-coat, such as a
solvent-based aliphatic urethane, is then deposited on the
discontinuous metal layer, and subsequently polymerized to
encapsulate metal islands of the discontinuous metal layer and to
bond them to the polymer basecoat.
[0005] However, formations of metal islands on various types of
polymers can be difficult. Also, bonding of a urethane top layer
during polymerization to a polyurethane basecoat can be poor. One
attempt to improve adhesion has been to etch the basecoat and
discontinuous metal layer with a sodium hydroxide solution to
remove residual metal between islands of the discontinuous metal
layer. A limitation to this method is that etching can result in
the formation of blackened areas in the metal layer, thereby
detracting from the appearance of the resulting laminated part.
[0006] There are several other problems that can be associated with
polymerizing a top layer in situ to form metallized polymeric
sheeting. For example, polyurethanes, in particular, generally are
not sufficiently hydrophobic to prevent weathering over extended
periods of time and are easily attacked by sodium hydroxide and
acids, such as nitric acid. Thicker layers of polyurethane top-coat
are difficult to form because in situ polymerization can cause the
resulting composite to appear irregular. In addition, evaporation
of a solvent component during polymerization of urethanes can cause
"popping" or bubbles to form, also diminishing the appearance of
the finished product. Further, methods which employ deposition of a
basecoat, such as a resinous urethane basecoat, require that the
basecoat be applied to a substrate, from which the resulting
metallized composite generally cannot be removed. Therefore, the
utility of this method for forming various products, having
different applications, is limited.
[0007] Therefore, a need exists for a metallized composite and a
method for forming such a metallized composite that overcomes or
minimizes the above-referenced problems.
SUMMARY OF THE INVENTION
[0008] The present invention is directed to a metallized sheeting,
such as a formable metallized plastic sheet, and a composite. The
invention is also directed to a method for forming the sheeting and
composite.
[0009] In one embodiment, the invention is a formable metallized
plastic sheet which, upon molding, does not cause degradation of
reflectivity of the metal sheet.
[0010] In another embodiment, metallized composite includes a first
thermoplastic layer and a discontinuous layer on the first layer.
The discontinuous layer is formed of discrete islands of metal in
an adhesive. A second thermoplastic layer is disposed over the
discontinuous layer, whereby the discontinuous layer is between
said first and second thermoplastic layers.
[0011] In still another embodiment, the metallized sheeting
includes a continuous thermoplastic sheet and at least one
discontinuous layer of metal within said thermoplastic sheet.
[0012] The method includes depositing a metal on a first
thermoplastic layer to form a discontinuous layer of the metal. A
second thermoplastic layer is laminated onto the discontinuous
layer.
[0013] The present invention has several advantages. For example,
neither thermoplastic layer of the composite is polymerized in
situ. Rather, the thermoplastic layers are laminated together to
sandwich the discontinuous layer of metal islands in an adhesive
bedding. Consequently, a wider variety of polymers can be employed
to form the composite, thereby enabling greater opportunity for
improving specific qualities of the composite and for tailoring
construction of the composite for specific uses. For example, the
choice of polymerized web materials can be selected for improved
formation of discrete metal islands, such as by combining a
particular metal with a polymer web that minimizes residual metal
between metal islands. Alternatively, a polymer web can be selected
that is preferably suitable for specific methods of metal
deposition. By minimizing the amount of metal that remains between
metal islands of the discontinuous layer, the need for etching can
be significantly reduced or eliminated.
[0014] Further, because a top polymeric layer is not formed in
situ, greater thicknesses can be employed without diminishing the
appearance of the finished product, thereby improving resistance to
environmental use conditions, such as weathering. In some
instances, a plasma of unsaturated monomers, such as acrylates or
methacrylates, may need to be polymerized on indium in vacuo; in
such instances, the top layer would be added in another operation.
Also, evaporation of solvents during polymerization is eliminated,
thereby preventing "popping" and other potential processing
problems. Moreover, a wider variety of methods of forming the
composite can be employed, such as by depositing metal islands
first on a thermoplastic drum surface, and subsequently
transferring the metal islands to a first continuous thermoplastic
web. A second thermoplastic web can then be applied over the
discontinuous layer to form the composite. In other embodiments,
the first and second thermoplastic webs can be bonded to each other
by melting, use of an adhesive, or by compression. All of these
processing options provide potential sources for reducing the cost
of production and increasing overall product quality and
productivity.
