KR810002141B1 - Anti-buckling seamless container - Google Patents

Abstract

The container(1) is made of raw metal without ironing working and has not no seam in side wall and at a boundary line between the side wall and the bottom face. The easy-buckling portion of the side wall(the height of 5-20mm from the bottom) is tapered at the angle of 30-5≰ and the diameter of container is decreased downwards, and the circumferential reinforcement region is composed of the metal which forms the radius of curvature 5-25mm.

Description

Buckling resistant seam container

1 is a schematic cross-sectional view of a seamless container of the present invention.

2 is a cross-sectional view showing the winding portion of the tube body and the tube lid.

3 is a schematic cross-sectional view showing another specific example of the container of the present invention.

4 is an explanatory diagram showing a region for buckling of the tube body.

5 is an enlarged cross-sectional view showing the main surface reinforcement region of the tube body of the present invention.

6 is an enlarged cross-sectional view showing another form of the main surface reinforcement region.

7 is an explanatory diagram for explaining the procedure of processing by the method of the present invention.

8 is a cross-sectional view for explaining a drawing process of a metal material.

9 is a cross-sectional view for explaining the ironing processing of the side wall portion of the cup-shaped molding.

10-a and 10-b are cross-sectional views of the ironing punch for use in the method of the present invention.

11-a, 11-b and 11-c are explanatory views for explaining the additional step of the method for forming a seam tube of the present invention,

Figure 11-a shows a domming process,

11-b is the inking process,

Figure 11-c shows the flange machining process, respectively.

The present invention relates to a seamless container excellent in buckling resistance, and more particularly, despite having a very thin sidewall portion formed by drawing and ironing, A metal seamless container having strength and resistance to stress corrosion.

In recent years, in the field of canning, in particular canning for beverages, canning using seamless tubular bodies is capable of continuous printing on the entire surface of the tubular body, and the joining of the tubular sidewall seam is unnecessary and the winding of the tubular base is not necessary. Iii) attention has been paid for the reason that the process can be omitted.

The seam-less tube is formed into a cup shape by a drawing process between a drawing punch and a drawing die between a metal material punched in the shape of a disc or the like, and then the cup-shaped molded product. The side wall of is manufactured by ironing between an ironing punch and an ironing die, and the seam tube manufactured in this way is made of a relatively thick pipe bottom (pipe end) which is not substantially subjected to ironing. A relatively thin sidewall portion formed by ironing is provided.

In such a seamless tube body, thinning of the container side wall portion is greatly desired in order to reduce the weight per volume of the tube body and to reduce the cost of the metal material required for producing the tube body.

However, such a demand is severely limited in terms of the operation of the seam pipe, and in terms of the strength and the resistance to deformation at the time of canning, or the preservation of the internal food.

For example, when thinning the side wall portion of a seam tube, the axis of the tube in a double winding process during doming, necking, flange processing, or canning of the tube. It becomes a big problem that it is easy to produce buckling of a tubular body by the pressure applied to a direction.

In addition, the seam-less tube having a thin side wall portion is susceptible to deformation during the can filling process and transportation as well as the above-described manufacturing process, and this tendency is that in a pressure-resistant tube filled with contents, the tube itself is always It is influenced by pressure and becomes larger due to the heat cycle such as cooling or heat sterilization in the can filling process.

Again, the corrosion resistance of the side wall of the tube body is also a problem, and even if a single pinhole is formed in the side wall, a problem such as deterioration of the contents or deterioration of flavor due to corrosion at this part is caused. Will be generated.

The present inventors, in the above-described seam tube, the most problematic part in terms of buckling resistance and corrosion resistance is the pipe bottom portion that is not substantially subjected to the ironing process and the side wall portion of the tube body subjected to the high ironing process; Joint (the buckling easy region, and by making the connecting portion the main surface reinforcement region described in detail below, the buckling resistance and the corrosion resistance of the seamless container are remarkably improved. I found that you can.

