JP2002178049A - Manufacturing method for resin-coated seamless can body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a resin-coated seamless can body at high speed basically formed of aluminum which is ecofriendly and excellent in can characteristics such as corrosion resistance. SOLUTION: A lubricant is applied to a resin-coated aluminum plate which is formed by coating both sides of the aluminum plate with thermoplastic polyester resin. This resin-coated aluminum plate is drawn to form a cup body 5. The cup body 5 is ironed by a punch 10 and ring dies 26, 27 and 28 in one stroke in a dry state to continuously manufacture a seamless can body at high speed. The resin-coated seamless can body is manufactured by performing the ironing under a condition that the dynamic friction force between the punch 10 and the seamless can body during each ironing and after each ironing is as small as possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a resin-coated seamless can, and more particularly, to a method for cooling and using a punch and a plurality of ring dies in a dry state without using a lubricant, that is, a coolant. The present invention relates to a method for producing an aluminum seamless can coated with a high speed at a high speed.

[0002]

2. Description of the Related Art As a resin-coated seamless can, a resin-coated tin-free steel plate having a thermoplastic polyester resin film formed on both sides of a metal plate, preferably a tin-free steel plate, is drawn, bent and stretched and redrawn. Processed and manufactured products are widely used. This is because the processing is performed in a dry state, that is, the processing is performed without using a coolant, which has an advantage of being environmentally friendly and further has excellent can properties such as corrosion resistance (for example, see JP-A-7-275961). .

The above method has been commercially successful when the metal plate is a steel plate, but the metal plate is made of aluminum (herein referred to as aluminum including aluminum alloy for cans). In some cases, high-speed production has not been sufficiently successful. In particular, in the case of a so-called 500 ml can (having a height of about 167 mm) having a relatively large can height, application was difficult. Aluminum, compared to steel,
This is probably because mechanical properties such as strength, r-value, and critical drawing ratio are inferior, and the body is likely to break during redrawing and ironing including large bending and stretching.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a resin-coated seamless can made of aluminum, which is environmentally friendly and has excellent can properties such as corrosion resistance, at a high speed. I do.

[0005]

SUMMARY OF THE INVENTION The method for producing a resin-coated seamless can according to the present invention comprises applying a lubricant to a resin-coated aluminum plate having both surfaces of an aluminum plate coated with a thermoplastic polyester resin, and then coating the resin with a resin. A method in which a cup body is formed by drawing an aluminum plate, and the cup body is ironed in one stroke and in a dry state by the cooperation of a punch and a ring die to continuously make a seamless can body at a high speed. The ironing process is performed under such a condition that the dynamic frictional force between the punch and the seamless can body during and after each ironing process is as small as possible (claim 1).

[0006] In the present specification, the aluminum plate generally refers to a strip-shaped aluminum plate unwound from a coil, that is, an aluminum strip. Thermoplastic polyester resin is a thermoplastic polyester copolymer resin,
Includes blended resin containing polyester as a main component. The resin to be coated, that is, the coating, may be a single layer or may be composed of a plurality of layers having different compositions.

At the time of drawing to form the cup body, a light ironing process may be added. Ironing includes redrawing-ironing and pure ironing without redrawing only. "Redrawing" in redrawing and ironing is not a so-called "bending / thinning stretch redrawing" as described in JP-A-7-275961,
Refers to "redrawing" used in normal DI can manufacturing. Usually, a plurality of ring dies are provided. The “dry state” refers to a state in which the cooling lubricant is not injected. Each ironing refers to one-stroke ironing, and thus, after each ironing includes the point at which the punch is pulled out by the stripper.

[0008] Since both surfaces of the seamless can are covered with a thermoplastic polyester-based resin, the can is excellent in corrosion resistance even after being made into a can. Since the base material is an aluminum plate, even if the content is beer, there is little possibility that the flavor of the beer is impaired. The cup body formed from the resin-coated aluminum plate coated with the lubricant is ironed under the condition that the dynamic frictional force between the punch and the seamless can body during or after each ironing process becomes as small as possible. And the punch is removed from the seamless can body by stripping during ironing due to a large dynamic friction force, or by buckling at the opening end and its vicinity when the punch is removed from the seamless can body after ironing (stripping). Impossible (rollback)
Is unlikely to occur. Therefore, it is difficult for the apparatus to stop due to collapse or rollback. Even when redrawing is performed, severe bending and thinning stretching are not performed at the processing corner of the redrawing die, so that even if an aluminum plate having a small strength and elongation rate is used as a base plate, it is generally 500 ml without being broken. A seamless can having a relatively large can height / diameter ratio, such as a can, can be manufactured at high speed.

