JPS59105094A - Forming of metallic container for drinks - Google Patents

Abstract

PURPOSE:To prepare a metallic container for drinks which do not cause exudation of metal into contents nor corrosion of a can body and have excellent shape retention and high draw ratio, by forming a lubricant layer consisting of triglyceride on an organic coating film of a metallic plate and then forming the metallic plate by pressing. CONSTITUTION:A liquid lubricant consisting mainly of a triglyceride of a 2-18C saturated fatty acid and having 10-35 carbon atoms in total, is applied at normal temperature for formation of a uniform layer of the lubricant over an organic coating film on a metallic plate formed by relative movement of punch and die in an axial direction. The metallic plate is formed into a container for drinks by multi-step cold pressing. When the total carbon number of the unsaturated fatty acid falls short of the range of 10-35, good lubrication is unobtainable while when it exceeds said range, the lubricating and degreasing effects become poor.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for molding a beverage scrap metal container, and more specifically, it is free from troubles such as metal leaching into the contents and corrosion of the container, and the molding method is such that there is no problem such as metal leaching into the contents or corrosion of the container. (Flavor) Excellent retention,
Moreover, the present invention relates to a method for manufacturing a beverage metal container with a high drawing rate and good processing workability.

For metal containers for beverages, metal materials such as aluminum and tinplate are deep-drawn or squeezed to form a flange-fitted pot, which is then double-sealed with a flange. Alternatively, the above-mentioned material is pressed to produce a cup-shaped lower body with a bottom and a cup-shaped upper body with a spout, and A bottle-shaped container is used by joining the open end of the container with stonework.

In this drawing or pressing process, it is important to provide an organic coating film on the metal material before the process, in terms of drawing processability and productivity. Although it is preferable because it does not require the trouble of painting the case, it is preferable to use paint! When attempting to deep draw one material through several stages of press working, the following drawbacks still occur.

That is, with known painted metal materials, there is a certain drawing limit, and if this drawing limit is exceeded, it is easy to cause breakage at the head or flange part, and therefore the ratio of height to diameter decreases. It is difficult to produce large beverage cups)■t.

In addition, when the drawing ratio increases during this press processing, coating defects such as peeling, breakage, cracks, and cracks are likely to occur in the coating film on the material, and gold debris elutes into the contents < 4f.
Corrosion such as iron leaching) and pitting corrosion of the casing are likely to occur.

Furthermore, it may be possible to improve drawing processability by coating the coating film with a known lubricant, but in this case, it would be difficult to degrease the lubricant on the coating film, and the coating would be difficult to apply. A fatal drawback is that the lubricant remaining on the film tends to impair the flavor of the beverage, which relies on delicate flavor.

The present inventors applied a lubricant mainly consisting of triglyceride, which is composed of glycerin and a saturated fatty acid having 2 to 18 carbon atoms, and in which the total number of carbon atoms in the saturated fatty acids is 10 to 5, to the coating surface of a painted metal material. It has been found that when applied in the form of a solution and prior to drawing, metal beverage containers are obtained in which all of the above-mentioned disadvantages are eliminated.

That is, an object of the present invention is to provide a method for forming a metal beverage container in which the above-mentioned drawbacks are eliminated.Other objects of the present invention are to provide a method for forming metal containers for beverages that eliminates the above-mentioned drawbacks; This article provides a method for forming a metal beverage container.

Still other objects of the present invention are that the paint film on the material does not become defective during the drawing process, that it is easy to degrease and clean after molding, and that even when lubricant remains on the paint film, the contents do not lose their flavor. The purpose of the present invention is to provide a molding method for a metal beverage container that requires almost no cost.

According to the present invention, a method for forming gold, FA-J, and gold, on which an organic coating film is formed by relative axial movement of a punch and a stick, into a gold 14 container by multi-stage press working in a cold state. In this method, a liquid lubricant mainly consisting of triglyceride, which is composed of glycerin and a saturated fatty acid having 2 to 18 carbon atoms, and in which the total number of carbon atoms in the saturated fatty acids is 10 to 5, is added in the form of a solution to the organic coating of base 1 (1). There is provided a method for forming a metal beverage container, which comprises applying the lubricant to the bottom surface at room temperature to form a uniform lubricant layer, and then subjecting the lubricant to press working.

The present invention will be explained in detail below. .

