JPS6021133A - Production of adhered can for opening by winding - Google Patents

Abstract

PURPOSE:To obtain an adhered can for food, etc. having excellent opening property by winding, corrosion resistance, etc. by subjecting the end edge of a blank material for can provided with a tongue piece for initiation of winding to the end of a joint and provided with an adhesive agent layer on the opposite surface of the joint to high frequency induction heating and forming the material to a cylindrical shape. CONSTITUTION:A tongue piece 6 for opening is provided to the end 3 of a blank material 1 for a painted can and the neck part thereof is scored 7a, 7b. A thermoplastic adhesive tape is provided to the end edge 2 on the inside of the joint. Both end edges of such blank material 14''' are set in a pair of high frequency induction heaters 22a, 22b. A conductor 26 is interposed between the piece 6 and the heaters 22a, 22b in this stage to shield the electromagnetical coupling and to couple electromagnetically both end edges of the material 14''' to the heaters 22a, 22b. Overcurrent is thus induced in the end edges of the blank material by which the adhesive material layer is heated. The blank material is then transferred to a can making stage where the material is formed to a cylindrical shape and the superposed parts are cooled under pressure to form the adhered joint.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a roll-opening adhesive, and more particularly, it has a combination of excellent roll-opening properties, sealing properties, corrosion resistance, and hygienic properties. The present invention relates to a method for efficiently manufacturing a winding and unsealing adhesive nail.

Conventionally, roll-open cans have been widely used as containers for storing livestock products such as corned beef, beef, and luncheon meat. The most widely used tin can with a seam formed with a seam is a tongue piece formed at the outer end of the seam, and a tongue piece is formed from the base of the tongue piece. A plurality of scores are engraved around the circumference, and when opening the package, the tongue piece is inserted into the hole of the winding key, the key is turned to break the score, and the strips of tin between the scores are rolled up. Open the package.

This known roll-opening can has several significant drawbacks associated with the use of a knife for seam formation. That is, NO-NDA is an alloy of tin and lead, which has an undesirable effect on the contents.

Of course, it is possible to use gold-tin powder that does not contain lead, but gold-tin/'% powder has lower strength than alloy powder, making it difficult to form joints that can withstand high-temperature heat sterilization. . Next, when unrolling, it is necessary to break the score while peeling off the seam, but the cohesive force of solder is an order of magnitude larger than that of resin, so it is necessary to break the score while peeling off the seam. A considerably large force is required, and troubles such as breakage of the tongue often occur when starting to unwind and unseal. In addition, tin cans have the problem that compounds produced by the decomposition of meat, etc., react with metal tin, resulting in a black coloration, so-called sulfide blackening.

Conventionally, as an alternative to soldering cans, adhesives are made of tin-free steel (RPS: electrolytic chromic acid treated steel plates, etc.) and the side seams are joined with thermal adhesive using thermoplastic resin adhesive such as nylon. BACKGROUND ART Cans have come to be widely used for carbonated beverages and other beverages.

When applying this joint-to-face seam bonding using thermal adhesive to the start of winding and unsealing, there are several important issues to be solved, including the adhesion and sealing of the seam where the tongue for starting winding and unsealing is provided. It has been found that corrosion resistance is generally low.

In other words, side seam adhesives generally involve applying thermoplastic adhesive to the edges of painted metal plates to be joined, and applying high-frequency induction heating to the edges coated with the adhesive to melt the adhesive resin. It is manufactured by forming the material into a cylindrical shape in the state of , and overlapping both edges with molten adhesive [~], and then cooling this under pressure. The reason for this is thought to be that heating is concentrated at the edge portion where the tongue piece is provided, and the primer coating and adhesive resin in this portion are likely to deteriorate due to heat and oxidation.

Accordingly, an object of the present invention is to provide a method for manufacturing a rolled-up adhesive can which overcomes the above-mentioned conventional drawbacks.

