A METHOD FOR MANUFACTURING AN ALUMINIUM TUBE, A METHOD FOR MANUFACTURING AN ALUMINIUM SLUG, AN ALUMINIUM TUBE AND AN ALUMINIUM SLUG

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a method for manufacturing an aluminium tube and an aluminium slug and to an aluminium tube and an aluminium slug.

BACKGROUND OF THE INVENTION

[0002] Tubes are collapsible containers or packages which can be in particular used for pasty or semiliquid products like food stuff, cosmetics, care products, pharmaceutical products such as ointments or technical products such as adhesives, paints, and the like. Tubes offer many advantages. For example, they exhibit excellent barrier properties to protect the tube content against negative external influences such as light, moisture or microorganisms. In addition, tubes facilitate efficient and complete discharge of the tube content and a wide variety in terms of dimension and decoration possibilities.

[0003] In principle, tubes can be made either from polymers or aluminium. Indeed, during the last decades, polymers have been applied more widely in tube production. However, the application of polymers has raised serious ecological issues with respect to disposal of plastic waste and an omnipresent pollution of the environment with plastic waste.

[0004] Aluminium tubes are typically produced from primary, i.e. virgin, aluminium alloy, in particular from an aluminium alloy having the composition EN-AW 1070A according to DIN EN 573-3. Though, primary aluminium alloy does not raise any omnipresent pollution issues, it suffers from the drawback that its production is based on an energy-intensive process.

[0005] A process for manufacturing containers such as aerosol cans using aluminium scrap is known from WO 2013/040339 A1. Adversely, the maximum proportion of aluminium scrap is limited to 60 % by weight, based on the total weight of the container, so as to avoid any impairment of the containers' quality. Thus, the process described in WO 2013/040339 A1 still requires a high amount of primary aluminium alloy to ensure reproducible and high quality of the final products.

OBJECT AND SOLUTION

[0006] In view of the foregoing, the object underlying the present invention is therefore to make available a method for manufacturing an aluminium tube, a method for manufacturing an aluminium slug and to make available an aluminium tube and an aluminium slug, which at least partly circumvent disadvantages as described above in the context of tube production.

[0007] This object is accomplished by a method for manufacturing an aluminium tube according to independent claim 1, a method for manufacturing an aluminium slug according to independent claim 13 and by an aluminium tube and an aluminium slug as defined in claim 14. Preferred embodiments are defined in the dependent claims and the present description. The subject-matter and wording, respectively, of all claims is hereby incorporated into the description by explicit reference.

[0008] According to a first aspect, the invention relates to a method for manufacturing or producing an aluminium tube, in particular a flexible, preferably collapsible or squeezable, aluminium tube.

[0009] Preferably, the aluminium tube is made of 100 % by weight of aluminium scrap, based on the total weight of the aluminium tube, or is preferably made of a blend of aluminium scrap and primary aluminium alloy, wherein the aluminium scrap has a proportion of > 90 % by weight, based on the total weight of the aluminium tube, and preferably wherein the primary aluminium alloy has a proportion of < 10 % by weight, based on the total weight of the aluminium tube. More preferably, the aluminium tube is made of 100 % by weight of aluminium scrap, based on the total weight of the aluminium tube, i.e. is free from primary aluminium alloy.

[0010] The method comprises the following steps:

a) providing a slug made of > 90 % by weight of aluminium scrap, based on the total weight of the slug, or manufacturing a slug using > 90 % by weight of aluminium scrap, based on the total weight of the slug, and

b) impact extrusion of the slug to form an aluminium tube, in particular having a shoulder and a neck.

[0011] The term "tube" as used according to the present invention preferably refers to a collapsible or squeezable package, wherein the package is at least in sections, in particular only in sections or continuously, in its longitudinal direction in the form of a circular or oval cylinder. In other words, the term "tube" as used according to the present invention preferably refers to a collapsible or squeezable package, wherein the package has at least in sections, in particular only in sections or continuously, in its longitudinal direction a circular or oval cross-section.

[0012] Preferably, the aluminium tube has a shoulder and a neck. The shoulder is typically a conical shaped portion of the aluminium tube which is arranged between a tube body of the aluminium tube and a neck portion of the aluminium tube. Expediently, the shoulder immediately merges into the neck portion. The neck portion is adapted to allow discharge of the tube content via an opening. Expediently, the neck portion comprises a thread, in particular a circular external or male thread, which allows closing of the aluminium tube by means of a cap having a complementary internal or female thread.

[0013] Further, the aluminium tube may have a tube volume or storage volume which ranges from 1,5 ml to 350 ml, in particular 20 ml to 220 ml.

[0014] Further, the aluminium tube may have a wall which at least partly, in particular only partly or completely, surround or encase the above-mentioned tube volume or storage volume. In particular, the aluminium tube may have an open rear end, i.e. an open end opposite to an end of the aluminium tube having the shoulder and the neck which allows a customer to fill the aluminium tube with a desired content such as cosmetics (e.g. tooth paste), pharmaceutical products (e.g. ointments), artists paints, adhesives, caulks, and the like. After filling, the aluminium tube is preferably folded and/or crimped and/or sealed at its rear end. Accordingly, it may be preferred according to the present invention that the aluminium tube has a folded and/or crimped and/or sealed end, in particular rear end.

[0015] Further, the aluminium tube may have a wall having a thickness from 0.07 mm to 0.19 mm, in particular 0.07 mm to 0.16 mm. Further, the aluminium tube may have a length from 45 mm to 230 mm, in particular 90 mm to 220 mm. Further, the aluminium tube may have a diameter from 11 mm to 50 mm, in particular 22 mm to 40 mm.