In FIG. 1 showing the cross-sectional structure of a metal material to be press-formed, the metal material 1 for forming is comprised of a metal substrate 2 made of an aluminum plate, tin plate, etc., and an organic coating film provided on both surfaces of the substrate. The important feature of the present invention is that the organic coating film 3/2゜6b consists of
Prior to pressing, a solution layer 4a, 4h of a liquid lubricant mainly composed of triglyceride, which is composed of glycerin and a saturated fatty acid having 2 to 18 carbon atoms, and the saturated fatty acid has a combined carbon number of 10 to 55, is applied to the surface of the . It consists in providing uniformly. That is, the lubricant used in the present invention is made of triglyceride like normal animal and vegetable oils, but
The fatty acid that makes up the triglyceride is a saturated fatty acid with 2 to 18 carbon atoms, and the number of carbon atoms in this saturated fatty acid is in the range of 10 to 65, which is a remarkable difference from these fats and oils.

First, this triglyceride is composed of saturated mono-fatty acids and is characterized by being a liquid having an appropriate viscosity in relation to having the above-mentioned number of carbon atoms.

However, this liquid erasure is retained on the organic coating surface of the material and forms a lubricating surface with a high oil film strength, reducing stress on the special 5I parts, that is, the head and flange parts, even when machining with a high drawing rate. This has the advantage of alleviating concentration, improving the dispersion processability, and significantly improving the drawing limit. -Also,
Since the lubricant of this coating film-L is essentially liquid, the degreasing operation is easier than with solid lubricants, which brings about the advantages of λ)A. Furthermore, since the fatty acids that make up triglycerides are saturated 71-[11] fatty acids, they are tasteless and odorless compared to those made from unsaturated J]α fatty acids. Even if this substance remains, it has the advantage that it does not impart any off-taste or odor to the contents.

In addition, triglycerides formed from saturated fatty acids having the above-mentioned carbon number (-) have outstanding uniformity of coating on the surface of the organic coating on the material and excellent disintegration properties. By applying it to the organic coating surface in the form of
; E wetness 141: or uniform application 1'1 is +l et al.
do. Moreover, the various advantages mentioned above are combined and [7] According to the A-invention, the tric-lyceride-based liquid (even with Jfi-containing where the coating 1N of agent No. 1 is significantly less), Nissin's high-speed drawing process and high speed
] The advantage of being able to do so is also achieved.

In this study, it is also important that the number of saturated fatty acids constituting l-1 glycerides is in the range of 1U to '55, especially 15 to 25, and that the number of saturated fatty acids constituting l-1 glycerides is in the range of 1U to '55, especially 15 to 25. is also small, A1. mentioned above in terms of lubricity.
1 point is not achieved, and on the other hand, when it is thicker than the above range, it becomes disadvantageous both in terms of wetness 1' (9) performance and in terms of easy degreasing property of 114.

The six saturated fatty acids constituting the triglyceride used in the present invention may be the same or different from each other within the range that satisfies the above requirements.Also, it is preferable that the saturated fatty acids are straight octopus fatty acids. , it can also be a branched button fatty acid. Examples of suitable constituent fatty acids are acetic acid, butyric acid,
Caproic acid, caprylic acid, capric acid, lauric acid, milinostenoic acid, palmitic acid, stearic acid, etc.
Suitable examples of triglycerides include, but are not limited to, the following:

tributyrin, tricaproin, tricabrilin, 1.2-diaceto-6-palmitine, 1.2-diaceto-ro-stearin, 1.2-diaceto-ro-myristin, 1.2-diracto-6-laurin, 1.2-diracto-6-myristin, 11'Moto-2-Lacto-Ro1 Laurin.

In the present invention, the liquid lubricant (-C) is preferably composed of saturated fatty acid triglyceride alone (as described above); It can also be used interchangeably with other lubricants, provided they contain fatty acid triglycerides and are entirely liquid. Use in combination]-7
As the lubricant, other fatty acid glycerides, fatty acids, fatty acid esters, fatty acid amides, higher alcohols, paraffins, etc.7 can be used. These liquid lubricants are applied in the form of a solution to the coated surface of the material. ) As a solvent for liquid formation?
1! i Substantially dissolves the lubricant but dissolves the organic coating) 1
For example, lower alcohols such as ethanol to methanol;
Examples include ethers such as methyl ether and ethyl ether; hydrocarbon solvents such as benzene, toluene, and xylene; however, the solvents that can be used are of course not limited to these. The concentration of liquid lubricant in solution is generally frost,
If the weight ratio is in the range of 1 to 20, particularly 1 to 10, satisfactory results can be obtained in terms of -spreadability and (4) bone properties.

