JP2004276068A - Method of manufacturing metallic can for aerosol container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily manufacture a metallic can for an aerosol container which is light in weight, is excellent in appearance and can suitably be fitted with a cap for covering a valve. <P>SOLUTION: In the case the metallic can for the aerosol container is manufactured by seaming and fixing a bottom cover made of another member on the side of the open end of the body part after forming the inclined shoulder part and the open curled part on the side of the bottom to a blind cylindrical seamless can the body part of which is thinned, an annular flat part 4 having an approximately horizontal plane is formed by pressing with an inner die inserted into the can from the side of the open end of the body part of the can 1 and an outer die which is arranged out of the can oppositely to the inner die before the bottom cover is seamed and fixed in the vicinity of the top of the shoulder part 3 which is extended without a seam from the body part 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a metal can for high pressure resistance used for an aerosol container provided with a valve for injection, and in particular, for such a metal container for an aerosol container, it is lightweight, has good appearance, and has a valve. The present invention relates to a method for manufacturing a metal can in which a cap for covering can be suitably mounted.
[0002]
[Prior art]
High pressure-resistant metal cans used for aerosol containers equipped with a valve component for injection, ie, an open curl portion for mounting the valve component for injection (an outer curl formed at an edge of the opening portion) Part), a metal can for an aerosol container provided with a bottom lid is fixedly fastened to a cylindrical welded can body (or a cylindrical seamless can with a bottom and a bottom integrally formed). On the other hand, there have been conventionally known many types in which a can lid of a separate member having an inclined shoulder portion and an opening curl portion is wound and fixed to the body opening end side (for example, Japanese Patent Publication No. Sho 42). No. 23119, Japanese Patent Publication No. 50-2443, Japanese Patent Publication No. 5-34063, etc.).
[0003]
In addition, for a bottomed cylindrical seamless can having a body and a bottom integrally formed, a type in which a body opening end side is integrally formed with a shoulder portion and an opening curl portion which are inclined, or a body. The bottom can be integrally molded into a shoulder and an open curl, and a bottom lid of another member can be wound around the open end of the body. Conventionally, a fixed type is also known (for the former type, see, for example, JP-A-3-8527, JP-A-9-39975, JP-A-2001-121230, etc. For the latter type, see, for example, JP-A-63-168238 and JP-A-1-180732.
[0004]
[Problems to be solved by the invention]
By the way, when examining each type of the metal can for the aerosol container as described above, a relatively small part is used for a type in which a can lid of a separate member having a shoulder portion and an opening curl portion is fastened and fixed. The shoulder and opening curl can be easily formed by pressing the can lid, and the shoulder and opening curl can be easily provided on the can simply by winding the can lid of another part. In addition, when the cap for covering the valve is attached, there is an advantage that the cap can be attached in a stable state by bringing the lower end of the cap into contact with the inside of the tightened portion of the can lid. However, since the canned portion of the can lid protrudes from the upper portion of the can, not only the appearance is poor, but also there is a problem that dust and dirt easily accumulate in the concave portion inside the canned portion.
[0005]
On the other hand, in the case of a cylindrical seamless can with a bottom and a body integrally formed with a bottom, the type in which the opening end side of the body is molded into a shoulder and an open curl, the upper end of the can Since there is no tightening part, the appearance is good and there is no accumulation of dust and dirt, but the neck opening end side of the can is gradually reduced in diameter by multiple neck-in processings Since it is necessary to mold the shoulder and the part to be later processed into the opening curl part, not only does the neck-in processing take many steps and time, but also such a large number of neck-in processings are required. Considering that, at least near the upper end of the body of the can, it is necessary to reduce the elongation of the material during the production of the seamless can (reduce the degree of work hardening). Need to be meat and can metal For even fee, practice is limited to processed easy aluminum-based metal.
[0006]
In addition, regarding the point that the wall thickness of the can becomes relatively thick, conventionally, there was a regulation on the wall thickness of the container (the wall thickness of the metal can is 0.215 mm or more) in the safety standard of the aerosol container. Although this was not a problem in itself, in recent years, the safety standards for aerosol containers have abolished the thickness control of containers, and if the strength can be sufficiently guaranteed, it has become free to reduce the thickness of containers. It has been desired to reduce the material cost by reducing the thickness of the can, thereby reducing the weight.
