CA1094405A - Metallized flexible plastic automobile trim component - Google Patents

Abstract

A B S T R A C T
A metallized flexible plastic automobile trim com-ponent, such as a fender extension, is made by applying a series of four coatings to a polymeric substrate of the desired configuration, preferably of a molded thermoplastic urethane. The coatings comprise:
1) a primer coat of A baked pigmented urethane lacquer or enamel, the urethane being preferably an inherently light stable aliphatic urethane, 2) a leveling base coat of a thermosetting resin, e.g. a baked melamine-formaldehyde and more preferably a blend of an aliphatic urethane with an anhydride cured epoxy, 3) a vacuum deposited layer of stainless steel or chromium, or of aluminum when the part is to be used in an interior application, and 4) a top coat of a tough abuse-resistant acrylic and/or urethane lacquer and moot preferably one com-prising a blend of an aliphatic urethane, acrylic and melamine resins.

Description

J O~ O.~
P-535~536 BACKGRO-~ND AND PRIOR ART
Vacuum metallizing o~ plastic sur~aces has been practiced f~r some time. For example, see U. S. Paten-ts Nos.
3,201,271; 3,740,254, 2,~93,806j and 3,783,012. More recentl~, attempts have been rnade to manufacture automobile exterior trim components such as bumpers, bumper sections or fender ex-tensions of a tough but flexible, abuse-resistant plastic hav-ing a bright metal-like surface. Generally speaking, such metallized surfaces have not had the low-temperature flexi-bility, the resistance against impact from gravel, the corro-sion resistance, the chrome-plated appearance, and the like required for automotive use. An article in the December 1974 issue of Modern Plastics, "Restoring the Luster to Metallized Markets", pp. 42-~6, by C. Otis Post presents a good summary.
In that article it is noted with regard to making metallized coatings environmentally acceptable that:
"The relationships among plastic substrate, base coat, metallized coating, and top coat are so intricate that changing any one member usually means re~ormulating one or more of the others. It ~O~L~L4L05 The present invention generally relates to a metal-lized flexible plastic article having a composite coating which is built up in a specific manner from certain select films or ingredients.
One aspect of the invention provides a metallized plastic article comprising-(a) a molded flexible elastomeric plastic substratehaving an extensibility greater than 30%, (b) a light-blocking primer coat of a pigmented resin on and immediately contiguous to the surface of said substrate, ~ c) a vacuum deposited metal film on said primer coat having a thickness in the range of 200 to 1000A, and (d) a moisture impervious well-adhered flexiblc top coat thereover of a non-opaque acrylic lacquer;
the whole of said article having been heat treated to cure said acrylic lacquer sufficient to develop light passing micro-fissures in said vacuum deposited layer.
Another aspect of the invention provides a metallized plastic article comprising:
~ a) a flexible elastomeric plastic substrate having an extensibility greater than 30%, (b) a light-blocking pigmented primer coat on a surface of said substrate, ~ c) a base coat over said primer coat of a baked thermosetting resin, ~ d) a vacuum deposited layer thereon of a metal selected from the group consisting of chromium, stainless steel and aluminum, said layer being in the range of approximately 200 to 1000A thick, and ~ e) a moisture impervious well-adhered flexible film thereover of a non-opaque acrylic lacquer.

J~.09 ~405 A further aspect of the invention provides in a metallized plastic article which includes a synthetic polymeric substrate having an extensibility greater than 30% and which tends to degrade upon exposure to sunlight, a deposited metal film thereon and a transparent protective polymeric topcoat over said metal film, said metal film having a thickness in the range of 200 to lOOOA and being thick enough as deposited to block passage of any detrimental amounts of said sunlight but being minutely fissured through said metal film to permit passage of said sunlight, the improvement comprising first placing on said plastic substrate a light-blocking pigmented polymeric layer over which is disposed said deposited metal film, the pigment con-tent and thickness of said pigmented polymeric layer being suf-ficien~ to stop passage of said sunligh~ from said fissures, The metallizing advantageously involves the use of vacuum deposited chromium or stainless steel such as a "ferrous-chrome" containing 13% to 30% chromium when the part is designed for exterior use on an automobile. Such a stainless steel or chromium coated part can also be used in the interior of an automobile such as for trim for an instrument cluster. One may prefer to use aluminum instead of stainless steel where weather-ing and abuse resistance are not too important as aluminum gives a more pleasing chromium plated-like appearance, i.e, it more nearly duplicates t~e appearance of conventional electroplated chrome parts. However~ ~hen a thin layer of aluminumoxidizes it becomes transparent or translucent and the metallic luster is lost. In an exterior application such as a bumper section, if there is a break or ~lemish caused by a stone nick or the like, an aluminum layer disappears at the break or blemish point in a short period o time and then will continue to oxidize and dis-appear until the entire aluminum layer is gone.