[0015] Different polymers can be employed for the two thermoplastic
sheets, thereby further broadening the utility of the composites of
the invention. In addition, neither the first nor the second
thermoplastic web is bound to a substrate. Consequently, composites
of the invention can be made to be flexible. Specific applications
of flexible reflectors or mirrors can include adjustable rear-view
mirrors for use in automobiles and as substitutes for conventional
chrome-plated metal parts. In another embodiment, the composites
can be molded after formation without degradation of the
reflectivity of the discontinuous metal layer. Molding, such as
embossing, for example, can provide an inexpensive means for
incorporating a logo into flexible patches, such as can be applied
to apparel, footwear, etc., that have the appearance of being
perfectly reflective.
[0016] Other uses include in-mold decoration, blow molding and
thermoforming. In-mold decoration, for example, includes injection
molding a thermoplastic behind the sheet of composite to enable
formation complex plastic art, such as parts having a reflective,
mirror-like surface. The injection molding resin should be
compatible with the first layer (the layer that will contact the
molten injection molding resin). Preferably, the composition of the
injection molding resin and the composition of the first layer of
the composite will be the same; for example, injection molding a
thermoplastic polyolefin (TPO) onto a composite which has as its
first layer (facing the polymer melt) a TPO. Alternatively, the
first thermoplastic layer and the injection molding resin should be
compatible in the melt stage. An example of such a combination is a
thermoplastic sheet of polycarbonate and an injection molding resin
of polycarbonate-ABS blend.
[0017] Blow molding is similar to injection molding except that the
molding resin is melted, extruded through a die and then blown with
air or gas pressure against the walls of a mold cavity. In this
case, a sheet of composite would be inserted into the mold and then
the resin would be injected behind it.
[0018] In a thermoforming operation, the sheet is heated to soften
it and then pushed into a cavity of a particular shape by a hot die
surface. Vacuum forming is a similar process that also incorporates
a vacuum to draw the softened sheet into the mold cavity as die
pressure is applied to the opposite face.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a cross-section of one embodiment of the composite
of the invention, wherein first and second thermoplastic layers are
bound together by an adhesive.
[0020] FIG. 2 is a cross-section of another embodiment of the
composite of the invention, wherein a continuous thermoplastic
layer encapsulates a discontinuous layer of metal.
[0021] FIG. 3 is a schematic representation of one embodiment of
apparatus suitable for forming a composite of the invention.
[0022] FIG. 4 is a schematic representation of an alternate
apparatus for forming a composite of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The features and other details of the apparatus and method
of the invention will now be more particularly described with
reference to the accompanying drawings and pointed out in the
claims. It will be understood that the particular embodiments of
the invention are shown by way of illustration and not as
limitations of the invention. The principal features of this
invention can be employed in various embodiments without departing
from the scope of the invention. All parts and percentages are by
weight unless otherwise specified.
[0024] The invention is directed to a formable metallized plastic
sheet and a method for forming the metallized plastic sheet. The
term "formable," as defined herein, includes, inter alia,
suitability for in-mold decoration, blow molding, thermoforming,
vacuum forming, etc. The formable metallized plastic sheet, upon
molding, does not cause degradation of reflectivity of the metal
sheet.
[0025] In one embodiment, shown in FIG. 1, metallized composite 10
includes first thermoplastic layer 12. Discontinuous layer 14 is on
first thermoplastic layer 12 and includes first side 16 and second
side 18. Discontinuous layer includes discrete islands of metal 20
and adhesive 22. Second thermoplastic layer 24 is on discontinuous
layer 14, whereby discontinuous layer 14 is between the first and
second thermoplastic layers. Discontinuous layer 14 preferably
includes discrete specular islands of metal. Suitable metals, as
defined herein, are those that can be deposited, or formed, on a
suitable thermoplastic polymer. Examples of suitable metals include
indium, zinc, tin, gallium, aluminum, cadmium, copper, nickel,
cobalt, chromium, iron, gold, platinum, palladium, rhodium, etc.
