JPS60240343A - Metallic can and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to the field of metal container manufacturing. In particular, the present invention provides a metal mouthpiece with a thermoplastic lining that is free of tin or lead. The bar joint is joined by melting a thermoplastic lining laminated to the metal.

The present invention further relates to a method for manufacturing the metal can.

BACKGROUND OF THE INVENTION Food products are currently packaged and sold in many types of containers. These containers are designed to be stored either at room temperature, below freezing humidity, or refrigerated. Containers stored at room temperature contain dry or liquid food products. When the food product contains a liquid, the container is usually made of metal.

However, the interior metal surfaces of the container must be coated or lined with a protective material lining to prevent corrosion of the surfaces. Metal containers for food products, i.e. metal cans, are three-component cans Bwo-piece ca.
n) or three-piece can
ce can). The three-part @configuration can is formed of a cylindrical part having a closing end at both ends, and a can end sealed to the open end. Typically, the cylinder is made by bending tin-coated IlI sheets into a cylindrical shape and joining them along side seams.

When the three-part canister is made to withstand high temperature disinfection operations, the side seams are usually formed with interconnecting barbed ends, and the ends are sealed with lυ soldering. It was sealed. Each of said can ends is connected to each open end of said cylindrical part by a double interconnecting hooked joint between the can end and the cylindrical part, and the curved surface of said can end is provided with gaskets 1 to 1. The lining is covered. Using a tin-coated steel plate for the cylindrical portion avoids increasing costs. However, said use requires that appropriate soldering connections be made at the side seam locations. Current technology for soldering at the side seam location has reduced the amount of lead used in the side seam to a very small amount, yet food product cans are still 100% lead-free. Legislation of a law stipulating that it should be carried out is imminent.

In three-piece constructions, side edge lap seams formed by either welding or adhesive bonding are an alternative to soldered side hook seams. Although such side edge lap seams have eliminated the need for soldering, each of these techniques has its own technical complexities.

Forming welded side seams requires the use of expensive and unique electrical, cooling, welding and support equipment. Despite this, it is difficult to achieve perfect welding without variations. Welded side seams are formed by bending sheet metal into a cylindrical shape, overlapping the edges, and welding along the overlapping edges. After the side seams are welded, the side bands are coated to protect the bare metal around the welded seams.

Added to this side band coating is another base coat, which is applied to the remaining inner surface of the cylinder. The undercoat and side bands are required to protect the metal against corrosion due to gun contents. Epoxy Commonly used as a base coat for phenolic resins or enamels. Welded and seamed cans require two separate coating operations, the base coat and the side strips, and each such coating requires a separate curing process, so the welding process is unnecessary. The manufacturing cost is rather expensive. A particularly complex problem associated with welded seams is that the side band sheathing must simultaneously bond to both the exposed metal and the F coating around the welded seam. Welded side seams and related techniques are described in U.S. Pat.
, 339.483, 4.3/116.814, 4,352,001, 4,376.884, 4.382,525, 4.384.657 J3 and No. 4,387.830.

Adhesive bonding or cement bonding requires thermoplastic adhesive $3
Side edge overlap seams can be formed by taking one strip and joining the contacting and overlapping edge portions of the cylindrically bent sheets. Nylon 11, nylon 12, nylon 610 (nylo
Nylon, such as N 11 , Nylon 12, Nylon 610) are examples of thermoplastic adhesives used in adhesive bonded side lap seams. The adhesive is applied as a film, tape or powder in a process separate from the step of applying the protective primer. Another problem that occurs with adhesive bonding of side seams is caused by the exposed metal edges located inside the side edge lap seams (
It is. This exposed metal edge is a potential source of corrosion, and U.S. Pat. Added target culm. Undercoat (b
A common problem associated with ase coatings is the creation of discontinuities in the protective coating due to improper application or subsequent scratches. An example of an adhesive bonded side edge lap seam is shown in U.S. Patent No. 3.898.9.
No. 45, No. 4.101.534 and No. 4.296.182.

Two-piece metal cans can be made of metals other than tin-coated steel. This is because the metal cans do not irritate side seams that require a high degree of structural integrity in interconnecting solder joints that can withstand high sterilization temperatures. However, three-component metal guns require high costs due to their manufacturing equipment;
It has been found that due to the heavy use of materials and cost limitations in manufacturing large two-piece cans, as is well known to those skilled in the art, relatively limited commercial use has been achieved. One open end of the cylindrical part is closed by the can end by forming a double joint in the interconnecting curved surface between the flange of the cylindrical part and the can end. In order to achieve a highly complete hermetic seal, a gas fitting 1-lining is installed in the area of the curved section.