That is, it is an object of the present invention to provide a novel seamless container having a structure in which a buckling zone is reinforced in the vicinity of a boundary portion between the side wall portion of the tube body and the bottom of the tube side portion, that is, the lower portion of the side wall portion of the tube body. have.

Another object of the present invention, in the reinforcement region, the metal container material is continuously changed from a metal material that is not substantially ironed to a metal material subjected to ironing, thereby buckling tendency or stress corrosion of the container It is to provide a new seamless container with a markedly improved trend.

According to the present invention, there is provided a relatively thick pipe bottom portion made of a metal material substantially unironed, and a relatively thin pipe body side wall portion formed by drawing and ironing of the metal material, and further comprising the pipe side wall portion and In the seam-free container of the metal seam container which does not have a seam at the boundary part of the said pipe | tube side wall part and a pipe | tube bottom part, it is easy to buckling area | region of the pipe | tube side wall part in the range which ranges from a position of 5-20 mm in height from Tapered shape with gradually decreasing diameter in the downward direction is tapered in the range of 0 ° 30 'to 5 °, secondary curvilinear shape in the range of 5-25 mm in the radius of curvature, or a combination thereof. A main surface reinforcement area made of a metal material is provided, and in the main surface reinforcement area, the metal container material is not substantially subjected to ironing. The metal shim leg vessel, characterized in that it is continuously changed from a child to a material receiving the ironing process is provided.

The present invention is described in detail below.

In FIG. 1 showing a schematic cross-sectional structure of a seamless container of the present invention, the seamless container (tube member) 1 is a tubular side wall connected to the tube bottom portion 2 and the tube bottom portion 2. It is a part (3). There is substantially no seam in the circumference of the side wall part 3 of the tube member 2 and the connection part 4 between the side wall part 3 and the tube bottom part 2. The tube side wall part 3 is formed by a draw and ironing process of a metal material, and is relatively thin, while the pipe bottom part 2 is a metal material which is not substantially ironed and is relatively thick.

In the upper edge part of the side wall part 3, the flange 5 is made, and after sealing the contents, the peripheral part and the flange 5 of the pipe lid member 6 covered on this flange 5 are covered. ), As shown in Fig. 2, a sealing portion (winding portion) 7 is formed. The inner surface of the tube member 1 and the inner surface of the tube lid member 6 are provided with a corrosion resistant protective resin film 8 to prevent direct contact between the contents and the metal material. do.

Instead of making the bottom part 2 flat, as shown in FIG. 3, a spherical smooth projection (dom 9) is placed inside the bottom part 2 as shown in FIG. Direction, thereby preventing the tube bottom 2 from protruding outwardly by the pressure of the contents, and improving the seating of the tube, and as shown in Fig. 3, the tube member ( A neck 10 is formed in the upper edge portion of the side wall portion 3 of 1), and the winding portion 7 between the tube flange 5 and the periphery of the tube lid member is a tube member. It is possible to prevent protruding outward from the main surface of the side wall portion of the can, and to reduce the storage volume at the time of packaging the tube or can.

As the metal material constituting the tubular body, any metal material, for example, steel plate, tin plate, zinc, plated steel plate, chromium-treated steel plate, such as various plating, electrolytic or chemically treated steel plate, or light metal plate such as aluminum tube, Or composites thereof.

An important feature of the present invention is that the buckling-use region located in the vicinity of the connecting portion 4 between the tube side wall portion 3 and the tube bottom portion 2, that is, the lower portion of the tube side wall portion 3, gradually goes downward. The main surface reinforcement area | region made from the metal material shape | molded by taper shape, a secondary curve shape, or these combined shapes which diameter becomes small is provided.

In the seamless container by the conventional drawing and ironing method, in view of the extremely thin thickness of the side wall of the tube body as compared to the thickness of the tube bottom part, the tube can be identified after ironing, for example, neck-in. In the process or the flange process, or in the winding process in the canning production, it is a big problem that the buckling of the tube body easily occurs to a certain percentage by the load applied in the axial direction of the tube body. In terms of production efficiency and cost, it is still not satisfactory enough.

