ALLOY FOR TABSTOCK AND CAN END

Abstract

This application discloses 3XXX aluminum alloys useful in fabricating can ends and tabs used for opening cans, particularly AA3104 and AA3204 aluminum alloys. This application discloses 3XXX aluminum alloys useful in fabricating cans comprising a body, end and tab, particularly AA3104 and AA3204 aluminum alloys.

Description

PRIOR RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/017,995, filed Jun. 27, 2014, the content of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to the fields of metallurgy, aluminum alloys, aluminum fabrication, and related fields. In particular, the present invention provides 3XXX alloys useful in fabricating can ends and tabs used for opening cans.

BACKGROUND

Can ends and tabs used to open cans are usually made from an AA5182 aluminum alloy because it possesses good strength and formability. The requirements for can ends and tabs are quite different than those for can bodies. In general, greater strength is required for can ends and tabs, and that requirement has dictated that such can ends and tabs be fabricated from an aluminum alloy, such as AA5182. AA5182 typically contains Mg in an amount of about 4.4% by weight (wt %), thus adding to the cost of the alloy used for can ends and tabs. Thus, there is a need to replace the AA5182 with a more cost-effective alloy with required strength.

In the can-making industry, it is widely considered that can ends and tabs made from an AA3104 alloy are not viable, because they have diminished strength compared to the current industry standard AA5182 alloys, and thus, there is a need to increase thickness, which, in turn, increases costs.

SUMMARY

The terms “invention,” “the invention,” “this invention” and “the present invention” used herein are intended to refer broadly to all of the subject matter of this patent application and the claims below. Statements containing these terms should be understood not to limit the subject matter described herein or to limit the meaning or scope of the patent claims below. Covered embodiments of the invention are defined by the claims, not this summary. This summary is a high-level overview of various aspects of the invention and introduces some of the concepts that are further described in the Detailed Description section below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification, any or all drawings and each claim.

The present invention solves the problems in the prior art and provides a more cost-effective material alternative to the use of AA5182 alloy for can ends and tabs. Cans include, but are not limited to, cans that contain food or beverages.

It has unexpectedly been found that a stay-on tab made from a 3XXX aluminum alloy, such as an AA3104 alloy or an AA3204 alloy, provides suitable strength and forms properly without undesirable cracking Further, this stay-on tab allows for up to 100% recyclable content, thereby enhancing aluminum recycling.

It has unexpectedly been found that a can end made from a 3XXX aluminum alloy, such as an AA3104 alloy or an AA3204 alloy, provides suitable strength and forms properly without undesirable cracking Further, this can end allows for up to 100% recyclable content, thereby enhancing aluminum recycling.

In one embodiment, the present invention provides a stay-on tab made from either an AA3104 alloy or an AA3204 alloy for use on “200” (2 inch diameter) or “202” (2 inch ⅛″ diameter) can ends for beverage cans. In a specific embodiment, the beverage can is the EVERCAN™ (Novelis, Atlanta, Ga.).

In another embodiment, the present invention provides a stay-on tab made from a 3XXX series alloy comprising: about 0.15-0.40 wt % Si, about 0.30-0.55 wt % Fe, up to 0.10 wt % Cu, for example, 0.001-0.10 wt % Cu, about 0.70-0.90 wt % Mn, about 0.50-3.10 wt % Mg, for example, about 2 wt % or about 3 wt % Mg, up to 0.05 wt % Cr, for example, 0.001-0.15 wt % Cr, up to 0.15 wt % Zn, for example, 0.001-0.15 wt % Zn, up to 0.05 wt % Ti, for example, 0.001-0.05 wt % Ti, and up to 0.15 wt % impurities, for example, 0.001-0.15 wt % impurities, with the remainder as Al, for use as “200” or “202” can ends for beverage cans.