[0009] The conditions under which the dynamic frictional force between the punch and the seamless can body during or after each ironing operation is as small as possible, specifically, the effect of reducing the coefficient of friction is large, and Use of an appropriate amount of a lubricant that can be volatilized and removed by heating at 200 ° C., maintaining the surface temperature of the punch during continuous can making (ironing) at an appropriate temperature (A ° C.) within the range of 35 to 100 ° C., A large number of point-shaped recesses, linear circumferential recesses, or cross-hatch-shaped recesses (for example, as described in JP-A-7-300124) are provided on at least the surface of the portion in contact with the inner surface of the seamless can body after molding. Is formed to reduce the contact area with the resin film and at the same time to form a reservoir for the lubricant.

[0010] Since a seamless can is formed in a dry state, no cooling lubricating liquid (coolant) is used, so that it is environmentally friendly. After the lubricant is volatilized and removed in a later step, printing can be performed on the outer surface of the seamless can body. Therefore, satisfactory outer surface printing is possible without ink being repelled by the lubricant film. After ironing with one stroke, the punch is extracted and a seamless can is formed. Therefore, since the molding machine is not a multi-step system such as a transfer press, the number of transfer devices in the press and the number of dies can be reduced.
Therefore, since the equipment cost is low and the number of steps is small, the cost is low as a whole.

Further, in the method for producing a resin-coated seamless can according to the present invention, a lubricant is applied to a resin-coated aluminum plate obtained by coating both surfaces of an aluminum plate with a thermoplastic polyester resin, and then the resin-coated aluminum plate is drawn. And forming a cup body, ironing the cup body in one stroke and in a dry state by cooperation of a punch and a ring die, and continuously producing a seamless can body at a high speed. When the surface temperature is such that the dynamic friction coefficient (μ) between the resin-coated aluminum plate and the cemented carbide globules is 0.05 to
Ironing is performed while maintaining the temperature appropriately within the range of 0.07 (claim 2).

As shown in FIG. 9, the temperature of the resin-coated aluminum plate whose dynamic friction coefficient (μ) is in the range of 0.05 to 0.07 is about 35 to 100 ° C. It is considered that the surface temperature of the punch in the continuous can is substantially equal to the temperature of the resin film on the inner surface side of the seamless can body to be formed. Therefore, the ironing process is performed while maintaining the surface temperature of the punch at an appropriate temperature between 35 and 100 ° C., as described below.
Satisfactory ironing becomes possible without causing collapse or rollback.

[0013] In the case of the method for producing a resin-coated aluminum seamless can according to claims 1 and 2, from the viewpoint of productivity,
The continuous can making speed, that is, the ironing speed is preferably 100 strokes / min or more (claim 3).

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference numeral 4 in FIG. 1 shows a resin-coated aluminum plate in which both surfaces of an aluminum plate 1 are coated with thermoplastic polyester resin coatings 2 and 3, respectively. The thermoplastic polyester-based resin coatings 2 and 3 are unwound from a coil (not shown) and are formed on both sides of a traveling aluminum strip 1,
Extrusion lamination, or unstretched cast film
Amorphous and non-stretched materials that have been quenched after thermal bonding by a laminating method are preferred. The non-stretched, amorphous thermoplastic polyester-based resin film has excellent extensibility and adhesiveness, and can be used as a thin base material for aluminum plates even during severe ironing with a large can height / diameter ratio. It is possible to follow the elongation and contraction deformation accompanying the formation without causing damage such as peeling or cracking. Inner surface thermoplastic polyester resin coating 2
1 is composed of two layers having different compositions, that is, the outer layer 2a and the inner layer 2b in FIG. 1, but may be composed of one layer or three or more layers. Outer surface thermoplastic polyester resin coating 3
Although FIG. 1 includes two layers having different compositions, that is, the outer layer 3a and the inner layer 3b, it may include one layer or three or more layers. When the polyester resin coatings 2 and 3 are composed of multiple layers, they are usually formed by a co-extrusion method. The thermoplastic polyester-based resin film 2 or 3 may be a film obtained by bonding a stretched film by thermal bonding or an adhesive layer depending on the case.

