JPH0613334B2 - How to seal the lid of a can - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for continuously virgin sealing a covered surface of a can.

(Prior Art) Canned beer and canned coffee are sold in vending machines for easy drinking, but the covered surface of a can with a pull-top is dusty, dusty, or germs. Therefore, capping is conventionally performed for hygiene. As a method thereof, generally, a non-stretched thermoplastic resin is vacuum-molded, and a can is simply covered with a resin. Therefore, these containers have the drawback that they have no virgin function at all, such as during transportation and at the front of the store, because dust and bacteria infiltrate through the gaps to contaminate them and the caps come off.

(Problem to be Solved by the Invention) It is an object of the present invention to provide a method for continuously sealing a cap body having a virgin sealing property and not displaced during transportation.

(Means for Solving the Problems) According to the present invention, first, a heat-shrinkable film is continuously formed into a cap body having a specific shape, and the cap body is continuously placed on a lid surface of a can. This is a series of methods for heat shrinking and closely adhering.

That is, the present invention provides "1. In a method of virgin sealing the covered surface of a can, 1). The heat shrinkable film 1 is protected from shrinkage even when it is affected by heat, and adheres closely to the heating belt 3. The preheating step A, in which the preheating step is continuously carried out while being preheated, and 2). The outer diameter of the lid surface of the can, which is opened toward the outside on the peripheral surface of the continuous rotary molding drum 6, is substantially the same as A preheated film is brought into close contact with a vacuum forming mold 7 having an inner diameter and a flat upper wall portion, and the upper surface of the film is pressed by a heating belt 3,
Molding step B in which the pressure in the molding die is reduced and the vacuum molding is continuously performed while elastically pressing from the back of the heating belt with the pressing roller 4, and then the molding drum is detached from the heating belt, and molding is performed. Cutting step C for cutting the formed film into a cap shape
And 4). A transfer step D for transferring the cap body 14 that has been cut to the capping step E while the cap body 14 is housed in the mold, and 5).
With a transfer device that transfers the
Capping step E in which the molded cap body is detached from the molding die and placed, 6). The top surface of the cap body is pressed by the pressing tool 22 and the bottom of the can is pressed by the can bottom receiving plate 26 and the can is rotated at the same time. Then, hot air is blown around the sleeve of the cap body to shrink the cap body, and the upper surface is flat, and the shrinking step F for bringing the sleeve periphery into close contact with the peripheral wall of the can is joined. Method.

2. In the shrinking step F, first, hot air is blown around the sleeve of the cap body to shrink the cap body and bring it into close contact with the peripheral wall of the can, and then on the upper surface of the cap body.
The method for sealing a lid portion of a can according to claim 1, characterized in that hot air is blown to shrink and make a flat shape.

3. The method for sealing the lid of a can according to claim 1 or 2, wherein a film having an adhesive layer provided on the side facing the can wall is used as the heat-shrinkable film 1. It is.

The present invention is a method of forming a cap body having a flat upper surface in advance, covering the cap body with a lid portion of a can, and shrinking and sealing.

The hot air blown onto the sleeve portion for shrinking may be from the side surface or obliquely from above.

Further, in the shrinking process of the cap body, the presser for pressing the upper surface of the cap body presses the film with the rim of the can to prevent the shrinkage of the upper surface, and may be a flat plate-like body, such as a metal mesh. A woven fabric, a perforated plate, a plate provided with slits, or the like having air permeability can also be used.

In addition, a ring-shaped retainer may be used.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a side view of a preferred embodiment of the method of the present invention, and FIG. 2 is a plan view thereof.

Thickness 15 to 2 formed of a single layer of polyvinyl chloride, polyethylene, polypropylene, polystyrene, polycarbonate, polyester, etc. or a composite using these.
The 0 μm, biaxially stretched thermoplastic resin film with a stretching ratio of 1.01 to 10 times is continuously fed to the preheating step A and wound around the rotational molding drum 6.

A vacuum molding die 7 is provided on the peripheral surface of the molding drum so as to open outward.

In the present invention, this vacuum forming mold has an inner diameter that is substantially the same as the outer diameter of the covered surface of the can, and has a flat upper wall portion that covers the covered surface of the can. There is.

The molding drum 6 on which the heat-shrinkable film clamped so as not to heat-shrink is rotated in the direction of the arrow 20, and is heated to 60 to 200 ° C. on the upper surface of the clamped heat-shrinkable film by a heat medium or a casting heater. The heat-resistant silicon belt 3 having a thickness of 5 to 15 mm is brought into close contact with the heated roll 2 to preheat the film while moving together with the heat-shrinkable film, and then elastically formed by the pressing roller 4 from the back surface of the belt. The drum is pressed to heat the heat-shrinkable film to a temperature at which it can be formed.

When the molding drum 6 rotates to enter the molding process B, the vacuum region 8
The inside of the molding die is depressurized by this, and the heat-shrinkable film is continuously molded to provide the continuous film 10 on which the target cap body is formed.

When the forming drum 6 further rotates and enters the cutting step C, the cutting device 11 that reciprocates along the peripheral surface of the forming drum 11.
By the punching blade 12 attached to, the unnecessary portion of the formed film is cut and the cap body is punched while running in parallel with the drum.