Another object of the present invention is to provide a method by which adhesive cans can be produced which have a combination of excellent roll-opening performance, sealing properties, corrosion resistance and hygienic properties.

Still another object of the present invention is to provide a method for efficiently manufacturing the above-mentioned rolled-up adhesive can.

According to the present invention, a tongue piece for starting winding is integrally provided on the edge portion that is to be the outer side of the seam, and a plurality of winding pieces are formed from the base of the tongue piece to the entire surface that is to be the outer surface of the seam. A can material with a thermoplastic adhesive layer engraved with a plastic score and a thermoplastic adhesive layer provided on the opposing surfaces of both edges that should form a seam is supplied to a high-frequency induction heating region to heat the edges. A conductor is interposed between the tongue and the high-frequency induction heating device to prevent electromagnetic coupling between the tongue and the high-frequency induction heating device. There is provided a method for producing an adhesive pin for winding and unsealing, which is characterized in that the adhesive seam is formed by molding into a shape and pressing and cooling both overlapping end edges (7) to form an adhesive joint.

The invention will be explained in detail below on the basis of specific examples included in the accompanying drawings.

In FIG. 1, which shows an unfolded adhesive can for opening a roll according to the present invention, the adhesive can is made of a painted metal plating material 1 as a whole. It has an end 6 on the left side that should be on the outside of the seam. Its upper and lower ends are still flanged portions 4 and 5 for seaming with the can lid.

An opening tongue piece 6 that protrudes outward from the edge is provided at the end portion 6 that should be the outside of the seam, and a plurality of score 7a shift h- −
-1 are engraved in parallel over the entire longitudinal direction of the material 1. It is preferable to provide notches 8α and Bh at the base of the tongue piece 6 in order to facilitate the breakage of the score when starting to open the bag. The material 1 (see FIG. 1) consists of a metal substrate 9, such as tin-free steel or aluminum, and a primer coating 1o provided on this metal substrate. This primer coating film 10 has the function of protecting the metal substrate from corrosion and promoting adhesion of the thermoplastic resin adhesive described later. A polyamide-based or polyester-based thermoplastic adhesive tape 11 is provided on the edge 2 that is to become the inner side of the seam, and a portion of this tape 11 extends outward from the cut edge 12 of the edge. The cut edge 12 is completely protected by being applied so as to protrude and being turned back 180 degrees at the cut edge 12. It is possible to provide the adhesive tape layer 16 also on the surface of the end 6 which should be the outside of the seam and which is to be overlapped with the inner end 2.
This is important from the viewpoint of adhesive workability.

According to the present invention, the inner edge 2 and the outer edge 6 of the can material shown in FIGS. 1 and 2 are bonded together, as shown in the perspective view in FIG. The adhesive is formed so as to overlap with each other via the adhesive layers 11 and 16 and to have a predetermined cross-sectional end shape, and the adhesive is melted and solidified by suppressed cooling to form a bonded nail.

It is an object of the present invention to eliminate problems such as poor adhesion and poor sealing at the end edge of the base of the tongue piece 6, and to efficiently perform the iron making operation.

In FIG. 5 for explaining the manufacturing process of the present invention, first, in the score engraving step (A) VC, the coated metal material 14
The score engraving blade 15 is applied to engrave scores 7α and 7b (see FIG. 1) on one surface of the material 14.

The coated metal plates 14' on which the scores have been engraved are stacked at a supply station (B), and fed one by one from the supply station (B) by a feeder 16 for the next series of processing. First, in a heating step (C), both end edges of the material 14' to be joined are guided to a pair of high-frequency induction heating devices 17a and 17b, and these end edges are heated by induction.

