JP6534494B2 - High-speed blow molding process for forming aluminum containers using high recycle content 3XXX alloy - Google Patents

Description

  The present disclosure provides a high speed blow molding process for forming aluminum containers using high recycle content 3xxx can stock.

This application claims the benefit of US Provisional Patent Application No. 62 / 166,212, filed May 26, 2015, which is incorporated herein by reference in its entirety.

  Metal cans are well known and are also widely used for beverages. Conventional beverage cans generally have a simple upstanding cylindrical sidewall. However, for aesthetic reasons, consumer appeal and / or product identification, different, more complex shapes may be provided to the side walls and / or the bottom of the metallic beverage container, in particular other than the common cylindrical can shape. It may be desirable to provide a metal container with a bottle shape.

  Methods for pressing metal containers from preforms are known in the art, for example as described in US Pat. No. 8,683,837. However, there is a need for rapid production of aluminum containers using high recycle content metals.

  The methods described herein provide an effective high speed blow molding process for forming aluminum containers using high recycle content conventional 3xxx can stock alloys. For example, the method can be performed on an alloy having a recycle content reaching 50% to 100% by weight.

  The terms "invention", "the invention", "this invention", and "the invention" as used in this document broadly refer to all the subject matter of the present patent application and the claims which follow. Is intended. It is to be understood that the description, including these terms, does not limit the subject matter described herein, or limit the meaning or scope of the claims which follow. The embodiments of the present invention to be covered are defined by the claims, not by the summary of the invention. The summary of the invention is a summary of various aspects of the invention, and introduces some of the concepts further described in the Detailed Description below. The summary of the present invention is not intended to identify important or necessary features of the claimed subject matter, nor is it intended to be used alone to determine the scope of the claimed subject matter. The subject matter should be understood by reference to the entire specification, any or all drawings, and appropriate parts of each claim.

  The present disclosure provides a method for blow molding of high and low temperature 3xxx series aluminum of a fully and partially annealed aluminum alloy squeeze and iron (D & I) preform. The preform is generally a hollow workpiece having an opening opposite the closed end and a generally cylindrical wall. D & I preforms are preforms made by the D & I process.

  The preforms used in the methods described herein are typically about 2.5 inches (in) to about 3.0 inches in diameter, and about 10.0 inches to about 12.5 inches in height. , A wall thickness of about 0.006 inches to about 0.020, and a dome depth of about 0.400 to about 1.00 inches.

  The preforms used in the methods described herein can be coated or uncoated depending on the application. For example, conventional can coating systems can be used for the preforms. Conventional can coating systems comprise an inner spray, an ink and a top coat.

  The present disclosure provides a method for forming aluminum at temperatures ranging from ambient temperature (ie, about 18 ° C. to about 25 ° C.) up to about 300 ° C. and is also greater than the diameter of the original preform. Provides a method for expanding a preform to a 40% larger diameter. The present disclosure provides a method for low pressure molding operations operating at up to 420 psi (about 30 bar) using a single segmented mold.

  The method disclosed herein is commercially useful because it uses blow molding to expand preforms made by the D & I process. D & I processes are more efficient than alternative impact extrusion (IE) processes. The D & I process can be operated at a much faster production rate than the IE process, which makes the D & I process an economic option for high speed mass production plants. Furthermore, the D & I process can be performed on alloys with high recycling content. The IE process requires the use of high purity 1xxx series aluminum alloys, as the required deformation is quite large, which is not recycling friendly. Thus, the disclosed method is advantageous over conventional methods, at least in those conventional methods, as aluminum bottles are manufactured by impact extrusion (IE) processes.

  The blow molding method described herein uses high pressure gas to expand the aluminum preform to conform to the female mold. The disclosed method can also be applied to product lines using hydroforming which uses liquid instead of the gas used in blow molding.