The buckling tendency of the tube body can be prevented by thickening the side wall portion of the tube body, but thickening the side wall portion loses the advantages of the weight reduction of the tube body by the drawing process and the economical efficiency of the material.

In view of the above, the present inventors earnestly studied the seamless container by the drawing and ironing process for the purpose of improving the pressure-resistant strength and the resistance to deformation of the pipe body while thinning the pipe side wall portion.

In the course of this study, the inventors found that the area where the buckling most likely occurred in the through-wall side wall portion is high when the height of the side wall portion 3 of the tube body is H as shown in FIG. Is located at a position lower than H / 2, more precisely, from the position of the bottom 2 to a height ranging from 5 mm to 20 mm, and thus for this buckling zone (h)

It was found that by providing the reinforcement area of the above-mentioned main surface shape within the range, the greatest selling pressure strength and the resistance to deformation are obtained.

This main surface reinforcement area | region can be provided by shape | molding the metal material located in the said easily buckling area | region to the taper shape, secondary curve shape, or these combined shapes which gradually become small diameter.

For example, in FIG. 5 showing an embodiment of the present invention, the diameter of the buckling easy region Ah that extends from the end edge of the tube bottom part 2 to the tube side wall part 3 gradually decreases downward in diameter. A main surface reinforcement region 11 made of a metal material molded into a differential curve shape is provided.

The secondary curve may be, for example, an arbitrary secondary curve such as a circle, an ellipse, or radiation, and is smoothly connected to the surface of the side wall portion 3 of the tube body and the surface of the tube bottom portion 2 and protrudes outward. All you need is a curve. The curvature R of the secondary curve in the main surface reinforcement region 11 may be selected such that the main surface shape reinforcement region 11 is positioned over the entire buckling region Ah, and therefore the radius of curvature R is 5 to 25 mm. In particular, a suitable value is preferably selected in the range of 10 to 15 mm.

According to the present invention, a new reinforcing structure is introduced by forming a main surface 11 whose diameter gradually decreases downward in the tube body located in the buckling region Ah.

That is, in FIG. 5, between the tube bottom part 2 made of the metal material 12 which was not substantially ironed, and the tube body side wall part 3 made of the metal material 13 which was ironed. Into this, a connection portion (transient) 14 which continuously and gradually changes from the metal material 12 which has not been substantially ironed to the metal material 13 which has been ironed is introduced. In the conventionally known tube for drawing and ironing (Dl tube), in the connection portion 14 between the tube bottom portion 2 and the tube body side wall portion 3, the metal is not substantially subjected to ironing. Rapidly changing from the material 12 to the metal material 13 subjected to the ironing process, this connection part is a mechanical defect that tends to concentrate stress, and due to such a tube or an axial load It tends to be easily buckled, and in the case of pressure-resistant containers, deformation due to pressure occurs. In contrast, in the container of the present invention, in the connection portion 14 between the pipe bottom portion and the side wall portion, the metal material 14 subjected to ironing is continuously applied from the metal material 12 which has not been ironed. And since it changes gradually, the strain tends to be deformed due to the buckling resistance and pressure of the tube body (buckling pressure: the pressure indicating the strain that rises due to the pressure difference) ) Can be significantly improved.

This fact is easily understood by referring to Example 1 and Comparative Example, which will be described later. That is, according to the present invention, the Kanto body provided with the main surface phenomenon reinforcement area in the easy buckling area can withstand loads of 480-540 kg as a conventional tin plate and 230-280 kg as an aluminum plate. Except for the same, a conventional manipulator is impossible to withstand a load of 190-210 kg in the latter 400-500 kg in the former.

One of the novel and unexpected effects of the seams container of the present invention is that the corrosion resistance by the contents of the tube body is remarkably improved. In the conventional pipe body in which the ironing degree of metal material is rapidly changing at the boundary portion between the pipe bottom portion and the side wall portion, a stress residual region always exists at this boundary portion, and stress corrosion is prevented at this portion. Tends to occur.