Preferably, the metal is indium. Also, preferably, discontinuous
layer 14 is reflective; most preferably, discontinuous layer 14 has
a mirror or mirror-like appearance. Optionally, discontinuous layer
14 can include specular islands of metal alloy. Examples of
suitable alloys include stainless steel, nichrome, etc.
[0026] Examples of suitable adhesives of discontinuous layer 14
include at least one compound selected from the group consisting of
styrene-butadiene copolymers, ethylene vinyl acetates, polyesters,
polyamides, epoxies, acrylic pressure-sensitive adhesives, silicone
pressure-sensitive adhesives, polyurethanes and isocyanate-cured
polymers. The adhesive can be a thermally-activated adhesive.
[0027] In one specific embodiment, the adhesive includes two
components. Preferred embodiments of adhesives that include at
least two components include combinations of polyester,
polychloroprene or polyurethane with isocyanate-functional
crosslinkers, and a combination of water-based polyurethane
dispersion with aziridine or with a water-dispersable isocyanate
crosslinker. In another specific embodiment, the adhesive can be
suitable for curing by exposure to ultraviolet light. An example of
such an adhesive is ultraviolet light-curable pressure-sensitive
adhesive.
[0028] First and second thermoplastic layers include at least one
suitable thermoplastic polymer. These layers can also be formed of
the same material, or they can be formed of different materials. A
suitable thermoplastic polymer, as defined herein, is a
thermoplastic polymer that effectively shields discontinuous layer
14 from environmental factors, such as weathering, humidity, and
acidic or basic solutions encountered during ordinary intended
final use of the composite. Examples of acidic and basic solutions
include mild solutions of nitric acid or caustic. Specific examples
of suitable thermoplastic polymers include, inter alia,
polyethylene, polystyrene, polycarbonate, polyethylene
terephthalate (PET), glycol-modified polyethylene terephthalate
(PETG), polyvinylchloride (PVC), thermoplastic polyurethane (TPU),
acrylonitrile butadiene styrene (ABS), polymethylmethacrylate,
polypropylene, polyvinyl fluoride (PVF), TPO, polyethylene
napthalate (PEN), polymethylpentene, polyimide, polyetherimide,
polether ether ketone (PEEK), polysulfone, polyether sulfone,
ethylene chlorotrifluoroethylene, cellulose acetate, cellulose
acetate butyrate, plasticized polyvinyl chloride, polyester
polycarbonate blends, ionomers (Surtyn), and co-extruded films or
sheets of these thermoplastics, etc. The thermoplastic polymers can
be elastomeric thermoplastics, and are commonly referred to as
thermoplastic elastomers or TPE's. Examples include polyurethane
(TPU), styrene-butadiene-styrene (SBS),
styrene-ethylene-butadiene-styrene (SEEBS). Examples of opaque or
translucent thermoplatics include polypropylene, polyamide,
polyphenylene sulfide (PPS), styrene-maleic anhydride,
polytetrafluoroethylene (PTFE), polycarbonate-ABS blends,
polycarbonate polyester blends, modified polyphenylene oxide
(PPO).
[0029] In one embodiment, first thermoplastic layer 12
predominantly includes a first thermoplastic polymer and a second
thermoplastic layer 24 predominantly includes a second
thermoplastic polymer. Examples of suitable combinations of first
and second thermoplastic polymers are combinations of
polyvinylidene difluoride (PVDF) and acrylonitrile butadiene
styrene (ABS), PVDF/TPO, TPU/PVC, etc.
[0030] First thermoplastic layer 12 or second thermoplastic layer
24, or both, can be clear or tinted. Examples of suitable
components for tinting continuous thermoplastic layers 12 and or 24
include suitable organic or inorganic dyes or pigments, etc. As an
alternative to tinting the thermoplastic layer, the adhesive can be
tinted. This has the advantage of being cheaper than adding
colorant to plastic sheeting; moreover, the plastic sheeting can
screen the colorant for exposure to ultraviolet light (UV), thus
making it possible to use nonlight-fast colorants. In another
embodiment, first thermoplastic layer 12 or second thermoplastic
layer 24 can be opaque. Examples of suitable components that can
cause opacity include carbon black, iron oxide, titanium dioxide,
etc.