[0007]
In view of the inconvenience of winding the can lid of such a separate part and the demand for a thinner can, for example, it is described as an example in JP-A-63-168238. For such a seamless can that is formed into a cylindrical shape with a bottom by drawing and ironing, a type in which the bottom side is formed into a shoulder and an opening curl portion, the shoulder portion and the opening curl portion upward from the body. Is integrally molded and there is no wrapped part at the top of the can, so the appearance is good, there is no accumulation of dust and debris, and the bottom side of the can close to the original plate thickness is a shoulder And the opening curl, even if the body of the can is made thinner by drawing and ironing, the shaping of the shoulder and the opening curl is not restricted.
[0008]
On the other hand, the current safety standards for aerosol containers require that the valve be protected by a cap or the like.Therefore, when a cap for covering the valve is attached to the can, the shoulder and the opening curl are required. In the type in which the can lid of a separate member with a portion is wound and fixed, the lower end of the cap can be stably fixed by the wrapped portion of the can lid, but the type without such a wrapped portion For example, as described in Japanese Patent Application Laid-Open No. 2001-121230, an annular (ring-shaped) concave portion is formed near the lower end of the shoulder portion by a processing tool that is brought into contact with the can from the outside. It is necessary to fit the protrusion formed on the inner surface side (the tip inside the hem) near the lower end of the cap into the concave portion. Therefore, specifically, the shoulder portion is re-formed by a roll. It has been proposed further methods such as forming the groove by the tool from.
[0009]
However, in such a method in which an annular concave portion is formed by a processing tool that is brought into contact with the can from the outside, for example, a metal can for an aerosol container using an aluminum impact can conventionally conventionally commercialized is used. If the wall thickness of the can is relatively thick and it is easy to process, the annular recess may be able to be formed without any problem.However, a seamless can whose thickness is thinned by drawing and ironing etc. In the case of a metal can for an aerosol container in which the bottom side is molded into a shoulder portion and an open curl portion, the wall thickness of the can is sufficiently thin, and it is difficult to process it further. Even if the can has a pressure resistance enough to withstand the high internal pressure of the can, there is a risk that the can may be dented when a processing pressure is applied to the can only from the outside in the absence of the internal pressure of the can.
[0010]
An object of the present invention is to solve the above problems. Specifically, a method for manufacturing a metal can for an aerosol container is lightweight, has good appearance, and has a valve. It is an object of the present invention to easily and easily manufacture a can to which a cap for covering can be suitably attached.
[0011]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention forms a shoulder and an opening curl portion having a small diameter on a bottom side of a cylindrical seamless can having a thinner bottom. Then, a bottom cover of another member is wound and fixed to the opening end side of the body portion, thereby manufacturing a metal can for an aerosol container having an opening curl portion for mounting a valve component. An annular flat portion having a substantially horizontal surface is provided near the tip of a shoulder portion extending seamlessly from the body portion before being fixedly fastened to the inner portion of the can, which is inserted into the can from the body opening end side of the can. And an outer die arranged outside the can corresponding to the inner die.
[0012]
According to the method as described above, the body is thinned by drawing and ironing, etc., and, for a metal can in which the shoulder and the opening curl portion are seamlessly connected from the body, near the tip of the shoulder. In addition, an annular flat portion can be easily and easily formed, and by forming such an annular flat portion, it is possible to cover the valve against the opening curl portion after the valve component is mounted. By attaching the lower end of the cap to the flat portion when attaching the cap, the cap can be attached to the can in a stable state.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a method for manufacturing a metal can for an aerosol container of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a metal can for an aerosol container according to an embodiment of the method of the present invention, and FIG. 1 shows (A) the overall external shape of the can and (B) a longitudinal cross-sectional structure of an opening curl portion and a shoulder portion. FIG. 2 schematically shows an example of a manufacturing process of a can. FIG. 3 shows a shoulder portion and a small-diameter bottomed cylindrical portion (a portion which is later formed into an open curl portion) in the manufacturing process shown in FIG. FIG. 4 shows molds for forming an annular flat portion, and FIG. 5 shows a state when an annular flat portion is formed by each mold shown in FIG. It is.
