JPS6220101B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a composite can and a method for manufacturing the same, and more particularly to a composite can that has barrier properties and preservability comparable to metal cans, is lightweight and can be incinerated, and a method for manufacturing the same. Among various types of containers, metal cans have particularly excellent barrier properties of completely shielding the contents from the outside air and are excellent in preserving the contents. There is a problem in that it is difficult to dispose of. In order to reduce the weight of the metal can itself and reduce the cost of the metal used, various attempts have been made to reduce the material thickness of the metal can. However, these attempts have not been fully successful. For example, in the case of cans that are filled with contents that have their own pressure, such as beer or carbonated drinks, that is, internal pressure cans, deformation of the can due to internal pressure will not become a problem even if the thickness of the can body is considerably reduced. There aren't many, but
Due to the rolling force applied when tightening the can body and can lid,
Since the can body undergoes deformation such as buckling, it is extremely difficult to reduce the thickness of the can body beyond a certain limit value. In addition, in cans where the contents are stored under reduced pressure, such as fruit juice cans and regular food cans, in other words, baquium cans, the thickness of the can body must be considerably thicker than that of internal pressure cans, otherwise external pressure will be applied to the can body. As a result, the can body is easily deformed. In recent years, the weight of containers has already been reduced by taking advantage of the excellent gas barrier properties of metals and using metals as a component of composite materials. The most typical type of composite material container is called a laminated pouch, which is a flexible laminated pouch consisting of a metal foil with a heat-sealable resin layer on the inside and a more heat-resistant plastic film layer on the outside. The sheets are stacked one on top of the other with the heat sealant facing each other, and the periphery is heat sealed. This laminated pouch not only lacks self-reliance and shape retention as a container, but also has problems with the preservation of the contents. The long-term shelf life of the contents cannot be expected due to the formation of so-called blisters between the container and the metal foil, resulting in a decrease in barrier properties. Furthermore, this type of container has a productivity limitation in that it must be sealed by heat sealing. With heat sealing, sealing is only possible through heat transfer to the heat sealant layer and melting of the heat sealant layer, so it requires a long time of 1 to 2 seconds to seal, and the sealing operation is mechanically performed. Although it is possible to fill at high speeds of 250 to 1200 cans/min with heavy seaming, it is clear that productivity is extremely poor. Therefore, an object of the present invention is to provide a metal foil, a plastic layer provided on the outer surface of the metal foil, and a protective coating film provided on the inner surface of the metal foil, and to have barrier properties and storage properties comparable to those of metal cans. It is an object of the present invention to provide a composite can which has the following features and which can be sealed by double seaming. Another object of the present invention is to reduce the thickness of the metal material used to the same level as foil without impairing barrier properties or double-sealing properties, and as a result, to create a composite can that is lightweight and inexpensive. is to provide. Still another object of the present invention is to provide a composite can that allows the empty can to be easily disposed of by incineration. Still another object of the present invention is to provide a method for manufacturing a composite can, which can be manufactured using conventional can manufacturing equipment, with the same operation as a conventional can manufacturing operation, except for the use of composite materials. It is on offer. Still another object of the present invention is to provide a method for manufacturing a composite can that can be manufactured and sealed at a high production rate. According to the present invention, in a can formed by double-sealing a can body member and a pair of can end members vertically, the can body member is located on the inner surface side and is made of metal having a protective coating on the inner surface. It is formed from a laminate of foil and an outer plastic layer, at least the metal foil in the laminate having a seam extending from one end of the can body to the other, and the protective coating is carbonyl based. , hydroxyl group, ether group, and epoxy group at a concentration of 10 to 2000 mmol/100 g of resin, and the plastic layer has a polar group of at least 85 kg/mm ² or more. A composite can is provided having a modulus of elasticity and a thickness sufficient to provide self-retention to the can body. The invention will now be described with reference to specific examples shown in the accompanying drawings. In FIG. 1 showing the composite can of the present invention, the composite can consists of a can body member generally designated 1 and a pair of can end members generally designated 2 and 2', both of which are double-sealed. integrated and sealed. One of the important features of the composite can of the present invention is that, as shown in the cross-sectional view of FIG. It consists in being formed from a laminate with a plastic layer 5 located on the outer side. That is, the present invention has a laminated structure in the order of protective coating 3/metal foil 4/plastic layer 5 from the inner surface to the outer surface of the can, thereby making it easier to mold the can body, flange processing, and more. This is based on the knowledge that the double-sealing operation is the easiest to perform and achieves the best barrier properties and preservation of the contents. In this case, it is preferable to provide an adhesive layer 6 between the metal foil 4 and the plastic layer 5 in order to ensure good moldability and further strengthen the self-holding properties of the molding. As already mentioned, in a composite container in which a plastic layer is provided on the inner surface of the metal foil 4, when filled with highly corrosive contents, blisters are generated between the plastic layer and the metal foil.
Corrosion of the metal foil and associated deterioration of gas barrier properties occur. However, if even one hole occurs in the metal foil due to such corrosion, the plastic layer has considerable gas permeability to varying degrees, and there is a large pressure difference between the inside and outside of the can, so Gas leakage occurs, reducing the shelf life of the contents. The reason for this is not completely clear, but the plastic layer itself has a non-negligible permeability to corrosive components such as ions and water.
It is thought that corrosive components permeate through areas where there is poor adhesion between the plastic layer and the metal foil, eventually leading to the formation of blisters. On the contrary,
According to the present invention, by providing the protective coating film 3 within the metal foil 4, not only the adhesion with the metal foil is significantly improved, but also the permeation of corrosive components toward the metal foil is suppressed. This prevents blistering and corrosion of the metal foil, and achieves the continuous gas barrier effect of the metal foil. In addition, the metal foil itself has extremely poor machinability, and furthermore, it is easily deformed and scratched during processing. On the other hand, according to the present invention,
By bonding plastic to the outside of the metal foil to form a laminate, the inner layer of the metal foil is free from wrinkles, cracks, pinholes, etc.
It is possible to form a can body with a smooth inner surface, and furthermore, this can body can be plastic-processed into a flange and can be double-sealed with a can end member. The can body member 1 of the composite can of the present invention is formed from a laminate of the painted metal foil 4 and the plastic layer 5, as described above, and at least the metal foil 4 of this laminate extends from one end of the can body to the other end. It has a seam 7 extending to the end. In the specific example shown in FIG. 1, this seam 7 extends vertically and straight from one end of the can body to the other, but this seam can also extend in a so-called spiral shape from one end to the other. Furthermore, it can take any shape such as a curved line or a bent line. Seams in metal foils or in laminates of integral metal foils and plastic layers may be formed by lap joints, butt joints, lock seams, or combinations thereof, as detailed below regarding manufacturing methods. can be formed. In the present invention, the protective coating film is carbonyl

[Formula] 10 to 2000 mmol/100 g of resin, especially 50 to 1600 mmol/
It is also extremely important from the point of view of adhesion to the metal foil that the resin or resin composition, especially a thermosetting resin or its composition, be contained at a concentration of 100 g of resin. That is, those containing polar groups in an amount greater than the lower limit of the above concentration have excellent adhesion to metal foil,
When contained in an amount smaller than the above upper limit, the coating film itself has good durability. Furthermore, it is desirable for the protective coating to have a density of greater than 1.0 g/cc, particularly from 1.1 to 1.4 g/cc, from the viewpoint of barrier properties against corrosive components. In the polar group of the protective coating film of the present invention, carbonyl

