CA1160552A - Method for producing a laminate combination - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A laminate combination has the following consecutive layers: a paper substrate having a weight of at least 30 g/m2; an adhesive layer which is situated on one side of the paper substrate and which has a wet weight of 5 to 8 g/m2 and a solids content of 40-50% when applied to the paper substrate; a metal layer on the adhesive layer; and a lacquer layer on the metal layer. The lacquer of the lacquer layer is elastic, readily film-forming and metallizable with a thermal stability of at least 90°C. Further, the lacquer layer outwardly displays a highly glossy metallic appearance of the underlying metal layer. The metal layer and the lacquer layer have a combined thickness of about 20µ at the most.

Description

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BACKGROUND OF THE INVENTION

The invention relates to a laminate material comprising a paper-like substrate onto which is glued a combination of at least one lacquer layer and one metal layer.
Moreover, the invention relates to a method for producing a laminate comprising a paper-like substrate onto which is glued a combination of at least one lacquer layer and one metal layer, the combination having been previously built up on a carrier foil and transferred therefrom to the paper-like substrate.
U.S. Patent No. 3,080,270 discloses the coating of a substrate with planar cutouts of a laminate. The substrate is essentially a material on which these cutouts are glued as decorations. These cutouts are separated from a laminate which is initially built up over the full area of a carrier foil. The laminate includes a lacquer layer which is applied to the carrier foil and onto which a metal layer is vapor-deposited. The substrate is glued to the metal layer. Only those parts of the substrate are brushed with the adhesive on which, after pressing the laminate together with the substrate, the cutouts are intended to adhere. After pressing the laminate together with the substrate, the laminate adheres to the adhesive to such an extent that the laminate separates from the carrier foil at the parts provided with the adhesive and the cutouts adhere firmly to the substrate.

Since the nonremoved portions adhere to the carrier foil, the latter cannot be reused for the application of a new laminate.
The method is unsuitable for the production of a metallized paper panel. Metallizing a paper panel has previously been effected by vapor-depositing the metal in a vacuum onto a paper panel. This produced relatively rough metal surfaces since the metal penetrated into the pores of the paper. The cheaper the paper and thus the larger the pores therein, the coarser was the surface of the metallized paper panel. The product produced in this manner couldnot compete with a metal foil since its surface was too coarsely porous to produce a perfect metallic effect.
To improve the metallic surface, it would be conceivable to transfer, according to the method disclosed in U.S. Patent No. 3,080,270, a laminate panel in its entirety onto the substrate. Such a transfer would be meaningful only if in this way a metal coating having a perfectly glossy metallic surface were produced on the substrate. Such an effect, however, cannot be obtained with the method disclosed in ~.S. Patent No. 3,080,270.
Its purpose is the removal of individual sections from the metal layer when, after gluing the substrate together with the metal layer, the carrier foil and the remaining coating are pulled away from the substrate provided with ~s~s~z the cutouts. The cutouts adhering to the substrate do not have a perfec-tly ylossy metallic surface. This surface is stamped from a relatively thick carrier foil which has a correpondingly coarse surface configuration. This carrier foil must have such a thickness that it will not tear when the cutouts are removed. After removal of the cutouts from the laminate, the carrier foil to which the unused laminate portions still adhere, can no longer be used.
Moreover, the carrier foil is coated with a lacquer which enhances removal of the lacquer/metal layer from the carrier foil. This lacquer layer is built up of a lacquer which forms a brittle layer and tears when the carrier foil is removed therefrom. Further, in the method according to U.S. Patent No. 3,080,270, this brittling effect of the lacquer is desirable because the brittling of the lacquer surface on the metallic cutouts remaining on the substrate after separation of the carrier foil from the lacquer layer produces a cracked surface which is desirable for a laminate to be produced by this method. This laminate has primarily a fabric substrate. The cutouts thus serve as decoration of fabric panels. These fabric panels are to have a ma-tte effect, not a metallic, highly glossy effect to ensure that the remaining fabric ramins unnoticed compared to these cutouts.

