Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D51/00—Making hollow objects
  • B21D51/16—Making hollow objects characterised by the use of the objects
  • B21D51/38—Making inlet or outlet arrangements of cans, tins, baths, bottles, or other vessels; Making can ends; Making closures
  • B21D51/44—Making closures, e.g. caps
  • B21D51/50—Making screw caps
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
  • B21D22/20—Deep-drawing
  • B21D22/28—Deep-drawing of cylindrical articles using consecutive dies
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D41/00—Caps, e.g. crown caps or crown seals, i.e. members having parts arranged for engagement with the external periphery of a neck or wall defining a pouring opening or discharge aperture; Protective cap-like covers for closure members, e.g. decorative covers of metal foil or paper
  • B65D41/02—Caps or cap-like covers without lines of weakness, tearing strips, tags, or like opening or removal devices
  • B65D41/04—Threaded or like caps or cap-like covers secured by rotation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D41/00—Caps, e.g. crown caps or crown seals, i.e. members having parts arranged for engagement with the external periphery of a neck or wall defining a pouring opening or discharge aperture; Protective cap-like covers for closure members, e.g. decorative covers of metal foil or paper
  • B65D41/62—Secondary protective cap-like outer covers for closure members

Definitions

• the invention relates to the field of stopper caps comprising a metal outer shell made of aluminum alloy and in particular screw caps having a long skirt such that when the cap is unscrewed, the bottom of the skirt remains in place on the neck of the bottle.
• These capsules are intended for sealing containers, essentially glass bottles containing alcoholic beverages and in particular wine or spirits.
• the invention relates more particularly to a method of manufacturing these capsules making it possible to obtain capsules having a skirt of thickness less than the thickness of the blank and constant over its entire length, as well as a skirt having a layer of varnish. interior and exterior continuous and intact along the entire length of the skirt.
• Aluminum alloy sealing caps are typically manufactured as follows:
• a stamping press forms capsule blanks from a strip or sheet also called format, cut into blanks, varnished on both sides, with a typical thickness ranging from 0.15 to 0.25 mm without taking counts the thickness of the varnish.
• a typical thickness ranging from 0.15 to 0.25 mm without taking counts the thickness of the varnish.
• one to three stamping passes may be required.
• the long capsules are obtained by a process comprising several stamping passes.
• these successive stamping passes result in a capsule whose thickness of the skirt is irregular.
• This irregularity can cause problems when using the capsule, for example, sometimes making it more difficult or sometimes too easy for the user to break the bridge line.
• the bridge line is the line along which the cap breaks when a user spins it around to open the bottle. The aim is to obtain a capsule that is more reliable on opening, for which the opening torque is less variable and more reproducible.
• Some capsules can be obtained by a stamping step followed by a stretching step, but they are not long capsules and the process for obtaining them seeks to solve a particular problem:
• the varnish be added before the stamping and drawing steps.
• the varnish applied before stamping and stretching retains its integrity over the entire surface of the capsule, and in particular over the entire length of the skirt of the capsule, inside and out. the outside of the capsule.
• the present invention has multiple advantages: making the thickness of the skirt uniform over its entire height by minimizing the quantity of material used, or by allowing the manufacture of taller capsules without increasing the quantity of material, while guaranteeing good mechanical properties and a continuous and intact varnish layer along the entire length of the capsule skirt.
• the invention aims to solve the problem of compromise between the regularity of thickness of the skirt of the capsule while ensuring the integrity of the varnish applied before stamping and stretching over the entire length of the skirt, and while guaranteeing good mechanical properties of the skirt, by proposing a process that can be carried out under industrially economical conditions for the market for long caps for capping beverage bottles.