In the adhesive application step (D), two adhesive application rollers 1 are used, corresponding to the surfaces to be faced when the materials are overlapped and joined.
8. z and 18b are provided, and the supplied thermoplastic resin adhesives 11' and 16' are adhered to heated predetermined positions of the material. For the edges that are to be on the inside of the seam, the adhesive tape 11' is applied in such a way that it protrudes outward from the cut edge, while for the edges that are to be on the outside of the seam, it is applied from the outside. Tape 16' is adhered so as to be located a certain distance inwardly from the cut edge in connection with providing the opening initiation tongue. In the next edge covering step (E), a suitable bending mechanism 19 is used to bend the portion of the adhesive tape 11' that protrudes from the edge.
Cover the cut edges. Adhesive tape 11' and 1
6' is applied continuously across the material sheets that are fed next to each other, so in the cutting process CF), the cutting mechanisms 20α and 20h cut and remove the adhesive that spans between the material sheets. 0 The adhesive tape that spans each material sheet can be cut without using a cutting machine by tearing the adhesive tape by pulling the material sheets together before the adhesive tape hardens.

In the cooling process (G), the material 14'' to which the adhesive has been applied is cooled by cooling mechanisms 21a, 21i5 such as blowing cold air to solidify the adhesive layer.

In the notching step (H), the metal material outside the adhesive layer 16 is sheared using a press die or the like (not shown) to form the opening initiation tongue 6 and the notches 8tl and 8h at the base.
(see Figure 1), and the edges to be overlapped are notched. Then, if desired, the opening initiation tongue formed in the bending step <1) is coated with the adhesive layer 13. Bend it to the side at almost a right angle.

In the heating step CI), the can material on which the tongue piece 6 is provided and the adhesives 11 and 16 are applied is guided to the high-frequency induction heating devices 22α and 22b, and is intermittently stopped at the position of this device. Both ends to be joined are heated by induction.

At this time, according to the present invention, a conductor is interposed between the tongue piece 6 and the high-frequency induction heating device 22h to prevent electromagnetic coupling between the two, thereby preventing the tongue piece 6 and its surroundings from being heated up.

In the present invention, in FIGS. 6-A, 6-B, and 6-c showing details of the high-frequency induction heating device used in this step, the high-frequency induction heating device 22h (22i1) is made of heat-resistant material such as Bakelite. A holder 26 having a U-shaped cross section and made of electrically insulating resin, and this holder 2
It consists of a pair of cores 24 made of a magnetic material such as ferrite that are supported vertically in opposing directions within the core 6, and a conductor (coil) 26 for passing high frequency current provided in a groove 25 in the core. This conductor 26 and core 24 are the material 14 for can manufacturing.
The conductor and the core are electromagnetically coupled to the edge of the material, and an eddy current is induced in the edge of the material. Heating of the edges and thus of the adhesive layer takes place.

The induction heating device 225 for heating the edge on the side where the tongue piece 6 is provided includes a magnetic shielding device along the ferrite core 26 in order to prevent concentrated heating on the tongue piece 6. A conductor 27 is provided. This conductor 27 is made of, for example, a copper plate with excellent electrical conductivity and thermal conductivity, and has a portion 28 along the outer side wall of the core 26 and a portion 29 along the horizontal wall of the core 26, and is used for shielding. Although the vertical side wall portion 28 of the conductor is provided over almost the entire surface,
The horizontal wall portion 29 is provided only in a portion corresponding to the tongue piece 6. Further, since the magnetic shield conductor 27 is heated by the eddy current, a cooling vibro 0- is provided to cool it, and the conductor 27 is cooled by passing cold water or the like inside the pipe.