As the aluminum plate 1, a hard aluminum alloy for cans (for example, H19 material) is preferably used. It is preferable that both surfaces of the aluminum plate 1 are subjected to a surface treatment such as a chemical conversion treatment after cleaning, but may not be subjected to a surface treatment. However, in the latter case, the surface needs to be completely cleaned. The thickness of the aluminum plate 1 is usually about 0.15 to 0.40 mm.

The thermoplastic polyester resin is a copolymer or a blend containing polyethylene terephthalate or polybutylene terephthalate as a main component, and preferably has a melting point of about 200 to 260 ° C. The thickness of the polyester resin coatings 2 and 3 is usually about 5 to 40.
μm.

A lubricant is applied to the surfaces of the polyester resin coatings 2 and 3 by a conventional method, for example, by roll coating. As the lubricant, those which do not have a problem in food hygiene and can be easily volatilized and removed by heating at about 200 ° C., such as glamor wax, liquid paraffin, synthetic paraffin, white petrolatum, palm oil, various natural waxes, and polyethylene wax are preferable. Used. Among them, those having particularly excellent lubricity, for example, glamor wax are preferably used. The application amount is usually about 0.1 to 200 mg / m ^2.
(Single sided), and a punch 10
And the amount by which the dynamic frictional force with the seamless can body 60 during and after each ironing operation is as small as possible is selected.

From a resin-coated aluminum plate 4 coated with a lubricant, a cupping press (for example, JP-A-7-299) is used.
No. 534 (see FIGS. 3 and 4), a drawing cup body 5 as shown in FIG. 2 is formed at a high speed by a punching and drawing method. The aperture ratio is usually 1.2 to 2.
0.

The method of manufacturing the seamless can 60 (see FIG. 6) by drawing the punch cup body 5 in a dry state and in one stroke in a single stroke after re-drawing, ironing and bottom processing, and then removing the punch from the punch is as follows. Without using (cooling lubricating liquid), cooling is performed by internally cooling each tool such as a punch and ironing ring die, and lubrication is performed using a lubricant. Etc. are almost the same.

[0020] 35-70 ° C in the punch 10 before continuous can-making
The heating liquid kept at an appropriate temperature (B ° C.) in the range of (1) is circulated, and the liquid circulating in the punch 10 immediately before or immediately after the start of the continuous can-making is heated in the range of 15 to 70 ° C. Further, ironing is performed by switching to a cooling liquid at an appropriate temperature (C ° C.) of B ° C. or lower. The appropriate temperature (C ° C.) is a temperature at which the surface temperature of the punch can be maintained at an appropriate temperature (A ° C.) within a range of 35 to 100 ° C. during continuous can making.

The surface temperature of the punch 10 during continuous can production is 35
If the temperature is lower than ℃, the thermoplastic polyester resin coating 2
It seems that the fluidity of the lubricant was poor.
Since the kinetic frictional force between the seamless can bodies 60 after the ironing is increased, the end face of the open end 62 of the seamless can body 60 and its vicinity (which is made of an aluminum alloy and has relatively small strength) buckle. The punch cannot be pulled out (that is, rolled back), and the apparatus is easily stopped. When the surface temperature of the punch 10 is higher than 100 ° C.,
Since the temperature of the thermoplastic polyester-based resin 2 or 3 covering the aluminum plate 1 is much higher than the glass transition point (Tg) of the resin, the resin is softened and easily adheres to a punch and a ring die. As a result, the dynamic frictional force between the seamless cans 60 during the ironing process is increased, so that the outer surface of the seamless can 60 is vertically scratched, broken, or rolled back, and the apparatus is easily stopped.

When the punch 10 is at a relatively low temperature (for example, about 20
° C), when continuous can making (ironing) is started at high speed without spraying coolant, the punch 10 and
It is considered that the coefficient of dynamic friction (μ) between the resin coatings on the surface of the seamless can body 60 during ironing is large, that is, the dynamic friction force is large (the lubricant does not work effectively due to low temperature). Rolling back occurs in the ironing operation of the first can, and the apparatus stops, so that subsequent processing becomes impossible. 35-70 ° C in punch before starting continuous can
The heating liquid maintained at an appropriate temperature (B ° C.) in the range of (1) is circulated, and the liquid circulating in the punch immediately before or immediately after the start of continuous can making is circulated in the range of 15 to 70 ° C. B
Switching to a cooling liquid at an appropriate temperature (C ° C.)
This trouble can be prevented by ironing.

