Lid film for food packaging

Abstract

The present invention relates to a lid film for packaging of e.g. human or pet food. The lid film has a multi-layer structure and comprises a sealing layer, a barrier layer, a print primer layer, a print layer, an optional print protection layer, and a relief layer. The sealing layer, the barrier layer, the print primer layer, the print layer and the optional print protection layer are essentially flat. The relief layer is arranged at least on a part of the print layer and comprises at least n three dimensional structures per cm.sup.2 projecting at an essentially right angle from a surface of the adjacent print layer or the optional print protection layer and said three dimensional structures forming an non-continuous elevated surface, wherein the total of said elevated surface area formed by the three dimensional structures equals at least m % of a total surface area of the lid film and wherein the three dimensional structures have a minimal height of 5 m.

Claims

1. A lid film for packaging having a multi-layer structure comprising a sealing layer, a barrier layer, a print primer layer, a print layer, an optional print protection layer, and a relief layer, wherein the sealing layer, the barrier layer, the print primer layer, the print layer and the optional print protection layer are essentially flat, wherein the relief layer is arranged at least on a part of the print layer or on the optional print protection layer and comprises at least n three dimensional structures per cm.sup.2, wherein n is at least 1, projecting at an essentially right angle from a surface of the adjacent print layer or the optional print protection layer and said three dimensional structures forming an non-continuous elevated surface, wherein the total of said elevated surface area formed by the three dimensional structures equals at least m % of a total surface area of the lid film, m being at least 10%, wherein the three dimensional structures have a minimal height of 5 m, and wherein the lid film is sterilizable.

2. A lid film according to claim 1, wherein n is in the range of 1 to 100.

3. A lid film according to claim 1, wherein m is in the range of 10% to 50%.

4. A lid film according to claim 1, wherein the three dimensional structures of the relief layer are randomly arranged on the surface of the optional print protection layer or the print layer.

5. A film according to claim 1 wherein the three dimensional structures of the relief layer are arranged on the surface of the optional print protection layer or the print layer in a regular array.

6. A lid film according to claim 1, wherein the relief layer is made of a one or more acrylic lacquers comprised of at least one acrylic resin and at least one photoinitiator hardened by radical polymerization initiated by UV radiation which is or are colorless.

7. A lid film according to claim 1, wherein the relief layer is made of one or more acrylic lacquers comprised of at least one acrylic resin and at least one photoinitiator hardened by radical polymerization initiated by UV radiation which is or are colored.

8. A lid film for food packaging according to claim 1, wherein the three dimensional structures of the relief layer have a height in the range of 5 m to 45 m.

9. A lid film for food packaging according to claim 1, wherein the barrier layer comprises aluminium and has a thickness in the range of 20 m to 90 m.

10. A film according to claim 1, wherein the lid film comprises an opening flap arranged at an edge of the lid film, said opening flap being at least partially covered by the relief layer.

11. A food pack comprising a lid film according to claim 1.

12. A method for the manufacture of a lid film according to claim 1 comprising the steps of coating a barrier layer with a sealing layer on one side and with a print primer layer on the opposite side of the barrier layer, applying a print layer on the print primer layer by printing, and applying a relief layer on the print layer by printing, wherein the relief layer is made of a colorless or a colored lacquer, and wherein the lid film is sterilizable.

13. A method for the manufacture of a lid film according to claim 12, wherein the printing is done by UV-flexoprint and wherein the colorless or colored lacquer is bisphenol A free.

14. A lid film according to claim 1, wherein n is in the range of 3 to 50.

15. A lid film according to claim 1, wherein m is in the range of 15% to 40%.

16. A lid film for food packaging according to claim 1, wherein the three dimensional structures of the relief layer have a height in the range of 7 m to 30 m.

17. A lid film for food packaging according to claim 1, wherein the barrier layer comprises aluminium and has a thickness in the range of 40 m to 80 m.

18. A film according to claim 1, wherein the lid film comprises an opening flap arranged at an edge of the lid film, said opening flap being fully covered by the relief layer.

19. A lid film for packaging having a multi-layer structure comprising a sealing layer, a barrier layer, a print primer layer, a print layer, an optional print protection layer, and a relief layer, wherein the sealing layer, the barrier layer, the print primer layer, the print layer and the optional print protection layer are essentially flat, wherein the relief layer is arranged at least on a part of the print layer or on the optional print protection layer, is made of a solvent-free UV-flexoprint ink cured by UV radiation or an acrylic lacquer comprised of at least one acrylic resin and at least one photoinitiator hardened by radical polymerization initiated by UV radiation, and comprises at least n three dimensional structures per cm.sup.2, wherein n is at least 1, projecting at an essentially right angle from a surface of the adjacent print layer or the optional print protection layer and said three dimensional structures forming an non-continuous elevated surface, wherein the total of said elevated surface area formed by the three dimensional structures equals at least m % of a total surface area of the lid film, m being at least 10%, and wherein the three dimensional structures have a minimal height of 5 m.