[0014]
In a metal can for an aerosol container manufactured by the method of the present invention (an empty can before valve components are mounted), as shown in FIG. 1, a vertical cross section is formed upward from a large-diameter cylindrical body 2. An opening curl portion 5 curled into an outer winding is formed through an arc-shaped dome-shaped shoulder portion 3 and an annular flat portion 4 having a substantially horizontal surface formed near the tip (upper end) thereof. And is formed integrally so as to form an edge portion that annularly surrounds the periphery of the body portion, and is formed at the lower end opening end of the body portion 2 (a flange portion formed at the lower end opening end of the neck portion formed at the lower end of the body portion 2). , A bottom lid 6 of a separate member having a pressure-resistant shape concaved upward in a dome shape is fixedly fastened tightly, and not shown in the opening curl portion 5 at the upper end of the can. A valve component (opening) for injecting liquid stored in a high internal pressure can by opening Those assembled valve portion to the central portion of the lid portion of the lid) comes to be fixedly mounted by the lid portion.
[0015]
Regarding a method for manufacturing an empty metal can 1 in which such a valve component is not mounted, the method of the present embodiment is an application of a method for manufacturing a bottle-type can developed by the present applicant. The manufacturing process (the process of simply forming the shape of a can, omitting the description of printing and painting of the can, amorphization of the protective coating, removal of the lubricant, etc.) will be schematically described below.
[0016]
In the method of this embodiment, a metal plate material for cans such as a resin-coated metal plate in which a protective coating of a thermoplastic resin is laminated on both surfaces of a surface-treated steel plate or the like is used, and on both surfaces (on the resin film). After applying the lubricant, as shown in FIG. 2, first, in a cup forming step (1st press), a metal plate material is punched into a disk-shaped blank and drawn to form a shallow cup. In the next can body forming step (2nd press), the shallow cup is thinned by drawing and ironing (for example, at least one of redrawing and at least one of stretching and ironing). It is processed to form a cylindrical bottomed seamless can (a vertically long cup with one end open at the body) with a thinner body.
[0017]
In the top dome forming step (3rd press), a bottomed cylindrical portion having a smaller diameter than the body portion is formed on the bottom side of the seamless can whose thickness is reduced in the top dome forming step (3rd press). After forming a curved shoulder (curved surface at the lower part of the shoulder) with an arcuate longitudinal section, the second drawing (redrawing) is performed from the bottomed cylindrical part formed by the first drawing. After reshaping a small-diameter bottomed cylindrical portion and a tapered surface having a linear cross-sectional shape approximating an arc of a virtual curved surface following a shoulder curved surface, such re-drawing is performed one or more times (as shown in the drawing). After repeating the process twice), the plurality of shoulder tapered surfaces formed by approximating the shoulder curved surface are stretched into a smooth curved surface continuous with the shoulder curved surface, and the shoulder is re-formed. The whole is made into a dome-shaped curved surface and the tip of the shoulder Press forming a near flat portion of the annular.
[0018]
The top dome forming step (3rd press) will be described in more detail. First, as shown in FIG. 3 (A), with the bottom side of the seamless can (vertical cup) turned up, When performing the first drawing process, using a wrinkle holding tool (die 11 and pusher 12) having a curved surface that closely adheres to the lower part of the shoulder to be formed, the bottom corner portion of the can (vertical cup) By pressing the flat bottom with a punch 13 into a cylindrical shape with a bottom while pressing the wrinkles strongly, a bottomed cylindrical portion having a smaller diameter than the body of the can is formed, and a vertical section is formed below it. A surface is formed into an arcuate shoulder curved surface (curved surface below the shoulder).
[0019]
This shoulder curved surface is formed once by using one device having a wrinkle holding tool (die 11 and pusher 12) having a curved surface that is in close contact with the lower part of the shoulder and a punch 13 as described above. Is preferably performed from the viewpoint of preventing generation of wrinkles on the shoulder portion, the shortening of the manufacturing line and the miniaturization of the equipment, but in some cases, the top dome forming step (3rd press) is one step. The shoulder curved surface is formed in advance as an independent process before performing the second drawing process, or when forming a bottomed cylindrical seamless can in the can body forming process (2nd press). The first drawing process may be performed by the punch 13 in a state where the formed shoulder curved surface is wrinkled by the wrinkle pressing tool (die 11 and pusher 12).