If the temperature of the heating liquid is lower than 35 ° C., the surface temperature of the punch at the start of continuous can making is lower than 35 ° C., so that the punch 10 and the seamless can 60 during ironing are processed.
Since the dynamic frictional force between the resin coatings on the surface is large (the lubricant does not work effectively due to the low temperature), troubles such as rollback occur, which is not preferable. On the other hand, if the temperature is higher than 70 ° C., the heat generated by the molding of the can body causes the heating liquid to be changed to the cooling liquid immediately before or immediately after the continuous can-making, and the cooling is not in time, and the punch surface temperature is 100 ° C. Beyond
Rollback and the like occur, making continuous can making impossible.

FIG. 3, FIG. 4, and FIG. 5 are explanatory drawings of a horizontal redrawing-ironing apparatus 6 for carrying out the method of the present invention. FIG. 3 shows the upstream part of the device 6 and FIG.
Indicates a downstream portion of the device 6. As shown in FIG. 5, the punch 10 mainly includes a support cylinder 13 and a sleeve 14 (made of cemented carbide). The punch 10 is a punch post 11
And an air blowing hole 12 for can stripping penetrates the center. At least the surface of the portion of the sleeve 14 that is in contact with the inner surface of the molded seamless can 60 is provided with a number of point-shaped concave portions, linear circumferential concave portions, or cross-hatched concave portions (for example, see Japanese Patent Application Laid-Open No. 7-300124). (As described). This is for facilitating the removal (stripping) of the punch 10 from the seamless can body 60.

A first water circulation guide hole 15 extending in the horizontal direction is formed in the support cylinder 13. The tip of the water circulation guide hole 15 is connected to a spiral water circulation guide hole 16 provided between the support cylinder 13 and the sleeve 14. Water circulation hole 1
6 is connected to a horizontally extending second water circulation guide hole (not shown) formed in the support cylinder 13. The diameter of the portion 10a of the punch 10 that is to be in contact with the relatively thick open end 62 of the seamless can 60 to be formed is set to be slightly smaller than the diameter of the main punch portion 10b. A short cylindrical hole 17 and a ring-shaped portion 18 are formed at the end of the punch 10. The outer surface of the ring-shaped portion 18 is a slender lower inclined surface 18a whose cross section is slightly concave near the center in the height direction. The peripheral surface 17a of the hole 17 and the inclined surface 18a are connected via a curvature 18b.

In FIGS. 3 and 4, reference numeral 20 denotes a wrinkle retainer, in which a cylindrical water circulation guide hole 22 is provided. Reference numeral 22a denotes an inlet for water, and an outlet (not shown) is provided near the inlet 22a. Wrinkle holder 20
The flange portion 21 is pressed toward the downstream side under elastic pressure by a pressing device (not shown).
A redrawing ring die 26, a first ironing ring die 27, a second ironing ring die 28, a third ironing ring die 29, and the like are mounted on the holder 25. If the ironing is pure ironing, an ironing ring die (not shown) is provided instead of the redraw ring die 26.

The redrawing ring die 26, the first ironing ring die 27, the second ironing ring die 28, and the third
Water circulation guide holes 31, 32, 33, and 34 are provided to surround the ironing ring die 29, respectively. 31
a, 32a, 33a and 34a are water circulation conduits 3 respectively.
1, 32, 33 and 34 entrances. Although not shown, an outlet for water is provided near each of the inlets 31a, 32a, 33a and 34a. Redraw Ring Die 2
6 has a radius of curvature of 2.9 times the thickness t of the resin-coated aluminum plate 4, that is, greater than 2.9 × t.

Reference numeral 40 denotes a known stripper device including a plurality of fingers 41, a ring spring 42, and an O-ring 43. The inner diameter formed by the plurality of fingers 41 due to pressing inward in the circumferential direction by the ring spring 42 is determined to be slightly smaller than the outer diameter of the punch 10. Therefore, when the punch 10 and the seamless can body 60 before bottom molding pass, the fingers 41
Presses the punch 10 and the seamless can 60 before the bottom is formed elastically.

