Structured packaging film and method of making same

Abstract

A structured packaging film is made by first of feeding a flat, unembossed first film web in a gravure printing device to a cylindrical print roller having an engraving on its surface with an array of cavities having a depth of at least 50 m. Printing laquer is applied to the print roller to fill the cavities. Then the roller is rolled on the first film web to transfer the laquer to the web to form thereon a printed image in gravure printing. The laquer is dried on the web to have a thickness of at least 30 m and the printed areas form clearly perceptible structuring.

Claims

1. A packaging film comprising: an outer film having a thickness of less than 30 m and forming a first outer face; a support laminate; and a printed image between the outer film and the support laminate and comprised of printed and unprinted areas, the printed area formed of a printing lacquer having in the printed areas a layer thickness of greater than 30 m, the printing lacquer directly juxtaposed with the outer film or at a spacing of less than 15 pin from the outer film, the areas of printing lacquer and the unprinted areas forming structuring through the outer film on the first outer face of the outer film, the printing lacquer containing inorganic nonmetallic particles having an average particle diameter greater than 25 m.

2. The film defined in claim 1, further comprising: a colored layer having a layer thickness of less than 5 m and overlying in at least partial alignment the printing lacquer.

3. The film defined in claim 1, further comprising an adhesive layer that extends over an entire inner surface area of the outer film such that, after solidifying of the adhesive layer, the adhesive layer is present with a weight per unit area between 2 g/m.sup.2 and 8 g/m.sup.2.

4. The packaging film defined in claim 1, wherein the outer film is formed from a material selected from the group comprising oriented polyethylene terephthalate (O-PET), oriented polypropylene (O-polypropylene), oriented polylactic acid (O-PLA), oriented polyamide (O-PA), and cellulose.

5. The packaging film defined in claim 1, wherein the printing lacquer is colored.

6. The packaging film defined in claim 5, wherein the printing lacquer contains cellulose nitrate.

7. A packaging film comprising: an outer film having a thickness of less than 30 m and forming a first outer face; a support laminate having a thickness between 20 m and 150 m and a weldable layer on a second outer face opposite the outer film; and a printed image between the outer film and the support laminate and comprised of printed and unprinted areas, the printed area formed of a printing lacquer having in the printed areas a layer thickness of greater than 30 m, the printing lacquer directly juxtaposed with the outer film or at a spacing of less than 15 m from the outer film, the areas of printing lacquer and the unprinted areas forming structuring through the outer film on the first outer face of the outer film.

8. The film defined in claim 7, further comprising: a colored layer having a layer thickness of less than 5 m and overlying in at least partial alignment the printing lacquer.

9. The packaging film defined in claim 7, wherein the outer film is formed from a material selected from the group comprising oriented polyethylene terephthalate (O-PET), oriented polypropylene (O-POLYPROPYLENE), oriented polylactic acid (O-PLA), oriented polyamide (O-PA), and cellulose.

10. The film defined in claim 7, further comprising an adhesive layer that extends over an entire inner surface area of the outer film such that, after solidifying of the adhesive layer, the adhesive layer is present with a weight per unit area between 2 g/m.sup.2 and 8 g/m.sup.2.

11. The packaging film defined in claim 7, wherein the printing lacquer is colored.

12. The packaging film defined in claim 11, wherein the printing lacquer contains cellulose nitrate.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

(2) FIG. 1 shows a packaging bag formed from a packaging film according to the invention;

(3) FIGS. 2 to 5 are large-scale sections through various structured films according to the invention; and

(4) FIG. 6 is a schematic drawing illustrating the method of this invention.

SPECIFIC DESCRIPTION OF THE INVENTION

(5) As seen in FIG. 1 a film packaging bag 2 is formed from a packaging film according to the invention. It carries raised indicia 1 that stand out from the front face of the bag 2.

(6) As explained in greater detail below, the film packaging bag has structuring that is formed by a printing lacquer 1, the printing lacquer 1 being provided in a printed image made up of printed and unprinted areas.

(7) According to one possible embodiment of the packaging film according to the invention of FIG. 2, the printing lacquer 1 is applied to a support laminate 2 in areas. The support laminate together with the printing lacquer 1 form the overall packaging film. The support laminate 2 has multiple layers, and in the illustrated embodiment has a layer 3 of oriented polyethylene terephthalate provided on an inner face with a metal layer 4 and is joined via laminating adhesive 5 to a weldable layer 6 of polyethylene on the face provided with the metal layer 4. Thus the metal layer is between the layer 3 of oriented PE and the PE layer 6.

(8) According to the invention, when the printing lacquer 1 on the support laminate 2 is dry it has a thickness of at least 30 m, for example between 35 m and 40 m. Due solely to the printing lacquer 1, this results in 3D structuring that is also clearly perceivable to a user. When the printing lacquer 1 itself is colored, a color pattern results that matches the spatial structure.

