JPH0613333B2 - How to seal the lid of a can - Google Patents

Description

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

(Prior art) Canned beer and canned coffee filled in stackable cans are sold at vending machines for easy drinking, but the covered surface of cans with pull-tops is dusty or dusty. , Or bacteria are attached, so capping is conventionally performed for hygiene. As a method thereof, generally, a non-stretched thermoplastic resin is vacuum-formed, and the can is simply covered by fitting. Therefore, these containers have the drawback that they have no virgin function at all, such as during transportation and at the storefront, because dust and bacteria enter through the gaps to contaminate them and the caps come off.

As a cap having adhesion, there is a capping method using a biaxially stretched thermoplastic resin film or sheet (hereinafter abbreviated as heat shrink film), but this is limited to a flat top surface, It was difficult to stack them when arranging them in stores.

(Problem to be solved by the invention) It is to provide a method for continuously sealing a cap body which has a virgin sealing property, can be stacked, and does not shift during transportation.

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

That is, the present invention relates to a method of virgin-sealing a covered surface of a stacking can, 1). A preheating step A in which the heat-shrinkable film 1 is continuously fed to the molding step B while being preheated by closely contacting with the heating belt 3 while protecting the heat-shrinkable film 1 from being shrunk even under the influence of heat; The preheated film is brought into close contact with a vacuum forming mold 7 having an inner peripheral surface having an almost same shape as the covered surface of the stacking can, which is open to the outer peripheral surface of the continuous rotational molding drum 6, and the film upper surface is attached. A heating step for pressing the heating belt 3 and elastically pressing the pressing roller 4 from the back surface of the heating belt while depressurizing the inside of the molding die to continuously perform vacuum forming, 3). Next, the forming drum is detached from the heating belt, and the forming film is cut into a cap shape, 4). Cut cap body 1
Transfer step D in which 4 is transferred to the capping step E while being stored in the molding die, 5). A capping step E in which a molded cap body is detached from a molding die and placed on a covered surface of a can that has been conveyed by a transfer device that fills contents and transfers the covered can to the capping step E. And 6). While the upper surface of the cap body is protected by the presser 22 from the hot air, and at the same time the bottom of the stacking can is pressed by the can bottom receiving plate 26, the stacking can is rotated, and hot air is blown from around the sleeve of the cap body. And a shrinking step F in which the periphery of the sleeve is brought into close contact with the peripheral wall of the can are combined.

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.
00 μm, biaxially stretched at a stretch ratio of 1.01 to 10 times,
The thermoplastic resin film is continuously sent to the preheating step A and wound around the rotational molding tram 6.

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

This vacuum forming mold has an inner peripheral surface having substantially the same shape as the covered surface of the stacking can, and therefore exhibits the same unevenness as the covered surface of the stacking can.

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 performed so that the covered surface of the stacking can 15 conveyed by the conveying device 18 arrives directly below, and the pressurizing region By the air pressure from 9, the cap body is separated from the mold and placed on the covered surface of the stacking can.

The stacking 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 stacking can 16 on which the cap body is placed is transferred from the carrying device 18 to the rotary table, the upper surface of the cap body is pressed by the cap body pressing plate 22 having cushioning property, and the bottom of the stacking can is pressed by the can bottom receiving plate 26. 2-4 minutes per minute
While rotating, the sleeve portion of the cap body 24 is shrunk by blowing hot air from the side surface and diagonally from above, and is brought into close contact with the upper wall portion of the stacking can.

At this time, since the cooling water 23 is passed through the cap body pressing plate 22 to cool it, the molded portion of the cap body is protected from hot air and is not contracted and deformed.

When stacking is not required, the upper surface of the cap body may be shrunk to form a flat sealing film on the upper surface of the can.

(Effect of the invention) According to the method of the present invention, a heat shrinkable film is preliminarily formed in the same shape as the covered surface of the stacking can, and the bottom flange of the stacking can and the cover are used for virgin sealing. Since the projections of the parts fit well with each other, they can be stacked in multiple stages when they are displayed in a store or the like.

Since it uses a heat-shrinkable film, it can be adhered to the upper wall of the can and cannot be peeled off from the can unless it is broken, so the virgin sealing function is extremely high.

Where the method of the present invention is particularly excellent, it is possible to vacuum-form a heat-shrinkable film by using a heating belt so that the heat-shrinkable film is not heat-shrinked, and cap the stackable can with a virgin seal. It means to carry out the process 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 tram, 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 (rotation direction of forming tram), 21 ... Shrinking rotary table, 22 ... Cap body pressing plate (self-rotating type, 2 to 4 revolutions), 23 ... Cooling water, 24 ... Cap body, 25: Stacking cans (self-rotating, 2 to 4 rotations), 2
6 ... Can bottom receiving plate, 27 ... Hot air, 28 ... Shrinkable sleeve of cap body.

Claims (1)

[Claims] 1. A method of virgin-sealing a covered surface of a stacking can, 1). A preheating step A in which the heat shrinkable film 1 is protected from shrinkage even when it is affected by heat, preheated by closely contacting with the heating belt 3 and continuously fed to the molding step B; 2). The preheated film is brought into close contact with a vacuum forming mold 7 having an inner peripheral surface having an almost same shape as the covered surface of the stacking can, which is open to the outer peripheral surface of the continuous rotational molding drum 6, and the film upper surface is attached. A heating step of pressing the heating belt 3 with the heating belt 3 and elastically pressing the pressing roller 4 from the back surface of the heating belt while depressurizing the inside of the molding die to continuously perform vacuum forming, 3). Next, a cutting step C in which the forming drum is detached from the heating belt and the formed film is cut into a cap shape.
And 4). A transfer step D in which the cut cap body 14 is transferred to the capping step E while being stored in the molding die, 5). Capping process E of the can with the contents filled and the lid covered
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). While the upper surface of the cap body is protected by the presser 22 from the hot air, and at the same time the bottom of the stacking can is pressed by the can bottom receiving plate 26, the stacking can is rotated, and hot air is blown from around the sleeve of the cap body. A method of sealing a lid portion of a can, characterized in that a shrinking step F for shrinking the sleeve and tightly adhering the periphery of the sleeve to the peripheral wall of the can is combined.