• the invention relates to a method of manufacturing metal closure caps comprising the following successive steps:
• a stamping step in one or more passes, preferably at least two passes, more preferably two or three passes, even more preferably two passes, of said blanks, preferably using a stamping lubricant , so as to form a stamped blank, comprising a head and a skirt;
• a drawing step consisting in passing the stamped blank through at least one drawing ring in order to lengthen the metal and thin it, so as to form a capsule comprising a head preferably having a diameter of 20 to 40 mm, more preferably 25 to 35 mm, a skirt preferably having a length of 40 to 85 mm, more preferably 40 to 83 mm, even more preferably 40 to 80 mm, even more preferably 40 at 70 mm, and even more preferably from 45 to 65 mm, the top of the capsule being on the side of the head and the bottom of the capsule on the side where the skirt ends, the skirt having a constant thickness of 0.12 to 0 , 27 mm, preferably 0.15 to 0.25 mm, over at least 20% of its length from the bottom of the capsule, and preferably up to 60% of its length from the bottom of the capsule , and comprising a continuous and intact layer of varnish over the entire length of the skirt, both inside and outside the capsule; d) an optional step of degreasing said capsule;
• the subject of the invention is also a metal closure cap manufactured by the method according to the present invention, which comprises a head, a skirt, the top of the cap being on the side of the head and the bottom of the cap on the side where the skirt ends, characterized in that the thickness of its skirt is constant over at least 20% of its length starting from the bottom of the capsule (and preferably up to 60% of its length starting from the bottom of the capsule) and is 0.12 to 0.27 mm, preferably 0.15 to 0.25 mm, and in that it comprises a continuous and intact layer of varnish along the entire length of the skirt, inside as on the outside of the capsule, the head of the capsule preferably having a diameter of 20 to 40 mm, more preferably 25 to 35 mm, and the skirt of the capsule preferably having a length of 40 to 85 mm, more preferably from 40 to 83 mm, even more preferably from 40 to 80 mm, even more preferably from 40 to 70 mm, and even more preferably entirely from 45 to 65 mm.
• the invention also relates to a punch for stamping and stretching an aluminum alloy blank, characterized in that it has two different diameters along its length, a first diameter DI corresponding to the part of the punch coming into contact first. with the metal to be stamped and then drawn and a second diameter D2 corresponding to the part of the punch coming into second contact with the metal to be stamped and then drawn, the two parts having different diameters being connected to each other by a conical transition part , the first diameter DI being less than the second diameter D2, the difference in diameter between DI and D2 being from 0.02 to 0.1 mm, preferably from 0.03 to 0.07 mm.
• Figure 1 is a diagram of a long capsule.
• Reference 1 represents the molding
• reference 2 the bridge line
• reference 3 the crimping line
• reference 4 the capsule
• reference 5 the head of the capsule
• reference 6 the skirt of the capsule, which includes a upper part (reference 7) and a lower part (reference 8).
• FIG. 2 is a graph illustrating the evolution of the thickness of a capsule as a function of the part of the capsule considered.
• the abscissa axis corresponds to the curvilinear abscissa, that is to say the distance from the center of the head of the capsule (0) to the ends of the skirt (-40 and 40), in mm.
• the ordinate axis corresponds to the metal thickness, in pm.
• the Caps.l reference corresponds to a capsule after stamping alone.
• References Caps. 2 and Caps.3 correspond to two capsules after stamping and stretching according to the process of the present invention.
• FIG. 3 shows an advantageous punch according to the present invention.
• the reference L represents the total length of the punch, the reference DI the first diameter and the reference D2 the second diameter, as described below.
• the numerical values are given by way of example.
• the references A and B represent section planes.
• Figure 4 shows a draw ring as used in the examples.
• D corresponds to the diameter of the drawing rings given in the table of examples.
• Figure 5 is a photo of the capsules produced according to the example.
• Figure 6 is a micrograph of a section of varnished metal before stamping and drawing, as used in the example below.
• Reference 9 corresponds to the aluminum alloy
• reference 10 to the exterior varnish of a first sample
• reference 11 to the interior varnish of another sample
• reference 12 to the resin in which the samples were coated.
• the subject of the invention is a method for manufacturing metal closure caps comprising the following successive steps:
• a stamping step in one or more passes, preferably at least two passes, more preferably two or three passes, even more preferably two passes, of said blanks, preferably using a stamping lubricant , so as to form a stamped blank, comprising a head and a skirt;
• a drawing step consisting in passing the stamped blank through at least one drawing ring in order to lengthen the metal and thin it, so as to form a capsule
• a head preferably having a diameter of 20 to 40 mm, more preferably 25 to 35 mm
• a skirt preferably having a length of 40 to 85 mm, more preferably 40 to 83 mm, even more preferably 40 to 80 mm, even more preferably 40 at 70 mm, and even more preferably from 45 to 65 mm
• the top of the capsule being on the side of the head and the bottom of the capsule on the side where the skirt ends
• the skirt having a constant thickness of 0.12 to 0 , 27 mm, preferably 0.15 to 0.25 mm, on at at least 20% of its length from the bottom of the capsule (and preferably up to 60% of its length from the bottom of the capsule), and comprising a continuous and intact layer of varnish along the entire length of the skirt , inside and outside the capsule;
• the strip or sheet of step a) is coated on both sides with a single layer of varnish.
• the blank has a thickness of 0.15 to 0.35 mm without taking into account the varnish.
• the blank has a diameter of 80 to 96 mm.
• the blank can have two different diameters.