[0016] The term "aluminium scrap" as used according to the present invention refers to aluminium alloy waste, in particular primary aluminium alloy waste, left over from product manufacturing and/or consumption. Thus, "aluminium scrap" as used according to the present invention may also be termed as "recyclable aluminium alloy" or "secondary aluminium alloy".

[0017] The term "primary aluminium alloy" as used according to the present invention refers to a virgin aluminium alloy, typically produced by means of an aluminium smelter, comprising at least 99.5 % by weight of pure, i.e. elemental, aluminium, based on the total weight of the aluminium alloy. For example, the term "primary aluminium alloy" and "virgin aluminium alloy", respectively, as used according to the present invention can refer to the aluminium alloy EN-AW 1050A and/or EN-AW 1070A.

[0018] The term "slug" as used according to the present invention refers to a circular or non-circular, in particular oval or polygonal, disk, i.e. cylinder, in particular flat cylinder. Preferably, the slug according to the present invention has the form of a circular disk, in particular circular cylinder. In particular, the slug can have a diameter of 10.5 mm to 45 mm, in particular 21 mm to 40 mm and/or a height of 3 mm to 8 mm, in particular 3.8 mm to 6 mm.

[0019] The term "impact extrusion" as used according to the present invention refers to a process utilized to convert a slug into an aluminium tube. The aluminium tube is formed inside a confining die from a slug made of aluminium scrap or aluminium scrap and primary aluminium alloy. The slug is contacted by a punch. The force from the punch softens and deforms the slug and the slug flows upwards and downwards along the die. Thus, a tube body is backward extruded in one direction and in particular a tube shoulder and a tube neck is forward extruded in the other direction.

[0020] The present invention is in particular based on the surprising finding that aluminium tubes, in particular collapsible or squeezable aluminium tubes, made of > 90 % by weight of aluminium scrap can be produced without impairment of desired characteristics of the aluminium tubes, in particular in terms of diameter and/or length and/or shoulder thickness and/or wall thickness and/or porosity and/or annealing grade (see the example section). Thus, aluminium tubes can be manufactured in producible and high quality despite of a very low proportion of primary aluminium alloy or even despite of using no primary aluminium alloy at all for manufacturing the aluminium tubes. Thus, energy consumption and energy costs can be significantly reduced. In addition, the present invention emphasizes the value of aluminium as a recyclable and in particular substitute material for manufacturing tubes, thereby avoiding the ecological issues with respect to polymers.

[0021] In an embodiment of the invention, the slug is made of > 95 % by weight, preferably > 97 % by weight, more preferably > 99 % by weight, of aluminium scrap, based on the total weight of the slug. In particular, the slug can be made of < 5 % by weight, preferably < 3 % by weight, more preferably < 1 % by weight, of primary aluminium alloy, based on the total weight of the slug. More preferably, the slug is made of 100 % by weight of aluminium scrap, i.e. is free from primary aluminium alloy.

[0022] Accordingly, the aluminium tube, preferably collapsible or squeezable aluminium tube, according to the present invention is preferably made of > 95 % by weight, preferably > 97 % by weight, more preferably > 99 % by weight, of aluminium scrap, based on the total weight of the aluminium tube. In particular, the aluminium tube, preferably collapsible or squeezable aluminium tube, according to the present invention can be made of < 5 % by weight, preferably < 3 % by weight, more preferably < 1 % by weight, of primary aluminium alloy, based on the total weight of the aluminium tube.

[0023] More preferably, the aluminium tube, preferably collapsible or squeezable aluminium tube, according to the present invention is made of 100 % by weight of aluminium scrap, i.e. is free from primary aluminium alloy.

[0024] In a further embodiment of the invention, the aluminium scrap is a post-industrial waste, i.e. a waste left over from product manufacturing and/or a post-consumer waste such as municipal aluminium alloy waste, in particular collected by means of respective collection systems. Preferably, the aluminium scrap is a post-industrial waste.

[0025] Preferably, the term "post-industrial waste" as used according to the present invention refers to industrial in-house aluminium scrap from the production of aluminium workpieces, in particular aluminium slugs, and/or from the production of semi-finished aluminium products, in particular raw aluminium cans, in particular raw aluminium aerosol cans, and/or raw aluminium tubes, and/or from the production of finished aluminium products, in particular aluminium cans, in particular aluminium aerosol cans, and/or aluminium tubes.

[0026] Accordingly, the aluminium scrap is preferably a waste from the production of aluminium workpieces, in particular aluminium slugs, and/or from the production of semi-finished aluminium products such as raw aluminium cans, in particular raw aluminium aerosol cans, and/or raw aluminium tubes, and/or from the production of finished aluminium products such as aluminium cans, in particular aluminium aerosol cans, and/or aluminium tubes.

[0027] The aluminium workpieces, in particular aluminium slugs, and/or the semi-finished aluminium products, in particular raw aluminium cans, in particular raw aluminium aerosol cans, and/or raw aluminium tubes, and/or the finished aluminium products, in particular aluminium cans, in particular aluminium aerosol cans, and/or aluminium tubes, can be made of primary aluminium alloy or a blend of primary aluminium alloy and aluminium scrap. For example, the primary aluminium alloy can be EN-AW 1050A and/or EN-AW 1070A.