  In some embodiments, the process for forming the aluminum container comprises: stamping a disc from a sheet of 3xxx series aluminum alloy; placing a preform in a mold cavity; Sequential steps of applying directional load to the preform and injecting inert gas into the interior of the preform with sufficient pressure until the preform expands and fills the mold cavity including. Optionally, the sheet has a thickness in the range of about 0.0150 in to about 0.0250 in. Optionally, the disc has a diameter in the range of about 6.0 inches to about 9.5 inches.

  In some embodiments, the preform is heated to the molding temperature prior to injecting the inert gas. In some cases, the molding temperature is about 200 ° C to about 300 ° C. In some cases, the molding temperature is about 250 ° C. to about 255 ° C., or a nominal 250 ° C. When the process involves heating the preform to the forming temperature, heating can be performed while the preform is under axial load. That is, heating can be performed while an axial load is applied. Axial loading prevents the preform from expanding axially, but axial loading does not compress the preform (ie does not reduce its length).

The inert gas is injected after reaching a preset axial load. In some embodiments, the axial load that is set in advance, in the range of about 100~250lb / ft ^2. As the preform expands, the axial load decreases so that the injected gas applies pressure to the preform at a controlled rate.

  In some embodiments, the preform can be annealed prior to being placed in the mold cavity. In some cases, the annealing temperature is about 100 ° C to about 400 ° C. In some cases, the annealing temperature is about 300 <0> C to about 400 <0> C.

  Also included within the scope of the present disclosure are aluminum bottles made by any of the methods disclosed herein.

  The flexibility of the method disclosed herein enables products of elaborate design in the aluminum bottle market, which may be difficult with other aluminum forming methods, such as mechanical forming.

FIG. 7 is an illustration of a mold cavity according to the methods described herein. FIG. 1 is a schematic view of a blow molding process according to the methods described herein. FIG. 7 is a graph of molding parameters of an expanded D & I preform for filling a mold during a high speed blow molding process.

  The methods described herein provide shaped aluminum bottles from conventional 3xxx can stock alloys with recycle content up to 100%. In some cases, the method produces a preform having a wall, a closed end, and an opening by a D & I process, and expanding the preform into a molded container by high speed blow molding. Including.

  By way of example and not limitation, the disc is stamped from an aluminum sheet. The blank can be shaped by any method known in the art such as punching or cutting. In one embodiment, the outer cutting tool is about 0.0150 in to about 0.0250 in (eg, 0.0150 in to 0.0200 in, 0.0180 in to 0.0200 in, 0.0180 in to 0.0250 in, or 0. The 3xxx series aluminum sheet having a thickness in the range of 0200 in-0.0250 in) is cut into discs and the discs are immediately drawn into cups. The disc can be drawn into a cup by an inner cup forming tool. Cutting and drawing are performed by a double-acting press, in which the first operation cuts the disc and the second performs molding of the cup in a continuous motion. In order to provide sufficient material for aluminum bottles, including large aluminum bottles, the cut disk may be about 6.0 in to about 10.0 in (eg, for example, 6.0 in, 6.2 in, 6) .5 in, 6.7 in, 7.0 in, 7.2 in, 7.5 in, 7.7 in, 8.0 in, 8.2 in, 8.5 in, 8.7 in, 9.0 in, 9.2 in, 9.5 in , 9.7 inches, or 10.0 inches).

  The molded cup has a rather large diameter, which requires further work to reduce its size to smaller diameters and to facilitate subsequent work. This is achieved by the redrawing process. Suitable redrawing processes for the methods described herein include, for example, direct redrawing, where the process is from the inside of the cup base by using a similar cup forming tool The cup is drawn to reduce its diameter and displace the material to form a higher cup wall. Another suitable redrawing process for use in the method described herein is reverse redrawing, which involves drawing the cup from the bottom of the cup and folding the metal in the opposite direction And mold the cup wall higher. The methods disclosed herein can include any of these preform redraw processes, but are not limited to these redraw processes. Depending on the machine requirements, limitations, and process requirements, there may be multiple redrawing processes or combinations of redrawing processes.