1~605~:2 SUMMAR~ OF THE INVENTION

It is an object of the present invention to produce a laminate of the above-mentioned type in such a way that is receives a metallic, highly glossy surface.
This object and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, 1. the paper-like substrate is a paper having a minimum weight of 30 g/m ;

2. an adhesive layer of 5 to 8 g/m2 is applied wet with a solids content of 40% to 50% to the paper;

3. the metallic side of the metal/lacquer layer combination, whose total thickness does not exceed about 20~, is glued to the adhesive layer; and

4. the lacquer layer of the metal/lacquer layer combination is an elastic layer having a strong tendency to form a film and, with a temperature stability of at least 90C, it can still be metallized and imparts the highly glossy metallic impression of metal.
Such a laminate can be produced over the entire area of a panel and has a highly glossy metallic surface which is so smooth that the impression of a thin metal foil is created. Tearing of this laminate is prevented by the elastic lacquer layer. Damage to the coated papers panels produced in this manner is therefore sub-stantially eliminated. Moreover, this coated paper ~anel ~6VS5Z

has a high gas impermeability. Thus, it can be used -even better than metal foils - to package butter, chocolate, tea and other goods which must he protected against atmospheric effects. Moreover, a very inex-pensive and thus large-pore paper can be used to produce the coated paper panel without impairing the metallic effect. The use of the wet adhesive disclosed by ~e invention compensates for all surface unevennesses so that a uniformly smooth surface is produced.
A method according to a preferred embodiment of the invention for producing a laminate comprising a paper-like substrate onto which is glued a combination of at least one lacquer layer and one metal layer, the combination having been previously built up on a carrier foil and transferred therefrom to the paper-like substrate, is characterized in that a) a layer of a release lacquer is applied to a carrier foil having a thickness of 19 to 30~ so as to form after drying, an elastic and gas-tight film which can still be metallized with a temperature stability of at least 90C;
b) a metal layer of no more than 5/10~ is vapor-deposited on the lacquer film so as to form a combination layer of no more than 20~ with the lacquer film;
c) a quantity of 5 to 8 g/m pf a wet adhesive containing 40% to 50% solids is applied over the entire area of the metallic side of the lacquer/metal layer in a gravure process;

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d) in a calender, the paper-like substrate is pressed onto the wet adhesive layer.
e) the carrier foil with the laminate com-bination of lacquer layer and metal layer, adhesive layer and paper-like su~strate is passed through a drying tunnel in which the moisture is removed to 7% final moisture content; and f) immediately after leaving the drying tunnel, the carrier foil is separated from the entire area of the lacquer layer and the paper-like substrate provided with the lacquer-and-metal layer as well as the adhesive layer and the carrier foil are reeled separately.
The laminate according to the invention can be best produced with the above-outlined method. The laminate so obtained has dimensions which permit the most favorable combination according to the invention. Moreover, the process is inexpensive because it requires only small quantities of adhesive, lacquer and metal. A laminate is produced which is very light-weight and nevertheless exhibits the already described positive characteristics, such as gas-tightness and resistance to tearing.
For the carrier foil, a polyester foil is given primary consideration. It is, however, also feasible to use a polypropylene foil which is particularly well suited for the intended purposes if it is biaxially stretched.

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Decisive for other foils is that they must not exceed a thickness of 19 to 30u. Such foils have a smooth surface on which the lacquer/metal layer to be transferred can be built up very well.
The success of the process according to the invention and the quality of the laminate according to the invention are decisively dependent on the selection of the basic lacquer to be applied to the carrier foil. This lacquer, on the one hand, must have such characteristics that it permits separation of the carrier foil from the laminate according to the invention and, on the other hand, still has a smooth surface after being separated from the carrier foil. Applicable lacquers are only those which easily form a film and have a high softening point.
These lacquers must be easy to roll and must at least withstand the condensation temeperature of the metal deposited thereon. They must not tear during the process and, in particular, must not peel off the metal layer.
Applicable lacquers are sintering lacquers, as for example those which has a basis of salts of acrylic acid.
Good film formation and elasticity are exhibited by such lacquers if their dry weight is within the limits of 1.5 to 3 g/m2.
All metals known in the applicable art, particularly aluminum, are suitable for vapor-deposition. However, copper, silver or gold can also be vapor-deposited.
Moreoever, compounds of a plurality of metals can also be considered for the metallization.