~ ~a -r~

4(~5 The base plastic from which the part is made is a tough but flexible elastomer, preferably an injection molding grade thermoplastic polyurethane (TPU), By "flexible elastomer"
is meant a natural or synthetic thermoplastic or thermoset plastic or polymer hav7ng an extensibility of greater than approximately 30 percent, as compared to a "rigid" plas~ic which may be considered to have an extensibility of less than 10 per-cent. While it is preferred to use a molded thermoplastic urethane because of its other properties, such a urethane is more deleteriously affected by sunlight than many other plastics, that is, it is light sensitive.

~ 2b ,, ~

10~ 405 p_535/535 An article o~ the ~esired shape mad~ ~rom the elastomer, after sur~ace cleaning if required, is successively coated in accordance with the present -lnventlon wl-th preferab]y four well-bonded layers or films to produce -the ~inal lustrous metallic appearance desired~
The cleaned plastic part is first prime coated with a plgmented and thus llght-blocking urethane lacquer having a dry film thickness o: o.8 to 1.2 mils, wh;ch ls air flashed and baked. While aromatic urethanes have been used, the urethane is pre~erably an allphatic one which is inherently more llght stable. This ls ~ollowed by a base coat of a melamine formaldehyde resin or preferably, a urethane-epoxy resin having a dry ~ilm thlckness of about 0.~ to 1.2 r~ils.
The base coat is also baked~ and 1~ lt were applied dlrectly to the plastic substrate, it would not adhere well. On the other hand, the pigmented urethane lacquer prime coat wlll not flow readily and ~orm the level, sheeny and smooth uni-form surface required ~or the vacuum deposited metal.
Desirably, the base coat should also be light stable.
Depending on the appearance desired in the ~inal part~ the base coat can be applied to be sheeny or to be matte appearing. It is preferred to apply the base coat "wet-on-wet" directly onto the alr~flashed but not completely baked primer as be-tter intercoat adhes-lon is obtained.
The metal is then vacuum deposited onto the base coat using preferably the resistance method. Electron beam and sputtering vacuum depositing can also be used. Sputtering giJes a deposit that is brighter appearing than the others, but a lacquer top coatlng thereover tends to microcræck in the metal layer~ Xeslstance coatlng is favored as the re-quired invest~ent in equipment is substantially les~.

The metal c~ating is ~x$~*~y about 200~-1000 A

~ 0 ~ i~ 0 5 thick -- thick enough to develop the proper metallic color.
The chromium content of the stainless steel is essential, but the steel can a~so have incorporated therein minor amounts of nickel and/or magnesium and/or other metals. The use of essentially pure chromium ls -lncluded within the ambit of this invention because, contrary to what some believed, it was *ound that chromium could be success~ully vacuu~l deposited ~or this application. Essentially pure aluminum gives the more pleasing appearance and most closely matches that of traditional electrodeposited chromium on metal parts. Chromium deposited by resistance vacuum metallizing is the next most effective in matching electrodeposited chromium.
The thin metal coa-ting is not5 o~ course~ resistant to mechanical abuse and to long-term weathering and needs to be protected While various flexible abuse-resistant non-opaque top coats, such as an acrylic lacquer might be used, it has been found that a clear lacquer derived from a blend of acrlyic, aliphatic urethane and melamine resin has defini-te advanta~es and is to be preferred. This particular top coat can also be used in other applications such as for the pro-tection of painted parts.
The film thickness of the top coat is preferably in the range of 0.8 to 1.2 mils, dry basis, and it is preferably thoroughly baked, e.g. at 2~0F, but too high a temperature may cause some yellowing and/or iridescence. The top coat is ~ormu-lated to adhere to the metal layer as well as to the base plastic. By deliberately overlappingjb the top coat, the metal coat and the two underlying layers can be "encapsulated"
between it and the base plas-tic, eliminating edge delamina-tion.
The development work on this invention turned upan interesting ~inding, ~iz: that light may penetrate the lO~i~40S

