APPARATUS AND METHOD FOR LAMINATION

Abstract

A laminating station comprises a chill roll (8), a press roll (4) parallel to the chill roll (8), a back-up roll (10) for biasing the press roll (4) towards the chill roll (8), an extrusion arrangement which serves to deposit a layer entering a nip between the rolls (4) and (8), a belt-guiding arrangement (14,16) extending parallelly to the roll (4), leftmost and rightmost endless belts (12) extending over the roll (4) and the belt guiding arrangement (14,16) and through the nip, and, between the leftmost and rightmost endless belts (12), intermediate endless belts (24) extending over the roll (4) and the belt guiding arrangement (14,16) and through the nip. The belts (12) serve to deter contact, with the press roll (4), of the layer being deposited. The belts (14) and (16) have that function and/or the function of pressing an outer tie layer of the laminate being produced into holes through a core layer of the laminate and so into contact with an outermost layer of the laminate.

Claims

1. A laminating station comprising: a first roll, a second roll parallel to said first roll, a biasing arrangement for relatively biasing the first and second rolls together, a depositing arrangement which serves to deposit a layer at one side of a substrate prior to said substrate and said layer entering a nip between said first and second rolls, a belt-guiding arrangement extending parallelly to said first roll, leftmost and rightmost endless belts extending over said first roll and said belt guiding arrangement and through said nip, and, between said leftmost and rightmost endless belts, at least one intermediate endless belt extending over said first roll and said belt guiding arrangement and through said nip.

2. A laminating station according to claim 1, wherein said substrate is formed with at least one row of holes distributed therealong and for covering by said layer at one side of said substrate and by a gas barrier layer at the opposite side of the substrate, said at least one intermediate endless belt being allocated to said at least one row of holes.

3. A laminating station comprising: a press roll, a second roll parallel to said press roll, a biasing arrangement for relatively biasing said press roll and said second roll together, a depositing arrangement which serves to deposit a layer upon a substrate prior to said substrate and said layer entering a nip between said press roll and said second roll, which substrate is formed with at least one row of holes distributed therealong and which holes are covered by said layer, a belt-guiding arrangement extending parallelly to said press roll, and, for the or each row of holes, an endless belt extending over said press roll and said belt-guiding arrangement.

4. A laminating method comprising: depositing a layer at one side of a substrate prior to said substrate and said layer entering a nip between a first roll and a second roll, and urging said substrate and said layer away from said first roll by means of a leftmost, a rightmost and at least one intermediate, endless belt, the or each belt extending over said first roll and a belt-guiding arrangement and through said nip.

5. A laminating method comprising: providing a substrate formed with at least one row of holes distributed therealong, depositing a layer upon said substrate prior to said substrate and said layer entering a nip between a press roll and a second roll, and squeezing said web and said layer together at the regions of said holes by means of, for the or each row of holes, an endless belt extending over said press roll and through said nip.

6. A method according to claim 5, wherein said press roll comprises a rigid core and a resilient covering sleeve on said core and co-axial therewith.

7. A method according to claim 4, wherein said substrate comprises a layer of paperboard.

8. A method according to claim 4, wherein said substrate comprises, progressing inwardly therethrough, a moisture barrier layer, a core layer, a tie layer and an oxygen barrier layer.

9. A press roll comprising a rigid core and an elastic cover on said core and co-axial therewith, said elastic cover comprising a non-adhesive outer surface.

10. A press roll according to claim 9, wherein said surface comprises polytetrafluoroethylene.

11. A station according to claim 1, wherein said press roll comprises a rigid core and a resilient covering sleeve on said core and co-axial therewith.

12. A station according to claim 2, wherein said press roll comprises a rigid core and a resilient covering sleeve on said core and co-axial therewith.

13. A station according to claim 3, wherein said press roll comprises a rigid core and a resilient covering sleeve on said core and co-axial therewith.

14. A method according to claim 5, wherein said substrate comprises a layer of paperboard.

15. A method according to claim 6, wherein said substrate comprises a layer of paperboard.

16. A station according to claim 1, wherein said substrate comprises a layer of paperboard.

17. A station according to claim 3, wherein said substrate comprises a layer of paperboard.

18. A station according claim 1, wherein said substrate comprises, progressing inwardly therethrough, a moisture barrier layer, a core layer, a tie layer and an oxygen barrier layer.