The bottom forming device 50 includes the doming die 5
1. A fixed retainer 53 having a hold-down ring 52 and an inward flange portion 53a is provided. The hold-down ring 52 is constantly pressed toward the upstream side by a plurality of shafts 54 with elastic pressure. Therefore, before and after the punch 10 enters and exits the fixed retainer 53, the free end face of the hold-down ring 52 has an inward flange portion 5.
It is in contact with the inner surface of 3a. Hold down ring 52
Is provided with an annular water circulation guide hole 55. 55a
Is an inlet of the water circulation guide hole 55, and an outlet (not shown) is provided on a shaft (not shown) adjacent to the shaft 54 having the inlet 55a.

The surface 51a of the doming die 51 has a curved surface and is connected to a cylindrical tube portion 51b having an outer diameter slightly smaller than the inner diameter of the ring-shaped portion 18 of the punch 10.
The molding surface 52a of the hold-down ring 52 is
It has a shape similar to the inclined surface 18a of the zero ring-shaped portion 18.

The re-drawing and ironing device 6 manufactures the seamless can 60 at a high speed of 100 strokes / minute or more, for example, 400 strokes / minute, as follows. Prior to the start of continuous can making (ironing), the water circulation guide hole 16 of the punch 10 is set to an appropriate temperature (B
(° C) is circulated. Wrinkle retainer 2
0, redraw ring die 26, first ironing ring die 2
7. Each of the water circulation guide holes 22, 31, 32, 33, 34, and 55 of the second ironing ring die 28, the third ironing ring die 29, and the hold down ring 52 also has heating water (preferably about 15 (Appropriate temperature between ７０70 ° C.).

Immediately before or immediately after the start of continuous can-making, the punch 1
The heating water circulating in the chamber 0 is switched to cooling water at an appropriate temperature (C ° C.) in the range of 15 to 70 ° C. and not more than the above B ° C., and the cooling water in the continuous can making (ironing) is supplied to the water circulation hole. 1
6, and the surface temperature of the punch during continuous can making (ironing) is adjusted to an appropriate temperature (A) within the range of 35 to 100 ° C.
° C).

At the same time, the water circulation guide holes 22 of the wrinkle presser 20, the redrawing ring die 26, the first ironing ring die 27, the second ironing ring die 28, the third ironing ring die 29, and the hold down ring 52 , 31, 32, 3
Heating water circulating in 3, 34 and 55 is 15 to 70
The cooling water is switched to cooling water of an appropriate temperature in the range of ° C., and the cooling water in the continuous can is circulated through the circulation holes 22, 31, 32, 33, 34, and 55, and the wrinkle presser 20 during the continuous can is manufactured. Drawing ring die 26, first ironing ring die 27, second
Ironing ring die 28, third ironing ring die 29
And the surface temperature of the hold-down ring 52 is set to 20 to
It is kept at an appropriate temperature within the range of 100 ° C.

The surface temperature of the punch at the time of continuous can making is as follows:
Maintaining the appropriate temperature within the range of 35 ° C. and the glass transition point (Tg: about 70 to 80 ° C.) of the resins of the polyester resin coatings 2 and 3 is effective in preventing the formed seamless can 60 from being rolled back. In addition, it is preferable from the viewpoint of preventing scratches on the outer surface (see Table 1 Experimental Example 5). If the surface temperature of the punch exceeds the glass transition point (Tg), it is considered that the resin films 2 and 3 are softened. The punch 10 and the dies 26, 27, 2
By maintaining the surface temperatures of the 8, 29 at an appropriate constant temperature, the average height of each can in the continuous can can be made constant.

As best shown in FIG. 3, the drawing cup body 5 is placed on the re-drawing ring die 26, and the wrinkle presser 20 is moved in the downstream direction so that the peripheral edge of the bottom 5b of the drawing cup body 5 is removed. Is pressed under elastic pressure between the ring die 26 and the wrinkle presser 20, the punch 10 is moved downstream (in the direction of the arrow), and re-drawing and ironing are performed three times. By the ironing process, the body wall portion 5a of the drawn cup body 5 is reduced in thickness and height is increased. Bottom 5b
Are substantially the same. After ironing, punch 1
0 passes through the stripper device 40, and then, in cooperation with the bottom forming device 50, performs bottom processing to form the bottom 61 of the seamless can 60 (see FIG. 6), as shown in FIG.