metal coating and base coat film and reach the surface of the underlying primer coat, causing degradation thereof and inter-facial loss of adhesion between the base coat and the primer coat. That light penetrates the metal film, which appears to the eye to be continuous and opaque, is surprising. This was found to be 30 as follows: When a metallized layer de-posited on a film of the base coat supported on a gl&ss plate is exposed to visible light, including ultraviolet light rays, the light will not pass through. When, however, the acrylic top coat is applied thereover and baked, some of the light will pass through. It is belie~ed that this is because minute, microscopic cracks or fissures through the metal film were formed which allowed the light to pass. Apparently the solvents normally used in the top coat material and the difference in thermal expansion of the metal and resin films during baking cause these minute cracks to appear.
As the light does pass through the metal layer, as the base coat is not pigmented, and as the thermoplastic urethane base part is quite light sensitive, the skilled in the art will appreciate that it is quite desirable to make the primer coat light opaque and to use a resin therein that is, preferably~ irlherently light stable, such as an aliphatic urethane. Long term outdoor, e ~ g. Florida sunshine ~or one year~ weathering tests have conclusively established that interfacial adhesion loss will occur between the base coat ` and the primer coat before it will occur at the in~erfaces of the other layers. Use of a properly formulated, pig-ment~d and applied primer coat will offse-t this lnterfacial adhesion Ioss.
There i8 little question that this finding of light penetration and ef~ect is an important one that lends con-siderable merit to the present claim for inventiveness for 10~4~L0S

the described multi-layered metallized product. And, o~
course~ as the m~tal film ls in a sense deliberately micro-crazed or minutely cracked in a controlled regulated manner, this permits later ~lexing and bending of the product without 5 appreciable or too ob~ectionable change in its appearance.
Moseover, light ls reflected back through these microscopic cracks to some extent, and this characteristic can be used to esthetic advantage. A white or tinted light-blocking pigmented primer coat can be effectively employed to ad-vantageously change the appearance of the metal layer andenhance the overall appearance of th0 multi-layered metallized plastic article.
THE DRAWIN~ -The drawing is a greatly enlarged schematic cross-sectional view of a metallized surface made according to th~s inventlon, ln which the number designating the layers are: -13 In~ection molded thermoplastie urethane.

2) Baked urethane lacquer.

3) Baked melamine ~ormaldehyde resin.
~; 20~ ~ 4) 800 A vacuum deposited ~errous-chrome-20 stainless steel.
5)~Clear acr~lic lacquer.
EXAMPLE I
~:B ~ :The sample part made wag a 1975 Cadillac1 Fender ,, ~
25~ ~xtension, part~number X1605647.
An e1astomeric thermoplastic urethane was "in house"
manu~actured~from a gra~ted poly (oxypD~pylene) diol (Union Carbide;Company's NIAX D-432, 270 Park A~enue, New York, ew~York 10017), 100 parts by weight, polytetramethylene ether glycol (Quaker Oats Company PolymegllOO, Merchandise Mark Plaæa, Chicago, Illinois 60654), 28 parts, 4', 4' di-phenylmethane diieocyanate, 86 parts; and 1, 4 butanediol, r~n?~ -6-.

~.0~4 0 5 26 parts. This thermoplastic urethane is fully described in U.S. Patent No. 3,933,938. Commercially available Uniroyal thermoplastic urethane designated E-2A could also be used (Uniroyal, Inc., 1230 Avenue of the Americas, New York, New 5 York 10020). The nature of the flexible urethane substrate does not appreciably affect the performance of the applied coatîng. The urethane cannot be so stiff or rigid that it will not serve its intended function as a flexible trim com-ponent nor can it be too flexible or elastomeric. The present coating system can, o~ course, be applied and used wlth a substantially more rigid substrate, but other methods of bright trimming such as plating may be more economical to use on firm or hard surfaces.
The urethane lacquer primer was a standard pro-duction item sup~lied by PPG Industries, 3800 West 143rdStreet, Cleveland, Ohio, under the code designation DEI.-600-32906. Any equivalent light-blocking primer that adheres well to the molded thermoplastic urethane can be used. The one used was a thermoplastic and was not considered too stable to ultraviolet light as it was an aromatic urethane.
It was pigmented to a gray color with black and white pig-ments. The primer was sprayed as supplied by the manu-facturer-in three or four passes onto the properly cleaned surface at room temperature to a thickness of 1.0 ~ 0.2 mils (dry basis).
The appli~d coating requires an air flash for 10 minutes or so, but it was not baked at this point. One of the findings made during the development of this invention was that the subsequent base coat could be applled "wet-on-wet"
with improved intercoat adhesion and the consequent saving coming from the elimination o~ the primer ba~ing step.