[Formula] The group may be a carbonyl group based on a carboxylic acid, a carboxylate, a carboxylic acid ester, a carboxylic acid amide, a carbonate ester, a urea, or a urethane bond. It may be contained as a pendant group or a terminal group on the molecular chain. Suitable examples of protective coatings include thermosetting resin coatings, such as phenol-formaldehyde resins, furan-formaldehyde resins, xylene-formaldehyde resins, ketone-formaldehyde resins,
Urea-formaldehyde resins, melamine-formaldehyde resins, alkyd resins, unsaturated polyester resins, epoxy resins, bismaleimide resins, triallyl cyanurate resins, thermosetting acrylic resins, silicone resins, oil-based resins, or thermoplastic resin coatings, such as chloride Vinyl-vinyl acetate copolymer, partially saponified vinyl chloride-vinyl acetate copolymer, vinyl chloride-maleic acid copolymer, vinyl chloride-maleic acid-vinyl acetate copolymer, acrylic polymer, saturated polyester resin, etc. be. These resin coatings may be used alone or in combination of two or more. From the standpoint of adhesion to the metal foil substrate and corrosion resistance, a thermosetting coating film with a gel fraction in the range of 50 to 100%, determined by extraction in chloroform at 60°C for 60 minutes, is preferred. It is. The most suitable protective coatings for the purposes of this invention are compositions containing epoxy resins and other resins. As epoxy resin component, epoxy compounds with more than one oxirane ring in the molecule, especially bisepoxides, are used; preferred epoxy resin components have an epoxy equivalent weight of 450 to 5500, especially 1000 to 5000. The most preferred epoxy resin components are aromatic epoxy resins derived from bisphenols and epihalohydrins. The other resin component (curing agent component) mentioned above has a functional group that can react with the epoxy resin on its molecular chain, such as a hydroxyl group, a carboxyl group, an acid anhydride group, an amino group, or an amide group, and is preferably Resins which themselves have coating film-forming ability may be used alone or in combination of two or more. Examples of suitable curing agent resin components include, but are not limited to:
Hydroxyl group-containing resins are as follows: resol type phenol aldehyde resin, xylene aldehyde resin, urea-aldehyde resin,
Melamine-aldehyde resin, vinyl chloride-vinyl acetate copolymer partially or completely saponified product, hydroxyalkyl ester type acrylic resin. Acid- or acid anhydride-containing resin: vinyl chloride-maleic anhydride copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, carboxylic acid-containing acrylic resin. Resins containing amino groups or amide groups: dimer acid-modified polyamide resins, aminoalkyl ester type acrylic resins. Curing agent resin components suitable for the purpose of the present invention are those containing hydroxyl groups or those containing acids or acid anhydrides. The epoxy resin component and hardener resin component are 95:
They are preferably used in combination at a weight ratio of 5 to 1:99, particularly 90:10 to 5:95. That is, when the amount of the epoxy resin component is less than the above range, the adhesion to aluminum foil tends to decrease, while when it exceeds the above range, the corrosion resistance tends to decrease. In the present invention, it is extremely important that the plastic layer, as a can body member, has sufficient strength and thickness to provide self-retention of the can shape during the can forming, can manufacturing and distribution steps. Prevents buckling of the can body due to compressive force or vertical load during high-speed flange forming and double seaming similar to conventional can manufacturing operations, as well as buckling due to vertical load when transporting empty cans and stacking them in warehouses. The most severe condition for form self-retention is the vertical load during double seaming. Although the vertical load varies depending on the material and thickness of the can flange and the diameter of the can body, a vertical load of 100 to 150 kg is usually required when performing high-speed double seaming similar to conventional can making operations. . Table 1 shows the experimental values of the longitudinal elastic modulus of the plastic body member and the critical elastic buckling thickness of the can shell under a vertical load of 150 kg, and Table 2 shows the tensile and flexural modulus of elasticity of various plastics. On the other hand, the plastic layer has several advantages in terms of formability into sheets, flange formability, size of the seamed part, can body formation (cylindrical formation), light weight, and economic efficiency.
It is desirable that it be in the range of 0.3 to 1.5 mm, especially 0.4 to 1.0 mm. In view of the above, the plastic layer should be at least 85 kg/kg to provide self-retention in form.
It is necessary to have an elastic modulus of mm ² or more. Suitable examples of such plastic layers include, but are not limited to, medium- or high-density polyethylene, isotactic polypropylene, polymethylpentene, crystalline propylene-ethylene copolymers, propylene-ethylene copolymers, etc. Olefin resins such as butene copolymers; vinyl chloride resins such as polyvinyl chloride, vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinylidene chloride copolymers; polystyrene, ABS resins (acrylonitrile-butadiene-styrene copolymers); Styrenic resins such as polyethylene terephthalate, polytetramethylene terephthalate, polyethylene terephthalate/isophthalate, polyethylene/butylene terephthalate, polyethylene naphthoate; polycarbonate resins; nylon 6, nylon 6,6, nylon 6/
Nylon 6,6 copolymer, nylon 12, nylon
13, polyamide resins such as nylon 6, 10, and nylon 6/nylon 10 copolymers; polyacetal resins; thermoplastic resins such as polymethyl methacrylate resins, high nitrile resins with a nitrile content of 60 wt% or more, and polyphenylene oxide resins. In particular, olefin resins, vinyl chloride resins, styrene resins, polyester resins, and polycarbonate resins are preferred from the viewpoint of melt extrudability, sheet moldability, and economical efficiency.

[Table] Indicates the minimum thickness at which bending occurs.