[0020]
Next, as shown in FIG. 3 (B), the tapered portion having a cross-section linear shape approximated to a cross-section arc of an imaginary curved surface continuing above the shoulder curved surface is applied to the bottomed cylindrical portion drawn to a smaller diameter than the body portion. Using a wrinkle holding tool (a die 14 and a pusher 15) having a surface, the bottom corner portion of the bottomed cylindrical portion is wrinkled down, and the punch 16 (smaller than the punch 13) is used to form a smaller-diameter bottomed cylinder. Although not shown, such re-drawing is repeated one or more times (two more times in the manufacturing process shown in FIG. 2) after the re-drawing, so that the inner diameter of the bottomed cylindrical portion is manufactured. It should be approximately the same as the inner diameter of the opening curl of the can.
[0021]
Then, as shown in FIG. 3C, a plurality of tapered surfaces of the shoulder formed following the shoulder curved surface by repetition of redrawing are formed into a pair of virtual curved surfaces extending upward from the shoulder curved surface. By pressing and extending with a forming tool (die 17 and pusher 18), a continuous smooth curved surface is reformed (reformed), and then a smooth curved shoulder portion is formed below the small diameter bottomed cylindrical portion. For the formed can, as shown in FIG. 4, an inner mold 21 inserted into the can from the body opening end side of the can 1 and an outer mold 22 disposed above the inner mold 21 are used. Then, as shown in FIG. 5, an annular flat portion 4 having a substantially horizontal surface near the tip of the shoulder portion 3 is formed by pressing the upper and lower portions of the can 1 with the molds 21 and 22 so as to sandwich the shoulder portion. Is molded.
[0022]
As shown in FIG. 2, the end of the body opening end of the seamless can having the small-diameter bottomed cylindrical portion, the annular flat portion, and the dome-shaped curved surface shoulder formed on the bottom portion thereof. After trimming the cans and adjusting the height of the can, in the trim / curl forming step, trim the top end of the bottomed cylindrical part to open it, and then curl the open end to the outer winding to curl the opening. Mold the part. Then, in the bottom cover winding step, neck flange processing (neck-in processing and flange processing for forming the lower end portion of the neck-in processing part into a flange) is performed near the opening end (lower end) of the body of the can. Then, a bottom lid of another member having a pressure-resistant shape concaved upward in a dome shape is wound and fixed to a flange portion formed at the lower end of the neck portion, so that a can (an empty can) before the valve component is mounted. ) Is completed.
[0023]
When a metal can for an aerosol container is manufactured by the method of the present embodiment according to the manufacturing process as described above, drawing and ironing in a can body forming process (2nd press) (at least one or more re-drawing processes, stretching By thinning the body by at least one of processing and ironing, the can can be reduced in weight, and since there is no wrapped portion on the top of the can, there is no dust or dust on the top of the can. Without accumulation, the shoulder portion and the opening curl portion continue seamlessly from the body portion, so that the appearance is improved. In addition, by forming an annular flat portion near the tip of the shoulder, when attaching a cap for covering the valve to the opening curl portion after the valve component is installed, the cap of the cap By contacting the lower end of the cap to the flat portion with the lower end inner surface engaged with the opening curl portion, the cap can be stably mounted on the can.
[0024]
The method of the present embodiment using the above-described manufacturing process is basically a diversion of a conventionally known method of manufacturing a bottle-type can developed by the present applicant. When the method for producing a bottle-shaped can is diverted to the production of a metal can for an aerosol container, even when producing a metal can for an aerosol container that does not have an annular flat portion near the tip of the shoulder, the conventional method can be used. There is an advantage that a metal can can be formed with a reduced number of manufacturing steps.
[0025]
By the way, as for the annular flat portion formed near the tip of the shoulder of the metal can for aerosol container manufactured as described above, the shape itself similar to that is a separate member having a shoulder and an opening curl portion. A metal can for an aerosol container of a type in which a can lid is wound and fixed has been conventionally known (for example, see a can lid shown in FIG. 10 in Japanese Patent Publication No. 50-2443). Aerosol container metal can of the type, i.e., an aerosol container metal can such that the shoulder and the opening curl portion are continuously connected from the body, such that an annular flat portion is formed near the tip of the shoulder. Things do not exist in the past.