• the blank may have a diameter of 90 to 96 mm, which corresponds to what is usually practiced in the field of long capsules.
• This variant can make it possible to produce capsules that are longer than what is usually practiced in the field of long capsules, for example from 60 to 105 mm. The additional length can thus be cut and then recycled.
• the advantage of the present invention here is to make it possible not to change all the production tools while allowing recovery of the metal not used to produce capsules of the same length but having a lower thickness than what is usually practiced in the field of long capsules.
• the blank may have a diameter of 80 to 92 mm, which corresponds to a diameter smaller than what is usually practiced in the field of long capsules.
• This variant can make it possible to produce capsules of the same length as what is usually practiced in the field of long capsules, for example from 40 to 70 mm.
• the advantage of the present invention here is to allow a saving of metal to produce capsules of the same length but having a lower thickness than what is usually practiced in the field of long capsules.
• the inventors have determined a formula, which could for example serve as a tool on an industrial scale, to make it possible to determine, with a margin of error of +/- 0.1 mm, the diameter D of the starting blank as a function of the diameter B and the height H of the capsule, as well as the initial metal thickness E0, the thickness of the skirt of the capsule after stretching E and the stretching rate Red.
• the stretch ratio Red is equal to 1- (E / E0).
• the formula is based on the relationship saying that the volume of metal of the starting blank (E0.nD 2/4) equals the volume of metal in the final capsule ([E0. PB 2/4] + [H. pBE]). Note that E is equal to E0. (L-Red).
• the formula is then the following, after simplification:
• D is the diameter of the starting blank in mm
• B is the diameter of the capsule in mm
• H is the height of the capsule in mm
• Red is the stretch ratio
• the stamped blank is axisymmetric in an axial direction of said blank.
• the stamped blank has a diameter of 27 to 31 mm and / or a thickness of 0.15 to 0.35 mm.
• the term “constant thickness” is understood to mean when the variation in thickness over the height of the skirt is less than 5%, preferably less than 3% relative to the total thickness of the skirt without counting the varnish. .
• the variation in thickness over the height of the skirt after stamping is generally about 20% relative to the total thickness of the skirt.
• the minimum stretching rate is justified by the fact that the latter must at least bring the thickness of the whole of the skirt substantially uniformly to the value of the minimum thickness locally obtained after stamping.
• the latter depends on the stamping conditions (roughness of the tool, play, pressure of the clamp, lubrication).
• the stamping step thickens the skirt, in a non-uniform manner over the length of the skirt (see Figure 2). Therefore, the thickness of the skirt of a stamped blank, after stamping and before stretching, is variable over the length of the skirt, and generally increasing from the head of the blank to the bottom of the skirt. The thickness of the skirt of a stamped blank, regardless of the length considered, is generally greater than the initial thickness of the blank before stamping.
• the sheet, the strip and the blank have the same thickness, that is to say the initial thickness E0.
• a stretch rate can be negative, equal to 0% or positive.
• a stretch rate of 0% means that the initial thickness of the blank is found uniformly at the level of the skirt.
• a negative draw ratio means that the thickness of the skirt is made uniform by the stretching step but without reducing this thickness to the same level as the initial thickness of the blank.
• a positive stretch rate means that the thickness of the skirt is made uniform by the stretching step by reducing this thickness to a level below the initial thickness of the blank.
• the degree of stretching is preferably greater than or equal to 0%, that is to say that the initial thickness of the blank is found at least. According to the most common mode, the degree of stretching (1 - final thickness E / initial thickness E0 of the sheet or of the strip or of the blank) is preferably greater than or equal to 2.5%.
• the maximum stretching rate is linked to the stretch limit before breaking (of the metal and / or of the varnish), intrinsic to the aluminum alloy / varnish complex, which must not be exceeded when drawing the bottom of the skirt, the thickest area after stamping.
• the maximum industrially accepted stretching rate is 40%.
• a maximum stretching rate of approximately 30% is then obtained to take account in particular of the limits of the varnish.
• the stretching rate is less than or equal to 30%.
• the varnish is drawable, that is to say that it is not damaged during stamping and stretching, and that it remains present and of good quality over the entire surface of the capsule, from head to skirt.
• the varnish is expected to form a continuous and intact layer along the entire length of the skirt, inside and out, even after stamping and stretching.
• the interior varnish that is to say that applied to the side of the blank which will become the interior of the capsule, can be an acrylic varnish, preferably having a basis weight of 2 to 6 mg / m 2 , more preferably from 3 to 5 mg / m 2 .