This tendency is a fatal flaw in the long-term shelf life of the beverage in containers with high corrosive contents, especially beverages, and the problem of dissolution or deterioration of contents due to metal dissolution and formula. Will occur. According to the present invention, since the connecting portion 14 continuously and gradually changes from the metal material not subjected to ironing to the metal material subjected to ironing, the stress tends to remain in this boundary region. This can be alleviated and, as a result, local corrosion tendency in this area can be eliminated.

In the present invention, instead of providing the main surface shape reinforcement area formed in the secondary curve shape in the buckling area Ah, as shown in FIG. 11 ').

At this time, the taper angle θ is a suitable angle in the range of 0 ° 30 'to 5 °, particularly 1 ° 30' to 3 ° so that the main surface shape reinforcement area 11 'is located over the entire region of the buckling area Ah. It is good to choose.

Of course, instead of using the secondary curved main surface reinforcement region shown in FIG. 5 or the tapered main surface reinforcement region shown in FIG. 6, the principal surface reinforcement of the shape which combined the secondary curve and the tapered straight line It will be apparent to those skilled in the art that regions can be used.

In the present invention, the length L of the transition region 14 transitioning from the metal material 12 not subjected to the ironing process to the metal material 13 subjected to the ironing process is the taper angle in the main surface reinforcement region ( In the case of the secondary curved surface, when the tangent or string angle is set to θ,

ℓ = TB / Sinθ

In the formula, T _B is the thickness of the pipe bottom.

It is the length indicated by. Therefore, the smaller the taper angle θ, the longer the length L of the transient region 15 is. However, it is not good to make the taper angle too small because the required amount of metal material increases, and it is not good to make the taper angle too large because the buckling tendency and the stress corrosion tendency become large. In view of this, in the present invention, the length L of the transition region 14 transitioning from the metal material 12 not subjected to the ironing process to the metal material 13 subjected to the ironing process is a kind of metal material. B, the thickness varies considerably depending on the thickness of the bottom of the pipe and the side wall of the pipe, but generally speaking, it is preferably in the range of 5.0 to 20.0 mm, particularly 10.0 to 15.5 mm.

In the seamless container of the present invention, when the thickness of the tube bottom part 2 is T _B and the thickness of the side wall part 3 is T _w , the value of (T _B -T _w ) / T _B is a metal material. Although it differs depending on the kind of, 0.35 or more, especially it is good to exist in the range of 0.5-0.8.

The tube bottom part 2 is not subjected to ironing, so that its thickness T _B is substantially the same as the platelet thickness, and the thickness T _w of the tube side wall part 3 is the residual plate thickness finally obtained by ironing. Since (T _B -T _w ) / T _B, the value is

Matches the value of the ironing roll, defined as

In the present invention, even in the case of high ironing of 0.5 or more in this manner, the buckling resistance and the corrosion resistance of the tube body can be improved.

The seamless container of the present invention is a method for producing a seamless container by a known drawing process and ironing of primary or aberrations of a metal material itself. Alternatively, an ironing punch having a shape coinciding with the inner surface of the manipulator shown in FIG. 6, i.e., a lower portion of the working surface in contact with the inner surface of the side wall of the draw cup, has a tapered shape and a secondary curve gradually decreasing downwardly. This is produced by using a pin ironing punch as the main surface to be in the shape or the shape thereof.

In FIG. 7 for explaining the procedure of processing by the method of the present invention, first, in the first step (a), the metal material is punched into an arbitrary shape such as a disc. Next, in the second step (b), the original plate 21 is put into the first draw step, molded into a relatively large cup-shaped molded article 22, and again in the third step (c) The molded article 22 is put into a redraw process and molded into a relatively small cup-shaped molded article 22 '.

In the fourth step (d), the cup-shaped molded article 22 'is subjected to aberration ironing, to iron the side wall portion of the cup-shaped molded article 22', and to obtain a relatively thick end portion (tubing). Part 2) and a relatively thin sidewall body 3 having a relatively thin side wall part 3.