The tip of the punch 10 is
When it enters the fixed retainer 53 together with 0, the curvature between the bottom and the body of the seamless can body 60 before the bottom processing (corresponding to the curvature portion 5c of the drawing cup body 5) is performed by the ring-shaped portion 18 of the punch 10. The outer wall portion 61a that moves in the downstream direction while being pressed under elastic pressure between the inclined surface 18a and the molding surface 52a of the hold-down ring 52 is formed to extend obliquely downward in the radial direction. At the same time, the bottom of the seamless can 60 is pressed by the doming die 51 to form a ground contact portion 61b, an inner wall portion 61c rising almost vertically, and a dome portion 61d (see FIG. 6).

Next, when the punch 10 is returned, the end surface 64 of the seamless can 60 engages with the finger 41 of the stripper device 40, and the punch 10 is pulled out of the seamless can 60. As shown in FIG. 6, the open end 62 of the seamless can 60 is slightly thicker than the thin body main portion 63, and the end face 64 has irregular irregularities due to the occurrence of ears. It has a shape. The vicinity of the end surface 64 having the above-described uneven shape is trimmed to a specified height along the alternate long and short dash line 65 to form a flat end surface. Trimming is performed by a commonly used trimmer having an inner blade and an outer blade.

After trimming, the seamless can 60 is
After heating to 00 ° C. to volatilize and remove the lubricant, printing is performed on the outer surface, and then the printed film is dried. Thereafter, a neck-in portion 67 and a flange portion 68 are formed at the opening end portion 62, and a seamless can 100 having the neck-in portion 67 and the flange portion 68 as shown in FIG. 7 is manufactured.

[0039]

EXPERIMENTAL EXAMPLE 1 The surface was treated with phosphoric acid chromate, the thickness was 0.300 mm, and the surface roughness (Ra) was 0.35 μm.
A 16 μm-thick polyester resin film is extruded and heat-bonded to both sides of an aluminum alloy plate 1 (A3004 H19) having a thickness of 0.5 m and immediately quenched to obtain an amorphous inner polyester resin coating 2 and an outer polyester resin film. A resin-coated aluminum plate 4 having a resin coating 3 was produced.

The inner polyester resin film 2 is composed of an outer layer 2a having a thickness of 3 μm, ethylene terephthalate / ethylene isophthalate copolymer (molar ratio: 95: 5);
b was composed of two layers of a 13 μm-thick ethylene terephthalate / ethylene isophthalate copolymer (molar ratio: 85:15). The layer structure of the outer polyester resin coating 3 was the same as that of the inner polyester resin coating 2. The melting points of the polyester resins forming these resin films 2 and 3 were about 230 ° C. and the glass transition point (Tg) was about 72 ° C.

On both sides of the resin-coated aluminum plate 4,
Glamor wax (melting point about 62 ° C)
An amount of m ² (per side) was applied. After the application, a circular blank having a diameter of 156.5 mm is punched out by a draw forming machine (not shown), drawn at a draw ratio of 1.72, and the average height of the body wall portion 5a is 45 mm, the inner diameter is 91 mm, and the curvature portion 5c. Was formed to have an inner surface side curvature radius of 6 mm. The thickness of the bottom 5b of the squeeze cup body 5 was 0.332 mm, the same as the thickness of the resin-coated aluminum plate 4.

The open end 6 of the sleeve 14 of the punch 10
The outer diameter of the portion 10a corresponding to No. 2 was 65.94 mm, and the outer diameter of the main punch portion 10b was 66.05 mm. At least during the molding of the sleeve 14, the resin-coated aluminum plate 4
The surface diameter is about 0.3 mm and the depth is about 3
A large number of dot-like concave portions (having a semispherical shape) of μm were formed at a pitch of about 1 mm. The outer diameter of the wrinkle retainer 20 is 90.80.
mm, and the inner diameter was 60.30 mm. The redrawing ratio is 1.
38, the first ironing ring die 27, the second ironing ring die 28, and the third ironing ring die 29 all had an ironing rate of 30%.

Prior to the start of continuous can making (ironing), each of the water circulation guide holes 16, 20, 31, 32, 33, 34 and 55 is provided.
The heating water of 55 ° C. is circulated through the punch 10, the wrinkle presser 20, the re-drawing ring die 26, the first ironing ring die 27, the second ironing ring die 28, the third ironing ring die 29, and The temperature of the hold-down ring 52 was set to approximately 53 ° C. Immediately before starting continuous can making (ironing), the heating water is switched to cooling water at 40 ° C. and the cooling water is circulated. During continuous can making (ironing), the punch 10, the wrinkle presser 20, The aperture ring 26 and the first ironing ring die 27, the second ironing ring die 28 and the third ironing ring die 29, and the hold-down ring 52 were cooled.