[0031] Metallized composite 10 can be embossed, such as by a
conventional method, including, for example, heat pressing. As
another option, metallized composite 10 can be formed, for example,
to form a part that is to exhibit a translucence that is a multiple
of the translucence of a single-ply of metallized composite. As
another alternative, metallized composite 10 can be supported by a
substrate, whereby metallized composite 10 is in contact with the
substrate. Examples of suitable substrates include thermoplastic
polyurethane, polyvinylchloride, glycol modified polyethylene,
thermoplastic polyolefin, fiber reinforced nylon, fiberglass,
aluminum, and metal alloys, such as steel, etc.
[0032] In another embodiment, metallized composite 26, shown in
FIG. 2, includes continuous thermoplastic sheet 28 that
encapsulates discontinuous layer 30 of metal. The metal, or metals
of discontinuous layer 30, and suitable thermoplastic polymers of
continuous thermoplastic sheet 28 are the same as those described
above with reference to FIG. 1.
[0033] As with the embodiments set forth above and shown in FIG. 1,
metallized composite 26 of FIG. 2 can include one or more
thermoplastic layers that are clear, tinted or opaque. Also,
elastomeric thermoplastic composite can be supported by a
substrate, formed or embossed. In one embodiment, discontinuous
layer 30 substantially partitions thermoplastic sheet 28, whereby
thermoplastic sheet 28 predominantly includes a first thermoplastic
polymer at first side 32 of discontinuous layer 30, and
predominantly includes a second thermoplastic polymer at second
side 34 of discontinuous layer 30.
[0034] The method for forming a metallized composite of the
invention generally includes depositing a metal on a first
thermoplastic layer to form a discontinuous layer of the metal. A
second thermoplastic layer is laminated onto the discontinuous
layer. Suitable methods for deposition of metal on the first
thermoplastic layer includes electron evaporation, sputtering, ion
plating, induction heating, thermal evaporation, transfer of a
preformed metal layer from a separate substrate, etc.
[0035] Optionally, the method includes bonding the first
thermoplastic layer to the second elastomeric thermoplastic layer.
Examples of suitable methods for bonding the thermoplastic layers
include heating, to thereby cause the layers to melt combined and
form a single, continuous thermoplastic layer. Alternatively, the
layers can be bonded by heating without melting, pressing the
layers together, or applying a suitable adhesive to the first
and/or second thermoplastic layer before laminating the layers
together.
[0036] In embodiments where an adhesive is employed that is curable
by ultraviolet light, the method includes exposing the
thermoplastic composite to ultraviolet light to thereby cure the
adhesive. Alternatively, a UV-curable adhesive applied to one
thermoplastic layer can be exposed to UV light and then laminated
to a second thermoplastic layer.
[0037] Conventional methods can be employed to conduct other
optional steps, such as molding, folding, and/or embossing the
metallized composite. In one embodiment, apparatus 40, shown in
FIG. 3, is employed to conduct a method of the invention. Therein,
first thermoplastic layer 42 is drawn from roll 44 across
deposition guns 46 by reel 48. Deposition guns 44 deposit a
suitable metal, such as indium on first thermoplastic layer 42.
Deposited metal forms discrete islands on first thermoplastic layer
42, which then passes across roller 50. Preferably, roller 50 cools
first thermoplastic web 42. Optionally, first elastomeric
thermoplastic web 42 is coated with an adhesive deposited prior to
or after deposition of specular islands of metal.
[0038] Second elastomeric thermoplastic layer 52 is drawn from roll
54 by reel 48. Optionally, second thermoplastic layer 52 is coated
with an adhesive. First and second thermoplastic layers 42, 52 meet
at rollers 56. In one embodiment, rollers 56 are heated.
Preferably, in embodiments where rollers 56 are heated, they are
heated to a temperature of about 300.degree. F. First and second
elastomeric thermoplastic layers 42, 52 become bonded to each other
while passing through rollers 56, to thereby form a thermoplastic
composite 58 of the invention. Thermoplastic composite 58 is drawn
across roller 60 and then collected on reel 48.