The base coat applied over the primer also was a ~,0~ L~ ~LO 5 P-535/53k so~ercially available tough melami.ne formaldehyde resi.n, d-iluted to spray viscosi.ty of 38 -~ 2 seconds (No. 1 Zahn Cup).
The base coat was SM~1240-6, supplied by Red Spot Pa-lnt &
Varnish Co.~ Inc., 100 ~.[ain Street, Evansville~ Indlana. It was applied to a thickness of 1.0 + 0.2 mils. The coati.ng was air flashed for 15 minutes, and then the two coatings were baked for 45 ,ninutes at 250F ~- 5F (oven air temperature).
After Gooling JO room temperature, the parts were vacuurn metallized using an Airco Temescal electron beam metallizer. The metal llsed was a ferrous-chrome-20 stai.nless steel supplied by Airco Temescal, 2850 Seventh Street, Berkeley, California 94710, and it was applied to a thickness of Cl Q
800 A + 20~ A. The procedure used was as f3110ws:
1) Metallizer was brought up to and maintained at steady state condition as per manufacturer's in-structions.
2) Samples were loaded into the interlock chamber.
3) Chamber was sealed and brou~ht down to proper vacuum.

4) Samples were moved into the metallizing chamber, through the metal vapor clou~ and back to the interlock charnber.

5) Interlock chamber was pressurized and the samples were removed.
The top coat was a solvent based acrylic lacquer spray applied by conventional methods. The base material is supplied by Pan Chemical Corp., 1 Washington Avenue~ Hawthorne, New Jersey, as o8-18~A or 68-202A. The coating was applied to a thickness of 1.3 to 1.6 mils (dry basi.s) followed by air flashin.g for 15 minutes and baking at 150~F ~ 2~F (oven air temperature) for 60 minutes.
Thermopla~tic urethane (T.PU) Cadillac Fender ~0~ 5 P-535/53~;
Extens:i.ons nade ~li.ti~ the "in house" mater.a.l and ,~letallized an~ co~ted as above described were subject to varlous te3ts wiih the resul-ts as gl-ven in the followlng Table.
~ RESIJLTS
Test Results _ 200 Weatherometer Hours (3) Sl-;æht dullin~ and water spotting Water IrQmersion (3) Pass Tape Adhesion ~3) Pass 10 Thermal Cycle Pass C.A.S~S. Test (1) Pass Cold Flex (3) Substrate Pass Finish Cracked Gravelometer (SAE Test J-400) Pass 15 Salt Spray (2) Pass Gravelometer plus CoA~SoS~ (3) Pass C-ravelometer plus Salt Spray (3) Pass Car Wash (3) at 1/2% Pass a-t 5~ Pass (1) General Motors Test 4476 P
(2) General Motors Test 4298-P
(3~ According to ~adillac 3right Trim Specifications 3o ~0 ~ 4 ~ 0 5 P-5~5~535 EXAMPLE Il The coating of Example I is applied to an lns~ru-ment gauge rim with the only difference being that an alumlnum is used in place of the stainless steel. The aluminwrl ls a 99.9~% high purity aluminum supplied by R. H. Cheney Inc. of Attleboro~ Massachusetts 02703, and is applied to a thickness of 800 A + 200 A~ This part is suitable for use in the in-terior of an automobile.
For critical exterior use, PPG Industries Dure-thane1300 is preferably used as the primer. This is a pig-mented enamel instead of a lacquer and is based in a thermo-setting resin. The resin is an aliphatic urethane which ls more light stable than the aromatic urethane of the DE~ 600-32906. Durethane 300 is weatherable, flexible at low tempera-tures and possesses good adhesion affinity for the moldedthermoplastic urethane surface.
Durethane 300 is white color and it has been found that this underlying white coat material enhances the pleas-ing metallic appearance of the product, i~e. the metal film is usually thin enough such that the color of the ~rimer coat can be seen through the metal ~ilm. Obviously, in some in-stances it may be desirable to tint the primer coat to im-prove the appearance of the part. Also, the use of a white primer coat has the additional advantage that if the metal film is scratched or scored, the whlte shows through, i.e.
one sees the white which is complimentary to the metal and not ~ome disfiguring color such as black or gray The following formulation has been found to work exceptionally well as a base coat ~ormulation in place of .~
the previously described Red Coat1 SM-1~40-~.