In the present invention, the shielding conductor is arranged so as to prevent concentrated heating of the tongue piece 6 and the notches 8a and f3h (the position and dimensions are currently being determined. In Fig. 7, opposing shielding conductors 27.
The distance t between the tongues 27 is desirably equal to or less than 15 in order to prevent concentrated heating on the tongue piece 6. This distance t is 1
If it exceeds 5wn, the shielding will be insufficient, the temperature of the tongue piece 6 will rise even more, and the heating efficiency will further decrease. Material 14'
When the thickness of the conductor is between 0.15 and 0.30, I! is appropriately within the range of 5 to 15, taking into account the plate distortion.On the other hand, the dimension t of the horizontal portion 29 of the conductor also depends on the distance t; as the - dimension decreases, the dimension also decreases. For example, if the dimension is smaller than 3 mm, t
may be zero. However, even in this case, the conductor portion 28 of the side wall portion is of course essential. 5 gates mentioned above ≦
In the range of t≦15 mm, the range of 4wn≦t≦10 is appropriate for the purpose of the present invention. According to the present invention, the shield made of the conductor described above is By applying high frequency induction heating to the tongue 6 or the vicinity thereof, it is possible to prevent concentrated heating of the tongue 6 or its vicinity, thereby preventing thermal deterioration or oxidative deterioration of the primer coating film and adhesive in this area, and furthermore, the adhesive It becomes possible to uniformly and efficiently heat the edge portion where the layer 13 is provided.

The part-making material 14# with heated both end edges provided with the adhesive layer is formed into a cylinder 31 in the iron-making process CK), and the overlapped end edges are cooled with a hammer 62. The seam is formed by pumping the edges, crimping the edges, and solidifying the adhesive by cooling.

Next, if desired, in a springing step (L), the cylindrical body 61 is cut into the springing dies 33, 33. ! :Mesh together to form the cylindrical body into a conductor 64 of a desired shape.

Finally, in the painting process (M), the housing 64 is
A protective film is applied to the outer surface of the film using a coating tool such as a coating roller 65, and the film is baked to form the rolled-up adhesive pin of the present invention.

The materials used for the opening adhesive of the present invention are not particularly limited, but the following are preferred.

As the metal material, any metal material for iron making that is difficult to join by soldering, such as tin-free steel (
rps ) material or aluminum material is used as the oTFS material, which includes a copper plate substrate such as a rolled steel plate, and a chromium coating layer selected from the group consisting of metallic chromium, nonmetallic chromium, and combinations thereof applied to the surface of the steel plate substrate. A compound consisting of the following is known, and this compound is preferably used for the purpose of the present invention.

The chromium-containing coating layer has a content of 0.06 to 3 in terms of chromium.
．． 6 Misaki/drr? , especially 0.1 to 2.5 fn
t/d, n? Films with a film thickness in the range of 100 to 100% are generally easily available and suitable for the present invention, but of course there is no need to be limited to this, and aluminum-plated steel sheets, nickel-plated steel sheets, etc. may also be used depending on the application. can.

As the aluminum material, in addition to so-called pure aluminum, an aluminum alloy mainly composed of alumina and containing at least one alloy component such as magnesium, manganese, silicon, iron, copper, etc. is used. 0 Thickness of metal material < 1 ) is generally in the range of 0.10 to 0.60, and within this range, it is [[) for TFS material, 12 to 0.35 mm, and 0.1 for At material.
It is desirable that the distance be in the range of 15 to 0.50 m.

In the present invention, the primer, that is, the protective paint and adhesion promoting paint is preferably an epoxy resin paint, that is, one containing an epoxy resin II), and the CocoF epoxy resin is dihydric phenols and shrimp halohydrin. A polycondensate or a modified product thereof is used. This epoxy resin can be used as it is as a paint component, and can also be used with known modifiers, such as higher fatty acids, aromatic acid anhydrides, -valent phenols, carboxylic acid-containing acrylic oligomers, and dimer polyamides. , rosin, etc., and can be used as a paint component in the form of a modified epoxy resin. The above-mentioned epoxy resin components are generally combined with other resin components, such as phenol-formaldehyde resins, furan-formaldehyde resins, xylene-formaldehyde resins, ketone-formaldehyde resins, which also act as curing agents for the epoxy resin component and also as film-forming components. Resin, urea/formaldehyde resin, melamine/formaldehyde resin, alkyd resin, unsaturated polyester resin,
It is used in combination with bismaleimide resin, thermosetting acrylic resin, urethane resin, vinyl chloride copolymer resin, silicone resin, etc.