[0039] In another embodiment, apparatus 70, shown in FIG. 4, is
employed to conduct a method of the invention. In this embodiment,
drum 72 includes a suitable thermoplastic coating 74. A suitable
thermoplastic coating is one that will enable formation of discrete
metal islands thereon by deposition, such as by electron beam
evaporation, and which is suitable for transfer of metal islands to
a first thermoplastic layer. An example of a suitable thermoplastic
coating of drum is JPS 1880 Glossy 2.RTM. sheet stock material
(urethane).
[0040] Drum 72 rotates, whereby metal plumes formed by deposition
guns 76 cause deposition of the metal onto thermoplastic coating 74
of drum 72. As drum 72 rotates, discontinuous layer 78 of metal
islands forms on thermoplastic coating 74 of drum 72.
[0041] First thermoplastic layer 80 is drawn from drum 82 by
take-up reel 84. During conveyance from drum 82 to take-up reel 84,
first thermoplastic layer 80 passes between rollers 86 and drum 72.
Rollers 86 press first thermoplastic layer 80 against discontinuous
layer 78 on drum 72, thereby transferring discontinuous layer 78 to
thermoplastic layer 80. In one embodiment, rollers 86 are
heated.
[0042] Second thermoplastic layer 88 is drawn from drum 90 by
take-up reel 84. Optionally, an adhesive is deposited on second
thermoplastic layer 88. First and second thermoplastic layers 80,
88 meet at rollers 92. Rollers 92 cause contact between first and
second thermoplastic layers 80, 88. Preferably, rollers 92 are
heated. Contact between first and second thermoplastic layers 80,
88 at rollers 92 causes formation of a thermoplastic composite of
the invention. The thermoplastic composite is subsequently
collected on take-up reel 84.
[0043] In another embodiment, indium is vacuum deposited on a first
thermoplastic layer. The metallized sheet is removed from the
vacuum chamber and laminated to a second thermoplastic layer or to
the second thermoplastic layer with adhesive pre-applied, using
conventional laminating methods employed in the coating/laminating
industry. Alternatively, the deposited indium layer is coated in
vacuo with a thin plasma-polymerized coating to protect the
metallization.
[0044] In still another embodiment, an interleaf of plastic film,
usually polyethylene or polyethylene terephthalate is wound with
the indium metallization to protect the metal layer as it is
rewound. It is subsequently stripped out as the metallized sheeting
is coated or laminated.
[0045] In a further embodiment, the metallized sheeting is
laminated to a film adhesive. A film adhesive consists of a layer
of adhesive between two release liners. One liner at a time can be
removed and the adhesive laminated to one thermoplastic sheeting.
The second liner can then be removed and the laminate is adhered to
the second thermoplastic layer.
[0046] The performance of the metallized composite can be further
improved by overcoating or overlaminating additional layers of
polymerized plastics or films over the composite to further improve
abrasion resistance, chemical resistance, weathering resistance,
etc. For example, a UV-curable hardcoat can be applied to the
metallized composite and then cure the coating by exposure to
high-intensity UV light.
[0047] The invention will now be further described by the following
examples, which are not intended to be limiting in any way. All
parts and percentages are by weight unless otherwise specified.
[0048] Exemplification
EXAMPLE 1
[0049] A sample of A-4100.RTM. clear urethane sheet stock, made by
Deerfield Urethane, A Bayer Company, South Deerfield, Mass., was
metallized in a 72" metallizer (Part #EJWIN403MM30, made by Kurt J.
Lesker Co., Inc., Clairton, Pa.). About 300 .ANG. of indium was
deposited, through electron beam deposition, onto the surface of
the urethane. A second sheet of A-4100.RTM. clear urethane sheet
stock was removed from its polyester released liner backing and was
gently pressed onto the surface of the indium. Special attention
was given to removing air bubbles that might expand in the
convection process. A heat gun was then utilized to heat the two
samples. The conventional heat gun was set to a temperature of
400.degree. F. and was held at a distance of approximately 4 inches
from target. When exposed to the heat, the two identical sheets of
material immediately showed signs of melting as the two materials
appeared to be fused together. The indium layer slightly discolored
during the convection heating. Samples of the same type were
repeatedly run to attempt to maximize appearance. Finally, a
convection oven set at a temperature of 300.degree. F. was used to
melt the materials together over a 4-5 minute duration. Slight
iridescence persisted with the fusing process. Since the initial
trials with the A-4100.RTM. clear urethane sheet stock, it was been
determined that the metallized unprotected sheet appeared to have a
finite shelf life, whereafter the sample will discolor, and
eventually turn white with thermal application of the top film. In
practice, it should be the intent of the designer to have the
materials mated as soon as possible to prevent this occurrence.