This metal material can be obtained in the form of a flat plate, a coil material, or the like, and is punched into an arbitrary shape such as a disc.

Although the thickness of this main board differs also according to the use of a final product, and the kind of material, generally speaking, it is good to exist in the range of 0.2-0.6 mm, and among these, 0.25-0.4 mm and aluminum In the case of light metal plates such as the above, it is preferably in the range of 0.35-0.55 mm.

The size of the material being sheared is determined by calculating the amount of metal required for the final product and obtaining this metal.

Next, as shown in FIG. 8, the punch 23 and the die 24 are formed by using the drawing punch 23 and the die 24 to form the original plate 21 of the metal material. By the relative motion with, the disc 21 of the metal material is formed into a cup-shaped molding 22.

At this time, between the effective diameter of the draw die 24 and the outer diameter of the draw punch 23, there is a clearance larger than the plate thickness of the metal material.

In the draw processing of a metal material, in order to prevent wrinkles from forming on the side wall of the cup-shaped molding 22, a wrinkled film 25 is provided on the punch insertion side of the die 24 to draw. The peripheral portion of the raw material 21 is also maintained to be able to be active between the die 24 and the wrinkled film 25.

The following formula

The draw ratio defined in the above is considerably different depending on the kind other than the material and the manufacturing conditions thereof, but in the case of aluminum in the practical draw ratio, it is generally in the range of 2.22 to 1.82 in the case of 1.89 to 1.69 steel sheet.

Therefore, in the case of various steel sheets, it is also possible to put the cup-formed product obtained by the drawing process of one step into an ironing process, but in the case of an aluminum plate, the comparatively large diameter cup-formed product obtained by a 1st drawing process is described below. It is generally necessary to put in the reed-lowing process described below.

The cup-shaped molded product obtained by the drawing process of a 2nd process is put into a reed drawing process using the combination of the draw punch of a small diameter, and drawing die rather than the draw punch of a 2nd process.

The principle of this redraw process is the same as that shown in FIG. 8 except that the diameter of the draw punch and the diameter of the draw die are smaller than those shown in FIG.

In the third draw step, the drawing direction of the cup-shaped molded article having a relatively large diameter is not particularly limited. For example, the cup obtained in the same direction as the draw direction of the second step, that is, the cup obtained in the second step. It is also possible to draw from the bottom of the shaped molding toward the tip side, or to draw in the opposite direction to the draw process of the ninth process, that is, to turn the cup-shaped molding obtained in the second process.

In addition, in the lead-lowing step of the third step, it is also possible to perform some ironing, so that the distance (clearance) between the punch outer diameter and the inner diameter of the die is slightly larger than the plate thickness of the material, or It may be the same as the plate thickness or may be slightly smaller than the plate thickness of the material.

The cup-shaped molding thus formed, i.e., the draw cup having a low height, is placed in the ironing process of several times between the ironing punch working surface and the ironing die, and the side wall portion of the draw cup is stretched. Thin.

In FIG. 9 for explaining this ironing process, the ironing punch 26 and the several ironing dice 27 are provided on the same axis as the ironing punch so that a movement is possible. The outer diameter of the working surface 28 of the ironing punch 26 coincides with the inner diameter of the side wall portion of the cup-shaped molded body 22 'obtained in the reed-lowering step, while the ironing die 27 The clearance between the working part tip 29 and the outer surface 28 of the ironing punch 26 is provided to be smaller than the thickness t of the side wall portion 30 of the cup-shaped molding 22 '. In general, a plurality of ironing dice 27a, 27b, and 27c are provided along the moving path of one eyerun punch 26, and each ironing die and each dice action are provided. The clearance with the sub-tip is gradually reduced as the ironing punch moves.

Thus, according to the present invention, the side wall 30 of the cup-shaped molding 22 'is subjected to ironing between the ironing punch 26 and the ironing die 27a, whereby the side wall 30 ) Increases as it becomes thinner.