【table】

[Table] * Indicates tensile elastic modulus or bending elastic modulus.
These plastics can be used alone or in the form of a blend of two or more types, and the plastic layer can be a single layer or a laminated plastic layer of two or more layers. Fillers or reinforcing agents may be added to the plastic layer in order to increase its weight and, without impairing the elongation of the plastic layer, particularly improve its formation into the can body and further improve the self-shape retention of the plastic layer. It can be blended. Such fillers include:
Various types of silica such as light to heavy calcium carbonate, vapor phase decomposition silica, neutralized silica or acid silica; magnesium fillers such as magnesium oxide, magnesium hydroxide, and magnesium carbonate; calcium silicate, magnesium silicate Examples include silicates such as , talc, and asbestos powder; aluminosilicates such as kaolin, bentonite, calcined kaolin, and other clays; and calcium sulfate such as anhydrite. As the reinforcing agent, powdered reinforcing agents such as carbon black and white carbon, fiber agents such as glass fiber and rock wool, and flaky reinforcing agents such as mica, metal flakes, and flaky glass are used. Furthermore, organic fillers or reinforcing agents such as wood flour, shell fibers, cotton, and aromatic polyamides can also be used. When thermoplastic resin is flanged at a relatively low temperature, elastic recovery after processing (spring back)
occurs. In particular, when the molded composite can is subjected to high temperatures such as retorting or hot-packing the contents, springback may cause poor seaming or deformation of the can. However, it has been found that springback can be significantly suppressed by mixing the filler described above. Furthermore, it has been found that by increasing the heat resistance temperature (heat deformation temperature) of the plastic layer itself, the form independence against heat and temperature of the composite can according to the present invention increases significantly. Next, the filler can be mixed into the thermoplastic resin within a range that does not impair the moldability into a sheet or film, the moldability into a can body, the flange plastic workability, and the double seamability. In other words, these fillers or reinforcing agents are
5 to 500 parts by weight per 100 parts by weight, especially 10 to 200 parts by weight
When used in the amount of parts by weight, good results are obtained with respect to the aforementioned objectives (suppression of spring back, formability into can bodies, flanging properties and double seaming properties). The plastic layer to be used may contain compounding agents known per se, such as colorants, antioxidants, ultraviolet absorbers, heat stabilizers, lubricants, plasticizers, antistatic agents, etc., according to known formulations. As the metal foil, light metal foil such as aluminum foil, iron foil, steel foil, tin foil, etc. are advantageously used. In order to improve the adhesion of the protective coating and plastic layer, these metal foils are preferably subjected to surface treatments such as phosphoric acid and/or chromic acid treatment, boehmite treatment, alumite treatment, electrolytic chromic acid treatment, etc. . In the present invention, the metal foil desirably has a thickness of 5 microns or more, especially 9 microns or more in terms of gas barrier properties, while it has a thickness of 100 microns or less, especially 60 microns or less in terms of economy. This is desirable. The thickness of the plastic layer, in combination with the metal foil, gives the can body self-shape retention, and it is generally advantageous to have a thickness of 0.3 to 1.5 mm, particularly 0.4 to 1.0 mm, in terms of workability. It is. The thickness ratio of the metal foil and the plastic layer is 1:3 to 1: from the viewpoint of economy and content preservation.
300, particularly preferably in the range of 1:8 to 1:100. From the viewpoint of corrosion resistance and processability, the protective coating film is
Preferably it has a thickness of between 20 and 20 microns, particularly between 3 and 15 microns. The composite can of the present invention can be manufactured by various methods. In one preferred embodiment of the present invention, the steps include the steps of: rolling a laminate in which a plastic layer and a metal foil are bonded together so that the metal foil is on the inside to form a can body having a side seam; A process of forming a protective coating on the inner surface of the metal foil before or after the forming process, a process of plastically working both ends of the can body member to form a flanged can body, and a process of forming a flanged can body and a pair of cans. A method for manufacturing a composite can is provided, which comprises a step of double seaming a body member and a body member at the top and bottom. Part 3-A showing this manufacturing process of the composite can of the present invention
In Figures 3-H to 3-H, first, as shown in Figure 3-A, a sheet-like laminate 8 made by laminating painted metal foil 4 and plastic layer 5 is prepared. Adhesive tapes or coatings 10, 1 as shown in FIG.
Apply 0'. At this time, the contact tape or coating 10 may be bent into a U-shape and applied to the edge 9 of the laminate that is inside the seam so as to completely cover the edge 9. good. As shown in FIG. 3-C, this laminate 8 is rolled up so that the coated metal foil 4 is on the inside, and both end edges 9, 9' of the laminate 8 are overlapped. Next, as shown in FIG. 3-D, the overlapping edge portions 9,
9' with bumper 11 and adhesive 10,1
0' to form the can body 12. In Figure 3-E showing the flange processing process,
Both ends of the can body 12 are pressed with tools 13, 13' called flange pilots and bent in an almost right angle direction, and flanges 15, 1 are attached to both ends of the can body 12.
5' is formed. Next, as shown in Figure 3-F, the can lid 16 is engaged with one end of the can body 12, and double seaming is performed between the flange 15 and the periphery of the can lid to close the can for filling with contents. It is assumed that the body is 12a. In the filling process (Figure 3-C), the can body 12a
The contents 18 are filled into the inside of the can body 12a, and in the final sealing process (Fig. 3-H), the can lid 16' is closed to the can body 12a.
The final composite can is then placed on top of the can and double-sealed between the periphery of the can lid and the flange 15'. The laminate used in the present invention is produced by laminating a plastic layer on one side of a metal foil and providing a protective coating on the other side. If the plastic layer itself has thermal adhesive properties to metal, the metal foil and the plastic layer can be bonded together by utilizing this thermal adhesive property, or by using hot melt adhesive, isocyanate adhesive, or epoxy adhesive. This can be carried out by interposing an acid-modified or acid anhydride-modified thermoplastic resin or an anchor agent between the two. The plastic layer may be adhered to the metal foil in the form of a preformed film or sheet, or the extruded plastic layer may be thermally bonded by a process called extrusion coating. At this time, the adhesive or anchor agent may be provided on the metal foil side or on the plastic layer. Hot melt adhesives use a base resin such as polyethylene or ethylene-vinyl acetate copolymer, and a styrene resin, petroleum resin, rosin, modified rosin, etc. as an adhesive.Isocyanate adhesives are known per se. One-component or two-component isocyanate adhesives are graft-modified with acid- or acid anhydride-modified thermoplastic resins such as maleic acid, maleic anhydride, acrylic acid, methacrylic acid, citraconic anhydride, itaconic anhydride, etc. Olefin resins, petroleum resins, etc. are used, and organic titanate-based and isocyanate-based anchor agents are used as anchor agents. These adhesives may be applied in the form of solutions, suspensions, emulsions, etc., or may be applied by powder coating, extrusion coating, multilayer coextrusion, sandwich lamination, etc. To form the protective coating, the above-mentioned resin component is mixed with an aromatic solvent such as toluene or xylene; a ketone solvent such as methyl ethyl ketone; or a cellosolve solvent such as butyl cellosolve, etc., so that the solid content is 10 to 50%. It is formed by dissolving, applying this solution, and then baking it. The baking of the paint film is