Description

(1) The lid film according to the present invention is explained in more detail below with reference to exemplary embodiments in the drawings, in which, purely schematically:

(2) FIG. 1 shows a first embodiment of a lid film;

(3) FIG. 2 shows a second embodiment of the lid film;

(4) FIG. 3 shows an embodiment of the lid film with a first type of three-dimensional structures;

(5) FIG. 4 shows a further embodiment of the lid film with a second type of three-dimensional structures;

(6) FIG. 5 shows an embodiment of the lid film with a third type of three-dimensional structures;

(7) FIG. 6 shows an embodiment of the lid film with a further type of three-dimensional structures;

(8) FIG. 7 shows another embodiment of the lid film with different three-dimensional structures;

(9) FIG. 8 shows a further embodiment of the lid film with three-dimensional structures extending over the entire lid film;

(10) FIG. 9 shows another embodiment of the lid film;

(11) FIG. 10 shows a further embodiment of the lid film;

(12) FIG. 11 shows the outer side of a lid film according to the present invention comprising a relief layer and the outer side of an embossed lid film of the prior art;

(13) FIG. 12 shows the inner side of a lid film according to the present invention and the inner side of an embossed lid film of the prior art.

(14) FIG. 1 shows a first embodiment of lid film 1 according to the present invention. The lid film 1 comprises a sealing layer 3, arranged on one side of a barrier layer 5. On the side of the barrier layer 5 opposite to the sealing layer 3, there is a print primer layer 7 arranged. On top of the print primer layer 7 the print layer 9 is arranged. The relief layer 11 is then arranged on the print layer 9. As illustrated in this embodiment the three dimensional structures 13 are arranged in a random manner. The three-dimensional structures 13 form a non-continuous elevated surface 14.

(15) FIG. 2 shows a second embodiment of lid film 1 according to the present invention. The lid film 1 comprises a sealing layer 3, arranged on one side of a barrier layer 5. On the side of the barrier layer 5 opposite to the sealing layer 3, there is a print primer layer 7 arranged. On top of the print primer layer 7 the print layer 9 is arranged. The print layer 9 is sandwiched between the print primer layer 7 and the print protection layer 15. The relief layer 11 is then arranged on the print protection layer 15. In this embodiment the three dimensional structures 13 are arranged in a regular array. The three-dimensional structures 13 form a non-continuous elevated surface 14.

(16) FIG. 3 shows an embodiment of the lid film 1 comprising a first type of three-dimensional structures 13. The sealing area 17 running along the outer edge 15 of the lid film 1 and being arranged between the outer edge 15 and the margin 19 of central area 21 of the lid film 1 is essentially free of three-dimensional structures 13. The three-dimensional structures 13 are regularly arranged in an array in the central area 21 and have an essentially quadratic shape. Also shown is an opening flap 23 arranged at the edge 15 which is fully covered with the three-dimensional structures 13 that form the relief layer. The opening flap 23 protrudes the edge of a container (not shown) the lid film 1 is sealed to.

(17) FIG. 4 shows a further embodiment of the lid film 1. The three-dimensional structures 13 are concentric, closed lines having an essentially quadratic shape and rounded corners arranged in the central area 21. The sealing area 17 arranged between the edge 15 and the margin 19 is free of three-dimensional structures 13.

(18) FIG. 5 shows another embodiment of the lid film 1 whereby the lid film 1 comprises different types of three-dimensional structures 13 and 13, such as lines and ellipses, the latter including the word My Cat. These structures are again arranged in the central area 21 of the lid film 1 and do not extend to the sealing area 17 located between the edge 15 and the margin 19 of the central area 21.

(19) FIG. 6 shows an embodiment of the lid film 1. The three-dimensional structures 13, 13 include different types of three-dimensional structures such as lines and a stylized head of a cat. The three-dimensional structures 13, 13 are arranged in the central area 21 of the lid film 1 whereas the sealing area 17 delimited by the edge 15 and the margin 19 is kept free of three dimensional structures 13, 13.

(20) FIG. 7 shows the same embodiment as seen in FIG. 6 whereby an additional type of a three-dimensional structure 13 in the form of round dots is comprised. These dots 13 are arranged at even distance on the margin 19 of the central area 21 and thus extend into the sealing area 17 of the lid film 1.

(21) FIG. 8 shows a further embodiment of the lid film 1. While there is only one type of three-dimensional structures 13, lines, these three-dimensional structures are arranged on the whole surface of the lid film 1. This means they extend not only over the central area 21 but also to the sealing area 17 which is delimited by the edge 15 and the margin 19 of the central area 21. In the upper left corner an opening flap 23 is shown which is fully covered with three-dimensional structures 13. The opening flap 23 is formed by a non-sealing area 25, i.e., in the non-sealing area the lid film is not sealed to a container (not shown) so that the lid film 1 may be easily pinched and lifted off the container in order to open the container. It should also be noted that the opening flap 23 does not protrude the edge of the container.

(22) FIG. 9 shows another embodiment of the lid film 1. The lid film 1 has an oval shape. The three dimensional structures 13 are quadratic dots arranged in the central area 21. The sealing area 17 between the edge 15 and the margin 19 of the central area 21 is free of three dimensional structures 13.

(23) FIG. 10 shows a lid film 1 that has a star-like shape. Two different three dimensional structures 13 and 13 are arranged in the central area of the lid film. There are no three dimensional structures 13 and 13 within the sealing area 17 arranged between the edge 15 and the margin 19 of the central areal 21.

(24) FIG. 11 shows the outer side A of a lid film according to the present invention comprising a relief layer. The three-dimensional structures 13 have a dot-like form. Also shown is the outer side B of an embossed film of the prior art. As the outer side of the prior art film is embossed there are no three-dimensional structures on the outer side of the prior art film. There are rather embossing marks in the form of tiny indentations.

(25) FIG. 12 shows the inner side C the lid film according to the present invention which is completely flat. The inner side D of the prior art lid film on the other hand shows numerous protrusions caused by the embossing of the outer side.