[0026]
Considering the reason, when the shoulder and the opening curl are integrally formed by pressing the can lid of another member, an annular flat part near the tip of the shoulder (similar to that) Shape) can be easily formed, and by forming such an annular flat portion (a shape similar thereto), when the valve component is mounted on the opening curl portion, the lid portion of the valve component can be formed into a flat portion. The valve part can be securely fixed so as not to fall out from the opening curl portion by entering the lower part of the valve part.
[0027]
On the other hand, for metal cans for aerosol containers in which the shoulder and the opening curl continue seamlessly from the body, the shoulder and the opening curl are mostly located at the body opening end side of the bottomed cylindrical seamless can. It is a type that is integrally molded into the can, and the body opening end side of the can is gradually reduced in diameter by a number of neck-in processes to form the shoulder and the part that will be later processed into a curl part In such a type of metal can, the bottom and the body are already integrated, and the diameter of the upper opening of the can is relatively small, so the mold was put in the can. It is practically impossible to press-mold in this state, and it is difficult to form an annular flat portion (a shape similar thereto) near the tip of the shoulder of the can.
[0028]
On the other hand, according to the method for manufacturing a metal can for an aerosol container of the present embodiment by the above manufacturing process, as shown in FIGS. The inner mold 21 is inserted into the can 1 from the body opening end side (lower end side) of the can 1 with respect to the can 1 having the shoulder portion and the inner mold 21. By pressing the outer mold 22 arranged outside the can at the top so as to sandwich the shoulder 3 of the can 1 from above and below, the annular flat portion 4 is easily formed near the tip of the shoulder 3. be able to.
[0029]
Although the flat portion 4 is formed near the tip of the shoulder portion 3 in this manner, although not shown, a valve conventionally used for an aerosol container of a type in which a separate can lid is wound and fixed. By using the same parts as those described above, the valve part is inserted into the bottom of the flat part 4 in the can, so that the valve part can be securely mounted so as not to come out of the can, and the metal part can be attached to the metal can. After attaching the cap, when attaching the cap for covering the valve, the lower end of the cap is brought into contact with the upper surface of the flat portion 4 so that the cap can be attached to the can in a stable state. .
[0030]
As a specific example of the metal can for an aerosol container manufactured by the method of the present embodiment as described above, a TFS (tin-free steel) plate having a thickness of 0.25 mm is placed on the inner surface side of the can. Using a resin-coated metal plate laminated with a thermoplastic resin film (a resin film of a mixed resin of polybutylene terephthalate resin and polyethylene terephthalate resin) so as to have a thickness of 25 μm and a thickness of 12 μm on the outer surface of the can, The blank was punched out into a disk having a diameter of 170 mm, and finally had a height of 148.95 mm, a weight of 48.70 g, a total internal volume of 291 ml, a curl inner diameter of 25.4 mm, and a curl outer diameter of 31. There is a metal can (empty can) manufactured so that the wall thickness of the metal plate at the body part is about 200 μm. Degrees (pressure resistant strength against the can internal pressure) was measured. As a result, the pressure for deforming the can, while the target value of 13.3kgf ^/ cm 2 (min), the average of the actual measurements 17.7kgf / Cm ² , and the target value for the pressure at which the can bursts is 15.3 kgf / cm ² (min), whereas the average of the actual measured values is 20.4 kgf / cm ^2. As a result, it was confirmed that each of them had sufficient pressure resistance.
[0031]
As described above, one embodiment of the method for manufacturing a metal can for an aerosol container of the present invention has been described.However, the method of the present invention is not limited to the above-described embodiment. Not only steel-based metal plate material, but also aluminum-based metal plate material may be used depending on the required compressive strength. In addition, for forming a shoulder portion and an opening curl portion on the bottom side of a bottomed cylindrical seamless can. The method is not limited to the method of forming a shoulder having a dome-shaped curved surface by the manufacturing process as shown in the above-described embodiment, and the shoulder having a shape other than the curved surface is formed by a different manufacturing process. It is needless to say that the method can be appropriately changed as needed, for example, such as the method described above.