In another embodiment, the present invention provides a can end made from either an AA3104 alloy or an AA3204 alloy for use as “200” (2 inch diameter) or “202” can ends for beverage cans. In a specific embodiment, the beverage can is the EVERCAN™ (Novelis, Atlanta, Ga.).

In another embodiment, the present invention provides a can end made from a 3XXX series alloy comprising: about 0.15-0.40 wt % Si, about 0.30-0.55 wt % Fe, up to 0.10 wt % Cu, for example, 0.001-0.10 wt % Cu, about 0.70-0.90 wt % Mn, about 0.50-3.10 wt % Mg, for example, about 2 wt % or about 3 wt % Mg, up to 0.05 wt % Cr, for example, 0.001-0.15 wt % Cr, up to 0.15 wt % Zn, for example, 0.001-0.15 wt % Zn, up to 0.05 wt % Ti, for example, 0.001-0.05 wt % Ti, and up to 0.15 wt % impurities, for example, 0.001-0.15 wt % impurities, with the remainder as Al, for use as “200” or “202” can ends for beverage cans.

In one embodiment, the present invention provides a can comprising a body, can end, and tab made from a 3XXX alloy.

In still another embodiment, the present invention provides a can comprising a body, can end, and tab made from an AA3104 alloy.

In yet another embodiment, the present invention provides a can comprising a body, can end, and tab made from an AA3204 alloy.

In yet another embodiment, the present invention provides a can comprising a body, can end, and tab made from a 3XXX series alloy comprising: about 0.15-0.40 wt % Si, about 0.30-0.55 wt % Fe, up to 0.10 wt % Cu, for example, 0.001-0.10 wt % Cu, about 0.70-0.90 wt % Mn, about 0.50-3.10 wt % Mg, for example, about 2 wt % or about 3 wt % Mg, up to 0.05 wt % Cr, for example, 0.001-0.15 wt % Cr, up to 0.15 wt % Zn, for example, 0.001-0.15 wt % Zn, up to 0.05 wt % Ti, for example, 0.001-0.05 wt % Ti, and up to 0.15 wt % impurities, for example, 0.001-0.15 wt % impurities, with the remainder as Al.

The present invention permits higher use of recycled metal. For example, the present invention permits use of at least 75%, 80%, 85%, 90%, 95%, or 100% recycled metal.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A shows several completed 100% 200 EVERCAN™ (Novelis, Atlanta, Ga.) samples with 3XXX alloys. AA3204 & AA3104 STOLLE Xl beverage tabs (Stolle Machinery Company, LLC Centennial, Colo.) were attached to 200 EVERCAN™ (Novelis, Atlanta, Ga.) ends that were produced. These tabs performed well and presented no opening issues.

FIG. 1B shows shells produced from 3xxx alloys with 3% Mg.

FIG. 2 shows an AA3204 STOLLE X1 beverage tabs, which produced no formability problems.

FIG. 3 is a schematic representation of the opening characteristics of a can end. When a can end is pulled at a certain angle, it pops. The pop (opening) is shown at around 26 degrees and 3 lbs, which is represented by the solid line. The dotted lines represent a normal specification limitation being used in the industry. The top dotted line represents the maximum of the specification and the bottom dotted line represents the minimum of the specification. The solid line at the bottom represents the standard deviation of the opening data. After the pop, the end continues to open until fully opened at around 63 degrees and 3.5 lbs (tear).

FIG. 4 is a tabular representation of 7 groups of alloy samples. The grey rows represent the tabulator tab strength in pounds for the 7 groups of alloy samples.

FIG. 5 is a schematic representation of average cold opening pop values for the 7 groups of alloy samples in FIG. 4. The solid lines represent specification limitations used in the industry.

FIG. 6 is a schematic representation of average cold opening tear values for the 7 groups of alloy samples in FIG. 4. The solid lines represent specification limitations used in the industry.

FIG. 7 is a schematic representation of a tab failure. The tab is turned 90 degrees so it can't open and then pulled until it bends (fails). As shown in the figure, with 5 lbs of pressure pulled at approximately 56 degrees, failure occurs.