The thickness of the primer coating is generally desirably in the range 0.5 to 20 microns, particularly 1 to 10 microns.

As the thermoplastic resin adhesive, a polyamide-based or polyester-based thermoplastic resin, which is known per se, is used, which melts when heated and firmly bonds the substrates together in the process of melting, cooling, and assimilation. This thermoplastic resin should have a melting point or softening point of 110 to 300 C for thermal bonding workability.

When forming the seam, the lap width should generally be in the range of 1 to 20 m, particularly 2 to 10 m, and the thickness of the adhesive layer interposed in the seam should generally be in the range of 0.001 to 0.25 m.
*It is best to set it in the range of 0.02 to 0.15 wun.

Note that the size of the tongue piece and the interval between the scores can be varied depending on the size of the end, etc., but since the adhesive nail of the present invention can be easily rolled up and unsealed, the interval between the scores is generally 2 to 20 mm. If the length of the tongue is within the range of 2 to 15 rRm, satisfactory opening performance can be obtained.

The invention is illustrated by the following example.

Example 1 Epoxy/phenolic paint (with a weight ratio of epoxy resin to phenol resin near 0/30) to a film thickness of 2 μm. An epoxy/phenol paint containing 5 pHR of wax was applied to the deflecting surface side of the coated plate, excluding the adhesive portions on the end side, to a film thickness of 5 μm and baked. After cutting this painted board into end blanks with a medium diameter of 235.5 W and a height of 75 mm, a scoring machine is used to score a pair of blade angles of 65° and a depth of 40 μm at a width of 6 mm in the longitudinal direction of the end blanks. Apply evenly. Next, both edges of the blank to be bonded were heated by high-frequency fat conduction heating, and a nylon adhesive tape with a thickness of 404 m2 and width of 8 ram was pasted on the edge of the blank, which was to become the inner surface of the end side, with the inner surface folded back by 2 mm. Arrived,
A similar adhesive tape with a width of 6 is affixed to the inner surface of the edge that should become the outer surface. Next, the adhesive tape is cut and the adhesive part is air-cooled, and then a notch or the like is formed by pressing on the winding and unsealing tongue part connected to the score and the edge part which is to become the wrapping part of the overlapping adhesive part.

Next, both ends of the blank were heated using a high-frequency induction heating device (No. 6-
(see figure A), or apply J! to the heating coil and ferrite core on the side with the winding and opening tongue. ,=6rr
The blank was heated using a high-frequency induction heating device equipped with a copper plate shielding plate (un, t = 8 rtan cm (see figure 7)), and then formed into a rectangular can using wing-form type aluminum alloy material, and both edges of the blank were wrapped with double wire. The parts are joined together and crimped by pumping with a cooled hammer, and the adhesive is cooled and solidified to complete the chain side joint.

Next, a spring ring process is applied to the side surface of the bell body, flanges are formed on both ends of the can body using the usual method, and double wrapping is performed on one side.

To this 1000 cans, add 180 tons of 0.4 chicitric acid - 1.5 chi salt solution, hot parakun, and 109 liters of lard.
- Apply a 90 minute retort. After cooling these ends, 37
After being stored for 6 months in R, all units were subjected to a diversion test, and the deflection vacuum was good at 30 to 45 cmHy, and no abnormalities were observed in the bonded part of the drum or part of the inner surface of the score, indicating extremely good performance. was.

On the other hand, score processing was performed using the same end blank,
When joining the same end blanks with the same adhesive and molded opening tongue notches, etc. to the end side, a heating device is installed at the part facing the opening tongue to prevent local heating. High-frequency induction heating was performed using a device without a shielding plate, and the bell body was pumped and crimped with a cooling hammer under the same conditions as described above, and the panel was formed in the same way and the bell body was tightened to confirm the fit and fail. - Filled with lard, retorted under the same conditions as above, and stored at 67C. - After several months, the degree of deflection vacuum was 0, so when we opened it and inspected it, we found "lifting" in the adhesive part at the base of the opening tongue.0 Example 2゜Same as Example 1 The size of the shielding copper plate for preventing local heating of the high frequency heating device for end side bonding is t = 2.
Luncheon meat was placed in a can made using the same process as in Example 1, except that mr and t = 20rtan. Fill it, retort sterilize it at 116C for 90 minutes, and cool it down to 37℃.
It was stored in C for 6 months.