~ rrac7~ rks ~.05~ 05 P-53~/536 Parts by we-lght Aliphatic urethane ~l (40~0 solids) 50.0 Epoxy resin (l) 3.0 HXPA (2) 3 Catalyst solution (3) L~.o B Cellosolve,l~acetate (4) 46.o Methyl ethyl ketone 50.0 156.0 (1) 3, 4 epoxy cylcohexylmethyl - 3~4 epoxy cyclohexane car-boxylate (2) hexahydrophthalic an'nydride (3) five parts by weight uranyl nitrate~ balance Cellosolve acetate (4) Union Carbide trade name for 23 ethyloxyethyl acetate The aliphatic urethane solution #l was based on re-acting epsilon caprolactone polyester diols and triols with cyclohexyl diisocyatate (CHDI) at 50~ solids in toluene, followed by dilution to the 40~ solids level with additional toluene. The polyesters were Union Car'bide Corporation's NIAX PCP-0200 (the diol) and NIAX PCP-0300 (the triol) and were reacted as follo~s:
Parts by weight PCP-0300 14.~98 PCP-0200 3.498 CHDI (l) 21.799 Toluene 59.99~, Catalyst (2) 0.011 100 . 000 (1) Hylene W--E.I. duPont de Nemours & Co., 100'7 Marl~et, Street~
'Wi~lmington, Delaware 1980~.
(2) dibu-tyl tin dilurate 10~3-~'lOS

As can be seen, this base coat formulation is com-posed of an aliphatic amine blended with an anhydride cured epoxy, with the curing belng catalyzed by the uranyL nitrate.
This blend was formulated to optimumize flexibility versus 5 hardness and to provide the excellent metal adhesion that the epoxies are noted for. The weight ratio of urethane resin to cured epoxy resin in the above is about 3 to 1 but this can vary from 1 to 1 to 1 to 2.
The following formulation has been found to work better as a top coat formulation than the pre~iously described Pan Chemical's 68-202~:
Parts by weight Aliphatic urethane #2 (40~ solids) 30.0 Acrylic (1) 16.0 15 Melamine (2) 3-Catalyst (3) .3 Methyl-ethyl ketone 50.0 Cellosolve acetate (4) 60.0 Toluene 40.0 199.3 _ (1) Cyanamid XC-~011 (carboxyl functional acrylic)--American Cyanamid Co., South Cherry Street, Wallingford, Con-necticut 06492 (2) Cyanamid 303 (hexamethoxymethyl melamine) (3) Cyanamid 4040 (acid catalyst) (4) Union Carbide trade name for 2, ethyloxyethyl aceta-te The aliphatic urethane solution ~2 was based on re-acting epsilon caprolactone polyester triol (NIAX PCP-0300) and 1, 6 hexane adipate diol with cyclohexyl diisocyanate (CHDI) at 40~ solids level as follows:

~ 9~ 5 P-5'~5/53,'~-, Parts by weight CHDI (1) 20.092 Catalyst (2) 0.011 P~P-0300 13.445 1, 6 EIexane adiPate diol (3)~ o7 Toluene ~9~995 100 . 00 (1) Hylene W
(2) Dibut,yl tin dilaurate (3) Ageflex16~1000--Witco Chemica,l Co., 277 Park Avenue, New York, New York 10017 The weight ratios of the resins in this top coat are such that the aliphatic urethane and acrylic resins are used in about equal amounts, although up to 5 times as much ure-thane as acrylic can be used. The melamine will usually amount to 5 to 20 weight percent of the acrylic resins.
TPU Cadillac fender extensions rnade with this metal-lized bright trim system give the following test results:

~ ~r~ n~k 3o 109440~
p 535/536 TEST RESULTS
__ Test ~esults -500 Weatherometer Hours ~3) Slight dulling and water spott ing Water ImmeTsion (3) Pass Tape Adhesion ~3) Pass The~lal Cycle Pass C.A.S.S. Tes~ ~1) Pass Cold Flex ( 3~ Subs ~rate Pass Finish Pass Gravelometer (SAE Test J-400) Pass Salt Spray (2) Pass Gravelometer plus C.A.S.S. ~3) Pass Gravelometer plus Salt Spray (3~ Pass 15 Car Wash (3) at lt2~ Pass at 5~ Pass (1) General Motors Test 4476-P
(2) General Motors Test 4298-P
20 (3) According to Cadillac Bright Trim Specifications Reference is directed pursuant to Rule 43 to our copending application Serial No. 268,148, filed December 17, 1976.

