CORE FOR COILED SHEET METAL, MANUFACTURING METHOD, AND METHOD FOR PACKAGING COILS

Abstract

A hollow cylindrical core (1), e.g. paperboard core, for coiled sheet metal (5), the core (1) being made from at least one ply of material wound into the shape of a tube, the core having an outer circumferential surface (2), an inner circumferential surface (3) and a cavity (4) inside the core (1) which is defined by the inner circumferential surface (3), and the core (1) being open at least at one end, wherein the core (1) is provided with a volatile corrosion inhibitor inside the cavity (4).

Claims

1. A hollow cylindrical core for coiled sheet metal, the core being made from at least one ply of material wound into the shape of a tube, the core having an outer circumferential surface, an inner circumferential surface and a cavity inside the core which is defined by the inner circumferential surface, and the core being open at least at one end, wherein the core is provided with a volatile corrosion inhibiting (VCI) composition inside the cavity.

2. The hollow cylindrical core according to claim 1, wherein the outer circumferential surface of the core is left free of any volatile corrosion inhibiting (VCI) composition.

3. The hollow cylindrical core according to claim 1, wherein the core is provided with a volatile corrosion inhibiting (VCI) composition also on the outer circumferential surface of the core.

4. The hollow cylindrical core according to any one of claims 1-3, in which the VCI composition is provided as a coating on, or an impregnation into, the material forming the inner and/or outer circumferential surface of the core.

5. The hollow cylindrical core of any one of the preceding claims, in which the VCI composition is provided as a coating on, or an impregnation into, an additional material layer inserted into the cavity within the core.

6. The hollow cylindrical core of any one of the preceding claims, comprising a plurality of material plies wound into a tube.

7. The hollow cylindrical core of claim 6, wherein the material plies are adhesively bonded to each other.

8. The hollow cylindrical core of any one of the preceding claims, in which at least one ply of material is a paperboard ply.

9. The hollow cylindrical core of any one of the preceding claims, further comprising sheet metal wound around the outer circumference of the core so as to form a metal roll or coil.

10. The hollow cylindrical core of claim 9, further including an end header at least at one longitudinal end of the metal roll or coil, wherein the end header is preferably also provided with a volatile corrosion inhibitor.

11. The hollow cylindrical core of claim 9 or 10, further including a packaging material wrapped around the metal roll or coil so as to enclose the metal roll or coil and the volatile corrosion inhibiting (VCI) composition in a substantially closed airspace.

12. A method of manufacturing a hollow cylindrical core for coiled sheet metal, the method comprising the steps of: winding at least one ply of material into the shape of a tube so as to obtain a core having an outer circumferential surface, an inner circumferential surface and a cavity inside the core which is defined by the inner circumferential surface, the core being open at least at one end, and providing a volatile corrosion inhibiting (VCI) composition inside the cavity.

13. The method of claim 12, wherein the outer circumferential surface of the core is left free of any volatile corrosion inhibiting (VCI) composition.

14. The method of claim 12, wherein the core is provided with a volatile corrosion inhibiting (VCI) composition also on the outer circumferential surface thereof.

15. The method according to any one of claims 12 to 14, in which the VCI composition is coated onto, or impregnated into, the material forming the inner and/or outer circumferential surface of the core.

16. The method of any one of claims 12 to 15, in which at least one ply of the material is coated or impregnated with the VCI composition before the ply or plies of material are wound into the shape of a tube.

17. The method of claim any one of claims 12 to 16, in which at least one ply of the material is coated or impregnated with the VCI composition while the ply or plies of material are wound into the shape of a tube.

18. The method of any one of claims 12 to 17, in which the material forming the inner and/or outer circumferential surface of the core is coated or impregnated with the VCI composition after winding the ply or plies of material into the shape of a tube.

19. The method of any one of claims 12 to 18, in which the VCI composition is coated onto, or impregnated into, an additional material layer and the additional material layer is inserted into the cavity inside the core.

20. The method of any one of claims 12 to 19, wherein the material plies are adhesively bonded to each other.

21. The method of any one of claims 12 to 20, wherein at least one ply of material is a paperboard ply.

22. A method of packaging a coiled metal sheet for storage or transport, comprising the steps of: placing a volatile corrosion inhibiting (VCI) composition inside the coiled metal sheet, and wrapping the coiled metal sheet in a packaging material so as to enclose the coiled metal sheet and the volatile corrosion inhibiting (VCI) composition in a substantially closed airspace.

23. The method of claim 22, further comprising the step of providing a core according to any one of claims 1 to 8 inside the coiled metal sheet, or winding a metal sheet about a core according to any one of claims 1 to 8.