One of the advantages of the present invention is that a remarkable effect can be obtained with an extremely small amount of liquid lubricant solution applied to the surface of the organic coating film. Satisfactory results can be obtained with a coating amount of 5 to 707"F/yr?, especially 5 to 5 (C&/W). If this coating amount is less than the above range, the lubricating performance is unsatisfactory, and on the other hand, the degreasing operation is more burdensome than in the above range, which tends to be disadvantageous both economically and in terms of flavor characteristics.

In the present invention, the liquid lubricant solution is applied to the coated surface by means known per se, such as roller coating, spray coating, 7-2 bond coating, foam coating, and the like.

The coated metal plates used in the present invention are known per se. For example, as metal materials, untreated steel plates (black plates), surface-treated steel plates, such as brocade-plated copper plates (tin plate), Galvanized steel sheet, aluminized steel sheet,
Plated steel sheets such as chromium-plated magnetic plates; electrolytically treated steel sheets such as electrolytic chromic acid treated sheets; chemically treated steel sheets such as phosphoric acid and/or chromic acid treated silver sheets, and light metal plates such as aluminum, etc. ．． Composite materials such as these are used. Suitable metal materials include rolled aluminum materials made of pure aluminum or aluminum alloys, which differ depending on the drawing conditions and purpose, but are generally 0.15 to C1.80, particularly 0.17 to 0.50. It is used with a material thickness of mm. Suitable other metal materials are those whose tin content, ie the number of tin bonds per base box, is in the range from 0.1 to 10, in particular from 0.15 to 0.75. This tin plating layer may be a no-reflow board (matte board) that has been electrolytically plated, or may be a flow board (prite board) that has undergone heat melting treatment on the electrolytic plating layer. The thickness of the base plate is generally 0.
．． 15 to 0, 51+Irh,! 0.15 to 0 for samurai.
Those in the range of 35+*m are used.

On the other hand, protective paints (~ are optional protective paints consisting of thermosetting and thermoplastic resins; modified epoxy paints such as phenol-epoxy modified Fl, amino-epoxy paints = e.g. vinyl chloride-vinyl acetate copolymers, Vinyl or modified vinyl paints such as partially saponified vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-maleic anhydride copolymers, epoxy-modified, epoxyamino-modified, or epoxyphenol-modified vinyl resin paints, acrylic resins Synthetic rubber coatings such as styrene-butadiene copolymers may be used alone or in combination of two or more.

These paints can be applied to metal materials in the form of organic solvent solutions such as enamels or lacquers, or in the form of aqueous dispersions or solutions, in the form of roller coating, spray coating, dip coating, electrostatic coating, electrophoretic coating, etc. Apply. Of course, if the resin paint is thermosetting, the paint may be baked if necessary.

From the standpoint of preventing corrosion and improving drawability, it is desirable that these textured coatings have a j7 thickness (dry state) of generally 2 to 60 μm, and 3 to 20 μm for f.

According to the present invention, as shown in FIG.
It is pressed between a punch 12 and a die 16 that are movable in the axial direction relative to each other, and is formed into a seamless cup with a bottom. At this time, the solution layer of the liquid lubricant may be dried and then subjected to press processing, but in general, the solution layer after application is It is preferable to press it in its original form, that is, in a wet state.

In the present invention, press working is performed several times while gradually reducing the diameter of the punch and die until the desired shape and desired height/diameter ratio are achieved.

At this time, the drawing ratio defined by the following formula is set to 1.20 to 2.10 in one step of press working. In particular, it is desirable to set the aperture ratio to 1.60 to 190 degrees, and to set the overall aperture ratio to 1.50 to 3.00 degrees, particularly 80 degrees to 2.70 degrees.

The cup body after drawing is trimmed and then
After the rice cake is subjected to a known degreasing operation such as hot water washing, solvent washing, and freon gas washing, it is used for subsequent rice cake production.