Although it varies depending on the type of paint, conditions of 1 second to 20 minutes at 150 to 400°C are best. Thermosetting adhesives such as isocyanate adhesives and epoxy adhesives can also be used to form seams, but in order to shorten the bonding time, the adhesive used should be a thermosetting adhesive. It is preferable to use thermoplastic resin. Suitable examples of such thermal adhesives include the aforementioned olefinic resins and petroleum resins modified with ethylenically unsaturated carboxylic acids or anhydrides, as well as thermal adhesives based on various polyamides and various copolyamides. agent is used. These thermal adhesives are preferably applied in tape form to the edges of the laminate material by thermal bonding. The laminate sheet can be easily formed into a can body using a roll former of a conventional can making machine. To alleviate the springback tendency of the plastic layer, the laminate can be preheated prior to roll forming to soften the plastic layer. When forming the seam, it is desirable from the viewpoint of productivity to preheat the edge portion of the laminate to which the adhesive is applied to a temperature equal to or higher than the melting point or softening point of the adhesive. Bumping of the edges of the laminate, i.e. the formation of lap seams, is easily and rapidly achieved by pressing the edges with the melted or softened adhesive with a cooled hammer or bumper. . As mentioned above, when the adhesive on the edge is preheated, the plastic layer on the edge also tends to melt or soften. On the contrary, the seam can be formed smoothly and reliably, and it is also possible to form an overlapping seam with a small level difference. Although the flange can be formed at room temperature by plastic working of plastic, it is generally desirable to preheat both ends where the flange will be formed in order to prevent springback. This heating temperature varies depending on the type, thickness, filler content, etc. of the plastic, but is from a temperature 60° C. lower than the melting point or softening point of the plastic to the melting point or softening point. Sealing with the can lid can also be done at room temperature, but the seaming may be performed after heating the flange portion to the above temperature. The laminate can be heated by infrared heating, ultrasonic irradiation, hot air blowing, contact with a heat roller, high frequency induction heating, or a combination thereof. In the present invention, the formation of the can body joint is not limited to the adhesive means described above. For example, if the plastic layer of the laminate has thermal adhesive properties, as shown in FIG.
The seam can be formed by heat sealing by pressing under heat at 9 and 19'. Further, as shown in FIG. 5, it is also possible to abut both end edges 9, 9' of the laminate 8 and heat these end edges with a heating mechanism 20 to form a seam by fusing. Furthermore, as shown in Figure 6-A, as a laminate,
A laminate 8a is manufactured which has a metal foil protrusion 22 at one end 9, and an adhesive layer 23 is provided on the surface that is the outside of this protrusion 22, and also on the metal foil 4 at the other end 9'. An adhesive layer 23' is provided, and then, as shown in FIG. 6-B, the metal foil protrusion 22 at one end and the metal foil at the other end are overlapped and bonded via the adhesive 23, and both ends of the plastic layer are bonded together. A seam can be formed by butt joining. Furthermore, as shown in FIG. 7-A, the laminate 8b
A seam fold 24 is formed at one end and a reverse seam fold 24' is formed at the other end of the laminate, and then these seam folds 24 and 2 are formed as shown in FIG. 7-B.
4' can be engaged via adhesive 23 to form a seam. According to another preferred embodiment of the present invention, the steps of: winding a metal foil on a mandrel, covering the metal foil with plastic, and drawing the formed laminate from the mandrel to form a can body; A process of forming a protective coating on the inner surface of the metal foil before or after the can body forming process, a process of plastically working both ends of the can body member to form a flanged can body, and a pair of flanged can bodies. A method for manufacturing a composite case is provided, which comprises a step of double-sealing a can end member and a can end member at the top and bottom. In FIGS. 8-A to 8-C showing the main parts of the manufacturing process of this method, first, as shown in FIG. 8-A, a metal foil or painted metal foil 4a is wrapped around a mandrel 25. In the specific example shown in FIG. 8-A, a metal foil 4a having a width slightly longer than the circumference of the mandrel 25 is supplied onto the mandrel 25, and is wound onto the mandrel 25 in the shape of a cylinder having a straight seam 28. . In this case, an adhesive layer 26 is provided on the overlapping edge of the metal foil 4a, and a heat seal roller 30 is placed on the mandrel 25.
is provided, and at the same time the metal foil is wrapped, the metal foil 4a is wrapped.
Perform overlapping joining. Next, as shown in Figure 8-B, the mandrel 2
A plastic layer 5a is coated around the metal foil cylinder 4b wrapped around the metal foil. In the specific example shown in FIG. 8-B, a crosshead die 31 is provided to surround the mandrel 25 for this coating, and the plastic is kneaded in an extruder 32 and then passed through the die 31 into a metal foil cylinder 4b. It is melt-extruded into a cylindrical shape around the periphery, and laminated onto metal foil at the same time as extrusion. As shown in the process diagram of FIG. 8-C, this cylindrical laminate 37 is pulled out from the die outlet, cooled and solidified in a sizing unit (calibrating die) 38 and a cooling tank 39, and cut into a predetermined shape by a cutting machine 41. It is then cut to size and formed into the can body member 1. The subsequent steps are performed in a manner similar to that detailed for the first method. Instead of wrapping the metal foil as shown in Figure 8-A, it is also possible to spirally wrap the metal foil 4c around the mandrel 25 as shown in Figure 9. It should be understood. Alternatively, instead of melt extrusion coating the plastic layer, a preformed plastic film or sheet 5b may be wrapped around the metal foil tube 4b on the mandrel 25, as shown in FIG. It is also possible to form a laminate 37 having a shape. In this case, the formation of the metal foil and plastic seam and the adhesion of the metal foil and the plastic layer can be carried out by means of the adhesives already described in detail. In the present invention, although not shown in the drawings, prior to the flange processing step, the tip of the can body or a portion close to this is made into a smaller diameter than the side wall portion by a die method or a spin method (roll method), which is known per se. It can also be squeezed to form a net. Further, in order to prevent the metal foil 4 from being scratched during molding into a can body, it is desirable to provide the above-mentioned coating film in advance on the outer surface of the laminate on the metal foil side. However, of course, this coating film may be provided on the inner surface of the can body after the laminate is formed into the can body.
Furthermore, a coating film may be applied to the outer surface of the metal foil in advance prior to molding into a can body, and a second coating film may be applied as a top coat to the inner surface of the can body after molding.
According to this aspect, the protection of the metal foil becomes even more complete. The invention will now be illustrated by way of example. Example 1 Epoxy resin (aromatic epoxy resin derived from bisphenols and epihalohydrin, average molecular weight 2900, epoxy equivalent weight 1900) and phenol resin (condensation product of phenols and aldehydes under alkaline catalyst, average molecular weight) on one side 640)
Apply paint mixed at 50:50 weight ratio and heat at 200℃
Baked for 10 minutes for 5 μm thick coating (polar group)
950mmol/100g resin content, gel fraction 85%, density
A 20 μm thick soft aluminum foil was prepared. On the other hand, eight types of plastic sheets having the thickness and physical properties shown in Table 1 were prepared and laminated by adhering them to the unpainted surface of the single-sided soft aluminum foil using an isocyanate adhesive. It was made into a sheet and cut into rectangles of 145 mm x 170 mm to obtain blanks for eight types of samples.
After removing the aluminum foil from one short cut side of the laminated sheet blank along the edge to a width of approximately 5 mm, a Teflon-coated stainless steel round bar with a diameter of 525 mm and a length of 145 mm was cut. Wrap the blank so that the coated surface faces the round bar, place and fix the blank so that the short edges of the plastic sheet face each other, and use ultrasonic welding to The overlapping plastic layers were glued together and formed into a cylindrical shape. Next, both ends of these cylindrical molded bodies were each cut by 4 mm to obtain eight types of test can bodies according to the present invention each having an inner diameter of 52.5 mm and a height of 137 mm. The width of both ends of these test can bodies is approx.
The plastic layer is softened by heating with an infrared heater over a length of mm, and a cooled flange forming jig is pressed from both sides to form a flange for double seaming. A test case was obtained by double-sealing an aluminum can lid. Using these test containers, we filled canned pulp beverages (nectar) and tuna pickled in oil using the hot filling method.
Canned fish meat that had been subjected to heat sterilization treatment at 115°C for 60 minutes was produced, and after being stored at room temperature for one year, the condition of the inner surface of the can and the contents were evaluated, and the results shown in Table 2 were obtained.