[0028] In a further embodiment of the invention, the aluminium scrap is a punching waste, in particular from aluminium slug production and/or a cutting waste, in particular from aluminium can production, in particular aluminium aerosol can production, and/or aluminium tube production. In principle, primary aluminium alloy such as EN-AW 1050A and/or EN-AW 1070A or a blend of primary aluminium alloy (such as EN-AW 1050A and/or EN-AW 1070A) and aluminium scrap can be used for the slug production and/or can production and/or tube production.

[0029] In a further embodiment of the invention, the aluminium scrap is an aluminium can waste, in particular aluminium aerosol can waste, i.e. a waste, which accrues during production of aluminium cans, in particular aluminium aerosol cans, and/or an aluminium tube waste, i.e. a waste, which accrues during production of aluminium tubes. Preferably, the aluminium can waste is in the form of aluminium cans, in particular deficient or damaged aluminium cans, in particular in the form of aluminium aerosol cans, in particular deficient or damaged aluminium aerosol cans, and/or in the form of aluminium tubes, in particular deficient or damaged aluminium tubes. The aluminium cans may be in particular in the form of raw or semi-finished aluminium cans, in particular without having an imprint, or in the form of finished aluminium cans, in particular having an imprint. Further, the aluminium tubes can be in particular in the form of raw or semi-finished aluminium tubes, in particular without having an imprint, or in the form of finished aluminium tubes, in particular having an imprint. In principle, the aluminium cans and/or aluminium tubes can be made of a primary aluminium alloy such as EN-AW 1050A and/or EN-AW 1070A or of a blend of primary aluminium alloy (such as EN-AW 1050A and/or EN-AW 1070A) and aluminium scrap.

[0030] In a further embodiment of the invention, the aluminium scrap comprises EN-AW 1050A. Preferably, EN-AW 1050A has a proportion of at least 10 % by weight, based on the total weight of the aluminium scrap.

[0031] The term "EN-AW 1050A" as used according to the present invention refers - according to DIN EN 573-3 - to an aluminium alloy comprising or consisting of 99.5 % by weight of Al (aluminium), at most 0.25 % by weight of Si (silicium), at most 0.4 % by weight of Fe (iron), at most 0.05 % by weight of Cu (copper), at most 0.05 % by weight of Mn (manganese), at most 0.05 % by weight of Mg (magnesium), at most 0.07 % by weight of Zn (zinc) and at most 0.05 % by weight of Ti (titan).

[0032] In a further embodiment of the invention, the aluminium scrap comprises EN-AW 1070A. Preferably, EN-AW 1070A has a proportion of at least 10 % by weight, based on the total weight of the aluminium scrap.

[0033] The term "EN-AW 1070A" as used according to the present invention refers to an aluminium alloy which has - in accordance with DIN EN 573-3 - a composition comprising or consisting of 99.7 % by weight of Al (aluminium), at most 0.03 % by weight of Cu (copper), at most 0.25 % by weight of Fe (iron), at most 0.03 % by weight of magnesium (Mg), at most 0.03 % by weight of Mn (manganese), at most 0.20 % by weight of Si (silicium), at most 0.03 % by weight of Ti (titan) and at most 0.07 % by weight of Zn (zinc).

[0034] In a further embodiment of the invention, the aluminium scrap comprises or is a blend, i.e. a mixture, of at least two different aluminium scrap fractions, namely at least of a first aluminium scrap fraction and a second aluminium scrap fraction. Preferably, the first aluminium scrap fraction and the second aluminium scrap fraction differ in terms of their composition.

[0035] Preferably, in accordance with the previous description, the first aluminium scrap fraction and the second aluminium scrap fraction can be independently selected from the group consisting of post-industrial waste and post-consumer waste.

[0036] Preferably, the first aluminium scrap fraction and the second aluminium scrap fraction are independently selected from the group consisting of waste from production of aluminium workpieces, waste from production of semi-finished aluminium products and waste from production of finished aluminium products. The aluminium workpieces and/or the semi-finished aluminium products and/or the finished aluminium products can be made of primary aluminium alloy or a blend of primary aluminium alloy and aluminium scrap. For example, the primary aluminium alloy can be EN-AW 1050A and/or EN-AW 1070A.

[0037] More preferably, the first aluminium scrap fraction and the second aluminium scrap fraction are independently selected from the group consisting of waste from production of aluminium slugs, waste from production of raw aluminium cans, in particular raw aluminium aerosol cans, waste from production of raw aluminium tubes, waste from production of (finished) aluminium cans, in particular (finished) aluminium aerosol cans, and waste from production of (finished) aluminium tubes. The aluminium slugs and/or the raw aluminium cans, in particular raw aluminium aerosol cans, and/or the raw aluminium tubes and/or the (finished) aluminium cans, in particular (finished) aluminium aerosol cans, and/or the (finished) aluminium tubes can be made of primary aluminium alloy or a blend of primary aluminium alloy and aluminium scrap. For example, the primary aluminium alloy can be EN-AW 1050A and/or EN-AW 1070A.

[0038] In a further embodiment of the invention, the first aluminium scrap fraction is a waste, in particular punching waste, from production of aluminium workpieces, in particular aluminium slugs, and the second aluminium scrap fraction is a waste from production of semi-finished aluminium products, in particular raw aluminium cans, in particular raw aluminium aerosol cans, and/or raw aluminium tubes, and/or from production of finished aluminium products, in particular aluminium cans, in particular aluminium aerosol cans, and/or aluminium tubes.