Six months later, 20 cans were opened, and the contents were inspected and the inner surface of the iron was observed and evaluated.

Concerning the contents, transfer of iron sulfide was observed in the area where the luncheon meat was in contact with the inner edge of the yard seam, and black discoloration was observed on the inner surface of the iron starting from the folded edge of the adhesive part, especially for opening. This is especially noticeable at the base of the tongue,
Part of it had progressed to the inner surface of the adhesive layer.

On the other hand, except for the thickness of the shielding copper plate, t = 4 mm and t = 14 m, cans manufactured under the same conditions were filled with luncheon meat in the same manner, and when the cans were stored under the same conditions, the contents were
No abnormalities were observed on the inner surface of the chisel, which remained in good condition even after some time had passed.

Example 6: Example 1 except that the shielding copper plate for preventing local heating of the high-frequency heating device for end side bonding is L = 12rrrm and t = 3-.
A can made under the same conditions as above was filled with Wiener sausages, retorted at 116C for 70 minutes, cooled, and heated to 3I.
'Kept in '. After 5 months, 20 cans were opened and 6
The track had a deflection vacuum of OcmHg. For those cans, peeling was observed in a part of the adhesive part at the base of the opening tongue.On the other hand, the cans were manufactured under exactly the same conditions except that the shielding copper plate was 1 = 10 mm and t = 5 fat. Filled with Wiener sausage under the same conditions and retorted it to 37 tl & C.
The stored canned contents exhibited good storage stability with no decrease in the degree of vacuum even after a certain period of time, and the condition of the inner surface of the iron was also good.

[Brief explanation of drawings]

Fig. 1 is a developed view of an example of the end side of the adhesive for winding and unsealing of the present invention, Fig. 2 is an enlarged sectional view of the unevenly assembled material shown in Fig. FIG. 4 is an enlarged sectional view of the seam of the adhesive end for winding and unsealing, FIG. 5 is an explanatory view showing the iron making process, and FIG. FIG. 4 is a perspective view showing the positional relationship between the material and the high-frequency induction heating device in step C1) in FIG. FIG. 6-0 is a longitudinal sectional view of the main parts of the induction heating device shown in FIG. 6-A, and FIG. 7 is a dimensional relationship of the main parts of the induction heating device shown in FIG. 6-A. FIG. 1 is the material for the can, 6 is the opening tongue, 7a and 7h are the scores,
11 is an adhesive tape, 22a and 22b are high-frequency induction heating coils, 24 is a core, 26 is a conductor, 27 is a magnetic shielding conductor, 28 is a portion along the outer side wall, and 29 is a portion along the horizontal wall, respectively. show. Figure 5-A Figure 6-8 Figure 6-C Figure 7

Claims (1)

[Claims] (1) A tongue for starting winding is integrally formed on the edge that is to be the outside of the seam, and a plurality of winding scores are engraved from the base of the tongue to the entire surface that is to become the outer surface of the can. The material for the can, which has a thermoplastic adhesive layer on the facing surfaces of both edges that are to become a seam, is supplied to a high-frequency induction heating area, and both edges are heated by a high-frequency induction heating device. At that time, a conductor is interposed between the tongue piece and the high-frequency induction heating device to shield the electromagnetic coupling between the two, and then the material with the heated end edge is formed into a cylindrical shape. A method for producing an adhesive nail for winding and unsealing, characterized in that both overlapping end edges are cooled under pressure to form an adhesive joint.