(Problems to be Solved by the Present Invention) An object of the present invention is to provide a two- or three-member metal can that solves many of the problems described above, and a method for manufacturing the same. Three-part apple molded metal cans according to the invention can be disinfected at high temperatures without the use of VF-coated metal and lead-containing soldering, and without the need for undercoat protective enamel or side seam bands. The required structural integrity to withstand processing can be achieved.

(Means for Solving the Problems) According to the present invention, an improved method for manufacturing a three-part apple molded metal can is provided. Formed by connecting a thin metal sheet to a cylindrical part having open ends at both ends at its side seams,
In the method for manufacturing a three-part apple molded metal gun in which each open end is closed with a can end, substantially all of the inner major surface and outer major surface of the thin metal sheet are made of thermoplastic at least a portion adjacent to the side joint. Covered with lining I material,
bending the sheet metal to define a cylindrical part so as to form a side seam at the contacting edge portions, and applying a thermoplastic lining material in the area of the side seam to seal the side seam; A method for manufacturing a metal can is provided, which is characterized by fusion bonding.

Preferably, said thin sheet metal is tin-free steel and said thermoplastic lining material is polypropylene. The present invention further provides a three-part apple molded metal can made by the present manufacturing method.

The fusion bonding occurs by applying heat and pressure to the area of the seam.

In another aspect of the present invention, there is provided an improved method of manufacturing gold reach that includes at least two pieces joined by at least one seam. The method for manufacturing metal cans comprises forming each metal member of the metal can by coating substantially the entirety of the inner surface of each metal member with an inner lining of polypropylene; By fusion bonding the lining polypropylene, the seam remains hermetically sealed during disinfection operations at temperatures above 112.8°C (below 235°C) without the use of aluminum or lead. 2. A method of manufacturing a metal overlay characterized by bonding the seam with sufficient strength to

(Effects of the Invention) The metal cans produced by the metal can manufacturing method according to the present invention have important advantages over metal cans currently on the market. Sanbe Ringo Formed Metal Can Manufacturing is able to provide highly structurally intact side seams that can withstand high temperature sterilization operations without the need for lead-containing soldering, yet It now offers metal cans made from cheaper, soot-free metal.

Since the use of lead-containing solder (=Jt) is no longer used, potential lead contamination is completely prevented. The present invention also has advantages over metal cans made by welding or forming adhesively bonded side seams. Eliminates the need to separately apply primer and side bands to welded seams. Since the present invention uses a pre-coated thermoplastic lining abrasive for both purposes as an internal protective coating and as a bonding material for the side seams, a separate primer coating carried out on said adhesively bonded side seams This simplifies the work and attaching the adhesive strip. When using the manufacturing method according to the invention for attaching the can end to either a two-part apple molded metal can or a three-part apple molded metal can,
This eliminates the need to use a rubber gasket, and furthermore, the tightness J'A
The sealing quality was improved by fusion bonding of the thermoplastic lining in the seam area. The method for manufacturing metal cans according to the present invention has a further advantage in that currently available metal can manufacturing equipment can be used. This is because the manufacturing method utilizes a standard seam shape and two heating steps already used to form the bond fJ4 seam. Therefore, expensive improvement investment costs were avoided.

The various advantages and novel features which characterize the invention are particularly pointed out in the claims and above. However, for a better understanding of the invention, and the advantages and advantages to be achieved by using the invention, as illustrated and disclosed in the accompanying drawings, which form a part of this specification, and the following description with reference thereto, Reference is made to some embodiments of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, in which similar parts are designated by like reference numerals, FIG. It is shown. Details of the lining of the can 10 are not shown in FIG. 1, but are shown in enlarged dimensions in FIGS. 3, 4 and 5. The can 10 is formed by a cylindrical portion 12 having opposing openings 14 and 16, and a pair of can ends 18 and 20.

In FIG. 1, can 10 is shown partially assembled. That is, the cylindrical part 12 is made by bending a flat metal sheet 22 into a cylindrical shape and joining the edges of the metal sheet 22 along the side seams 23.
Can ends 18 and 20 are in an unattached condition.