[0039] Preferably, the first aluminium scrap fraction is a waste, in particular punching waste, from production of aluminium slugs, and the second aluminium scrap fraction is a waste from production of (semi-finished or finished) aluminium cans and/or (semi-finished or finished) aluminium tubes. The aluminium workpieces, in particular aluminium slugs, and/or the semi-finished aluminium products, in particular raw aluminium cans, in particular raw aluminium aerosol cans, and/or raw aluminium tubes, and/or the finished aluminium products, in particular aluminium cans, in particular aluminium aerosol cans, and/or aluminium tubes, can be made of primary aluminium alloy or a blend of primary aluminium alloy and aluminium scrap. For example, the primary aluminium alloy can be EN-AW 1050A and/or EN-AW 1070A.

[0040] More preferably, the first aluminium scrap fraction is a punching waste from production of aluminium slugs and the second aluminium scrap fraction is an aluminium can waste, in particular aluminium aerosol can waste, i.e. a waste, which accrues during production of aluminium cans, in particular aluminium aerosol cans, and/or an aluminium tube waste, i.e. a waste, which accrues during production of aluminium tubes. Preferably, the aluminium can waste is in the form of aluminium cans, in particular deficient or damaged aluminium cans, in particular in the form of aluminium aerosol cans, in particular deficient or damaged aluminium aerosol cans, and/or in the form of aluminium tubes, in particular deficient or damaged aluminium tubes. The aluminium cans may be in particular in the form of raw or semi-finished aluminium cans, in particular without having an imprint, or in the form of finished aluminium cans, in particular having an imprint. Further, the aluminium tubes can be in particular in the form of raw or semi-finished aluminium tubes, in particular without having an imprint, or in the form of finished aluminium tubes, in particular having an imprint. In principle, the aluminium slugs and/or aluminium cans and/or aluminium tubes can be made of a primary aluminium alloy such as EN-AW 1050A and/or EN-AW 1070A or of a blend of primary aluminium alloy (such as EN-AW 1050A and/or EN-AW 1070A) and aluminium scrap.

[0041] In a further embodiment of the invention, the first aluminium scrap fraction has a proportion of 10 % by weight to 90 % by weight, in particular 30 % by weight to 50 % by weight, preferably 40% by weight, based on the total weight of the aluminium scrap, and/or the second aluminium scrap fraction has a proportion of 10 % by weight to 90 % by weight, in particular 50 % by weight to 70 % by weight, preferably 60% by weight, based on the total weight of the aluminium scrap.

[0042] In a further embodiment of the invention, the first aluminium scrap fraction comprises EN-AW 1050A. Preferably, EN-AW 1050A has a proportion of > 90 % by weight, in particular > 95 % by weight, preferably >97 % by weight, more preferably > 99 % by weight, based on the total weight of the first aluminium scrap fraction. In particular, the first aluminium scrap fraction can be made of 100 % by weight of a primary aluminium alloy, in particular EN-AW 1050A and/or EN-AW 1070A. In other words, the first aluminium scrap fraction can be in particular completely made of a primary aluminium alloy, in particular EN-AW 1050A and/or EN-AW 1070A.

[0043] In a further embodiment of the invention, the second aluminium scrap fraction comprises EN-AW 1070A. Preferably, EN-AW 1070A has a proportion of > 90 % by weight, in particular >95 % by weight, preferably >97 % by weight, more preferably > 99 % by weight, based on the total weight of the second aluminium scrap fraction. In particular, the second aluminium scrap fraction can be made of 100 % by weight of a primary aluminium alloy, in particular EN-AW 1050A and/or EN-AW 1070A. In other words, the second aluminium scrap fraction can be in particular completely made of a primary aluminium alloy, in particular EN-AW 1050A and/or EN-AW 1070A.

[0044] In a further embodiment of the invention, the aluminium scrap comprises or consists of the following composition:

• > 99.6% by weight of Al (aluminium),
• 0.04% by weight to 0.25% by weight of Si (silicium),
• 0.08% by weight to 0.35% by weight of Fe (iron),
• at most 0.05 % by weight of Cu (copper),
• at most 0.03 % by weight of Mn (manganese),
• at most 0.03 % by weight of Mg (magnesium),
• at most 0.05 % by weight of Zn (zinc),
• at most 0.03 % by weight of Ti (titan),
• at most 0.05 % by weight of V (vanadium) and
• at most 0.03 % by weight of other impurities, with the proviso that the aforementioned ingredients of the composition add to 100 % by weight.

[0045] Preferably, the aluminium scrap comprises or consists of the following composition:

• > 99.6 % by weight of Al (aluminium),
• 0.06 % by weight to 0.20 % by weight of Si (silicium),
• 0.12 % by weight to 0.30 % by weight of Fe (iron),
• at most 0.03 % by weight of Cu (copper),
• at most 0.03 % by weight of Mn (manganese),
• at most 0.03 % by weight of Mg (magnesium),
• at most 0.03 % by weight of Zn (zinc),
• at most 0.03 % by weight of Ti (titan),
• at most 0.01 % by weight of V (vanadium) and
• at most 0.03 % by weight of other impurities, with the proviso that the aforementioned ingredients of the composition add to 100 % by weight.

[0046] In a further embodiment of the invention, the slug is only, i.e. exclusively, made of aluminium scrap, i.e. is free from primary (virgin) aluminium alloy, in particular free from primary (virgin) aluminium alloy having the composition of EN-AW 1050A and/or EN-AW 1070A.

[0047] In a further embodiment of the invention, the method for manufacturing or producing an aluminium tube comprises between step a) and step b) a further step ab) applying a lubricant such as a metal stearate to the slug. Thus, friction during the impact extruding step (step b) can be advantageously minimized.