【table】

[Table] Comparative Example 1 The paint mixture of epoxy resin and phenolic resin shown in Example 1 was applied and baked to a thickness of 20 μm.
on the unpainted surface of soft aluminum foil, 200μ thick
m low-density polyethylene sheet (elastic modulus 25Kg/
mm ² ) were adhered using an isocyanate adhesive to produce a laminated sheet. Using the laminated sheet, a test can body of Comparative Sample 1 was produced by the method shown in Example 1, and a flange was further formed. An attempt was made to double-seal a regular 202-diameter aluminum can lid to one end of the flanged test can body of Comparative Sample 1, but the can body buckled elastically in the seaming machine, causing the can lid to tighten. It was not possible to attach it to the can body properly. Example 2 Epoxy resin (aromatic epoxy resin derived from bisphenols and epihalohydrin, average molecular weight 3750, epoxy equivalent weight 2900) and phenol resin (condensation product of phenols and aldehydes under alkaline catalyst, average molecular weight) on one side 380)
Apply paint mixed in a weight ratio of 80:20 and heat at 210℃
Baked for 10 minutes with
1030mmol/100g resin content, gel fraction 90%,
On the other side of a 30 μm thick soft aluminum foil with a density of 1.14 g/cc), a polypropylene film modified with maleic anhydride with a thickness of about 30 μm is thermally fused using a hot roll to form a laminated sheet.
The laminated sheet was cut into a rectangle of 211.1 mm x 112.5 mm to obtain a laminated sheet blank. On the other hand, a polypropylene sheet approximately 800 μm thick containing the fillers shown in Table 3 in the proportions shown in Table 3 was molded by compression molding, and cut into a rectangle of 206.1 mm x 112.5 mm. A plastic sheet blank was made. Next, the above laminated sheet blank was heated to 65.6 mm in diameter and 65.6 mm in length with a Teflon coating, which was maintained at 240 °C with a heating element embedded in it.
Wrap it around a 112.5 mm stainless steel round bar so that the painted surface faces the round bar, and place the laminated sheet blank so that the short side edges of the blank overlap each other. The overlapping portions of the two end edges were pressed together through a 3 mm thick silicone rubber sheet to adhere the two end edges to each other. Furthermore,
The plastic sheet blank was wrapped around the outside of the round rod around which the laminated sheet blank was wrapped, and the entire surface of the round rod was sequentially pressed with a silicone rubber pressure roll to form the modified polypropylene surface of the laminated sheet. and plastic sheet blanks were hot glued together. At this time, the edges of the short sides of the plastic sheet blanks were placed so as to face each other when wrapped, and were thermally fused together by pressing. Finally, cool the round bar to about 130℃, pull out the cylindrical laminate from the round bar, and attach 4
A test can body (211 diameter, No. 7 can) according to the present invention was obtained by cutting mm. Flanges were formed on these test can bodies according to the method shown in Example 1, and flanges were formed on one side.
A 211-diameter aluminum can lid was double-sealed, orange juice and consommé soup were filled, and the other end was double-sealed with a 211-diameter aluminum can lid, followed by a prescribed sterilization process. It was then subjected to a storage test.
Table 4 shows the results of evaluation after opening the can after being stored at room temperature for one year.

【table】

【table】

[Table] Comparative Example 2 The paint mixture of epoxy resin and phenol resin shown in Example 2 was applied and baked to a thickness of 30 μm.
In the same manner as in Example 2, a polypropylene film modified with maleic anhydride was heat-sealed to the unpainted surface of the soft aluminum foil and cut into a predetermined size to obtain a laminated sheet blank. On the other hand, resin
Polypropylene containing 800 parts by weight of calcium carbonate powder per 100 parts by weight was formed into a sheet approximately 800 μm thick and cut into a predetermined size to produce a plastic sheet blank. Using these laminated sheet blanks and plastic sheet blanks, a test can body of Comparative Sample 2 was prepared according to the method shown in Example 2, and a flange was attached according to the method shown in Example 1. formed. At one end of this flanged test can body, a regular 211
When an attempt was made to double-seal an aluminum can lid with a diameter of Ta. Example 3 Five types of metal foils having the thicknesses shown in Table 5 were prepared, and one side of each metal foil was coated with an epoxy resin (aromatic epoxy resin derived from bisphenols and epihalohydrin, average molecular weight 3300,
A paint made by mixing epoxy equivalent (2300) and phenol resin (condensation product of phenols and aldehydes under alkaline catalyst, average molecular weight 340) in a weight ratio of 20:80 is applied and baked at 205℃ for 10 minutes to thicken the coating. A coating film with a diameter of about 5 μm (containing 1100 m mol of polar group/100 g resin, gel fraction 80%, density 1.26 g/cc) was formed to produce a single-sided coated metal foil. On the other hand, a blend of ordinary polypropylene (modulus of elasticity 110 Kg/mm ² ) and calcium carbonate powder mixed with the above polypropylene (modulus of elasticity 310 Kg/mm ² ) at a ratio of 200 parts by weight per 100 parts by weight of the resin was used. A composite sheet having the thickness shown in Table 5 was prepared by coextrusion at a ratio of 1:1, and the calcium carbonate-free polypropylene side of the composite sheet and the non-painted side of the single-sided coated metal foil were coated with an isocyanate-based coating. A laminated sheet was obtained by bonding using an adhesive. Next, this laminated sheet
A laminated sheet blank was prepared by cutting into a rectangle of 206.1 mm x 112.5 mm. The laminated sheet blank is Teflon-coated with a diameter of 65.6 mm and a length of
Wrap it around a 112.5 mm stainless steel round bar so that the painted surface faces the round bar, and place the laminated sheet blank so that the short edges of the sheet are in contact with each other and face each other. The parts where the edges of the short sides face each other are heated ultrasonically to melt and adhere to each other to form a cylindrical shape.Furthermore, both ends of this cylindrical molded body are cut by 4 mm each to form a 211 diamond. A can body according to the present invention for a No. 7 can was manufactured. Flanges were formed on these test can bodies according to the method shown in Example 1, and a regular tin can lid with a diameter of 211 was double-sealed on one end, and 10% apple drink and tuna were added. The can was filled with boiling water, double-sealed with a regular tin can lid of 211 diameter on the other end, and subjected to a prescribed sterilization treatment before being subjected to a storage test. After being stored at room temperature for one year, the cans were opened and evaluated. As a result, no abnormalities were observed in the condition of the inner surface of the can or the storage condition of the contents.