DETAILED DESCRIPTION

In this description, reference is made to alloys identified by AA numbers and other related designations, such as “series.” For an understanding of the number designation system most commonly used in naming and identifying aluminum and its alloys, see “International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys” or “Registration Record of Aluminum Association Alloy Designations and Chemical Compositions Limits for Aluminum Alloys in the Form of Castings and Ingot,” both published by The Aluminum Association.

The present invention solves the problems in the prior art and provides a cost-effective alternative to the use of AA5182 aluminum alloy for can ends and tabs. Cans include, but are not limited to, cans that contain food or beverages.

It has also unexpectedly been found that a can end made from a 3XXX aluminum alloy, such as an EVERCAN™ AA3104 alloy or an EVERCAN™ AA3204 alloy, provides good strength, resists deformation, such as cracking, reduces the weight of the can, and reduces the cost of producing such a can. Further, a stay-on tab produced from a 3XXX EVERCAN™ alloy allows for up to and including 100% recyclable content, thereby decreasing cost and enhancing aluminum recycling.

In one embodiment, the present invention provides a stay-on tab made from either an EVERCAN™ AA3104 alloy or an AA3204 alloy for use on “200” or “202” can ends for beverage cans. In a specific embodiment the beverage can is the EVERCAN™ (Novelis, Atlanta, Ga.).

In another embodiment, the present invention provides a stay-on tab made from a 3XXX series alloy comprising: about 0.15-0.40 wt % Si, about 0.30-0.55 wt % Fe, up to 0.10 wt % Cu, for example, 0.001-0.10 wt % Cu, about 0.70-0.90 wt % Mn, about 0.50-3.10 wt % Mg, for example, about 2 wt % or about 3 wt % Mg, up to 0.05 wt % Cr, for example, 0.001-0.15 wt % Cr, up to 0.15 wt % Zn, for example, 0.001-0.15 wt % Zn, up to 0.05 wt % Ti, for example, 0.001-0.05 wt % Ti, and up to 0.15 wt % impurities, for example, 0.001-0.15 wt % impurities, with the remainder as Al, for use as “200” or “202” can ends for beverage cans.

In another embodiment, the present invention provides a can end made from either an AA3104 alloy or an AA3204 alloy for use as “200” or “202” can ends for beverage cans. In a specific embodiment the beverage can is the EVERCAN™ (Novelis, Atlanta, Ga.).

In addition, the stay-on tab and can ends may be used on 200 or 202 diameter can ends made from either an AA3104 alloy or an AA3204 alloy. This in turn, allows for lower costs and higher use of recycled metal, up to and including 100% recyclable content.

In another embodiment, the present invention provides a can end made from a 3XXX series alloy comprising: about 0.15-0.40 wt % Si, about 0.30-0.55 wt % Fe, up to 0.10 wt % Cu, for example, 0.001-0.10 wt % Cu, about 0.70-0.90 wt % Mn, about 0.50-3.10 wt % Mg, for example, about 2 wt % or about 3 wt % Mg, up to 0.05 wt % Cr, for example, 0.001-0.15 wt % Cr, up to 0.15 wt % Zn, for example, 0.001-0.15 wt % Zn, up to 0.05 wt % Ti, for example, 0.001-0.05 wt % Ti, and up to 0.15 wt % impurities, for example, 0.001-0.15 wt % impurities, with the remainder as Al, for use as “200” or “202” can ends for beverage cans.

In one embodiment, the present invention provides a can comprising a body, can end and tab made from a 3XXX alloy.

In still another embodiment, the present invention provides a can comprising a body, can end and tab made from an AA3104 alloy.

In yet another embodiment, the present invention provides a can comprising a body, can end and tab made from an AA3204 alloy.