[0032]
【The invention's effect】
According to the method of manufacturing a metal can for an aerosol container of the present invention as described above, the body is thinned by drawing and ironing, and the shoulder and the opening curl are continuously connected from the body. An annular flat portion can be easily and easily formed on the can near the tip of the shoulder. Then, by forming an annular flat portion near the tip of the shoulder portion of the metal can, a cap for covering the valve is attached to the opening curl portion after the valve component is attached. At this time, by bringing the lower end of the cap into contact with the flat portion, the cap can be stably mounted on the can.
[Brief description of the drawings]
FIG. 1 shows (A) a side view showing the overall appearance of a metal can for an aerosol container according to an embodiment of the method of the present invention, and (B) an opening curl portion, a flat portion, and an upper portion of a shoulder portion. FIG.
FIG. 2 is an explanatory side view schematically showing a manufacturing process of the metal can shown in FIG. 1;
FIG. 3 shows steps (A), (B), and (C) for forming a shoulder and a small-diameter bottomed cylindrical part (a part to be later formed into an open curl part) in the manufacturing process shown in FIG. 2; FIG. 3 is an explanatory longitudinal sectional view showing a molding state in FIG.
FIG. 4 is a longitudinal sectional view showing each mold used for forming an annular flat portion in the manufacturing process shown in FIG. 2;
FIG. 5 is a longitudinal sectional view showing a state when an annular flat portion is formed by each mold shown in FIG. 4;
[Explanation of symbols]
1 Metal cans for aerosol containers (empty cans)
2 Body 3 Shoulder 4 Flat 5 Open curl 6 Bottom lid 21 Inner mold 22 Outer mold

Claims (4)

After forming a slanted shoulder and a small-diameter opening curl on the bottom side of a cylindrical seamless can with a thinner bottom, a separate bottom lid is placed on the body opening end side. When manufacturing a metal can for an aerosol container equipped with an open curl for mounting valve parts by fastening and fixing the bottom lid, seamlessly from the body before the bottom lid is fastened and fixed Near the tip of the extending shoulder, an annular flat portion having a substantially horizontal surface is disposed outside the can corresponding to the inner mold and the inner mold that is inserted into the can from the body opening end side of the can. A method for producing a metal can for an aerosol container, wherein the metal can is press-formed with an outer mold. For a bottomed cylindrical seamless can with a thinner body, the bottom side is formed into a small-diameter bottomed cylindrical part and an inclined shoulder, and pressed into an annular flat near the tip of the shoulder. After molding, the tip side of the bottomed cylindrical portion is trimmed and opened, and the opened end is curled into an outer winding to form an open curled portion. The method for producing a metal can for an aerosol container according to claim 1, wherein the bottom lid is fixed by winding. In the process of forming the bottom side of a bottomed cylindrical seamless can into a small-diameter bottomed cylindrical part and an inclined shoulder, the bottom side of the can is drawn to form a bottomed cylindrical part with a smaller diameter than the trunk. After forming a surface arc-shaped shoulder curved surface, the bottom of the small-diameter bottomed cylindrical portion is formed by a pair of redrawing dies having a tapered surface approximated to a virtual curved surface following the shoulder curved surface and a wrinkle holding pusher. In a state where the corner portion is wrinkled, the bottomed cylindrical portion is re-formed into a smaller-diameter bottomed cylinder by redrawing using a redrawing punch, and such redrawing is performed on the bottomed cylindrical portion. Repeat until the inside diameter is almost the same as the inside diameter of the opening curl, and then, by such re-drawing processing, each tapered surface of the shoulder formed approximately to the curved surface, finally the shoulder With a pair of reshaping tools having a curved surface shape By reshaping extended press a continuous smooth curved surface was, method of manufacturing the aerosol container metal can according to claim 2, characterized in that as the entire shoulder the curved surface of the dome-shaped. The metal plate material used as a material for manufacturing a bottomed cylindrical seamless can with a thinner body is a resin-coated metal plate obtained by laminating a thermoplastic resin film on both surfaces of a surface-treated steel plate. The method for producing a metal can for an aerosol container according to any one of claims 1 to 3.

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