• This interior varnish should generally be suitable for food contact. It can be applied, for example, in a thickness of 1 to 6 ⁇ m, preferably 2 to 5 ⁇ m. Its color can for example be golden, silver or white.
• the exterior varnish that is to say that applied to the side of the blank which will become the exterior of the capsule, can be a polyester varnish, preferably having a basis weight of 3 to 17 mg / m 2 , more preferably from 4 to 16 mg / m 2 .
• This outer varnish can be applied, for example, in a thickness of 4 to 12 ⁇ m, preferably 5 to 11 ⁇ m. Its color can for example be golden, silver or white.
• a lubricant can be used for the stamping step.
• the lubricant is preferably volatile and removed by heating.
• the same applies to the lubricant used for drawing which, advantageously, is volatile and removed by heating, typically in a pass-through oven or in an oven.
• the same lubricant can be used for both stamping and drawing stages.
• the optional degreasing step is intended to remove the lubricant remains, to form a degreased capsule capable of being optionally varnished.
• Degreasing can be carried out using any known method.
• the degreasing can be thermal or chemical, preferably thermal.
• Thermal degreasing can for example be carried out in an oven.
• the temperature of the thermal degreasing is preferably 180 to 210 ° C.
• the duration of the thermal degreasing is preferably 3 to 5 min.
• This degreasing step is optional, because it is mainly useful in the case where the process comprises a printing and / or varnishing step. Also, generally, either both stages are present or both stages are absent.
• the method does not include steps d) of degreasing and e) of printing and / or varnishing.
• the stamping and drawing steps are linked without any other intermediate step. Even more advantageously, the last stamping step and the drawing step are carried out in one and the same press stroke.
• the aluminum alloy can be, but not exclusively, of the type AA3105 or of the type AA8011.
• the subject of the invention is also a metal closure cap manufactured by the method according to the present invention, which comprises a head and a skirt, the top of the cap being on the side of the head and the bottom of the cap on the side where the skirt ends, characterized in that the thickness of its skirt is constant over at least 20% of its length starting from the bottom of the capsule and is 0.12 to 0.27 mm, preferably 0.15 to 0 , 25 mm, and in that it comprises a continuous and intact layer of varnish over the entire length of the skirt, both inside and outside the capsule.
• the thickness of the skirt of the capsule is constant up to 60% of its length starting from the bottom of the capsule.
• the diameter of the head of the capsule is 20 to 40 mm, more preferably 25 to 35 mm.
• the length of the skirt of the capsule is 40 to 85 mm, more preferably 40 to 83 mm, even more preferably 40 to 80 mm, still more preferably 40 to 70 mm, and even more preferably 45 to 65 mm.
• the capsule according to the present invention has all the characteristics presented in connection with the process according to the present invention.
• the capsule is axisymmetric in an axial direction of said capsule.
• the capsule comprises a head having a thickness corresponding to the initial thickness of the blank, that is to say generally from 0.15 to 0.35 mm.
• the method according to the present invention uses a punch for the stamping / drawing step, the punch having two different diameters along its length, a first diameter D1 corresponding to the part of the punch coming into contact first.
• the two parts having different diameters being connected together by a tapered transition part , the first diameter D1 being smaller than the second diameter D2, the difference in diameter between D1 and D2 being 0.02 to 0.1 mm, preferably 0.03 to 0.07 mm.
• the first diameter D1 and the second diameter D2 are preferably 19 to 39.6 mm.
• the part having the diameter D1 preferably represents 25 to 35% of the height of the punch.
• the part having the diameter D2 is preferably 60 to 70% of the height of the punch.
• the transition portion is preferably 3 to 7% of the height of the punch.
• the length L of the punch is, in a manner known to those skilled in the art, to be adapted with respect to the length of the desired skirt.
• D1 may be about 29.53mm, D2 about 29.58mm, and the transition portion about 5mm.
• the part having the diameter D1 in this case represents approximately 28.9% of the height of the punch.
• This variant would make it possible to vary the thickness of the skirt of the capsule, the top of the skirt having a greater thickness than that of the bottom of the skirt.
• the top of the skirt has a thickness of 0.15 to 0.35 mm, more preferably 0.12 to 0.27 mm, and the bottom of the skirt has a thickness of 0.12 to 0.27 mm, knowing that the thickness of the top of the skirt is greater than the thickness of the bottom of the skirt.
• the greater thickness of the upper part of the skirt would make it possible to guarantee good mechanical resistance for the realization of the possible molding, the line of bridge and the line of crimping, as well as good mechanical resistance when the bottle is opened by the end user.