Assembly of can 10 in accordance with the present invention begins with the forming of sheet metal 22 having a layer or lining of thermoplastic lining material 124, preferably polypropylene, attached to both major surfaces thereof. Thermoplastic lining material 24
is coated over the entire main surface of the thin metal plate 22 forming the inner surface of the can 10. This method eliminates the need for a subsequent undercoat. A thermoplastic lining material 24 coated on the opposite major surface extends at least along the area of the side seam 23. however,
Preferably the opposite main surface (outer surface) of the thin metal plate 22
The entire body may be covered with a thermoplastic lining 24.

Vercules Inc. (1LE) is a thin sheet metal material coated with polypropylene on both major surfaces.
It was developed and is commercially manufactured by Rcules In-Corporatcd. thin metal sheet 22
is preferably made of glass-free steel; however, the sheet metal 22 may be made of other metals suitable for container manufacture, such as tinplate, tinplate with a differential coating, or aluminium. can.

The cylindrical portion 12 is formed from a flat sheet metal 22 in a known manner. That is, forming mutually connecting hooks 26 and 28 along both edges of the thin metal root 22, bending the thin metal plate 22 into a cylindrical shape, and bringing the two phase Ti connecting hooks 26 and 28 into contact with each other. The cylindrical portion 12 is formed by connecting the two edges and applying an impact or pressing to the inner piece stopper 26 and 28. A thermoplastic lining material 24 is coated onto the essential surfaces of the interconnecting hooks 26 and 28. heat in the area of the interconnecting hooks 26 and 28 forming the side seam 23; 1 melt bonding by applying heat to the plastic lining material 24;
Preferably the heat is applied by an RF generator.

The RF generator applies heat to the side seam 23 in a controlled and selective manner. Alternatively, other suitable heat sources can be used, such as gas burners, radiant or infrared heat sources.

Interlocking hooks 26 and 28 by deforming the metal vJ roots
Pressure is applied to the thermoplastic lining material 24 within the side seam 23 to cause it to form.

As best seen in FIG. 4, the can end 18 is similarly attached to the cylindrical portion 12 by fusion bonding the thermoplastic lining material within the interconnecting barbs. f)
The ends 18 and 2o are also made of thin sheet metal such as that used to form the cylindrical portion 12. The interior major surface of each can end 18J3 and 20 is entirely coated with a thermoplastic lining material 24, while the exterior major surface thereof is similarly coated at least along its outer periphery. Preferably, the entire major exterior surface is coated with a thermoplastic lining material 24. The thermoplastic lining material is preferably polypropylene.

The can ends 18 and 20 are shaped into cylinders in the following manner. A curved portion 30 (FIG. 1) is formed around each circumference of the can ends 18#3 and 20 by well known methods, and flanges 32 (FIG. 1) are formed around each of the open ends of cylindrical portion 12 by well known methods. 14 and 16, respectively. The curved portion 30 and flange 32 form interconnecting hooks 31 and 33 as shown in FIG.
The cylindrical portions 12 are interconnected and connected at each open end by well known methods. The subsequent heat source used when forming the side seams 23 was then applied to each of said interconnecting hooks 31.3.
The thermoplastic lining UI 24 in the region of 3 is heated to fuse and bond the thermoplastic lining material 24 in this region of each hook 31.33. Furthermore, pressure is also applied to the thermoplastic lining material 24 in the area of the interconnecting hook 31.33, deforming the sheet metal 22 to form a compressed interconnecting hook 31.33.

When the fusion bonded seam of the present invention is formed of polypropylene, the seam has structural integrity and is suitable for use with food products of, for example, 235°C (235°C) and above. The high temperatures that can occur during the disinfection process of filling operations can be withstood without loss of the hermetic seal. Such a hermetic seal can be maintained without the use of soot-bearing steel or leaded solder.

FIG. 2 shows a partially assembled two-part apple molding can 10' according to the present invention. Can 10' includes a cylindrical portion 12' having an integral end 20' and a separate can end 18' in a manner well known in the art.

The cylindrical part 12 and can end 18' with integral ends 20' are made of thin sheet metal and lined with thermoplastic lining material in the same manner as in the case of said cylindrical part 12 and can ends 18 and 2o. is coated on both major surfaces of the sheet metal. The cancer end 18' is attached to the only open end 14' of the cylindrical part 12', and the cancer end 18' and the cylindrical part 12' are connected to each other according to the method of the present invention as described above in connection with FIG. The open ends 14' are each attached by fusion bonding the thermoplastic lining material located between the interconnecting barbs formed therein.

FIG. 5 shows another embodiment of the invention, in which the cylindrical portion 12
The side seam 23″ of ″ is a side edge overlap seam (lap
-5ide seam) and tail.