Under the above conditions, as shown in Experimental Example 1 in Table 1, at a punch speed of 120 cans per minute, that is, 120 strokes / min, the height after trimming is 168.35 mm, and The inner diameter is 65.85 mm, the average thickness of the trunk main portion 63 is 0.118 mm, and the thickness of the opening end portion 62 is 0.17.
3mm seamless can 60 (for 500ml can)
Although 00 cans were continuously produced, no troubles such as a broken body, damage to the coating, peeling of the coating, and inability to strip (roll back) did not occur. The punch surface temperature in Table 1 was measured by a surface thermometer with the punch 10 stopped at the bottom dead center in the next stroke after the final can was formed. The can temperature was measured at the center of the body of the final can with a radiation thermometer. Experimental example 1
Table 1 shows the results of Nos. To 7.

[0045]

[Table 1]

Experimental Example 2: A seamless can 60 was produced in the same manner as in Experimental Example 1 except that the punch speed was set to 160 strokes / minute. As shown in Table 1, the punch surface temperature and the can temperature in this case are slightly higher than in the case of Experimental Example 1, but as in the case of Experimental Example 1, the seamless can 6 has no abnormality.
0 could be produced.

Experimental Example 3: A seamless can 60 was produced in the same manner as in Experimental Example 1, except that the punch speed was set to 200 strokes / minute. As shown in Table 1, the punch surface temperature and the can temperature in this case are slightly higher than those in the experimental example 2, but similar to the experimental example 1, the seamless can 6 has no abnormality.
0 could be produced.

Experimental Example 4: The temperature of the water for cooling the punch was 20 ° C.
A seamless can 60 was produced in the same manner as in Experimental Example 3 except for the point described above. As shown in Table 1, the punch surface temperature and the can temperature in this case were slightly lower than in the case of Experimental Example 3, but
As in the case of Experimental Example 1, the seamless can 60 was produced without any abnormality.

Experimental Example 5: A seamless can 6 was produced in the same manner as in Experimental Example 4 except that the temperature of the water for cooling the punch was 70 ° C.
0 was produced. As shown in Table 1, the punch surface temperature and the can temperature in this case were considerably higher than in the case of Experimental Example 3, but the seamless can 6
0 could be produced. However, slight abrasions occurred on the outer surface of the body of the can body 60.

Experimental Example 6: Experimental Example 3 except that the temperature of the heating water before continuous can making (ironing) was 30 ° C. below B ° C. and the heating water was circulated as cooling water as it was. When the ironing process was started in the same manner as described above, stripping (withdrawal of the punch 10) became impossible in the first can, and the apparatus was stopped. Punch 10 and seamless can 60 for low temperature
Has a larger coefficient of friction with the inner resin layer 2a, and the opening end 62 that engages with the finger 41 of the stripper device 40.
This is because the end face 64 and its vicinity (which is made of an aluminum alloy and has relatively low strength) buckled.

Experimental Example 7: Before starting continuous can making (ironing), circulating heating water at 55 ° C. to the punch 10 and stopping circulation of the heating water while maintaining the surface temperature of the punch at 53 ° C.
Immediately after that, except that the cooling water was not circulated, re-drawing and ironing were performed in the same manner as in Experimental Example 3, the surface temperature of the punch rose, and the roll stopped at about the 100th can and the device stopped. did. In this case, the punch surface temperature was measured by stopping the punch 10 artificially at a timing of about 10 cans before rollback should be performed. The can temperature was also measured for the cans made at that time. In this case, since the punch 10 is not cooled, the temperature of the punch 10 rises due to the heat generated during processing together with the number of cans to be manufactured. This temperature corresponds to the inner resin layer 2a.
Beyond the glass transition point (Tg: about 72 ° C.) of
The softening of the inner resin layer 2a becomes severe, and at the same time, the punch 10
It is considered that the rollback occurs because the coefficient of friction with the film becomes large.