(9) The provision of the printing lacquer 1 on a surface of the packaging film is also referred to in practice as recto printing.

(10) In one embodiment that in other respects is the same, FIG. 3 shows a refinement in which only a thin colored layer 7 is provided on an outer face of the printing lacquer 1. The thickness of the colored layer 7 in the dry state, i.e. in the packaging film as a finished product, is less than 5 m, for example between 1 m and 5 m.

(11) FIG. 3 shows strictly by way of example that the colored layer 7 is in precise alignment with the printed image of the printing lacquer 1. Such an arrangement is advantageous in particular when the printing lacquer 1 itself is not colored.

(12) If the printing lacquer 1 is transparent or at least translucent, the colored layer 7 may also be applied before the printing lacquer 1, so that the colored layer 7 is then under the printing lacquer 1 or between the inner face thereof and the outer face of adhesive layer 5.

(13) The illustration of the colored layer 7 in precise alignment with the printing lacquer 1 is by way of example only. In such an embodiment, the colored layer 7 assists in the structuring that is predefined by the printed image of the printing lacquer 1. Of course, the colored layer 7 may also be provided in the areas that are not printed with printing lacquer 1, in which case the colored layer 7 is to be applied before the printing lacquer 1. In addition, in multicolor printing, multiple colored layers may also be applied before or after the printing lacquer 1.

(14) In the embodiment according to FIGS. 2 and 3, the printing lacquer 1 and the colored layer 7 situated thereon lie on an outer face of the packaging film. To avoid abrasion, a the entire outer face may be coated with a protective lacquer. When such a protective lacquer is applied as a liquid state over the entire surface area, the protective lacquer conforms to the structuring that is predefined by the printing lacquer 1, so that the 3D structure is essentially maintained. In addition, a protective lacquer is very thin, having a layer thickness of less than 5 m, for example.

(15) FIG. 4 shows one preferred embodiment of the invention, with the printed image of the printing lacquer 1 covered by an outer film 8 that may be applied as a liquid curable to form a flexible coating.

(16) The thickness of the outer film 8 is less than the layer thickness of the printing lacquer 1, so that the outer film 8 conforms well to the contour of the printing lacquer 1, and the structuring is also visible through the outer film 8. The outer film 8 and the support laminate 2 may be glued together with laminating adhesive 5, the laminating adhesive 5 preferably being provided over the entire surface area, with a weight per unit area between 4 g/m.sup.2 and 6 g/m.sup.2 (based on the dry state).

(17) The thickness of the outer film 8 is preferably less than 20 m. For example, an outer film 8 made of oriented polyethylene terephthalate (O-PET), having a thickness of only 12 m, for example, is particularly suitable. In addition, the layer 3 made of oriented polyethylene terephthalate, which in this embodiment is provided with the metal layer 4 strictly by way of example, may have a thickness of 12 m. The thickness of the weldable layer 6 may be 100 m, for example.

(18) As explained in conjunction with FIG. 3, in the embodiment according to FIG. 4 at least one additional colored layer 7 may also be provided. This additional colored layer together with the printing lacquer 1 is generally also formed, covered, between the support laminate 2 and the outer film 8; with regard to the different embodiment options, reference is made to the discussion for FIG. 3.

(19) Within the scope of this embodiments, the terms outer film 8 and support laminate 2 refer to the arrangement of the packaging film in a film packaging as illustrated in FIG. 1. The outer film 8 hereby forms a generally transparent outer face of the film packaging, while the printing lacquer 1 and at least one additional colored layer 7 are then situated in a protected manner. For bag packaging, the support laminate 2 is situated in the interior; seams of the film packaging may be easily formed by thermal welding due to the weldable layer 6.

(20) In the present context, the term support laminate 2 does not refer to the printing of the printing lacquer 1.

(21) FIG. 5 shows one embodiment in which a colored layer 7 and the printing lacquer 1 are applied to the inner face of the outer film 8, the outer film 8 with the corresponding face then being laminated to the support laminate 2, which in other respects is as described above, using laminating adhesive 5.

(22) FIG. 6 shows how the raised printing lacquer is applied as the indicia 1 to the laminate 2 by a roller 9 supplied with the lacquer from an inking roller 10. Then a thin adhesive layer 5 is sprayed from a nozzle 11 over the laminate 2 carrying the raised lacquer indicia 1. Subsequently the thin and transparent cover layer 8 is applied over the adhesive 5 with the help of a roller 13 pulling the layer 8 from a supply 14. The roller 9 is formed with an array of cavities 13 shaped to form the desired raised indicia 1 and having a depth of at most 50 m.