Although the cap bodies are shown to be cut one by one in the drawings, it is of course possible to cut a plurality of cap bodies simultaneously and continuously.

The punched molded film 14, that is, the cap body 1.
4 is transferred to the capping process E by the rotation of the drum while being stored in the molding die installed on the molding drum.

On the other hand, the remaining film 13 with the cap body punched out
Is discharged out of the system between the cutting process and the capping process.

When the molding die accommodating the cap body 14 is transferred to the capping step, synchronization adjustment is made so that the covered surface of the can 15 conveyed by the conveying device 18 arrives directly below, and the pressurizing area 9 The cap body is separated from the mold by the air pressure from and is placed on the covered surface of the can.

The can 16 on which the cap body is placed is transferred to the shrinking process F and sealed.

Details of the operation in the shrinking process are shown in FIG.

Reference numeral 21 denotes a shrink rotary table attached to the shrink device 19.

The can 16 on which the cap body is placed is transferred from the transfer device 18 to the rotary table, the upper surface of the cap body is pressed by the cap body pressing plate 22, and the bottom of the can is pressed by the can bottom receiving plate 26. While rotating 2 to 4 times, the sleeve portion of the cap body 24 is shrunk by blowing hot air from the side surface or obliquely from above to bring it into close contact with the upper wall portion of the can to form a virgin seal having a flat upper surface.

At this time, if a heat-shrinkable film provided with an adhesive layer, such as a hot-melt adhesive such as ethylene-vinyl acetate copolymer resin on the side facing the can wall, is used, the adhesiveness is further improved. Even if a can that has been sealed with water is immersed in ice water, the seal does not peel off or water does not enter.

(Effect of the Invention) According to the method of the present invention, since the heat-shrinkable film is used, it can be adhered to the upper wall of the can and cannot be peeled off from the can unless it is broken. Therefore, the virgin sealing function is extremely high.

When a film having an adhesive layer provided on the side facing the can wall is used as the heat-shrinkable film, the virgin sealing function is further enhanced.

Where the method of the present invention is particularly excellent, a series of steps in which a heat-shrinkable film is vacuum-formed so as not to heat-shrink using a heating belt, and the heat-shrinkable film is capped on a covered portion of a can and virgin-sealed. Is to be carried out continuously. As a result, productivity was improved several times as compared with the conventional method.

[Brief description of drawings]

1 and 2 are a side view and a plan view showing an embodiment of the method of the present invention. FIG. 3 is a side view showing details of the operation in the shrinking process. 1 ... Heat shrink film, 2 ... Heating roller, 3 ... Belt, 4 ... Holding roller, 5 ... Belt driving roller, 6 ... Forming drum, 7 ... Vacuum forming die, 8 ...
... vacuum region, 9 ... pressurizing region, 10 ... formed film, 11 ... cutting device, 12 ... punching blade, 13 ... scrap film, 14 ... cut formed film (cap body), 15: can with lid, 16: can with cap mounted, 17: can with cap shrunk, 18: transport device, 19: shrink device, 2
0 ... Arrow (direction of rotation of forming drum), 21 ... Shrinking rotary table, 22 ... Cap body pressing plate (self-rotating type, 2 to 4 revolutions), 24 ... Cap body, 25 ... Can (self) Rotation type, 2 to 4 rotations), 26 ... Tube bottom receiving plate, 27
...... Hot air, 28 ...... Shrinkable sleeve of cap body.

Claims (3)

[Claims] 1. A method for virgin-sealing a covered surface of a can, 1). Preheating the heat-shrinkable film 1 by closely contacting it with a heating belt 3 while protecting the heat-shrinkable film 1 from shrinking even under the influence of heat. In addition, the preheating process A is continuously fed to the molding process B, and 2). The preheating process A has an inner diameter substantially the same as the outer surface of the covered surface of the can, which opens toward the outside of the peripheral surface of the continuous rotary molding drum 6. , The preheated film is brought into close contact with the vacuum forming mold 7 having a flat upper wall portion, and the upper surface of the film is pressed by the heating belt 3,
Molding step B in which the pressure in the molding die is reduced and the vacuum molding is continuously performed while elastically pressing from the back of the heating belt with the pressing roller 4, and then the molding drum is detached from the heating belt, and molding is performed. Cutting step C for cutting the formed film into a cap shape
And 4). A transfer step D for transferring the cap body 14 that has been cut to the capping step E while the cap body 14 is housed in the mold, and 5).
With a transfer device that transfers the
Capping step E in which the molded cap body is detached from the molding die and placed, 6). The top surface of the cap body is pressed by the pressing tool 22 and the bottom of the can is pressed by the can bottom receiving plate 26 and the can is rotated at the same time. Then, hot air is blown around the sleeve of the cap body to shrink the cap body, and the upper surface is flat, and the shrinking step F for bringing the sleeve periphery into close contact with the peripheral wall of the can is joined. Method. 2. In the shrinking step F, first, hot air is blown around the sleeve of the cap body to shrink the cap body so as to be in close contact with the peripheral wall of the can, and then hot air is blown onto the upper surface of the cap body to shrink. The method for sealing a lid of a can according to claim 1, wherein the lid has a flat shape. 3. The method for sealing a lid of a can according to claim 1 or 2, wherein a film having an adhesive layer provided on the side facing the can wall is used as the heat-shrinkable film 1.