Experimental Example 8 The resin-coated aluminum plate 4 having the structure described in Experimental Example 1 was coated with about 40 grammar wax.
mg / m2 [superscript] (per side)
The resin-coated aluminum plate 4 was uniformly heated at 0 ° C., 35 ° C., 80 ° C., and 120 ° C. from below using a band heater. As shown in FIG. 8, a 5 mm diameter cemented carbide tip terminal 70 attached to a rod-shaped support 71 is brought into contact with the upper surface of the resin-coated aluminum plate 4 heated to each temperature,
A load L of 1000 grams was applied from above. The resin-coated aluminum plate 4 was gradually moved to the left in the drawing, and the tip terminal 70 was rotated at a speed of 97 rpm so as to draw a circular locus 72 with a diameter of 150 mm without measuring the same place. At that time, a rotational torque applied to the support 71 was measured, and a dynamic friction coefficient was calculated from the torque. FIG. 9 shows measurement results showing the relationship between the temperature of the resin-coated aluminum plate 4 and the dynamic friction coefficient (μ).

[0053]

According to the present invention, a resin-coated seamless can made of aluminum as the base material, which is environmentally friendly and has excellent can properties such as corrosion resistance, can be continuously and stably manufactured at high speed. It works. In addition, there is an advantage that a resin-coated seamless can having a relatively large can height / diameter ratio and a base material of aluminum can be manufactured at a high speed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an example of a thermoplastic polyester resin-coated aluminum plate used in the production method of the present invention.

FIG. 2 is a longitudinal sectional view of an example of a draw cup body formed from the thermoplastic polyester resin-coated aluminum plate of FIG.

FIG. 3 shows an upstream portion of an explanatory longitudinal sectional view of an example of a redrawing-ironing apparatus for forming a seamless can body from the drawing cup body of FIG. 2;

FIG. 4 shows a downstream portion of an explanatory longitudinal sectional view of an example of a redrawing-ironing apparatus for forming a seamless can body from the drawing cup body of FIG. 2;

FIG. 5 shows an example of a punch used in the apparatus shown in FIGS. 3 and 4;
FIG.

FIG. 6 is a longitudinal sectional view of an example of a seamless can body manufactured by the apparatus of FIGS. 3 and 4;

FIG. 7 is a front view of an example of a seamless can formed from the seamless can of FIG.

FIG. 8 is an explanatory perspective view showing a method of measuring a dynamic friction coefficient (μ) between a resin-coated aluminum plate and hard metal alloy balls.

9 is a diagram showing a relationship between a dynamic friction coefficient (μ) measured by using the method shown in FIG. 8 and a temperature of a resin-coated aluminum plate.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Aluminum plate 2 Inner surface side thermoplastic polyester resin coating 3 Outer side thermoplastic polyester resin coating 4 Resin-coated aluminum plate 5 Cup body 6 Re-drawing and ironing device (device for manufacturing a resin-coated seamless can) 10 Punch 26 Redrawing ring die 27 First ironing ring die 28 Second ironing ring die 29 Third ironing ring die 60 Resin-coated seamless can body 70 Tip terminal

────────────────────────────────────────────────── ─── front page continued (51) Int.Cl. ⁷ identifications FI theme coat Bu (reference) B21D 51/26 B21D 51/26 X B65D 1/09 B65D 1/12 Z 1/12 1/00 C (72 ) Inventor Susumu Sakamoto 4601 Hongo, Hongo-cho, Toyota-gun, Hiroshima F-term (reference) 3E033 AA07 BA09 BA17 BB08 CA02 CA05 CA20 DA08 DD05 EA10 FA10

Claims (3)

[Claims] An aluminum plate is coated with a thermoplastic polyester-based resin on both sides of a resin-coated aluminum plate, and after applying a lubricant, the resin-coated aluminum plate is drawn to form a cup body. This is a method of continuously ironing a seamless can body at a high speed by performing ironing in one stroke and in a dry state by cooperation of a punch and a ring die. The punch and seamless processing during each ironing process and after each ironing process A method for producing a resin-coated seamless can, characterized in that ironing is performed under such a condition that dynamic frictional force with the can is minimized. 2. A lubricant is applied to a resin-coated aluminum plate obtained by coating both surfaces of an aluminum plate with a thermoplastic polyester resin, and then the resin-coated aluminum plate is drawn to form a cup body. This is a method for making a seamless can body at high speed continuously by ironing in one stroke and dry state by cooperation of a punch and a ring die. The surface temperature of the punch is controlled by resin-coated aluminum plate and cemented carbide. The coefficient of kinetic friction (μ) with small balls is 0.05-
A method for producing a resin-coated seamless can, characterized in that ironing is performed while maintaining the temperature appropriately within a range of 0.07. 3. The method for producing a resin-coated seamless can according to claim 1, wherein the ironing speed is 100 strokes / min or more.