il6(~S;~2 The substrate is attached by means of adhesives which are capable of uniformly covering the entire surface to which they are applied. Particular care must be taken that in the gra~ure process the adhesive is applied over the entire area of the metallic side of the metal/lacquer layer. The adhesive must be so adjusted that it is capable of compensating for unevennesses which may result, in particular, on the substrate. This task is met in particular by wet adhesives which have a solids content of about 40%. Suitable wet adhesives are primarily polyacrylates but also acrylic resin dis-persions. These have the particular advantage that they are self-crosslinking so that they can be processed in a relatively energy saving manner.
All types of paper are sui~able as substrates if they weigh at least 30 g/m . Better types of paper are of course well suited for practicing the method and for producing the laminate. The smoother the surface of the paper employed, the less wet adhesive need be used to glue the paper to the lacquer/metal layer. To produce a gas-tight packaging material, it is possible to use cardboard as the substrate. For this purpose all thicknesses of cardboard can be used which are flexible enough to be rolled up during processing.
In case gas-tight properties of the laminate are of particular importance, preferably an additional coating g 5~;2 of protective lacquer is applied to the metallic side of the lacquer/metal layer. This protective layer is also a lacquer which easily forms a film and which will not break even under heavy stresses from bending in the calender. Lacquers of polyvinylidene chloride may be used in this connection.

EXAMPLES

Example 1.

A lacquer which may be a salt of acrylic acid, such as, for example, Rohagit made by Rohm & Haas, is applied in a quantity of about 1.5 to 3 g/m2 over the entire area of a polyester foil having a thickness between 19 and 30~. This lacquer has a strong film-forming capability and has a hiyh softening point and further, it easily saponifies and can therefore be removed with ease, for example, form bottles. A thin layer of aluminum 3/10~ thick is vapor-deposited onto the lacquer layer in a conventional process. Then a wet adhesive is applied to the metal layer in a gravure process; the wet adhesive consisting of 40% solid components and 60% water. The gravure process is adjusted so that 5 g/m2 of the wet adhesive are applied over the entire area of the aluminum layer. Thereafter, a paper panel is pressed onto the -- ~,0 --11~i05S2, the still wet adhesive in a calender. The paper panel is made of a low quality paper weiqhing 30 g/m . The calender comprises a rubber roller which cooperates with a chrome-plated roller. Subsequent to the calender, the laminate panel passes through a drying tunnel in which under the influence of warm air thc water component of the adhesive is removed from the laminate panel to a residual moisture content of 7~. After leaving the drying tunnel, the polyester foil is separated from the laminate.
The polyester foil is wound on a reel for further use while the laminate is wound on another drum as the finished product.

Example 2.

A lacquer, which is a salt of acrylic acid, is applied over the entire area of a carrier foil, for example a polyester foil having a low surface roughness.
A quantity of 2 g/m dry lacquer is used for -this purpose.
Aluminum is deposited onto this layer to a thickness of about 3/10~. Then a protective lacquer is applied to the metal layer. This protective lacquer may be, in particular, a polyvinylidene chloride which is on the market, for example, under the trademark Saran made by Dow Chemical Company. The protective lacquer layer must ~os;~

be thin; it is, for example, to be applied to a thickness of 1.5 g/m . A wet adhesive is applied in a quantity of about 8 g/m to the protective lacquer layer in a gravure process. Thereafter, in a calender a layer of cardboard is rolled onto the moist wet adhesive. The cardboard is of such thicknessthat is suitable for package making, but it can be rolled in the calender. Immediately downstream of the calender, which comprises a rubber roller and a chrome-plated roller, the coated panel passes through a drying tunnel in which the moisture of the adhesive is reduced to a residual moisture content of 7%. Immediately upon leaving the drying tunnel, the carrier foil is removed from the laminate. The laminate and the carrier foil are wound on separate drums.

_xample 3.

A separating layer is applied thinly (for example, in a quantity of 1.5 g/m2) onto a carrier foil of biaxially stretched polypropylene. The separating layer may be a chrome complex compound as it is marketed, for example, by E.I.Dupontunder the trademark Quilon C. A
base lacquer, for example, a salt of acrylic acid having a dry weight of 1.5 g/m is applied to the separating layer. A layer of aluminum of 3/lO~ thickness is vapor-deposited onto the lacquer layer. Then a wet adhesive which may be a polyacrylate is applied to the metal ~os~z layer in a gravure process. ~he wet adhesive layer isapplied in a thickness of 6 g/m so that it is able to smoothen the roughness of a paper of inexpensive quality.
The paper is then pressed onto the moist adhesive layer in a calender. After leaving the calender, the paper is dried in a drying tunnel to a residual moisture content of 7~ and immediately thereafter the carrier foil is removed from the laminate. Carrier foil and laminate are each wound on a reel.