EXAMPLE 2
[0050] A sample of JPS 1880 Glossy 2.RTM. sheetstock material
(urethane) was metallized in a 72" metallizer (Part #EJWIN403MM30,
made by Kurt J. Lesker Co., Inc., Clairton, Pa.). About 300 .ANG.
of indium was deposited, through electron beam deposition, onto the
surface of the urethane. A sample of the A-4100.RTM. clear urethane
sheet stock, with the polyester release liner backing removed, was
then gently applied to the surface of the indium. The sandwiched
samples were then inserted into a 300.degree. F. convection oven
for a duration of 2 minutes. The samples were then removed from the
oven and allowed to cool to the touch. The samples were then
manually pulled apart by starting a separation at the edge. At this
point it was noted that the indium had been effectively transferred
to the A-4100.RTM. clear urethane sheet stock substrate. The indium
surface maintained its superior reflective properties with no
distortion evident. The sample of the JPS material was discarded,
while a second sheet of A-4100.RTM. clear urethane sheet stock was
thermally adhered to the first using the same process outlined
above.
EXAMPLE 3
[0051] Additional work was performed using an adhesive technique
for application of the protective film. Two samples of sheet, JPS
1880 Glossy 2.RTM. sheet stock and 30 mil E-grade double polished
PVC film were used. Both of the sheets generally had a transparent
appearance, but the E-grade double polished PVC film material had a
slight blue tint due to the resin's inherent nature. They were
metallized in a 72" metallizer (Part #EJWIN403MM30, made by Kurt J.
Lesker Co., Inc., Clairton, Pa.). About 300 .ANG. of indium was
deposited, through electron beam deposition, onto the surface of
the urethane. After metallization, an adhesive-backed film of PVC,
KPMF.RTM. black, supplied through Kay Automotive Graphics, Inc.
from KPMF, Inc., Wells, Okla., was carefully applied to the indium
layers of each sample. The sample, when viewed through the JPS 1880
Glossy 2.RTM. sheet stock material or E-grade double polished PVC
film material, exhibited a clear mirror-like appearance.
EXAMPLE 4
[0052] A standard vacuum web metallizer was used to vacuum
metallize continuous rolls of film with indium metal. Indium wire
(0.070") from Arconium Corporation was continuously fed to heated
ceramic boats. Highly reflective indium depositions were achieved
using web speeds of 50 to 300 ft/minute.
[0053] 1,100 linear feet of 40" wide 1-mil PET film was vacuum
metallized at web speeds from 30 to 50-ft/minute. The indium wire
feed rate averaged 28"/minute. This highly reflective, vacuum
metallized film was then adhesively laminated to 6.5 mil PET film
in a standard web coater-laminator to create a laminate with the
indium layer between two PET films. The adhesive used was National
Starch 3918 laminating adhesive modified with carbon black filler
to provide an opaque backing to the indium layer. The adhesive was
applied to the uncoated polyester film using a 165 quad gravure
cylinder; web speed was 50 feet/minute. The adhesive coated film
was then laminated in-line to the indium-coated film at a nip
temperature of 130.degree. F.
[0054] Samples of this laminate were then tested for lamination
strength using an Instron tester. Initial bond values (obtained
within 15 minutes of lamination) were 1.8-2.3 lbs./inch. Samples
aged at room temperature for three days had lamination strengths of
2.4-2.5 lbs./inch.
[0055] Equivalents
[0056] Those skilled in the art will recognize, or be able to
ascertain using no more than routine experimentation, many
equivalents to the specific embodiments of the invention described
specifically herein. Such equivalents are intended to be
encompassed in the scope of the claims.
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