[Table] Example 4 Epoxy resin (aromatic epoxy resin derived from bisphenols and epihalohydrin, average molecular weight
3750, epoxy equivalent: 2900) and phenolic resin (condensation product of phenols and aldehydes under alkaline catalyst, average molecular weight: 380) in a weight ratio of 80:20 was applied and baked at 210℃ for 10 minutes. coating film with a thickness of approximately 5 μm (polar group 1030 m mol/100
A single-sided coated aluminum foil was prepared by forming a gel containing g resin, gel fraction 90%, density 1.14 g/cc).
The laminated sheet for producing Sample 23 was obtained by adhering a 500 μm thick polypropylene sheet (modulus of elasticity 110 Kg/mm ² ) to the unpainted surface of the single-sided coated aluminum foil using an isocyanate adhesive. Sample 24
The laminated sheet for production was obtained by extrusion coating polypropylene (modulus of elasticity 110 Kg/mm ² ) on the non-painted surface of the single-sided painted aluminum foil to a thickness of about 500 μm using an isocyanate-based anchoring agent. The laminated sheet for making sample 25 was made by extrusion coating polypropylene modified with maleic anhydride to a thickness of about 10 μm on the non-painted side of the single-sided coated aluminum foil, and then heat-coating a polypropylene sheet with a thickness of 500 μm on this surface. It was obtained by melt-bonding using a roll. The laminated sheet for making sample 26 was made by applying polypropylene modified with maleic acid and regular polypropylene to the unpainted side of the single-sided coated aluminum foil.
Thickness of resin blended at 20:80 weight ratio 500μ
A m-sheet (elastic modulus: 112 Kg/mm ² ) was obtained by melt-bonding using a hot roll. These laminated sheets
A blank for can making is cut into a rectangle of 211.1 x 112.5 mm, and a 30 mm thick polypropylene modified with maleic anhydride is attached to the edges of both short sides of the blank.
A tape with a diameter of 65.6 mm and a diameter of 65.6 mm coated with Teflon was applied by heating the end edge locally with hot air and then pressing it with a pressure roll to cover the end edge. Length 112.5mm
Wrap the blank around a stainless steel round bar so that the painted surface faces the round bar, place the blank so that the short edges of the blank overlap each other, and weld the edges by ultrasonic welding. are melted and bonded and formed into a cylindrical shape.
Both ends of this cylindrical molded body were each cut by 4 mm to obtain four types of test can bodies according to the present invention. Flanges were formed on these test can bodies according to the method shown in Example 1, and then a normal aluminum 211 diamond can lid was double-sealed on one end, and coffee beverage and bonito flavored were filled. Then, the can lid was double-sealed to the other end to produce a can. These cans were subjected to a predetermined heat sterilization treatment and then subjected to a storage test. After being stored at room temperature for one year, the can was opened and evaluated, and no abnormalities were observed in the condition of the inner surface of the can or the storage condition of the contents. Comparative Example 3 Thickness of paint mixed with epoxy resin and phenolic resin applied and baked on one side as shown in Example 4
Polypropylene (modulus of elasticity 110
Kg/mm ² ) was extrusion coated to a thickness of about 500 μm. When an attempt was made to fabricate a can body using this laminated sheet according to the method shown in Example 4, the layer of polypropylene modified with maleic anhydride broke when the blank holder was removed after ultrasonic welding. However, the plastic layer was not able to peel off from the aluminum foil and recover elastically to obtain a cylindrical molded body. Example 5 A steel foil treated with electrolytic chromic acid and having a thickness of 50 μm was prepared. The single-sided coated metal foil used to prepare sample 27 was made by applying epoxy resin (aromatic epoxy resin derived from bisphenols and epihalohydrin, average molecular weight 3750, epoxy equivalent 2900) and phenol resin to one side of the steel foil treated with electrolytic chromic acid. (condensation product of phenols and aldehydes under alkaline catalyst, average molecular weight 380) was mixed in a weight ratio of 80:20 and baked at 210°C for 10 minutes to form a coating film with a thickness of approximately 5 μm ( A gel containing 1030 m mol of polar groups/100 g of resin, a gel fraction of 90%, and a density of 1.14 g/cc) was obtained. The single-sided coated metal foil used to prepare Sample 28 was made by applying epoxy resin (aromatic epoxy resin derived from bisphenols and epihalohydrin, average molecular weight 3750, epoxy equivalent 2900) and urea resin ( A paint made by mixing a condensate of urea and formaldehyde (average molecular weight 320) in a weight ratio of 85:15 was applied and baked at 200°C for 10 minutes to form a coating film with a thickness of approximately 5 μm (polar group: 1080 m).
Mol/100g resin content, gel fraction 70%, density 1.18
g/cc). The single-sided coated metal foil used to prepare Sample 29 was coated with 85 parts by weight of a copolymer of vinyl chloride and vinyl acetate (87 parts by weight of vinyl chloride, 13 parts by weight of vinyl acetate, average polymerization) on one side of the steel foil treated with electrolytic chromic acid. 8 parts by weight of a copolymer of vinyl chloride, vinyl acetate, and maleic acid (vinyl chloride 86
parts by weight, 13 parts by weight of vinyl acetate, 1 part by weight of maleic acid, average degree of polymerization 400), 7 parts by weight of partially saponified copolymer of vinyl chloride and vinyl acetate (vinyl chloride)
91 parts by weight of vinyl acetate, 3 parts by weight of vinyl alcohol, 6 parts by weight of vinyl alcohol, average degree of polymerization 500) was applied and baked at 180°C for 10 minutes to form a coating film with a thickness of about 5 μm (220 m mol of polar groups/ A gel containing 100 g of resin, a gel fraction of 2%, and a density of 1.35 g/cc) was obtained.
The single-sided coated metal foil used to prepare sample 30 was coated with 70 parts by weight of soft vinyl chloride paste (average polymerization degree of vinyl chloride resin) on one side of the steel foil treated with electrolytic chromic acid.
1100: Plasticizer: Epoxidized soybean oil, average molecular weight
960, epoxy equivalent 140, vinyl chloride resin: plasticizer = 50:20 (weight ratio)), 10 parts by weight of acrylic resin (40 parts by weight of methyl methacrylate, 30 parts by weight of ethyl acrylate, 30 parts by weight of ethylhexyl acrylate)
parts by weight of copolymer, average molecular weight 52000), 5 parts by weight of phenol resin (condensation product of phenols and aldehydes under alkaline catalyst, average molecular weight
380), a paint mixed with 5 parts by weight of epoxy resin (aromatic epoxy resin derived from bisphenols and epihalohydrin, average molecular weight 900, epoxy equivalent 500) was applied and baked at 200℃ for 10 minutes to determine the thickness. Approximately 5μm coating film (polar group 290mmol/100g
It was obtained by forming a gel containing resin, gel fraction 5%, density 1.14 g/cc). On the other hand, resin in high-density polyethylene
A sheet with a thickness of about 300 μm (elastic modulus 305
kg/mm ² ) and adhered to the non-painted surfaces of the four types of single-sided coated metal foils using an isocyanate adhesive to produce a laminated sheet. After cutting these laminated sheets into a rectangle of 216.1 mm x 112.5 mm, the edges of both short sides were heated with infrared rays over a width of about 5 mm, and the polyethylene was cured with maleic anhydride to a thickness of about 50 μm. Attach 4mm wide tape,
Furthermore, the edges of both short sides were folded over a width of 5 mm to the opposite side. These rectangular sheets with their short edges folded are then interlocked with each other so that the coated surface is on the inner surface, and then a Teflon-coated stainless steel sheet with a diameter It is fitted into a round bar of 65.6 mm and length 112.5 mm, fixed, and the interlocking parts of the folded parts are heated with infrared rays and pressed together through a 5 mm thick silicone rubber sheath to bond them together to form a cylinder. It was made into a shaped body. After cutting both ends of each of these cylindrical molded bodies by 4 mm, a flange was formed by the method shown in Example 1, and a normal
Four types of cans according to the present invention are made by double-sealing can lids made of 211-diameter electrolytic chromic acid-treated steel plates, filled with vegetable juices and tuna in dressing sauce under predetermined conditions, and then sealed at the other end. The can lid was double-sealed with an ordinary 211-diameter electrolytic chromic acid-treated steel plate, and after being subjected to a prescribed heat sterilization treatment, it was subjected to a storage test. Table 6 shows the results of evaluation after opening the can after storing it at room temperature for one year.
Shown below.