Example 4.

A thin separating layer of silicone is applied in a thickness notexceeding 1.5 g/m to a biaxially stretched polypropylene foil having a thickness of 19 to 30~.
A base lacquer which is a salt of acrylic acid is applied ~to the separating layer in a thickness of 1.5 g/m2.
Then aluminum is vapor-deposited to a thickness of 3/10 on the lacquer layer. Then a protective lacquer layer, such as polyvinylidene chloride is applied to the aluminum layer in a thickness of 1.5 g/m2. A wet adhesive is laminatedonto this layer in agravure process. For this purpose, 7.5 g/m of an acrylic resin dispersion are used, as marketed, for example, by Rohm & Haas as BV 410. This wet adhesive has the advantage of having good self-crosslinking properties. In a calender, a paper of the most inexpensive type having a weight of 33 g/m2 1~05~3;2 is pressed onto the moist adhesive layer. After leavingthe calender, the laminate panel passes through a dryiny channel in which warm air reduces mois-ture down to a final moisture content of 7~. Immediately after leaving the drying channel, the carrier foil is separated from the laminate and both are wound on a reel indepen-dently of ane another.

BRIEF DESCRIPTION GF THE DRAWING
_ Figure 1 is a cross-sectional view of a laminate combination according to the invention, before separation of the carrier foil;
Figure 2 isaschematic side elevational view of a system for practicing the invention, without applying a layer of protective lacquer;
Figure 3 is a schematic side elevational view of a system for practicing the invention, including the application of a layer of protective lacquer;
Figure 4 is a schematic side elevational view of a system for practicing the invention, including the application of a separating layer;
Figure 5 is an enlarged schematic side elevational view of part of the system illustrated in Figures 2, 3 and 4;
Figure 6 is a cross-sectional view of a laminate according to the invention,including a layer of protective lacquer. - 14 -1~605S~:~

DESCRIPTION OF THE PREFERRED EMBODIME~TS

Turning to Fi~ure 1, the laminate according to the invention essentially includes a base lacquer 3, a metal layer 4, a laminating adhesive 5 as well as a paper layer

6. This laminate is bullt up on a carrier foil 1, which may be a polyester foil. The laminate is produced in a system according to Figure 2. In this system, the carrier foil 1 is provided with the lacquer layer 3 by two superposed applicator rollers 50, 51. The lacquer layer is a base lacquer material 3' which is in a container 52 and which is withdrawn therefrom by the lower applicator roller 51. A stripper 53 ensures that the base lacquer is only thinly applied to the carrier foil 1. Thus, the base lacquer 3 should have a dry weight not in excess of 1.5 to 3 g/m2.
After the application of the base lacquer 3 the lacquered carrier foil 1 passes through a metal vapor-deposition station 54 in which metal, particularly aluminum, escapes from an evaporation crucible 55 toward the carrier foil under the effect of vacuum generated by with-drawing air at 56.
The evaporation crucible 55 is heated with the aid of an electric heater 57. The metal vapor condenses on the base lacquer layer 3 and forms a metal layer 4 thereon.
The metal layer 4 is coated in a gravure mechanism 8 with a wet adhesive 5' which is in a vessel 9 from which it is removed with the aid or a roller 58 and 1~6~52 transferred to the gravure mechanism 8 as a wet adhesivelayer 5. The application of the wet adhesive is set so that, depending on the roughness of the paper web 6, 5 to 8 g/m of ary mass are applied to -the metal layer 4.
The wet adhesive 5' has a solids content of 40% which is dispersed in 60% water.
The product emerges from the mechanism 8 as a transfer foil 7 which is pressed together in a calender 11 with the paper web 6 which is unrolled continuously from a roll 59. The calender 11 comprises a rubber roll 60 and a chrome-plated roll 61 over which the transfer foil

7 passes. The rubber roll 60 presses the paper web 6 into the moist wet adhesive 5 against the chrome-plated roll 61. After leaving the calender 11, the entire laminate combination is dried in a drying tunnel 10 to a residual moisture content of 7~. Immediately after leaving the drying tunnel 10, the surface of the laminate combination is cooled with the aid of a cooling roller 13 so that the carrier foil 1 can be separated from the laminate 62 including the paper 6, the adhesive layer 5, the metal layer 4 and the base lacquer 3. The carxier foil 1 is then wound on a reel 14 and can be reused immediately thereafter for a new laminating process.
The laminate 62 is wound on a reel 15 as a finished produc~ and may be marketed as metallized paper.