This thinned side wall portion is subjected to ironing in sequence between the next ironing die 27a and the ironing punch 26 located next, and ironed in the same manner until finally reaching a desired residual thickness. Receive.

According to the present invention, as the ironing punch 26, an ironing punch having a shape shown in FIGS. 10A and 10B is used.

The ironing punch used in the method of the present invention includes a main surface 32 having a tapered shape, a secondary collinear shape, or a combination thereof, in which a lower portion 31 of the working surface 28 gradually decreases downward. Doing.

This dimension of the main surface 32 must, of course, coincide with that of the main surface reinforcement region 11 of the manipulator described above with reference to FIGS. 5 and 6.

When the ironing processing of the drawing cup is performed by the ironing punch 26 and the ironing die 27 of the specific shape, the draw supported on the main surface 32 of the lower portion 31 of the ironing punch 26 is performed. In the portion of the in cup, ironing is gradually performed, and in the side wall portion of the drawing cup supported on the vertical working surface 28 of the ironing punch 26, the ironing punching surface 28 and the die are formed. The ironing process according to the clearance with the front-end | tip part 29 is fully performed.

In this manner, according to the present invention, in the ironing processing step, the easily buckling region of the tube body is subjected to the ironing processing process in the same way as the conventional ironing method except that the ironing punch of the specific shape shown in FIG. 10a or 10b is used. It is possible to introduce unusual reinforcing structures.

The tube body which finished drawing and ironing by the method mentioned above can be taken out from an ironing punch or put into a doming process in the state.

For example, as shown in FIG. 11-a, the bottom surface of the pipe body 2 of the tubular body 1 obtained by the drawing and ironing process is pressed by the same means as the press 33. By doing so, the smooth support 9 in one direction of the tube bottom part 2 can be formed.

This domming is especially effective when producing a pressure resistant pipe. In addition, as shown in Fig. 11-b, the portion of the opening edge 34 of the side wall portion 3 of the tubular body or the portion adjacent thereto is formed by a die method or a spin method (roll method). The neck 10 is formed by drawing to a smaller diameter than the side wall portion 3. The pipe which performed the necking process is put into flange processing next. This flange machining, for example, by using a flange die 35 as shown in Fig. 11-c, bends the portion of the neck 10 outward at approximately a right angle, thereby releasing the flange 5. This can be done by forming.

The tubular body of this invention does not produce a buckling and a flange crack also in a drawing and ironing process and these piping manufacturing processes performed subsequently.

On the inner surface of the tube member and the inner surface of the tube cover member, a corrosion-resistant protective resin film is constructed. As this corrosion resistant protective film, many paints made of thermosetting and thermoplastic resins such as modified epoxy resins such as phenol, epoxy paints and amino epoxy paints, vinyl or modified vinyl paints, etc. For example, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer partial saponification; Vinyl chloride-vinyl acetate-maleic anhydride copolymer or an epoxy modified, epoxy amino modified or epoxyphenol modified vinyl resin; Synthetic rubber-based paints such as styrene butadiene copolymers are used.

These coating films may be constructed as a single layer, or in a single layer, when properties such as corrosion resistance and peeling resistance are not sufficiently satisfied, they may be applied in the form of a composite layer composed of a plurality of resin layers. Can be. For example, in the tube body suitable for this invention, the base which consists of modified epoxy resin material in the side wall inner surface. A top constructed with cots, and then standing on this base, cots on vinyl or modified vinyl. Construct a coat. These resin protective layers generally contain the above-mentioned resins in the form of a solution of an organic solvent such as enamel or lacquer, or in the form of an aqueous acid solution or an aqueous solution, and impregnated coating, spray coating, electrostatic coating, electrophoretic coating. It may be carried out by means such as a powder or a melt, and then again by means such as flow immersion, electrostatic coating, flame spraying, or the like. Of course, when the said resin protective layer is made into a thermosetting resin, it hardens as needed.