  When the cup is drawn to the diameter of the final bottle preform, the ironing tool stretches and thins the cup wall to achieve the final preform wall thickness and length. At the end of the D & I process, a dome processing operation is performed in which the bottom of the preform, i.e. the dome profile, is formed. When used in the blow molding process described herein, the final preform may be about 2.0 to about 3.5 inches (e.g., 2.0 inches to 3.0 inches, or 2.5 inches to 3.times.). It may have a diameter in the range of 5 in) and may be about 10.0 in to about 12.5 in (e.g., 10.0 in, 10.5 in, 11.0 in, 11.5 in, 12.0 in, or 12.5 in) ) Can be about the height. The preform walls range from about 0.006 to about 0.020 (e.g., 0.006 in, 0.007 in, 0.008 in, 0.009 in, 0.010 in, 0.012 in, 0.014 in, Have a thickness of 0.016 in, 0.018 in, or 0.020 in). In some cases, the preform can have a constant wall thickness of about 0.010 in to about 0.020 (e.g., 0.012 in, 0.014 in, 0.016 in, 0.018 in). In other cases, the bottle preform has various wall thicknesses and is about 0.010 in to about 0.020 in (eg, 0.010 in, 0.012 in, 0.014 in) at the thicker portion of the top , 0.016 in, 0.018 in, 0.020 in), and in the central thinner part, about 0.006 in to about 0.012 in (eg, 0.006 in, 0.007 in, 0.008 in, 0) .009 in, 0.010 in, 0.012 in). The preform dome has a depth of about 0.400 in to about 1.00 in (e.g., 0.400 in, 0.500 in, 0.600 in, 0.700 in, 0.800 in, 0.900, 1.00 in) Have.

  During the molding process of the preform, the preform may be subjected to an optional annealing operation, the temperature is about 100 ° C. to about 400 ° C. (eg, 100 ° C. to 300 ° C., 100 ° C. to 200 ° C. , 200 ° C. to 400 ° C., 200 ° C. to 300 ° C., or 300 ° C. to 400 ° C.), and the duration time is about 1 minute to about 3 hours (eg, 1 minute to 1 hour, 1 minute to 30 minutes) 5 minutes to 20 minutes, 1 hour to 3 hours, 2 hours to 3 hours, or 1 hour to 2 hours). An annealing process can be performed to improve the formability of the metal. In certain cases, the annealing process may have a duration ranging from about 1 hour to about 3 hours. In other cases, the annealing process may range from about 1 minute to about 30 minutes. An annealing operation can be added during the production of the aluminum sheet or during the production process of one or more preforms. The annealing process can be applied locally to specific parts of the preform. For example, the annealing process can be applied to the neck portion of the bottle, to the body portion of the bottle, to the base of the bottle, or any combination thereof. The annealing process can also be applied to selective portions of the aluminum sheet prior to processing it into a preform. Thus, a gradient of mechanical properties is induced along the height of the sidewall of the preform. Alternatively, the annealing step can be applied as an intermediate step of the continuous operation of neck processing and shaping processing.

  In some embodiments, the method provides a high speed blow molding process for forming D & I preforms of conventional 3xxx can stock alloys with high recycle content. Recycle content may be present in amounts up to 100% by weight of the alloy. In some cases, the recycling content is 50 wt% to 100 wt% of the alloy (e.g., 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%) , 85 wt%, 90 wt%, 95 wt%, or 100 wt%).

  In one embodiment, a standard AA3104 can stock alloy is used. Other non-limiting alloys that can be used in the methods disclosed herein are AA3003, AA3004, AA3105, and AA3204.

  In one non-limiting example, the preform is optionally annealed in a box furnace prior to blow molding. After optional annealing, the preform is placed in the mold cavity for blow molding. The mold cavity typically has a major axis. The preform also has a longitudinal axis and is disposed substantially coaxially within the mold cavity. Optionally, the mold cavity is a part of a split mold, ie a mold made of two or more mating segments separable for the removal of molded containers, around the periphery of the mold cavity It is. With respect to the split mold, the defined shape may be asymmetric about the longitudinal axis of the cavity.

