CN1229384A - Laminated sheet and method of manufacturing laminated sheet - Google Patents

Abstract

A method for manufacturing a laminate is disclosed. The first step of the method includes bonding a metal foil (3) to a paper sheet (4). The method then includes printing a pattern on the outer surface of the paper sheet (4) or embossing a pattern on the metal foil (3). If the pattern is first printed on the paper sheet (4), the method also includes embossing a mirror image of the pattern printed on the paper sheet (4) onto the metal foil (3). Conversely, if the pattern is first embossed on the metal foil, the method also includes printing a mirror image of the pattern embossed on the metal foil (3) onto the outer surface of the paper sheet (4).

Description

Laminated sheet and method of manufacturing laminated sheet

The present invention relates to a laminated sheet and a method of manufacturing the laminated sheet.

In particular, the present invention relates to a laminate comprising metal foil and paper and a method of making the laminate.

Laminates, such as those made from metal foils and paper sheets, can be used in a variety of applications, including wrapping or wrapping paper. Consumer goods, such as confectionery, are often packaged individually or in packs with laminated sheets, while cigarettes or cigars are often sold in laminated-lined tins or boxes. Laminates are particularly useful as liners because the metal foil constitutes a barrier against light and moisture which are harmful to tobacco.

Laminates are often printed or embossed with graphics, such as trademarks, logotypes or company names of manufacturers or distributors, or other information to enhance the presentation of goods packaged or wrapped with the laminate.

Typically, the graphics are printed or embossed on only one side of the laminate. Typically, printed on one side of paper, or embossed on the foil side, but occasionally printed on foil, embossed on paper. Printing or embossing is carried out by methods well known in the art of printing technology, such as roll embossing and gravure printing.

Although the production of laminates comprising embossed foils and printed paper is well known in the printing and paper industries, no one has hitherto provided a laminate on which printed and embossed patterns It is in registration, that is, the pattern printed and embossed on it is exactly the same.

It is an object of the present invention to provide a laminate comprising printed paper and embossed metal foil wherein the printed and embossed patterns are in register.

Yet another object of the present invention is to provide a method of manufacturing said laminate.

The method for manufacturing laminated sheet of the present invention comprises the following steps:

(i) bonding metal foil and paper together;

(ii) printing a design on the outer surface of the paper; and

(iii) Embossing a mirror image on the metal foil in registration with the pattern printed on the paper.

The method for manufacturing laminated sheet of the present invention comprises the following steps:

(i) bonding metal foil and paper together;

(ii) embossing a pattern on the metal foil; and

(iii) Printing a mirror image on the outer surface of the paper in registration with the pattern imprinted on the metal foil.

As previously indicated, the order of the printing and embossing steps is not critical. However, the embossing step is preferably done before the printing step.

It is particularly preferred that the method comprises inspecting the first formed printed or embossed pattern, and controlling subsequent embossing/printing steps to ensure registration of the subsequently formed printed or embossed pattern with the original pattern.

The step of adhering the sheets of paper and foil together may be accomplished by any suitable method. In a preferred embodiment, the metal foil is passed through a coating roll which coats the adhesive on one side of the metal foil. The paper and foil are then passed through the nip of a pair of rollers, pressing the adhesive-coated surfaces of the paper and foil together to form a laminate.

The embossing step can be accomplished using any suitable method. In one embossing method, a workpiece (such as a roll) and an embossing die are placed on both sides of the laminate and assembled together, the die is brought into contact with the metal foil and the pattern is embossed thereon. In another embossing method, the workpiece is stationary while the stamp is moved up and down against the foil of the laminate. In another embossing method, the metal foil is pressed onto the embossing die by moving the workpiece against a paper sheet of the laminate.

The embossing step preferably involves feeding the laminate between two rollers, one of which acts as the work piece and is made of a relatively soft material such as paper, and the other roller acts as a stamp and is made of metal such as Made of steel.

The printing step can be accomplished by any suitable method. For example, the printing step may comprise letterpress or letterpress printing, offset printing or gravure printing, such as gravure or roll to roll gravure.

The laminated sheet of the present invention may have physical properties suitable for the intended use. For example, when intended for confectionary packaging, the laminate needs to be very flexible. Whereas the purpose is to line cigarette packs, the laminate needs to be relatively stiff so that the laminate can fold and maintain that fold.

Different physical properties of the laminate can be provided, in part, by selection of the grade and type of adhesive and paper and/or metal foil.

The metal foil preferably comprises a metal selected from the main group of the periodic table.

The metal foil particularly preferably comprises or consists of aluminum.

The method of the invention may include dyeing the metal foil. The dyeing step preferably comprises a roll-to-roll gravure printing process. Here the color is applied to the entire surface of the metal foil by passing the metal foil over an ink-coated gravure roll. The dyed ink applied to the metal foil by a gravure roll is dried by passing the metal foil through a hot air chamber or similar device.

The present invention is further described below with reference to accompanying drawing and embodiment, wherein:

Figure 1 is a schematic diagram of a preferred embodiment of the process of the present invention, with which the preferred laminates of the present invention can be produced;

Fig. 2 (a) is the plan view of the metal foil surface of the laminate made according to the method shown in Fig. 1;

Fig. 2 (b) is the plane view of the paper surface of the laminate made according to the method shown in Fig. 1;

Fig. 3 is a sectional view of the laminate shown in Figs. 2(a) and 2(b).