[0048] Preferably, the method for manufacturing or producing an aluminium tube comprises a further step c) cutting the aluminium tube, expediently at a rear end of the aluminium tube, i.e. at an end of the aluminium tube which is arranged opposite to an aluminium tube's end having a shoulder and a neck. Thus, the aluminium tube can be cut to a desired length. The cutting of the aluminium tube can be accomplished by means of a cutting device comprising a standard cutting knife.

[0049] Further, the method for manufacturing or producing an aluminium tube preferably comprises a further step d) forming a thread on or around a neck of the aluminium tube, in particular by using a thread rolling device.

[0050] Further, the method for manufacturing or producing an aluminium tube preferably comprises a further step e) annealing, i.e. heat treating, the aluminium tube. The aluminium tube can be annealed at a temperature from 380 °C to 490 °C. Further, the annealing step can be carried out during a period of 2 minutes to 3.5 minutes. Advantageously, the annealing step facilitates softening of the aluminium tube and makes it collapsible or squeezable.

[0051] Further, the method for manufacturing or producing an aluminium tube preferably comprises a further step f) applying a coating, in particular lacquer, on an interior surface of the aluminium tube. The coating can comprise or consist of an epoxy-phenol-resin and/or polyamide-imide and/or a polyester based lacquer. The coating can be applied by means of spray nozzles.

[0052] Further, the method for manufacturing or producing an aluminium tube preferably comprises a further step g) curing of the applied coating, in particular lacquer. The curing step may be carried out in a polymerization oven, in particular at a temperature from 200 °C to 280 °C and in particular during 5 minutes to 8 minutes.

[0053] Further, the method for manufacturing or producing an aluminium tube preferably comprises a further step h) applying a coating, in particular base coating, on an exterior surface of the aluminium tube. Advantageously, the coating, in particular base coating, serves as a primary coating facilitating application of subsequent layers or coatings. The coating, in particular base coating, can be a coloured coating. Further, the coating, in particular base coating, can be applied by means of paint rollers.

[0054] Further, the method for manufacturing or producing an aluminium tube preferably comprises a further step i) drying the applied coating, in particular applied base coating. The drying step can be carried out at a temperature from 100 °C to 130 °C and in particular during a period of 5 minutes to 8 minutes.

[0055] Further, the method for manufacturing or producing an aluminium tube preferably comprises a further step j) printing, in particular dry offset printing, the dried coating, in particular dried base coating. Typically, the printing step finalizes the decoration process of the aluminium tube. For example, a design can be printed onto the dried coating, in particular dried base coating. For example, the printing step can be carried out by means of an offset printing process which is then cured together with the first applied external coating in another furnace, in particular at a temperature from 160 °C to 190 °C and in particular during a period of 5 minutes to 8 minutes.

[0056] Further, the method for manufacturing or producing an aluminium tube preferably comprises a further step k) capping the aluminium tube, i.e. closing the aluminium tube by means of a cap. The capping step can be carried out by means of screwing a cap onto a neck of the aluminium tube, wherein the cap has an internal or female thread which is complementary to an external or male thread of the neck.

[0057] Further, the method for manufacturing or producing an aluminium tube preferably comprises a further step I) applying a latex coating or heat-sealable varnish on an interior surface of the aluminium tube which is close to a rear end of the aluminium tube, i.e. an end which is arranged opposite to an aluminium tube's end having a shoulder and a neck. Advantageously, application of the latex coating or heat-sealable varnish allows sealing of the rear end after folding and/or crimping the aluminium tube.

[0058] In a further embodiment of the invention, the method further comprises the following steps, expediently in chronological order:

c) cutting the aluminium tube, expediently at a rear end of the aluminium tube, wherein the rear end is arranged opposite to an aluminium tube's end having a shoulder and a neck,

d) forming a thread on or around the neck of the aluminium tube,

e) annealing the aluminium tube,

f) applying a coating, in particular lacquer, on an interior surface of the aluminium tube,

g) curing of the applied coating, in particular lacquer,

h) applying a coating, in particular base coating, on an exterior surface of the aluminium tube,

i) drying the applied coating, in particular base coating,

j) printing the dried coating, in particular dried base coating,

k) capping the aluminium tube,

I) applying a latex coating or a heat-sealable varnish on an interior surface of the aluminium tube which is close to the rear end of the aluminium tube, i.e. the end of the aluminium tube which is arranged opposite to the aluminium tube's end having the shoulder and neck and

m) packaging the aluminium tube.

[0059] With respect to further details and advantages of the steps c) - m), reference is made in its entirety to the previous description.

[0060] According to a second aspect, the present invention refers to a method for manufacturing or producing an aluminium slug.

[0061] Preferably, the aluminium slug is made of 100 % by weight of aluminium scrap, based on the total weight of the aluminium slug, or is preferably made of a blend of aluminium scrap and primary aluminium alloy, wherein the aluminium scrap has a proportion of > 90 % by weight, based on the total weight of the aluminium slug, and preferably wherein the primary aluminium alloy has a proportion of < 10 % by weight, based on the total weight of the aluminium slug. More preferably, the aluminium slug is made of 100 % by weight of aluminium scrap, based on the total weight of the aluminium slug, i.e. is free from primary aluminium alloy.