  In one embodiment, the high speed blow molding process uses a surrounding or heated mold cavity. In the case of a heated mold cavity, the temperature of the mold cavity is about 5 ° C. to 10 ° C. (eg, 5 ° C., 6 ° C., 7 ° C., 8 ° C., 9 ° C., or 10 ° C.) from top to bottom of the preform. A controlled temperature gradient can be used to vary. In practice, the top and bottom of the mold cavity are heated to a temperature of about 200 ° C. to 300 ° C. (eg, 200 ° C., 220 ° C., 240 ° C., 260 ° C., 280 ° C., or 300 ° C.) and the bottom is 5 ° C. to 10 ° C. higher than the top. In some embodiments, the mold apparatus includes a split mold having two halves (left and right), a backing ram (bottom) and a preform seal (top). In addition to the heated mold cavity, the backing ram and preform seal can also be heated. When the backing ram and seal are heated, the backing ram is generally about 215 ° C. to about 335 ° C. (215 ° C., 225 ° C., 235 ° C., 245 ° C., 255 ° C., 265 ° C., 275 ° C., 285 ° C., 295 ° C. Heated to a temperature of 305 ° C., 315 ° C., 325 ° C., or 335 ° C., and the preform seal is generally, for example, about 180 ° C. to 320 ° C. (eg, (200 ° C., 220 ° C., 240 ° C., 260 ° C., 280 ° C., 300 ° C., or 320 ° C.). FIG. 1 is a schematic view of a mold cavity showing one half of a split mold 110 and a backing ram 120.

FIG. 2 is a schematic view of the blow molding process. During the blow molding process, the mold cavity 210, the backing ram 220, and the preform seal 230 surround the preform 240, as shown in panel A of FIG. As shown in panel B of FIG. 2, the backing ram 220 places an axial load indicated by the arrow 250 on the preform 240 while the preform 240 is heated to its molding temperature . Axial load is typically in ^the range of ^{100lb / ft 2 ~250lb / ft 2} ( ^{e.g., 100lb / ft 2, 125lb /} ft 2, 150lb / ft 2, 175lb / ft 2, 200lb / ft 2, 225lb / Ft ² or 250 lb / ft ² ). The backing ram 220 loads the preform 240 but there is no significant compression or reduction in length of the preform. The displacement of the backing ram 220 is about 0 in to about 0.050 in (e.g., 0.025 to 0.05 in). The backing ram 220 is essentially stationary when placed in contact with the preform dome and during the molding process.

  Once the forming temperature is reached, as shown in panels C and D of FIG. 2, the preform 240 is an inert gas such as nitrogen until the preform 240 expands and completely fills the mold cavity 210. Pressurized at 260. Blowing pressure is applied to the preform at a controlled rate. As the preform 240 expands, the axial load decreases.

  In one non-limiting example, for a nominal temperature of 250 ° C. preform, the upper part of the mold cavity is heated to 250 ° C. and the lower part of the mold cavity is heated to 255 ° C. . The seal is heated to 250 ° C. and the backing ram is heated to 275 ° C. During the molding process, four parts (i.e., two halves of the mold, backing ram and seal) surround the preform. An axial load of about 200 lb / ft is placed on the preform while the preform is heated to its molding temperature. Once the molding temperature is reached, the preform is pressurized with nitrogen until the mold cavity is filled.

  Optionally, the blow molding process can be carried out at ambient temperature, ie without heating the mold apparatus. When molding under ambient temperature conditions, for example 23 ° C., the preform is pressurized with an inert gas as soon as a preset axial load is reached. The pressure rate is about 1 second and the pressure is held until the blow molded preform completely fills the mold cavity.