The outer surface of the tube according to the present invention may be partially printed or printed on the entire surface thereof.

For example, on the outer surface of the tubular body, a modified white resin, a modified polyester resin, a modified alkyd resin, or a white coat or transparent coat made of a combination thereof is applied to the white coat or transparent coat. Alkyd-based, modified acrylic, modified phenol-based or a combination of these is applied by an ink composition, and then a finished varnish of a composition such as white coat or transparent coat is applied on this printed surface.

In the production of canned goods, the above-mentioned tube member is filled with contents such as beverages, the tube end member (tube lid) is covered, and then the tube flange and tube lid are double piped. It is sealed and canned.

The tubular body of the present invention is particularly useful for pressure-resistant canning containing contents such as beverages. Examples of such beverages include various kinds of beverages such as beer such as beer, fruit wine such as liquor, whiskey, shochu, wine, or ginpies. Alcoholic beverages including cattails; Various carbonated beverages including cola, cider, and soda, lemon juice, orange juice, plum, straight such as juice, grape juice, strawberry juice. Fruit juices, including juices and processed beverages such as Nectar; Vegetable juices including tomato juice, various vegetable juices; Synthetic beverages and vitamin-enriched drinks, including synthetic fruit juices using sugars such as sugar or fructose, citric acid, colorants, flavorings, etc. or, if necessary, added vitamins; Lactic acid bacteria drinks.

The tubular body of the present invention is, of course, also useful for the use of canned foods for accommodating livestock processed products such as sausages, hams, bacons, and other fruits and vegetables, in addition to the above-mentioned drinks.

These canning processes can be performed on the conditions of self-announcement. For example, the above-mentioned contents may be filled in cold or hot, depending on the type of the contents, or, if necessary, the air in the tube may be inert such as steam or carbon dioxide. After replacing with gas, winding of a pipe flange and a pipe lid is performed using a seamer known per se.

The canned goods filled with the contents are put into a heat sterilization treatment by a can warmer pasteurizer or a retort.

The seamless container of the present invention does not generate buckling even when subjected to an axial load in these canning processes, and deforms the tube body by a pressure difference even when subjected to a thermal cycle in the filling or sterilization process. It does not cause it. In addition, this seam container has a low tendency to corrode even when storing a highly corrosive beverage over a long period of time, and the effect of preventing alteration of contents and maintaining taste.

The present invention will be described as the following examples.

Example 1

The plated 0.32mm bright stone plated steel plate (aluminized steel, ingot material, temper T-1 equivalent, plating amount # 100/100) is punched into a disc of about 142mm diameter, and the draw punch according to the conventional method. The cup is shaped into a cup shape with an inner diameter of about 65.4mm between and the drawing dies.

Next, using an ironing punch of the shape shown in FIG. 10A (dimensions and shapes are as shown in the following table), as shown in FIG. 9, a draw cup is placed between the ironing punch and the ironing die. Ironing is applied to the 3rd round.

In this way, as shown in Fig. 11-a, the bottom of the manufactured ironing tube is pressed to form a dome, and then shown in Figs. 11-b and 11-c. As described above, the side wall opening end was necked-in and flanged to form a final tube having a shape shown in FIG.

The dimensions and physical properties of this final tube were as follows.

After degreasing and cleaning the inner surface of the tube with an accent, the epoxyphenol opening paint was applied to a thickness of 5 mu, heated at 210 ° C. for 10 minutes, and mixed with a vinyl chloride-vinyl acetate copolymer and an epoxy resin. The top coat was constructed to a thickness of 10 mu.

The white of the modified acrylic resin on the outer surface of the tube. The coat was applied at a thickness of 10-16 mu, and after printing again, the finished varnish of the same composition as the white coat was painted at a thickness of 6-9 mu.

Example 2

In Example 1, a seamless container was manufactured in the same manner as in Example 1 except that the ironing punch of FIG. 10B having a tapered main surface gradually decreasing in diameter downward was used below the working surface. It was.

The dimensions of this pipe body are as follows.