[0062] The method comprises the following steps, expediently in chronological order:

a) providing aluminium scrap or aluminum scrap and primary aluminium alloy,

b) melting the aluminium scrap or the aluminum scrap and primary aluminium alloy to form a molten mass with the proviso that the molten mass has a proportion of aluminium scrap > 90 % by weight, based on the total weight of the molten mass,

c) controlling the composition of the molten mass and optionally adding alloying elements to the molten mass,

d) casting of the molten mass to form a strip or casting of a remolten mass to form a strip,

e) hot rolling of the strip,

f) cold rolling of the hot rolled strip and

g) forming a slug from the cold rolled strip.

[0063] Preferably, the remolten mass of step d) is obtained by casting of the molten mass formed by means of step b) to form ingots and subsequently by remelting the ingots to form the remolten mass.

[0064] The term "hot rolling" as used according to the present invention refers to a strip made of primary aluminium alloy and/or aluminium scrap above the re-crystallization temperature of pure, i.e. elemental, aluminium, i.e. in a temperature range of 250°C to 500°C.

[0065] The term "cold rolling" as used according to the present invention refers to rolling of a hot rolled strip made of primary aluminium alloy and/or aluminium scrap below the re-crystallization temperature of pure, i.e. elemental, aluminium, i.e. below a temperature of 250°C.

[0066] Preferably, the step b) is carried out such that the molten mass has a proportion of aluminium scrap > 95 % by weight, preferably > 97 % by weight, more preferably > 99 % by weight, based on the total weight of the molten mass.

[0067] Further, it may be preferred that the molten mass has a proportion of primary aluminium alloy < 5 % by weight, preferably < 3 % by weight, more preferably < 1 % by weight, based on the total weight of the molten mass.

[0068] Most preferably, the method for manufacturing or producing an aluminium slug is carried out without using primary aluminium alloy, in particular without using primary aluminium alloy having the composition of EN-AW 1050A and/or EN-AW 1070A.

[0069] Further, the method for manufacturing or producing an aluminium slug can comprise between step b) and step d) a further step bd) cleaning of the molten mass, in particular by means of injection of argon or by means of alternative techniques.

[0070] By means of the step c), it is possible to selectively add alloying elements so as to obtain a molten mass having a desired composition, if need be. Further, the molten mass may be purged, in particular by means of argon. Thus, additional cleaning may be advantageously accomplished.

[0071] Further, the method for manufacturing or producing an aluminium slug can comprise between step c) and step d) a further step cd) casting of the molten mass to ingots which are subsequently remolten

[0072] Further, the step d) can be carried out using a casting speed of 4 m/min to 8 m/min.

[0073] Preferably, the step d) is carried out by means of a rotary casting device. The rotary casting device preferably comprises a casting wheel and a steel band. The molten mass can be transferred at a temperature of 680 °C to 750 °C to the casting wheel. Preferably, the molten mass is continuously casted on the casting wheel and solidified between the casting wheel and the steel band. A cooling necessary for solidification of the molten mass is preferably achieved by spraying water via nozzles on the casting wheel and the steel band.

[0074] Further, step e) is preferably carried out at a temperature from 460 °C to 500 °C.

[0075] Further, the method can comprise between step e) and step f) a further step ef) cooling the strip to a temperature of 10 °C to 90 °C, preferably 30 °C to 70 °C.

[0076] Further, the step f) is preferably carried out at a temperature from 10 °C to 90 °C, preferably 30 °C to 70 °C.

[0077] Further, the step g) is preferably carried out by punching out a slug of the cold rolled strip.

[0078] Further, the method for manufacturing or producing an aluminium slug can comprise a further step h) annealing of the slug. Preferably, the step h) is carried out at a temperature from 480 °C to 580 °C, preferably 500 °C to 550 °C and in particular during a period from 30 minutes to 3 hours. Thus, a homogeneous microstructure and in particular uniform distribution of the optional alloying elements can be accomplished.

[0079] Further, the method for manufacturing or producing an aluminium slug can comprise a further step i) cooling the annealed slug, in particular by forced air cooling, in particular with a cooling rate of 0.01 K/s to 0.1 K/s.

[0080] Further, the method for manufacturing or producing an aluminium slug can comprise a further step j) roughening of the cooled slug, in particular by placing the slug in a drum which is rotated or vibrated and thereby deburrs and roughens the slug's surface. Alternatively, the slug can be blasted with an abrasive.

[0081] With respect to further features and advantages of the method for manufacturing or producing an aluminium slug, in particular with respect to the slug, aluminium scrap and primary aluminium alloy, reference is made in its entirety to the embodiments described under the first aspect of the invention. The features and advantages described in the context of the first aspect of the invention, in particular with respect to the slug, aluminium scrap and primary aluminium alloy, do apply accordingly with respect to the method according to the second aspect of the invention.

[0082] A third aspect of the invention relates to an aluminium tube, in particular flexible aluminium tube, preferably collapsible or squeezable aluminium tube. The aluminium tube is made of > 90 % by weight, in particular > 95 % by weight, preferably > 97% by weight, more preferably > 99% by weight, of aluminium scrap, based on the total weight of the aluminium tube.

[0083] In particular, the aluminium tube, preferably collapsible or squeezable aluminium tube, can be made of < 10 % by weight, in particular < 5 % by weight, preferably < 3 % by weight, more preferably < 1 % by weight, of primary aluminium alloy, based on the total weight of the aluminium tube.

[0084] More preferably, the aluminium tube, preferably collapsible or squeezable aluminium tube, is made of 100 % by weight of aluminium scrap, i.e. is free from primary aluminium alloy, in particular free from primary aluminium alloy having the composition of EN-AW 1050A and/or EN-AW 1070A.