5~2 A significant advantage of the finished product made in the above-described manner is its gas-tightness which can be additionally increased by applying a coating of protective lacquer to the metal layer 4 before the wet adhesive 5 is applied thereto in the gravure mechanism 8. For this purpose, as shown in Figure 3, an applicator mechanism 63 for a protective lacquer layer 64 is provided downstream of the metal vapor-deposition station 54. The protective lacquer 64' is drawn by a roller 65 from a vessel 66 and transferred to an applicator roller 67. This arrangement ensures that the protective lacquer layer 64 is applied only very thinly to the metal layer 4. The layer thickness for the protective lacquer 64 should not be greater than 1.5 to 3 g/m .
Turning now to Figure 4, to protect the carrier foil 1, it is provided with a separating layer 2 to facilitate the release of the base lacquer layer 3 from the(carrier foil 1. For this purpose,the carrier foil 1 is provided, before the application of the base lacquer, with a separating layer 2 which is applied to the carrier foil l.
The material 2' suitable as separating layer 2 is generally a chrome complex compound as it is marketed, for example, by E.I. Dupont under the trademark Quilon C.
This substance is withdrawn from a vessel 68 with the aid of a transfer roller 71 and transferred to an applicator roller 69. The latter applies the separating ~ 6~5~, layer to the carrier foil l, while, at the same time,the counter roller 70 app]ies a counterpressure of such magnitude to the surface of roller 69 as to set the thickness of the separating layer to the desired dimension, that is, about 0.1 to l g/m . Additionally, silicones can be used for the separating layer.
After application of the separating layer, the coating process continues as described above. First, a layer of base lacquer 3' is applied by applicator rollers 50, 51 to the separating layer 2 of the carrier foil l and is dried. The lacquer layer 3 is thin and elastic and can be saponified under the influence of alkali washing agents so that labels made of such a laminate can be removed, for example, from bottles.
The lacquer is suitable to remain metallically highly glossy at temperatures of about 90C which prevail during the condensation of the metal on the lacquer layer.
After the metal has been vapor-deposited onto the base lacquer layer 3 in the metal vapor-deposition station 54, a protective lacquer layer 64 is applied to the base lacquer layer 3 with the aid of the applicator mechanism 63.
Thereafter, a wet adhesive 5 is applied to the protective lacquer 64 in the gravure mechanism 8 in such a thickness that unevennesses in the paper web 6 applied to the wet adhesive 5 in the calender 11 are compensated. After the laminate combination has passed through the drying OS~;2 tunnel 10, the carrier foil 1 is separated from thebase lac~uer layer 3 along the separating layer 2 on the cooling roller 13. Since the separating layer 2 ensures that the carrier foil 1 can be wound onto the reel 14 in a wear-free condition and without residues thereon, the carrier foil 1 can be reused immediately for the production ofanew laminate. The separating phase of the laminating process may be best observed in Figure 5 which shows the calender 11 and the cooling roller 13 on a larger scale. The cross section of a gas-tight laminate provided with a protective lacquer layer 64 is illustrated in Figure 6.
The essential advantages of the laminate according to the invention may be summarized as follows:
1. The most inexpensive papers can be used in the production of a high gloss laminate.
2. The base lacquer and adhesive are adjusted so that they easily saponify and therefore the laminate, when used for example, for labels on returnable bottles, can be easily removed in alkali solutions.
3. With the aid of the elastic base lacquer layer and possibly an additional layer of protective lacquer a highly gas-tight paper is produced which can be used for making gas-tight packages.
4. With the aid of the wet lamination process the method for producinq the laminate can be performed especially quickly andeconomically. The foil web is l~OS~Z

applied with the wet adhesive side so that it can effortlessly smoo-th out unevennesses in the paper surface.
Moreover, the wet adhesive is self-crosslinking so that no additional energy is required for the cross-linking.
5. The elastic lacquer layer has a high resistance to wear and is wrinkle resistant. Even at condensation temperatures of up to 90C to 100C
which occur particularly during the metallization, the lacquer layer remains elastic and does not become dull.