In yet another embodiment, the present invention provides a can comprising a body, can end and tab made from a 3XXX series alloy comprising: about 0.15-0.40 wt % Si, about 0.30-0.55 wt % Fe, up to 0.10 wt % Cu, for example, 0.001-0.10 wt % Cu, about 0.70-0.90 wt % Mn, about 0.50-3.10 wt % Mg, for example, about 2 wt % or about 3 wt % Mg, up to 0.05 wt % Cr, for example, 0.001-0.15 wt % Cr, up to 0.15 wt % Zn, for example, 0.001-0.15 wt % Zn, up to 0.05 wt % Ti, for example, 0.001-0.05 wt % Ti, and up to 0.15 wt % impurities, for example, 0.001-0.15 wt % impurities, with the remainder as Al.

The present invention permits higher use of recycled metal, further decreasing costs. For example, the present invention permits use of at least 75%, 80%, 85%, 90%, 95%, or 100% recycled metal.

Chemical compositions of AA3104 and AA3204 aluminum alloys are known to one of ordinary skill in the art and are available in the Teal sheets of the Aluminum Association.

In different embodiments, the stay-on tab may be coated with a BPA-Free or BPA-NI (Bisphenol-A Free or Bisphenol-A Non-Intent) coating, a laminate, or with standard roll coatings. Further, the stay-on tab may be of various designs and colors for marketing or promotional purposes.

In different embodiments, the can end may be coated with a BPA-Free or BPA-NI coating, laminate, or standard roll coating. Further, the can end may be of various designs and colors.

In different embodiments, the can body may be coated with a BPA-Free or BPA-NI coating, laminate, or standard roll coating. Further, the can body may be of various designs and colors.

This stay-on tab and can end may be used for any application that requires a tab to open a can, such as beverage and/or food can.

The aluminum alloy of the present invention was rolled using the single stand cold mill route. This single stand process route also increases the material strength due to the nature of the heat buildup and dissipation in the coil. The material may also be produced using a tandem or multi-stand cold mill practice.

The typical ultimate tensile strength range for alloys of the present invention in an unleveled condition is 46-51 kilopounds per square inch (ksi). The typical yield strength range for alloys of the present invention in an unleveled condition is 43.5-48.5 ksi, with an elongation >3.

The AA3104 and AA3204 tab samples were produced with Novelis' new state of the art STOLLE X1/X2 beverage tab die system (die designed and produced by STOLLE SIDNEY a division of Stolle Machinery Company, 2900 Campbell Road, Sidney, Ohio 45365). The tabs were attached to a 200 EVERCAN™ (Novelis, Atlanta, Ga.) can end.

The following examples will serve to further illustrate the present invention without, at the same time, however, constituting any limitation thereof On the contrary, it is to be clearly understood that resort may be had to various embodiments, modifications and equivalents thereof which, after reading the description herein, may suggest themselves to those skilled in the art without departing from the spirit of the invention. During the studies described in the following examples, conventional procedures were followed, unless otherwise stated. Some of the procedures are described below for illustrative purposes.

Example 1

Formability performance tests were performed by producing tabs with STOLLE commercial X1 beverage tab tooling in a Minster 100 ton conversion press utilizing CDL commercial tooling. The tabs were initially optically evaluated for cracking on a Zeiss AxioCam MRc5 Microscope System @ 50X. The tabs were then finally evaluated and photographed on a NIKON IMAGE ANALYSIS system using standard evaluation techniques and procedures. Opening tests on two types of industry standard commercial testers, an ALTEK “POP & PULL” tester and a TRAC tab testing machine, indicates the Tab Formability to be adequate for the 200 EVERCAN end design. STOLLE X1 beverage tabs produced with the AA3104 or AA3204 aluminum alloys displayed no formability or cracking issues.

All patents, publications and abstracts cited above are incorporated herein by reference in their entirety. Various embodiments of the invention have been described in fulfillment of the various objectives of the invention. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Numerous modifications and adaptations thereof will be readily apparent to those skilled in the art without departing from the spirit and scope of the present invention as defined in the following claims.