[0085] With respect to further features and advantages of the aluminium tube, in particular with respect to the aluminium scrap, reference is made in its entirety to the previous description, in particular to the embodiments described under the first aspect of the invention. The features and advantages described in the context of the previous description, in particular the first aspect of the invention, in particular with respect to the aluminium tube and aluminium scrap, do apply accordingly with respect to the aluminium tube according to the third aspect of the invention.

[0086] A fourth aspect of the invention relates to an aluminium slug. The slug is made of > 90 % by weight, in particular > 95 % by weight, preferably > 97 % by weight, more preferably > 99 % by weight, of aluminium scrap, based on the total weight of the slug.

[0087] In particular, the aluminium slug can be made of < 10 % by weight, in particular < 5 % by weight, preferably < 3 % by weight, more preferably < 1 % by weight, of primary aluminium alloy, based on the total weight of the aluminium slug.

[0088] More preferably, the aluminium slug is made of 100 % by weight of aluminium scrap, i.e. is free from primary aluminium alloy, in particular free from primary aluminium alloy having the composition of EN-AW 1050A and/or EN-AW 1070A.

[0089] With respect to further features and advantages of the aluminium slug, in particular with respect to the aluminium scrap, reference is made in its entirety to the previous description, in particular to the embodiments described under the first aspect of the invention. The features and advantages described in the context of the previous description, in particular the first aspect of the invention, in particular in terms of the aluminium slug and aluminium scrap, do apply accordingly with respect to the aluminium slug according to the fourth aspect of the invention.

[0090] Further features and advantages of the invention will become clear from the following description of preferred embodiments in form of an example in conjunction with the subject-matter of the dependent claims. The individual features can be realized either singularly or severally in combination in one embodiment of the invention. The preferred embodiments merely serve for illustration and better understanding of the invention and are not to be understood as in any way limiting the invention.

EXAMPLE SECTION

[0091] Aluminium tubes according to the present invention consisting of 100% by weight of aluminium scrap were produced from a blend of 40% by weight of post-industrial waste from slug production (waste material from punching the slugs) with a composition according to EN-AW 1050A or EN-AW 1070A and of 60% by wt. of post-industrial waste (either blank or coated) from aerosol can and tube production with a composition according to EN-AW 1050A or EN-AW 1070A.

[0092] The properties of the final aluminium tubes (4 batches were prepared, wherein batches A and B had a M11 thread and batches C and D had a M15 thread) were compared with those of conventional aluminium tubes made of 100% by weight of primary aluminium having a composition according to EN-AW 1070A produced with the same method except that the slugs were directly casted from the melt (without the intermediate step of forming ingots).

[0093] The blended scrap material was molten and casted to ingots which were then remolten and casted to an aluminium strip from which slugs were stamped out. Subsequently, the slugs were annealed at a temperature of around 500 °C to 520 °C for around 2 hours to 3 hours, followed by a cooling step at a cooling rate of lower than 0.05 K/s. The slugs prepared in such a way had a diameter of 24.7 mm and a thickness of 4.3 mm each.

[0094] From these slugs, tubes were formed by means impact extrusion (press type Herlan CP55) with a final length of 140 mm and a diameter of 25 mm.

[0095] After the annealing process at about 400 °C, an internal coating comprising a solvent-based epoxy-phenolic lacquer was applied by spraying which was then cured in a continuous polymerization oven at about 260 °C. Subsequently, an external coating based on a solvent-based modified polyester lacquer was applied and then dried in a drying furnace at about 125 °C. After a further printing step, the external coating was cured together with a printing layer in another furnace at about 175 °C.

[0096] The following physical properties/dimensions of the tubes were compared:

• diameter measured according to DIN EN 13046
• length measured according to DIN EN 13046
• shoulder thickness measured according to DIN EN 13046
• thickness membrane measured according to DIN 5059-1
• porosity measured according to DIN EN 15384-1, DIN EN 15384-2 and
• annealing grade measured according to DIN EN 16285.

[0097] The obtained results are shown in the below table 1:

Table 1: obtained results

properties/dimensions	specifications	primary 1070A (comparative example)	batch A	batch B	batch C	batch D
diameter (mm)	24.8 - 25.1	24.88	24.91	24.91	24.91	24.9
length (mm)	139.5 - 140.5	139.92	140.06	139.92	140.09	139.86
shoulder thickness (mm)	0.5 - 0.8	0.6	0.77	0.76	0.55	0.68
thickness membrane (mm)	0.06 - 0.14	0.11	0.13	0.14	0.14	0.13
porosity (mA)	≤ 25	5.86	13.8	11.69	15.25	13.07
annealing grade (mm)	8 - 13	10.63	9.49	9.76	8.67	8.73

[0098] The measurements confirm that the tubes produced from 100% by weight of aluminium scrap show almost identical properties/dimensions as the tubes produced of 100% by weight of primary aluminium (EN-AW 1070A), in any case within the limits of the required specifications.

Claims

1. A method for manufacturing an aluminum tube, preferably a collapsible or squeezable aluminium tube, comprising the steps of

a) providing a slug made of > 90 % by weight of aluminium scrap, based on the total weight of the slug, and

b) impact extrusion of the slug to form an aluminium tube having a shoulder and a neck.

2. The method according to claim 1, characterized in that the slug is made of > 95 % by weight, preferably > 97 % by weight, more preferably > 99 % by weight, of aluminium scrap, based on the total weight of the slug.