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Claims (11)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A metallized plastic article comprising:
(a) a molded flexible elastomeric plastic substrate having an extensibility greater than 30%, (b) a light-blocking primer coat of a pigmented resin on and immediately contiguous to the surface of said substrate, (c) a vacuum deposited metal film on said primer coat having a thickness in the range of 200 to 1000.ANG., and (d) a moisture impervious well-adhered flexible top coat thereover of a non-opaque acrylic lacquer;
the whole of said article having been heat treated to cure said acrylic lacquer sufficient to develop light passing microfis-sures in said vacuum deposited layer.

2. The article of claim 1 wherein said pigment is light colored and enhances the visual appearance of said metal film.

3. The article of claim 1 wherein said continuous pigmented polymeric layer is immediately contiguous to said plastic sub-strate as a primer coat and has applied directly thereto a base coat of a stable thermosetting resin on to which is directly applied said metal film by vacuum deposition.

4. The article of claim 3 in which said article is an ex-terior automobile trim component, said metal film is formed from a metal selected from the group consisting of stainless steel and chromium, said primer coat is a pigmented urethane lacquer having a dry film thickness of approximately 0.8 to 1.2 mils, said base coat is baked melamine formaldehyde resin having a dry film thickness of approximately 0.8 to 1.2 mils, and said top coat is a baked acrylic lacquer having a dry film thickness of approximately 1.3 to 1.6 mils.

5. The article of claim 3 when said article is an interior automobile trim component, said metal film is of aluminum, said primer coat is a pigmented urethane lacquer having a dry film thickness of approximately 0.8 to 1.2 mils, said base coat is a baked melamine formaldehyde resin having a dry film thickness of approximately 0.8 to 1.2 mils, and said top coat is baked acrylic lacquer having a dry film thickness of approximately 1.3 to 1.6 mils.

6. A metallized plastic article comprising:
a) a flexible elastomeric plastic substrate having an extensibility greater than 30%, b) a light blocking pigmented primer coat on a surface of said substrate, c) a base coat over said primer coat of a baked thermosetting resin, d) a vacuum deposited layer thereon of a metal selected from the group consisting of chromium, stainless steel and aluminum, said layer being in the range of approximately 230 to 1000 .ANG. thick, and e) a moisture impervious well-adhered flexible film thereover of a non-opaque acrylic lacquer.

7. The metallized plastic article of claim 6 wherein said primer coat and said base coat have the character-istics of having been spray-applied wet-on-wet and baked together and wherein said flexible film of said acrylic lacquer extends over the edges of said vacuum deposited layer, base coat, and primer coat onto said substrate, thereby encapsulating the three intermediate coats.

8. The metallized plastic article of claim 7 when an automobile trim component and wherein said plastic sub-strate is a molded thermoplastic urethane.

9. The automobile trim component of claim 8 wherein said base coat, when dry, is glossy such that the finished article has a sheeny metallic appearance.

10. In a metallized plastic article which includes a syn-thetic polymeric substrate having an extensibility greater than 30% and which tends to degrade upon exposure to sunlight, a deposited metal film thereon and a transparent protective poly-meric topcoat over said metal film, said metal film having a thickness in the range of 200 to 1000 .ANG. and being thick enough as deposited to block passage of any detrimental amounts of said sunlight but being minutely fissured through said metal film to permit passage of said sunlight, the improvement com-prising first placing on said plastic substrate a light-blocking pigmented polymeric layer over which is disposed said deposited metal film, the pigment content and thickness of said pigmented polymeric layer being sufficient to stop passage of said sun-light from said fissures.

11. The article of claim 10 wherein said pigment content imparts a light color to said polymeric layer and said metal film is thin enough to permit the presence of said light color to be visually apparent, as compared with the absence thereof.