The cylindrical part 12'' is made of a thin sheet metal 22'', and on both major surfaces of the sheet metal 22'', preferably over almost its entirety, a thermoplastic lining material 24'' is coated, as in the case of the cylindrical part 12. has been done. The metal sheet 22'' is bent into a cylindrical shape, and its side edges 36 and 38 are fitted together.

Overlapping side edges 36 and 38 form side seam 23''
are sealed and interconnected by fusion bonding the thermoplastic lining material located in the areas.

Said fusion bonding is accomplished by applying both heat and pressure (schematically indicated by arrows in FIG. 5) to the area around the side seam 23''. The pressure to be applied is preferably 2.8kgf/cm ~4..2k (If
'/cm (4.0 to 60 psi) and the heat is preferably 182.2°C to 193.3°C (360 below to 380 below). The heat and pressure are, for example, 5 to 12
applied over a relatively short period of time, such as seconds. By applying both heat and pressure to the side seam 23'', the thermoplastic lining material coagulates and flows to coat the exposed edges 42 and 44 of the sheet metal 22''.

After the thermoplastic lining material 24'' is melt bonded within the side seam 23'', the thermoplastic lining material 24'' is used to bond the seam and form a layer of protective material covering the edges 42 and 44. It acts as both.

The many features and advantages of the invention have been described above, along with the detailed structure and operation of the invention, and the novel features of the invention are pointed out in the claims. However, the above disclosure is illustrative, and modifications may be made in details, particularly in matters of shape and size, and without departing from the principles of the invention, to the fullest extent within the meaning of the terms of the claims. It goes without saying that this is possible depending on the arrangement of the members.

[Brief explanation of drawings]

Fig. 1 is a schematic developed side view with a part cut away of a three-part apple molded metal can based on the present invention, and Fig. 2 is a schematic developed side view with a partially cut away of a two-part apple molded metal can based on the present invention. 3 is an enlarged cross-sectional view taken generally along line 1--1 in FIG.
-5ide seam), FIG. 4 shows an enlarged sectional view of the seam for sewing between the can end and the cylindrical portion manufactured according to the present invention, and FIG. FIG. 4 is an enlarged cross-sectional view showing a side edge overlap seam formed based on the invention; io, io'...Can (metal can) 12.12', 12''...Cylindrical part 14.14'
, 16...opening end 18.18', 20.20'...can end 22.22
', 22''...Sheet metal 23. 23', 23''...Side seams 24.24', 24''...Thermoplastic lining material 26.28...Interconnecting hooks 31.33 ...Interconnecting hook part 36.38...Side edge (edge part) 42.44...Exposed edge (bare metal edge) Agent Koga Asamura 3.

Claims (1)