19. A station according to claim 3, wherein said substrate comprises, progressing inwardly therethrough, a moisture barrier layer, a core layer, a tie layer and an oxygen barrier layer.

20. A method according to claim 5, wherein said substrate comprises, progressing inwardly therethrough, a moisture barrier layer, a core layer, a tie layer and an oxygen barrier layer.

Description

[0015] In order that the invention may be clearly and completely disclosed, reference will now be made, by way of example, to the accompanying drawings, in which:

[0016] FIG. 1 is a fragmentary side elevation of a per se known laminating apparatus;

[0017] FIG. 2 is a fragmentary, diagrammatic perspective view from above of the per se known laminating apparatus; and

[0018] FIG. 3 is a view similar to FIG. 2 of either of two embodiments of the invention.

[0019] Referring to FIGS. 1 and 2, the apparatus includes a guide roll 2 and a press roll 4 with an elastomeric covering sleeve 6, a chill roll 8 and a back-up roll 10 which controls the width of and pressure in the nip between the rolls 4 and 8. Rightmost and leftmost belts 12 extend over tensioning and idling rollers 14 and 16 and through that nip. Downstream of the roll 8 is a roll 18. Seen in FIG. 1 but omitted from FIG. 2 for the sake of clarity is an extruder 20 feeding a die 22 from which flows a curtain 100 of thermoplastics, e.g. LDPE, to coat an advancing substrate 102. The stage shown can be an upstream one where an outermost LDPE layer (100) is applied by extrusion coating to the substrate 102 in the form of a paperboard core layer, or a downstream one where the laminate substrate so formed has been flipped over and carries at its upper surface an aluminium foil layer attached by a tie layer to the paperboard. The leftmost and rightmost belts 12 have the effect of deterring the edges of the layer 100 squeezed in the nip between the rolls 4 and 8 from contacting and adhering to the elastomeric sleeve 6. In a per se known system, the substrate 102 has been formed with rows of through holes 104 distributed therealong to constitute holes openable by manipulation of pour spout fitments following the per se known forming of cartons (from flat carton sleeves, or a reeled web, supplied to a liquid packaging form-fill-seal machine).

[0020] Referring to FIG. 3, where again the extruder 20, the die 22 and the curtain 100 have been omitted for the sake of clarity, at least one, in this case three, intermediate belts 24 are arranged between and parallel to the belts 12. The belts 24 are in the planes of the respective rows of holes 104 and deter the thermoplastics of the layer (100) from passing through the holes 104 and thus from contacting and adhering to the elastomeric materials of the sleeve 6. If the station in question is not that upstream one but is the downstream station where an innermost extrusion coating is applied to the outside of an advancing web comprised of outermost thermoplastic layer/paperboard layer/tie layer/aluminium foil, the intermediate belts (24) again extend in the same planes of the respective rows of holes 104, but perform the function of pressing the outermost LDPE layer against the tie layer backed-up by the aluminium foil and the innermost LDPE layer and thus promoting adhesion between the tie layer and the outermost LDPE layer.

[0021] In a particular example of production of a packaging laminate end product in which, progressing inwards, there are an outermost moisture-barrier layer of LPDE; paperboard; an outer tie layer; an aluminum foil oxygen barrier layer; an inner tie layer; and a innermost moisture-barrier layer of LDPE, there are three lamination stations. At the first the outermost LDPE layer is extrusion coated to the paperboard. At the second that web, flipped over, is merged with a web consisting of the outer tie layer and the aluminum foil. At a third the latter web, with the aluminum foil uppermost, a co-extrusion coating consisting of the inner tie layer and the outermost layer of LDPE is applied to the foil.

[0022] The first station is according to FIGS. 1 and 2, i.e. intermediate belts, are not employed, but instead a press roll 4 having a covering sleeve 6 comprised of rubber and an outermost layer 6. The layer 6 is non-adhesive, for example of TEFLON, namely polytetrafluoroethylene (PTFE). The second station is also according to FIGS. 1 and 2, with a press roll 4 having a covering sleeve 6 comprised of rubber and an outermost layer of TEFLON. The third station is according to FIG. 3. Thus adhesion between the outer tie layer and the outermost layer is promoted.