In addition, the part of the same dimension as Example 1 is abbreviate | omitted.

Comparative Example 1

In the said Example 1, the seamless container was manufactured like Example 1 except having used the conventional ironing punch.

The dimensions and physical properties of this pipe body are as follows except for the part common with Example 1.

The buckling load and the corrosiveness of the three kinds of pipe bodies of Examples 1 and 2 and Comparative Example 1 were tested.

The buckling load was obtained by sandwiching the tube body with an internal pressure plate in the axial direction and applying a load in the axial direction to obtain a load in which buckling occurs.

In the corrosion test, each of the three kinds of tubes was filled with 1% thiomasanoic acid ammonium solution, a carbon rod electrode was inserted in the center of the tube, the metal body of the tube was used as the anode, and the carbon rod was used as the cathode. This is done by applying a DC voltage of 6-7 volts to the liver. In a tube with a high corrosion tendency, the iron component is precipitated in the electrolyte in the form of red (tiocylic iron anthrate), and the change is visually observed to determine the presence of corrosiveness.

The results are shown in the first table below.

As a result of the first table, according to the present invention, the containers of Examples 1 and 2 in which the main surface development reinforcement zone in which the buckling capacity of the manipulator is gradually reduced downward in diameter are compared with those of the conventional Comparative Example 1. This indicates that the buckling load is remarkably improved and the corrosion tendency of the tube body is suppressed.

Example 3

A granular aluminum (soft 4S material) having a plate thickness of 0.44 mm is punched into a disc of about 122 mm in diameter, and is formed into a cup having an inner diameter of about 68 mm between the drawing punch and the drawing die according to a conventional method.

Next, the cup-shaped molded product is placed in a reed-lowing step, and then an ironing punch having a shape shown in FIG. 10A (dimensions and shapes are shown in the table below). 55 mm) was ironed between the ironing punch shown in FIG. 9 and the ironing die.

Next, this pipe body was made into a pipe body of the shape shown in FIG. The dimensions and physical properties of this tube were as follows.

Example 4

In Example 3, a seamless container is manufactured in the same manner as in Example 3 except that the ironing punch of FIG. 10B having a tapered periphery gradually decreasing in diameter to the lower side of the working surface is used.

The dimensions and physical properties of this pipe body are as follows except for being common to Example 1.

Comparative Example 2

In the said Example 3, the seamless container was manufactured like Example 3 except having used the conventional ironing punch.

The dimensions and physical properties of this pipe body are as follows except for being common to Example 3.

The three buckling bodies of Examples 3 and 4 and Comparative Example 2 were subjected to the buckling load by the method described above, and tested for corrosiveness by the following method.

Fill these three tubes with 10% saline, leave them at a temperature of 37 ° C for one week, remove the contents and clean the interior of the tube, and then see if corrosion occurs between the side walls of the tube and the bottom of the tube. Whether or not was observed with the naked eye and a microscope.

The results are shown in the second table below.

Comparative Example 3

In the said Example 4, the seamless container was manufactured like Example 4 except having used the ironing punch which enlarged the taper angle which gradually decreases a diameter downward under the working surface.

Claims (1)

A relatively thick pipe bottom portion made of a metal material substantially unironed, and a relatively thin pipe body side wall portion formed by drawing and ironing of the metal material, and the pipe body side wall portion and the pipe body side wall portion. In a conventional metal seamless container in which a seam does not exist at the boundary between the bottom of the pipe and the bottom of the pipe, the buckling of the side wall of the pipe body gradually falls downward in the region ranging from the position of the bottom of the pipe to a position of 5 to 20 mm in height. Tapered angle with smaller diameter is tapered in the range of 0 ° 30 'to 5 °, secondary curvature in the range of 5 to 25 mm in curvature radius, or metal molded into these assembled shapes A standing main surface reinforcement area is provided, and in the main surface reinforcement area, the metal container material is substantially unironed. As a child Material Received ironing processing from the metal material seam-less container, it characterized in that the continuously changed.

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