3. The method according to claim 1 or 2, characterized in that the aluminium scrap is a post-industrial waste, in particular a waste from production of aluminium workpieces, in particular aluminium slugs, and/or of semi-finished aluminium products, in particular raw aluminium cans, in particular raw aluminium aerosol cans, and/or raw aluminium tubes, and/or of finished aluminium products, in particular aluminium cans, in particular aluminium aerosol cans, and/or aluminium tubes.

4. The method according to any of the preceding claims, characterized in that the aluminium scrap is a punching waste, in particular from aluminium slug production and/or an aluminium can waste, preferably in the form of aluminium cans, in particular deficient or damaged aluminium cans, and/or an aluminium tube waste, preferably in the form of aluminium tubes, in particular deficient or damaged aluminium tubes.

5. The method according to any of the preceding claims, characterized in that the aluminium scrap comprises EN-AW 1050A, wherein EN-AW 1050A preferably has a proportion of at least 10 % by weight, based on the total weight of the aluminium scrap and/or the aluminium scrap comprises EN-AW 1070A, wherein EN-AW 1070A preferably has a proportion of at least 10 % by weight, based on the total weight of the aluminium scrap.

6. The method according to any of the preceding claims, characterized in that the aluminum scrap is a blend of at least two different aluminium scrap fractions, namely at least a first aluminium scrap fraction and a second aluminium scrap fraction.

7. The method according to claim 7, characterized in that the first aluminium scrap is a waste from production of aluminium workpieces, in particular punching waste of aluminium slugs, and the second aluminium scrap is an aluminium can waste, preferably in the form of aluminium cans, in particular deficient or damaged aluminium cans, and/or an aluminium tube waste, preferably in the form of aluminium tubes, in particular deficient or damaged aluminium tubes.

8. The method according to claim 7 or 8, characterized in that the first aluminium scrap fraction has proportion of 10 % by weight to 90 % by weight, in particular 30 % by weight to 50 % by weight, preferably 40 % by weight, based on the total weight of the aluminium scrap, and the second aluminium scrap fraction has proportion of 10 % by weight to 90 % by weight, in particular 50 % by weight to 70 % by weight, preferably 60 % by weight, based on the total weight of the aluminium scrap.

9. The method according to any of the claims 7 to 9, characterized in that the first aluminium scrap fraction comprises or consists of EN-AW 1050A and/or the second aluminium scrap fraction comprises or consists of EN-AW 1070A.

10. The method according to any of the preceding claims, characterized in that the aluminium scrap comprises or consists of the following composition:

- > 99.6 % by weight of Al,

- 0.04 % by weight to 0.25 % by weight, preferably 0.06 % by weight to 0.20 % by weight, of Si,

- 0.08 % by weight to 0.35 % by weight, preferably 0.12 % by weight to 0.30 % by weight, of Fe,

- at most 0.05 % by weight, preferably at most 0.03 % by weight, of Cu,

- at most 0.03 % by weight of Mn,

- at most 0.03 % by weight of Mg,

- at most 0.05 % by weight, preferably at most 0.03 % by weight, of Zn,

- at most 0.03 % by weight of Ti,

- at most 0.05 % by weight, preferably at most 0.01 % by weight, of V and

- at most 0.03 % by weight of other impurities, with the proviso that the aforementioned ingredients of the composition add to 100 % by weight.

11. The method according to any of the preceding claims, characterized in that the slug is only made of aluminium scrap, i.e. is free from primary or virgin aluminium alloy, in particular having the composition of EN-AW 1050A and/or EN-AW 1070A.

12. The method according to any of the preceding claims, characterized in that the method comprises between step a) and step b) a further step ab) applying a lubricant to the slug and/or further comprises at least one of the following steps, in particular all of the following steps, expediently in chronological order:

c) cutting the aluminium tube, expediently at a rear end of the aluminium tube, wherein the rear end is arranged opposite to an aluminum tube's end having a shoulder and a neck,

d) forming a thread on the neck of the aluminum tube,

e) annealing the aluminium tube,

f) applying coating, in particular lacquer, on an interior surface of the aluminium tube,

g) curing of the applied coating, in particular lacquer,

h) applying a base coating on an exterior surface of the aluminium tube,

i) drying the applied base coating,

j) printing the dried base coating,

k) capping the aluminium tube,

l) applying a latex coating or heat-sealable varnish on an interior surface of the aluminium tube which is close to the aluminium tube's rear end and

m) packaging the aluminium tube.

13. A method for manufacturing an aluminium slug comprising the following steps, expediently in chronological order:

a) providing aluminium scrap or aluminum scrap and primary aluminium alloy,

b) melting the aluminium scrap or the aluminum scrap and primary aluminium alloy to a molten mass with the proviso that the molten mass has a proportion of aluminium scrap > 90 by weight, based on the total weight of the molten mass,

c) controlling composition of the molten mass and optionally adding alloying elements to the molten mass,

d) casting of the molten mass to a strip,

e) hot rolling of the strip,

f) cold rolling of the hot rolled strip and

g) forming a slug from the cold rolled strip.

14. Aluminium tube, preferably squeezable or collapsible aluminium tube, or aluminium slug, characterized in that the aluminium tube or aluminium slug is made of > 90 % by weight, in particular > 95 % by weight, preferably > 97 % by weight, more preferably > 99 % by weight, of aluminium scrap, based on the total weight of the aluminum tube or aluminium slug.

15. The method according to claim 13 or the aluminium tube, preferably squeezable or collapsible aluminium tube, according to claim 14 or aluminium slug according to claim 14, further characterized by the features of the characterizing portion of at least one of claims 3 to 13.