• the invention also relates to a punch for stamping and stretching an aluminum alloy blank, characterized in that it has two different diameters along its length, a first diameter DI corresponding to the part of the punch coming into contact first. with the metal to be stamped and then drawn and a second diameter D2 corresponding to the part of the punch coming into second contact with the metal to be stamped and then drawn, the two parts having different diameters being connected to each other by a conical transition part , the first diameter DI being less than the second diameter D2, the difference in diameter between DI and D2 being from 0.02 to 0.1 mm, preferably from 0.03 to 0.07 mm.
• the first diameter DI and the second diameter D2 are preferably 19 to 39.6 mm.
• the part having the diameter DI is preferably 25 to 35% of the height of the punch.
• the part having the diameter D2 is preferably 60 to 70% of the height of the punch.
• the transition portion is preferably 3 to 7% of the height of the punch.
• ID may be approximately 29.53 mm, D2 approximately 29.58 mm and the transition part approximately 5 mm, the part having as diameter ID then representing approximately 28.9% of the height of the punch.
• Tests have been carried out in order to demonstrate the effectiveness of the process according to the present invention for obtaining capsules having a reduced skirt thickness while maintaining an intact layer of varnish over the entire length of the skirt of the capsule.
• it is in fact important that the varnish layer remains intact over the entire surface of the capsule, because said capsule is then generally subjected to a heat treatment, typically for 2 minutes at 160-180 ° C, and then to a print to decorate the walls of the capsule. If the varnish layer is not intact before these steps, the final capsule obtained will not meet the aesthetic criteria expected by the customer and the end user.
• the copper sulphate solution is composed of 50 g of copper sulphate (CuSC) in the form of crystals to be dissolved in 950 g of demineralized water, to which 20 ml of 36% hydrochloric acid are added. The whole is then mixed with a stirrer.
• CuSC copper sulphate
• the implementation of the test requires thermal degreasing.
• the capsules were then placed in a tank and immersed in the copper sulfate solution.
• the application time was 15 minutes. After this lapse of time, a simple observation with the naked eye makes it possible to see if the capsule has been attacked, each attack zone corresponding to a zone where there is no more varnish.
• the non-attacked areas are the same color as the original capsule, while the attacked areas are rust colored.
• the varnish layer is present and intact over the entire surface of the capsule.
• the blanks were varnished with a gold-colored varnish of the PPG-3117-3003 type for the interior of the capsules, and with a varnish as described in Table 1 below for the exterior of the capsules.
• the stamping step was carried out on said varnished blanks in order to obtain stamped blanks, with tools having the following characteristics (BUP 200): diameter of the punch of 33 mm and diameter of the stamping ring given in the Table 1 below.
• the lubricant was of the type known under the Klüber reference Paraliq P12 (colorless paraffin-based oil). It was deposited using an automatic device commonly used in capsule manufacturing plants. The blank holder pressure was adjusted so as to obtain a stamped blank without folds.
• the drawing step was carried out on the stamped blanks obtained according to the stamping step as described above, with tools having the following characteristics (BUP 200): diameter of the punch of 33 mm and diameter of the draw ring given in Table 1 below.
• the examples illustrate a possible reduction in the thickness of the skirt from 9 to 26%, while preserving the quality of the layer of varnish over the entire length of the skirt.
• These reductions in thickness can lead to a reduction in the quantity of metal of the order of 8 to 22%.
• various tests for manufacturing a capsule according to the present invention were carried out. They made it possible to obtain capsules whose skirt length was respectively 70 mm, 72 mm, 76.8 mm, 78.5 mm and even 78.7 mm.
• the tested sheets were cut. Several cuts have been made. For each cut, several samples were cut and stacked on top of each other.
• the tested capsules were cut longitudinally. Several longitudinal sections were made.
• FIG. 6 is a sample before stamping and stretching.
• the micrograph in Figure 6 shows that the observation of the different layers (interior and exterior varnish, metal and resin) and the measurement of the thickness of the exterior varnish can be done easily because the different layers are clearly visible and have a clear separation.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Closures For Containers (AREA)
• Containers Having Bodies Formed In One Piece (AREA)
• Shaping Metal By Deep-Drawing, Or The Like (AREA)

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• 2020
  • 2020-05-06 EP EP20723410.5A patent/EP3965977A1/de active Pending
  • 2020-05-06 US US17/609,184 patent/US20220324010A1/en active Pending
  • 2020-05-06 WO PCT/EP2020/062546 patent/WO2020225288A1/fr unknown
  • 2020-05-06 JP JP2021564692A patent/JP2022531588A/ja active Pending
  • 2020-05-06 MX MX2021012575A patent/MX2021012575A/es unknown

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