Claims

1. A can tab comprising a 3XXX aluminum alloy.

2. The can tab of claim 1, wherein the 3XXX aluminum alloy comprises about 0.15-0.40 wt % Si, about 0.30-0.55 wt % Fe, up to 0.10 wt % Cu, about 0.70-0.90 wt % Mn, about 0.50-3.10 wt % Mg, up to 0.05 wt % Cr, up to 0.15 wt % Zn, up to 0.05 wt % Ti, and up to 0.15 wt % impurities, with remainder Al.

3. The can tab of claim 1, wherein the 3XXX aluminum alloy comprises about 2% Mg or about 3% Mg.

4. The can tab of claim 1, wherein the 3XXX aluminum alloy is a AA3104 aluminum alloy or a AA3204 aluminum alloy.

5. A can end comprising a 3XXX aluminum alloy.

6. The can end of claim 5, wherein the 3XXX aluminum alloy comprises about 0.15-0.40 wt % Si, about 0.30-0.55 wt % Fe, up to 0.10 wt % Cu, about 0.70-0.90 wt % Mn, about 0.50-3.10 wt % Mg, up to 0.05 wt % Cr, up to 0.15 wt % Zn, up to 0.05 wt % Ti, and up to 0.15 wt % impurities, with remainder Al.

7. The can end of claim 5, wherein the 3XXX aluminum alloy comprises about 2% Mg or about 3% Mg.

8. The can end of claim 5, wherein the 3XXX aluminum alloy is a AA3104 aluminum alloy or a AA3204 aluminum alloy.

9. The can end of claim 5, wherein the can end is a 2 inch diameter can end or a 2 inch ⅛″ diameter can end.

10. An aluminum can comprising a tab comprising a 3XXX aluminum alloy, an end comprising a 3XXX aluminum alloy, or both the tab and the end comprise a 3XXX aluminum alloy.

11. The aluminum can of claim 10, wherein the can comprises the tab comprising a 3XXX aluminum alloy and the end comprising a 3XXX aluminum alloy.

12. The aluminum can of claim 11, wherein the can further comprises a body comprising a 3XXX aluminum alloy.

13. The aluminum can of claim 10, wherein the tab comprises a 3XXX aluminum alloy comprising about 0.15-0.40 wt % Si, about 0.30-0.55 wt % Fe, up to 0.10 wt % Cu, about 0.70-0.90 wt % Mn, about 0.50-3.10 wt % Mg, up to 0.05 wt % Cr, up to 0.15 wt % Zn, up to 0.05 wt % Ti, and up to 0.15 wt % impurities, with remainder Al.

14. The aluminum can of claim 10, wherein the tab comprises a 3XXX aluminum alloy comprising about 2% Mg or about 3% Mg.

15. The aluminum can of claim 10, wherein the tab comprises a AA3104 aluminum alloy or a AA3204 aluminum alloy.

16. The aluminum can of claim 10, wherein the end comprises a 3XXX aluminum alloy comprising about 0.15-0.40 wt % Si, about 0.30-0.55 wt % Fe, up to 0.10 wt % Cu, about 0.70-0.90 wt % Mn, about 0.50-3.10 wt % Mg, up to 0.05 wt % Cr, up to 0.15 wt % Zn, up to 0.05 wt % Ti, and up to 0.15 wt % impurities, with remainder Al.

17. The aluminum can of claim 10, wherein the end comprises a 3XXX aluminum alloy comprising about 2% Mg or about 3% Mg.

18. The aluminum can of claim 10, wherein the end comprises a AA3104 aluminum alloy or a AA3204 aluminum alloy.

19. The aluminum can of claim 10, wherein the end is a 2 inch diameter end or a 2 inch ⅛″ diameter end.

20. The aluminum can of claim 10, wherein the can is a beverage can or a food can.