Claims (11)

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

1. A laminate combination comprising:
(a) a paper substrate having a weight of at least 30 g/m2;
(b) a wet adhesive layer on one side of said paper sub-strate; said adhesive layer having a wet weight of 5 to 8 g/m2 and a solids content of 40-50% when applied to said paper substrate;
(c) a metal layer on said adhesive layer; and (d) a lacquer layer on said metal layer; the lacquer of said lacquer layer being elastic, readily film-forming and metal-lizable with a thermal stability of at least 90°C; said lacquer layer outwardly displaying a highly glossy metallic appearance of the underlying metal layer; said metal layer and said lacquer layer having a combined thickness of about 20µ at the most.

2. A laminate combination as defined in claim 1, further comprising a protective lacquer layer situated between said adhesive layer and said metal layer; the lacquer of said protective lacquer layer being elastic and gas tight.

3. A laminate combination as defined in claim 1, wherein the thickness of said metal layer is 0.5µ at the most.

4. A method of making a smooth, mirror-like laminate arti-cle, comprising the following steps:
(a) selecting a carrier foil of synthetic material having a smooth surface and a thickness of approximately 19-30µ;
(b) applying to a major continuous area of said smooth surface of said carrier foil a film-forming release lacquer liquid in an amount of from 1.5 to 3 g/m2 dry weight to constitute, after drying, a continuous, flexible release lacquer layer having a temperature stability of at least 90°C;
(c) vapor-depositing metal on said release lacquer to form thereon a bright, continuous metal layer having a thickness of 0.5µ at the most; said release lacquer and said metal layers to-gether forming a mirror-bright metallized laminate having a thick-ness of 20µ at the most;
(d) applying a wet adhesive of 40% to 50% solids content to the entire face of said metal layer in a quantity of 5 - 8 g/m2;
(e) pressing a paper sheet to the wet adhesive carried on said metal layer;
(f) heating the product made in steps (a) through (e) to reduce the moisture content thereof, whereby said metal layer is permanently bonded to said paper sheet by said adhesive; and (g) separating the carrier foil from the entire area of said lacquer layer.

5. A method of making a smooth, mirror-like laminate arti-cle, comprising the following steps:
(a) selecting a carrier foil of synthetic material hav-ing a smooth surface;
(b) applying to a major continuous area of said smooth surface of said carrier foil a film-forming release lacquer liquid in an amount of from 1.5 to 3 g/m2 dry weight to constitute, after drying, a continuous, flexible release lacquer layer having a temperature stability of at least 90°C;

(c) vapor-depositing metal on said release lacquer to form thereon a bright, continuous metal layer having a thickness of 0.5µ at the most; said release lacquer and said metal layers together forming a mirror-bright metallized laminate having a thickness of 20µ at the most;
(d) applying a wet adhesive of 30% to 50% solids content to the entire face of said metal layer in a quantity of 5 - 8 g/m2;
(e) pressing a paper sheet to the wet adhesive carried on said metal layer;
(f) heating the product made in steps (a) through (e) to reduce the moisture content thereof, whereby said metal layer is permanently bonded to said paper sheet by said adhesive; and (g) separating the carrier foil from the entire area of said lacquer layer.

6. A method as defined in claim 4 or 5, further comprising the step of applying, after step (c) and before step (d), a gas-tight protective lacquer layer on the metal layer.

7. A method as defined in claim 4 or 5, further comprising the step of applying, before step (b), a separating layer on said major continuous area for enhancing the subsequent step (g).

8. A method as defined in claim 4 or 5, wherein step (d) comprises the step of applying the adhesive in a gravure process.

9. A method as defined in claim 4 or 5, wherein step (e) comprises the step of pressing said paper to the wet adhesive by a calender.

10. A method as defined in claim 4 or 5, wherein step (f) comprises the step of passing said product through a drying tunnel.

11. A method as defined in claim 4, further comprising the step of winding up said carrier foil after step (g) separately from the laminate combination formed of said paper layer, said adhesive layer, said metal layer and said release lacquer layer.