In the process shown in Figure 1, the metal foil 3 and paper 4 enter from their respective rolls 1 and 2 and pass through a series of stations where the metal foil 3 and paper 4 are laminated together and a pattern is printed on the paper 4 , imprint the mirror image on the metal foil 3 .

Referring to Figure 1, a metal foil 3, usually silver aluminum alloy foil, is passed from a drum 1 through a coating roller 5, which applies adhesive to one surface of the metal foil 3, preferably forming a uniform adhesive film .

Then the metal foil 3 passes between the two laminating rollers (6a, 6b) together with the paper 4 coming down from the cylinder 2, so that the side of the metal foil 3 coated with adhesive and one side of the paper 4 are evenly pressed together, A laminate is formed.

The laminate is then brought into contact with a gravure roll 7 which deposits a layer of dyed ink on the outer surface of the metal foil 3, thereby dyeing the outer surface of the metal foil 3 of the laminate.

The wet ink is dried by passing the laminate through a drying chamber 8 in which heated air is circulated.

The laminate is then passed through a gravure cylinder 9 which prints a pattern on the outer surface of the paper 4 .

The wet ink on the paper is dried by passing the laminate through a further drying chamber 10 .

The laminate then enters an embossing station comprising a workpiece 12a and an embossing die 12b which embosses on the metal foil 3 a mirror image of the pattern printed on the paper 4 . A controller comprising sensors 11 is fitted upstream of the embossing station to detect the pattern printed on the paper 4 and to control the embossing process in any suitable manner to ensure that the mirror image imprinted on the metal foil 3 is identical to that printed on the paper 4. The patterns on the paper 14 are in registration.

Finally, the embossed and printed laminate is wound on a large roll 13 for storage, ready to be cut and wound on smaller rolls.

Figure 2a shows the outer surface of the metal foil 3 of a laminate segment manufactured as described above, on which a pattern 15 is embossed, including an arrangement of the word "tobacco". Figure 2b shows the outer surface of the paper 4 of the laminate segment shown in Figure 2a. The outer surface of the paper is marked with a printed pattern 17 comprising an arrangement of the word "tobacco". It is arranged so that the embossed and printed patterns correspond in shape, size and position.

Figure 3a is an enlarged cross-sectional view of a fragment of the laminate shown in Figures 2a and 2b showing the metal foil 3 and paper 4 held together by a thin layer of adhesive 18. The metal foil 3 has impressions 19 where the stamping die contacts and presses the surface of the metal foil. Since the embossed and printed patterns are in register, ink 20 is deposited on the paper, which corresponds to the imprint 19 on the metal foil 3 .

Figure 3b is an enlarged cross-sectional view of a fragment of the laminate shown in Figures 2a and 2b showing the metal foil 3 and paper 4 held together by a thin layer of adhesive 18. The metal foil 3 has an imprint 14 where the stamping die does not touch and press against the surface of the metal foil. Since the embossed and printed patterns are in register, ink 16 is deposited on the paper, which corresponds to the imprint 14 on the metal foil 3 .

It should be noted that the specific patterns shown in Figures 2a and 2b are chosen arbitrarily, and any suitable pattern can be embossed and printed on the laminate.

It should also be noted that it is believed that laminates having in-register mirror images of embossing and printing are an important way for buyers of eg tobacco goods to differentiate products from different merchants. In the tobacco industry, the main profit is based on being able to distinguish counterfeit cigarettes.

This invention has been described in terms of its preferred embodiments, and it is to be understood that various modifications will be apparent to those skilled in the art from the reading of the specification.

Claims (8)

1. A method of manufacturing a laminate, comprising the steps of: (1) metal foil and paper are glued together; (ii) printing a design on the outer surface of the paper; and (iii) Embossing a mirror image on the metal foil in registration with the pattern printed on the paper. 2. A method of manufacturing a laminate comprising the steps of: (1) metal foil and paper are glued together; (ii) embossing a pattern on the metal foil; and (iii) Printing a mirror image on the outer surface of the paper in registration with the pattern imprinted on the metal foil. 3. A method as claimed in claim 1 or 2, including detecting the first formed printed and embossed pattern and controlling the subsequent embossing/printing steps to ensure that the subsequently formed printed and embossed pattern is in register with the original pattern. 4. A method as claimed in any one of the preceding claims, wherein step (i) comprises contacting the metal foil with an applicator roll which coats the adhesive on one surface of the metal foil and applies the adhesive to one surface of the metal foil. The mixed metal foil and the paper sheet pass through the gap between a pair of rollers, and the paper and the adhesive-coated metal foil are pressed together to form a laminate. 5. A method as claimed in any preceding claim, wherein the metal foil comprises a metal selected from a main group of the periodic table. 6. The method of claim 5, wherein the metal foil comprises or consists of aluminum. 7. A method as claimed in any preceding claim which includes dyeing the metal foil. 8. A laminate produced by a method according to any one of the preceding claims.

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