[Table] Example 6 70 parts by weight of soft vinyl chloride paste (average polymerization degree of vinyl chloride resin
1100; Plasticizer: Epoxidized soybean oil, average molecular weight
960, epoxy equivalent 140, vinyl chloride resin: plasticizer = 50:20 (weight ratio)), 10 parts by weight of acrylic resin (40 parts by weight of methyl methacrylate, 30 parts by weight of ethyl acrylate, 30 parts by weight of ethylhexyl acrylate)
parts by weight of copolymer, average molecular weight 52000), 5 parts by weight of phenol resin (condensation product of phenols and aldehydes under alkaline catalyst, average molecular weight
380), a paint mixed with 5 parts by weight of epoxy resin (aromatic epoxy resin derived from bisphenols and epihalohydrin, average molecular weight 900, epoxy equivalent 500) was applied, and the mixture was heated in a hot air oven set at 280°C. It was run for 10 seconds and baked to form a coating film with a thickness of about 5 μm (containing polar groups 290 mm ² mol/100 g resin, gel fraction 6%, density 1.14 g/cc) to produce a single-sided coated aluminum foil. The outer layer material is polypropylene with a melt index of 1.0 g/10 min, and a melt index of 20
g/10min maleic anhydride modified polypropylene as inner layer material, diameter 115mm, effective length
An extruder for the outer layer has a built-in full-flight screw of 2530 mm, and an extruder for the inner layer has a built-in full-flight screw with a diameter of 40 mm and an effective length of 880 mm.
While extruding a two-layer pipe using a pipe forming machine consisting of a combination of a cross-head two-layer die, a sizing unit (calibrating die), a water-cooled cooling tank, a take-off machine, and a cutter, the pipe is directly connected to the core of the cross-head die and After slitting the aluminum foil coated on one side to a width of 167.9 mm on the core with an outer diameter of 52.5 mm protruding from the outside of the crosshead, wrap the aluminum foil so that the coated surface faces the core and the overlap amount is 3 mm. , a layer of modified polypropylene is applied to the non-painted surface of the single-sided coated aluminum foil wrapped around the core in the crosshead die by feeding the modified polypropylene into the crosshead die at the same feed linear speed as the extrusion linear speed of the two-layer pipe. Polypropylene was bonded through it. The pipe of the laminate obtained in this way, which is extruded and pulled out from the die head, is immediately passed through a vacuum sizing unit with an outer diameter of 52.5 mm, a cooling tank, a pulling machine, and a cutter, and has an inner diameter of 52.5 mm and a wall thickness of 0.614 mm.
It was molded into a can body with a height of 137 mm. Here, the thickness of the polypropylene layer is approximately 590 μm, and the thickness of the polypropylene layer modified with maleic anhydride is approximately 10 μm.
m, and the elastic modulus of the laminate of these two layers was 115 Kg/mm ² . Next, a polypropylene tape modified with maleic anhydride having a thickness of 50 μm and a width of 5 mm was adhered to the lap portion of the inner surface of the can body where the aluminum foil overlapped by pressing it using a hot roll. A flange was formed on the test can body (sample 31) according to the present invention produced in this way by the method shown in Example 1, and a regular aluminum can lid with a diameter of 202 mm was wrapped double-wrap around one end. Tighten,
Beer, carbonated orange drink, and clear carbonated drink were cooled and filled, and a regular 202 diameter aluminum can lid was double-sealed on the other end to obtain a bottled beverage. The cans filled with beer were sterilized at 70°C for 20 minutes and then subjected to a storage test with the rest intact. As a result of opening the can and evaluating it after storing it at room temperature for one year, no abnormalities were observed in the condition of the inner surface of the can or the storage condition of the contents, and the amount of aluminum leached into the contents was also the same as that of ordinary all-aluminum products. The level was the same as when using the can, and no abnormalities were observed. Example 7 Epoxy resin (aromatic epoxy resin derived from bisphenols and epihalohydrin, average molecular weight) was applied to one side of a 20 μm thick soft aluminum foil.
3750, epoxy equivalent: 2900) and phenolic resin (condensation product of phenols and aldehydes under alkaline catalyst, average molecular weight: 380) in a weight ratio of 80:20 was applied and baked at 270℃ for 1 minute. coating film with a thickness of approximately 5 μm (polar group 1030 m mol/100
A single-sided coated aluminum foil was prepared by forming an aluminum foil containing g resin, a glue fraction of 93%, and a density of 1.14 g/cc). On the other hand, 75 parts by weight of normal polypropylene, 25 parts by weight of polypropylene modified with maleic anhydride,
Powdered calcium carbonate 200 surface treated with fatty acids
Parts by weight were dry blended, kneaded by passing through a pelletizer, and then formed into a sheet with a thickness of about 300 μm (modulus of elasticity 305 Kg/mm ² ). Then,
The sheet was placed facing the non-painted surface of the single-sided aluminum foil and pressed with a hot roll to obtain a laminated sheet. Next, the laminated sheet was cut into a rectangle of 211.1 mm x 104.5 mm, and the 65.6 mm diameter rectangle was coated with Teflon.
Wrap it around a stainless steel round bar with a length of 112.5 mm and place it so that the coating surface faces the round bar, and apply ultrasonic waves from above to the part where the short side edges overlap each other. They are bonded together by applying ultrasonic waves while being pressed with a welding horn, and have an inner diameter of 65.6 mm and a height of
A 104.5 mm cylindrical can body (sample 32) was obtained. After forming flanges on these can bodies according to the method shown in Example 1, a regular aluminum can lid with a diameter of 211 was double-sealed on one end, and beer, transparent carbonated beverages, 50% It was filled with orange drink, coffee drink, tuna pickled in oil, and tuna boiled in water, and the other end was double-sealed with a regular aluminum can lid of 211 diameter to seal the can. Note that the beer and clear carbonated beverages were chilled and filled, and the beer was subjected to heat sterilization treatment at 70°C for 20 minutes. In addition, 50% orange drink and coffee drink were hot filled, and the canned coffee drink was subjected to heat sterilization treatment at 125°C for 20 minutes.
Furthermore, the tuna pickled in oil and the tuna boiled in water were filled and sealed using a vacuum seaming method, and subjected to heat sterilization treatment at 120°C for 60 minutes. After storing these cans for one year at room temperature, we evaluated them and found that there were no major defects such as metal corrosion or hydrogen expansion on the inside of the can, and there were no changes in taste or color of the contents. was also not recognized.

[Brief explanation of the drawing]

Figure 1 is an external view of the composite can of the present invention, Figure 2 is an enlarged cross-sectional view of the body of the composite can, and Figure 3-A is a composite can with painted metal foil and plastic layer prepared in the can manufacturing process. Figure 3-B shows the combined laminate, with the edges covered with adhesive tape, and Figure 3-C shows the process of rolling the laminate so that the painted metal foil is on the inside and overlapping both edges. , Fig. 3-D is a process diagram of forming a can body by pressing the overlapped edges of the laminate, Fig. 3-E
The figure is a flange forming process diagram, Figure 3-F is a process diagram for double seaming one end of the can body, Figure 3-G is a filling process diagram, and Figure 3-H is a process diagram for double seaming. Sealing process diagram, FIG. 4 is a conceptual diagram of heating and pressing can body forming by overlapping which is one form of the present invention, FIG. 5 is a conceptual diagram of ultrasonic heating can body forming by butting which is one form of the present invention, and FIG. - Figure A shows a laminate having a metal foil protrusion at one end, which is one form of the present invention, No. 6 -
Figure B is a process diagram for forming a can body from the laminate shown in Figure 6-A, Figure 7-A is a laminate with half-folds at both ends, and Figure 7-B is a process diagram for forming a can body from the laminate shown in Figure 7-A. Figure 8-A is a conceptual diagram of winding metal foil or painted metal foil on a mandrel, and Figure 8-B is a diagram of the process for forming the shell. Figure 8-B is a diagram of the metal wrapped around the mandrel obtained in Figure 8-A. Conceptual diagram of melt laminating a plastic layer on a foil in a crosshead die, Figure 8-C is similar to Figure 8-A.
Figure 9 and can body formation process diagram following Figure 8-B.
The figure shows a conceptual diagram of spirally winding metal foil or painted metal foil on a mandrel, and FIG. 10 shows a conceptual diagram of winding a plastic film or sheet on the metal foil wound around the mandrel. DESCRIPTION OF SYMBOLS 1...Composite can, 1a...Can body cross section shown in enlarged view in FIG. 2, 2, 2'...Pair of can body members, 3
...Protective coating film, 4, 4a, 4b, 4c...Metal foil, 5, 5a, 5b...Plastic layer, 6...
Adhesive layer, 7...can body joint, 8, 8a, 8b... laminate, 9, 9'... laminate edge, 10, 10'...
Adhesive tape, 11... Bumper, 12, 12a
... Can body, 13, 13'... Flange pilot, 14, 14'... Stop ring, 15, 1
5'...flange, 16, 16'...can lid, 17...
... Lifter plate, 18 ... Filling contents, 19
...Filling nozzle, 19,19'...Heat seal bar, 20,20a...Ultrasonic horn, 21,2
1', 21, 21a'... Guide, 22... Metal foil protrusion, 23, 23'... Adhesive, 24, 24'...
...Folding, 25...Mandrel, 26...Adhesive, 27...Adhesive application head, 28...Straight seam, 29...Guide, 30...Heat seal roll, 31...Cross head die, 32... …
Extruder, 33... Screw, 34... Adapter, 35... Shell chip, 36... Shell chip holder, 37... Cylindrical laminate, 38... Calibrating die, 39... Cooling tank, 40
...Taking machine, 41...Cutting machine.