24. The method of claim 22 or 23, wherein the packaging material also includes a volatile corrosion inhibiting (VCI) composition.

25. The method of any one of claims 22 to 24, wherein the packaging material is wrapped around the metal coil sufficiently loosely so as to allow for a circulation of air from the inside of the core towards the metal coil surfaces to be protected from corrosion.

26. The method of any one of claims 22 to 25, wherein an end header is provided on at least on one of the open ends of the coiled metal sheet within the sealed airspace of the packaging material, wherein the end header is preferably also provided with a volatile corrosion inhibiting (VCI) composition.

27. Use of a hollow cylindrical core according to any one of claims 1 to 8, or a hollow cylindrical core manufactured in a method according to any one of claims 12 to 21, for winding sheet metal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In the enclosed drawings,

[0057] FIG. 1 shows a paperboard core according to the present invention,

[0058] FIG. 2 shows a metal roll wound on the paperboard core of FIG. 1,

[0059] FIG. 3 illustrates the behavior of a volatile corrosion inhibitor (VCI) used in the paperboard core of FIG. 1,

[0060] FIG. 4 is a schematic view of the metal roll of FIG. 3 in a packaged state, and

[0061] FIGS. 5 and 6 illustrate two possibilities of wrapping a metal coil using the paperboard core of the present invention.

DESCRIPTION OF EMBODIMENTS

[0062] An embodiment of a paperboard core according to the present invention, a method of manufacturing the core and a method for packaging a metal coil using the core will now be described with reference to the drawings.

[0063] FIG. 1 shows a paperboard core 1 according to the present invention. The paperboard core 1 is a hollow cylindrical paperboard core for winding sheet metal. The core 1 is made from at least one ply of paperboard material wound, e.g. spirally, into the shape of a tube. The paperboard core can also be a convolute core, though. One possible example of the paperboard core is a Metallan® (trademark owned by Sonoco Products Company) core, which has a large inner diameter of e.g. 400 mm and is used to wind metal coils like coated aluminum.

[0064] The core 1 has an outer circumferential surface 2, an inner circumferential surface 3 and a cavity 4 inside the core 1 which is defined by the inner circumferential surface 3, and the core in this embodiment is open at both ends. Strictly speaking it would be sufficient for the core to be open at one end, but providing the core with two open ends is beneficial in view of the required circulation of air through the inside of the core which will be specified further below.

[0065] In accordance with the invention, the paperboard core 1 is provided with a volatile corrosion inhibitor inside the cavity 4. The volatile corrosion inhibitor can for example be provided as a coating on, or an impregnation into, the paperboard material forming the inner circumferential surface 3 of the core 1.

[0066] FIG. 2 shows a metal roll 5 wound on the paperboard core 1 of FIG. 1, and FIG. 3 illustrates the behaviour of the volatile corrosion inhibitor (VCI) provided inside the paperboard core 1: The VCI in the cavity 4 inside of the core 1 releases corrosion protective compounds. Since the core 1 is open at both its longitudinal ends, the VCI diffuses towards the outside of the paperboard core 1 and acts to protect the exposed surface of the metal coil 5 wound around the paperboard core 1 from corrosion.

[0067] The VCI becomes particularly effective when the metal coil 5 is wrapped in a packaging material 6, as illustrated in FIG. 4, so that the paperboard core with the VCI is in the same air space as the metal coil. Air can circulate inside the package, and the VCI provided inside the core acts to protect the metal roll wound onto the core 1.

[0068] The outer circumferential surface 2 of the core 1 can be left free of any VCI chemicals, but in embodiments, the core can be provided with a volatile corrosion inhibitor also on the outer circumferential surface of the core. Provided that gaps exist between the outer circumferential surface of the core and the coiled metal sheet, air can circulate there between, and the VCI additionally provided on the outer circumferential surface 2 of the core 1 acts to additionally protect the metallic material roll 5 wound onto the core 1.

[0069] FIGS. 5 and 6 make it clear that there are different possible ways of packaging a metal coil supported on a paperboard core 1 of the present invention: according to FIG. 5, the wrapping material is provided so as to constitute a substantially cylindrical enclosure encompassing the metal coil and the paperboard core, so that the metal coil and the paperboard core are confined within the same airspace and the VCI can diffuse towards the exposed surfaces of the metal coil. FIG. 6 shows that it would as well be possible to have the packaging material extend into the cavity inside the core and along the inner circumferential surface of the core, at least about a certain distance into the core but possibly even completely through the core. Also in this case, the inner circumferential surface of the core and the exposed surfaces of the metal coil are confined within the same airspace so that the VCI on the inside of the core can protect the exposed surfaces of the metal coil.