[Claims] (1) Made by connecting thin metal sheets at their side seams to form a cylindrical part having open ends at both ends, and closing each open end with a can end. In a three-component metal can manufacturing method, (2) covering almost the entire inner major surface and the portion of the outer major surface adjacent to the side seam of the thin metal plate with a thermoplastic lining; c) bending said sheet metal to define a cylindrical portion such that the contacting edge portions form a side seam; fusion bonding the thermoplastic lining material of the region;
A metal can manufacturing method characterized by the following. (2) In the method described in claim 1,
The method for manufacturing a metal can, wherein substantially the entire outer major surface of the thin metal sheet is coated with the thermoplastic lining material. (3) In the method described in claim 1,
A method for manufacturing a metal can, wherein the thin metal plate is made of steel that does not contain tin. (4) In the method described in claim 1,
The method of manufacturing a metal can includes heating the side seam using a radio frequency generator. (5) In the method described in claim 1,
The method for manufacturing a metal can, wherein the step (a) includes heating the side seam using a gas burner. (6) In the method described in claim 1,
The method for manufacturing a metal can includes heating the side seam using a radiant heat device. (7) In the method described in claim 1,
The method for manufacturing a metal can includes heating the side seam using an infrared heating device. (8) In the method described in claim 1,
A method for manufacturing a metal can, wherein the thermoplastic lining material is polypropylene. (9) In the method described in claim 1,
The metal can manufacturing method, wherein the contacting side edge portion is formed with an overlapping end portion. (10) In the method according to claim 1,
The contacting side edge portion is formed as one part of an interconnecting piece.7j Metal can manufacturing method. (11) A five-member metal can, including a cylindrical part having an open end, and separate first and second can ends attached to the open ends at both ends of the cylindrical part, The cylindrical part is seamed along a side seam and its inner surface is formed of a thin sheet metal coated entirely with a thermoplastic lining material, and the side seam is formed by the contact of the thin sheet metal. The outer surface of the cylindrical portion is formed along the edge so that at least the area of the side seam is protected from heat.
Metal can, characterized in that it is coated with a plastic lining material and the side seams are hermetically sealed by fusion bonding of the thermoplastic lining material in its area. (12. In the can according to claim 11, each said can end is formed of a thin sheet metal having an inner surface entirely coated with a thermoplastic lining material, and the part is attached to the open end of the cylindrical part by an interconnecting catch between the cylindrical part and the hook end and by fusion bonding of the thermoplastic lining material in the area of the interconnecting catch. Hermetically sealed metal can. (13) The can according to claim 11, wherein the thermoplastic lining material is polypropylene. (14) The can according to claim 12. In the metal can, the thermoplastic lining material covering the cylindrical part and the can end is polypropylene. (15) In the can according to claim 11, the thin metal sheet does not contain tin. A metal can formed of steel. (16) In the cancer according to claim 12, the thin metal plate forming the cylindrical part and the can end is a metal can made of soot-free steel. (17) The metal container according to claim 13, wherein the thin metal sheet is steel containing no 10%. (18) The metal container according to claim 14, The thin metal sheet forming the cylindrical portion and the can end is a soot-free steel. (19) A metal plate having at least two metal members connected by at least one seam. In the method of manufacturing a can, each metal member of the metal can is formed by covering an inner surface of each metal member substantially entirely with an inner lining material of polypropylene, and in the region of the seam, the inner lining polypropylene By fusion-bonding the joints, without the use of tin or lead, the joints are strong enough to remain hermetically sealed during disinfection operations at humidity above 112.8°C (below 235°C). (2. In the method according to claim 19,
The metal can is a two-part metal can, and the at least one seam is formed between interconnecting hooks formed by the open end of the cylindrical part and the can end, respectively. (2. In the method described in claim 19,
The metal can is a three-component metal can including a cylindrical part having a frontage end at both ends, and a can end part taken in each of the opening ends, and the cylindrical part is formed of a thin metal plate. and the at least one seam includes a side seam along the axial direction of the cylindrical portion and two end seams formed between each of the can ends and the cylindrical portion. Production method. (2. In the method described in claim 21,
The side seam is formed at interconnecting hooks along opposing edge portions of the sheet metal forming the cylindrical portion. (2. In the method described in claim 21,
The side seam is formed by overlapping edge portions of the metal sheets forming the cylindrical part. (2. In the method described in claim 22,
The metal can manufacturing method, wherein the gold IA thin plate forming the cylindrical portion is made of tin-free steel. (25) A method for producing a metal cancer according to the claims, wherein the thin metal plate forming and covering the cylindrical portion is made of steel without tin. (26) The method for manufacturing a metal can according to claim 21, wherein the outer surface of the thin metal plate at least in the region of the side seam is coated with polypropylene. (27) A three-piece structure made by connecting thin gold B thin plates at both ends with the open end of the cylindrical part and its side seams, and closing each open end with the cancer end. In the method for manufacturing a shape metal delivery box, (au) covering substantially the entire inner and outer major surfaces of the thin metal plate with a polypropylene lining, and (c) forming a side seam at the edge portion where the thin metal plate is bent and comes into contact. defining a cylindrical portion by (0) fusion bonding the polypropylene lining in the region of the side seam by applying heat and pressure to the region of the side seam to seal the side seam; (28) The method according to claim 27, wherein the pressure applied to the side seam is between 2.8 and 4.8.
A method for manufacturing metal cans ranging from 40 to 60 psi. (29) In the method as set forth in claim 27, the step (c) is performed by forming an edge portion of the thin metal plates overlapping each other such that the exposed metal edge is the end of the inner edge. forming a side seam, and step (f) comprising applying sufficient pressure to cause the polyp 1'' pyrene lining to flow and cover the exposed metal edges. . (30) The method according to claim 27, wherein step (c) includes forming a side seam without interconnecting hooks along the edge portion of the metal sheet. Production method. (31) The method of claim 27, wherein the heat applied to the side seam ranges from 182.2°C to 193.3°C (360'F to 380'
F) A metal can manufacturing method. 32. The method of claim 31, wherein the heat is applied to the side seam for about 5 to 12 seconds. (33) A method according to claim 31, wherein the pressure applied in the region of the side seam is between 2.8 and 4. 2kOf 7cm2 (40 to 60psi) metal fabrication method.