Claims (1)

[Scope of Claims] 1. A can formed by double-sealing a can body member and a pair of can end members vertically, wherein the can body member is located on the inner side and is made of metal having a protective coating on the inner surface. formed from a laminate of a foil and an outer plastic layer, at least the metal foil in the laminate having a seam extending from one end of the can body to the other, the protective coating having a carbonyl group. , hydroxyl group, ether group, and epoxy group at a concentration of 10 to 2000 mmol/100 g of resin, and the plastic layer has a polar group of at least 85 kg/mm ² or more. What is claimed is: 1. A composite can having a modulus of elasticity and a thickness sufficient to provide self-retention to a can body member. 2. A patent in which the plastic layer is a thermoplastic resin selected from olefin resin, vinyl chloride resin, styrene resin, polyester resin, polycarbonate resin, or polyamide resin, or a blend or composite of the thermoplastic resins. A composite can according to claim 1. 3. The composite can according to claim 1, wherein the plastic layer is a blend of the thermoplastic resin and an inorganic filler or reinforcing agent in an amount of 5 to 500 parts by weight per 100 parts by weight of the resin. 4. A patent claim in which the inorganic filler or reinforcing agent is carbonate, silicon oxide, metal oxide, metal hydroxide, sulfate, silicate, aluminosilicate, carbon black, carbon fiber, or glass fiber. Composite cans as described in item 3 of the scope. 5. A composite can according to claim 1, wherein said plastic layer is a blend of said thermoplastic resin and 5 to 500 parts by weight of organic filler per 100 parts by weight of said resin. 6. The composite can according to claim 5, wherein the organic filler or reinforcing agent is wood flour, pulp, shell fiber, cotton, or aromatic polyamide fiber. 7. The composite can according to claim 1, wherein the thickness ratio of the metal foil to the plastic layer is in the range of 1:3 to 1:300. 8. The metal foil and the plastic layer are bonded via a hot melt adhesive, an isocyanate adhesive, an acid-modified thermoplastic resin, an acid anhydride-modified thermoplastic resin, or an anchor agent. Composite can. 9. The composite can according to claim 1, wherein the protective coating has a density of 1.1 to 1.4 g/cc. 10. The composite can according to claim 1, wherein the protective coating film is made of a thermosetting resin or a thermosetting resin composition. 11 The protective coating film was prepared in chloroform at 60°C.
Gel fraction 50 to 50 determined by extraction for 60 minutes
10. A composite can according to claim 10 in the range of 100%. 12. The composite can according to claim 10, wherein the protective coating is a composition containing an epoxy resin component and other resin components in a weight ratio of 95:5 to 1:99. 13 A step of rolling a laminate in which a plastic layer and a metal foil are laminated together so that the metal foil is on the inside to form a can body having a side seam, and a step of forming a laminate of the metal foil before or after the can body forming step. A process of forming a protective coating on the inner surface, a process of plastically working both ends of the can body member to form a flanged can body, and a process of double wrapping the flanged can body and a pair of can end members vertically. A manufacturing method for composite cans, which consists of a tightening process. 14 The plastic layer is made of olefin resin,
The method according to claim 13, which is a thermoplastic resin selected from vinyl chloride resin, styrene resin, polyester resin, polycarbonate resin, or polyamide resin, or a blend or composite of the thermoplastic resin. . 15. The method of claim 13, wherein said plastic layer is a blend of said thermoplastic resin and from 5 to 500 parts by weight of inorganic filler per 100 parts by weight of said resin. 16. The method of claim 13, wherein said plastic layer is a blend of said thermoplastic resin and from 5 to 500 parts by weight of organic filler per 100 parts by weight of said resin. 17 Preforming the plastic layer into a sheet,
14. The method according to claim 13, wherein the sheet and metal foil are bonded with an adhesive to form a laminate. 18. The method of claim 13, wherein the plastic layer is extrusion coated onto a metal foil optionally provided with an adhesive or an anchoring agent to form a laminate. 19. The method according to claim 13, wherein a plastic layer and an adhesive layer are co-extruded onto a metal foil and formed into a laminate. 20. The method according to claim 13, wherein the laminate is formed by sandwich-extruding an adhesive layer between a preformed plastic layer and a metal foil. 21. The method according to claim 13, wherein a laminate whose edges are coated with adhesive tape or a coating is rolled up, and the edge portions are overlapped and bonded to form a can body. 22. The method according to claim 13, wherein both end edges of the laminate are overlapped, and the both end edges are pressed and bonded under heat to form a can body. 23. The method according to claim 13, wherein both end edges of the laminate are butted together and the both end edges are heated and fused to form a can body. 24 A protrusion of metal foil is formed at one end of the laminate, and an adhesive layer is provided on the surface of the protrusion that is to become the outside of the can body, and if desired, an adhesive layer is also provided on the metal foil at the other end. Then, the metal foil protruding portion and the metal foil at the other end are overlapped and bonded via an adhesive, and both ends of the plastic layer are butt bonded to form a can body. Method. 25 Claim 13, in which a can body is formed by forming a cross-fold at one end of the laminate and a reverse cross-fold at the other end, and then engaging these cross-folds through an adhesive. The method described in section. 26 A step of winding a metal foil on a mandrel, covering the periphery of the metal foil with plastic, and pulling out the formed laminate from the mandrel to form a can body, and a step of wrapping the metal foil before or after the can body forming step. a step of forming a protective coating film on the inner surface of the can body, a step of plastically working both ends of the can body member to form a flanged can body, and a step of forming a flanged can body and a pair of can end members vertically. A manufacturing method for composite cans, which includes the process of seaming. 27 The plastic layer is made of olefin resin,
The method according to claim 26, which is a thermoplastic resin selected from vinyl chloride resin, styrene resin, polyester resin, polycarbonate resin, or polyamide resin, or a blend or composite of the thermoplastic resin. . 28. The method of claim 26, wherein said plastic layer is a blend of said thermoplastic resin and from 5 to 500 parts by weight of inorganic filler per 100 parts by weight of said resin. 29. The method of claim 26, wherein said plastic layer is a blend of said thermoplastic resin and from 5 to 500 parts by weight of organic filler per 100 parts by weight of said resin. 30. The method according to claim 26, wherein a metal foil is wound on a mandrel, and then plastic is melt-coated around the metal foil tube in a cylindrical shape to form a can body. 31. The method according to claim 26, wherein the metal foil is wound on a mandrel, and then plastic is applied around the metal foil tube in an extruder die, and then cut to form a can body. 32. The method of claim 26, wherein the can body is formed by wrapping a metal foil onto a mandrel and then wrapping a preformed sheet of plastic around the tube of the metal foil.