  The expansion of the split mold increases to a diameter that is up to 40% (e.g., 15%, 20%, 25%, 30%, 35%, or 40%) larger than the original diameter. The molding temperature is ambient temperature, for example, in the range of 23 ° C. to about 300 ° C. (eg, 23 ° C. to 100 ° C., 23 ° C. to 200 ° C., 100 ° C. to 300 ° C., or 200 ° C. to 300 ° C.).

  FIG. 3 is a graph showing the evolution of molding parameters over time as the D & I preform is expanded relative to a linear wall mold in a high speed blow molding process. The fully molded bottle had a 40% expansion (up to 2.933 of the final diameter). The bottle is molded at a nominal temperature of 250 ° C., with a temperature gradient of 5 ° C. from top to bottom of the preform, ie the temperature at the top of the preform is 250 ° C. The temperature at the bottom was 255 ° C. As shown in FIG. 3, the entire molding process to make a straight walled container took about 5 seconds.

  The shaped aluminum containers described herein can be used for beverages including, but not limited to, soft drinks, water, beer, wine, nutritional drinks, and other beverages.

  All patents, publications and abstracts mentioned above are hereby incorporated by reference in their entirety. It is to be understood that what has been described above relates only to the preferred embodiments of the present invention, and that numerous modifications or alterations may be made in the embodiments without departing from the spirit and scope of the present invention. .

Claims (19)

A method for forming an aluminum container, comprising
Punching a disc from a 3xxx series aluminum alloy sheet,
Shaping the preform of the bottle by drawing, redrawing, ironing and doming the disc;
Placing the preform of the bottle in a mold cavity;
Applying an axial load to the preform of the bottle, wherein the application of the axial load does not reduce the length of the preform;
Injecting an inert gas into the interior of the bottle preform by pressure until the bottle preform expands to fill the mold cavity.   The method of claim 1, wherein the sheet has a thickness in the range of 0.0150 inches to 0.0250 inches.   The method of claim 2, wherein the sheet has a thickness in the range of 0.0180 inches to 0.025 inches.   4. The method of claim 3, wherein the sheet has a thickness in the range of 0.0200 inches to 0.025 inches.   5. A method according to any of the preceding claims, wherein the disc has a diameter in the range of 6.0 in to 10.00 in.   6. The method of claim 5, wherein the disc has a diameter in the range of 6.0 in to 7.0 in.   6. The method of claim 5, wherein the disc has a diameter in the range of 8.0 in to 9.50 in.   8. A method according to any of the preceding claims, further comprising heating the bottle preform to a forming temperature prior to injecting the inert gas.   The method according to claim 8, wherein the molding temperature is 200 ° C to 300 ° C.   The method according to claim 9, wherein the molding temperature is 250 ° C to 255 ° C.   The preform of the bottle has a top and a bottom, and the molding temperature comprises a temperature gradient from the top to the bottom of the preform, the molding temperature of the bottom of the preform The method according to claim 8, wherein the temperature is 5 ° C to 10 ° C higher than the molding temperature of the top of the preform.   A method according to any of claims 8 to 11, wherein the heating is performed while the axial load is applied.   13. A method according to any of the preceding claims, wherein the inert gas is injected after reaching a preset axial load.   The method according to any of the preceding claims, wherein said 3xxx alloy is selected from the group consisting of AA3104, AA3003, AA3004, and AA3105.   15. A method according to any of the preceding claims, wherein the 3xxx alloy comprises at least 50% by weight recycled material.   The method according to any of the preceding claims, further comprising fully or partially annealing the bottle preform prior to placing the bottle preform in the mold cavity.   The method according to claim 16, wherein the annealing temperature is 100C to 400C.   The method of claim 17, wherein the annealing temperature is 300 ° C. to 400 ° C. The preform of said bottle is
2.5in to 3.0in diameter,
10.0in to 12.5in height,
The method according to any of the preceding claims, having a wall thickness of 0.006 "to 0.020" and a dome depth of 0.400 "to 1.00".

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