That is, in a normal deep-drawn can with a two-piece structure, neck-in processing and flange processing are performed as necessary, and after the contents are filled, the can is double-sealed to form a can.

- In the case of a bottle-shaped metal container having a circumferential side seam, a lower body 20 consisting of a bottomed cup as shown in FIG.
An upper body 21 consisting of an inverted cup with an opening is formed, and as shown in FIG. 4, these two are overlapped and joined via an adhesive layer 22 to form a bottle-shaped container.

The invention is illustrated by the following example.

Example 1 Liquid vinyl paint was applied to the inner and outer surfaces of an aluminum plate (0041119 material) with a base thickness of 0261 mm, so that the total coating amount was 1.
50 v'g / 4 + 2.60"! / dn?
IJn [Symbol/1. -11 (fatty acid carbon number: 8, fatty acid gold side carbon number: 24) was diluted to 5% by weight using ethanol. Apply wedge lubricant to the inner and outer coating surfaces if6 using a roll method at room temperature.5rny/n? become"
, evenly applied to the sea urchin.

Thereafter, it was punched into a disk with a diameter of 250 mm, thoroughly squeezed, and then adjusted in the same manner as in Example 1, and coated on a lh plate.
After donating blood, put it into a multi-stage press during c'l+ time and insert the drinking metal utensil.

These 11 contents were filled in the same manner as in Example 1, and the respective properties were evaluated. Table 1 shows the results.
Shown below.

Example: Tin-plated copper plate with a thickness of 020 (tin plated, plated-1)
# 25 / 25, Temper T-2) was coated with epoxy tA fl on the inner and outer surfaces, and the total coating amount was 10.
0 rpq/rln? , 5 (l m)/dn?
Press molding was carried out using the same liquid lubricant as in Example 1, except that coating and baking were carried out so that As a result, even in the case of epoxy-based (tin-plated steel sheets coated with i" material), according to the forming method of forming the liquid lubricant of the present invention, the press formability is improved. There was no difference in terms of metal elution and flavor.1 (It was found that good metal containers similar to those of Examples 1 to 5 were obtained.0 [Evaluation of metal containers] The above examples, In comparative examples, metal containers were evaluated according to the method described below.

(b) Fill a metal container with 1% chloride l]um aqueous solution,
A voltage of 7V was applied, and the frost value (mA) flowing at that time was evaluated. Ten pieces of each were measured, and their arithmetic mean value was adopted as the result.

(b) Metal eluted metal The synthetic carbonated beverage was filled in a container, and the amount of eluted metal was measured by atomic absorption spectrometry after the container was allowed to cool for 7 days. 1 (III) was determined for 10 each, and their 3γ surgical average value was adopted as the result.

(c) Flavor test After storing the synthetic carbonated beverage in a metal container for 6 months at room temperature, a flavor test was conducted by 20 people. ,5(button~1(
Evil) and 1 to [7.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing the drawing of the scrap metal material used in press forming. Fig. 2 is a cross-sectional view of a pot explaining the drawing process of the gold striped moon. Figs. 6 to 4 are press forming methods according to the present invention. 1 is a diagram showing a specific example of a metal container for explaining the river fish number 1 is a metal material, and 2 is gold I-μ(÷t'j, filter a
. 6b is an organic coating film, 4a and 4b are liquid lubricant solutions? IT layer,
10 is a painted metal material, 11 is a wrinkle presser, 12 is a punch,
16 is a guide, 20 is a lower body, 21 is an upper body, 22 is an adhesive layer, and 26 is a joint edge. Patent applicant Kishi Kishi 1113 Figure 3-619- Figure 4

Claims (2)

[Claims] (1) In a method in which a metal material on which an organic coating is formed by relative axial movement between a punch and a die is formed into a metal container by cold multi-stage press working, a saturated carbon material containing glycerin and a carbon number of 2 to 18 is used. A liquid lubricant mainly composed of triglycerides consisting of fatty acids and saturated fatty acids with a total carbon radius of 10 to 65 is applied in the form of a solution to the organic coating surface of the material at room temperature to form a uniform lubricant layer. 1. A method for forming a metal beverage container, the method comprising: applying the material to press processing. (2) The method according to claim 1, wherein the solution of the liquid lubricant is applied to the surface of the organic coating film in an amount of 5 to 70 π/day based on nonvolatile components.