JPH0245331A - Can lid sealing method - Google Patents

Abstract

PURPOSE:To seal cans continuously, to be stackable, with virgin sealing property by forming a heat-shrinkable film continuously into a specific shaped cap body, placing this film on a surface to be capped of a stackable can, and attaching the film continuously by making it heat-shrink. CONSTITUTION:A clamped heat-shrinkable film 1 so as not to give heat-shrinkage is continuously sent out to a pre-heating process A and is wound around a rotational molding drum 6, on the peripheral surface of which a vacuum forming die 7 is provided. This forming die has an inner peripheral surface which has the approximately same shape as the surface to be capped of a stackable can. The molding drum 6 revolves, and the heat-strinkable film 1 is heated by a heat resistant silicone belt 3, pressing roller 4, which are heated by a heating roll 2, and is continuously formed into a cap body at a vacuum region 8 of a forming process B, and is die-cut at a cutting process C. The die-cut cap body 14 is transferred to a capping process E while being stored in the forming die. The surface to be capped of a separately carried stackable can 15 is adjusted so that it positions directly under the cap body 14. The cap body is removed from the forming die by the air pressure at a pressurizing region 9, placed on the surface to be capped of the stackable can, and transferred to and sealed at a shrinking process F.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for continuously virgin-sealing covered surfaces of M-stack cans.

(Prior art) Canned beer and canned coffee filled in stackable cans are sold in vending machines because they are easy to drink, but the covered surface of cans with pull tops is free from dust and dirt. , bacteria, etc. may adhere to it, so capping it has been conventionally done for hygiene reasons. The method is -f
It was made by vacuum forming an unstretched thermoplastic resin, and simply fit over the can. As a result, these containers have the disadvantage that they do not have any virgin properties, such as dirt and bacteria entering through the gaps and contamination during transportation or at stores, or the character 1 coming off.

In addition, as a cap with adhesive properties, there is a capping method using a biaxially stretched thermoplastic resin film or sheet (hereinafter abbreviated as heat-shrinkable film), but this is limited to caps with a flat top surface. It was difficult to stack them when displaying them in stores.

(Problems to be Solved by the Invention) It is an object of the present invention to provide a method for continuously sealing cap bodies that have virgin sealing properties, can be stacked, and do not come off during transportation.

(Means for Solving the Problems) The present invention continuously forms a heat-shrinkable film into a cap body of a specific shape, continuously places this film on the cover surface of stacked cans, and then attaches the cap body. This is a series of methods that involve continuous heat shrinking to make them adhere.

That is, the present invention provides a method for virgin-sealing the covered surfaces of stacked cans by: 1) bringing the heat-shrinkable film 1 into close contact with the heating belt 3 while protecting the heat-shrinkable film 1 from shrinking even under the influence of heat; a preheating step A in which the drum is continuously fed into the molding step B while being preheated; and 2) a continuous rotary molding drum 6.
The preheated film is brought into close contact with a vacuum forming mold 7 which has an inner circumferential surface that is open toward the outside and has an inner circumferential surface that is approximately the same shape as the lid surface of the stacked cans, and the upper surface of the film is heated with a heating belt 3. 3) a forming step B in which vacuum forming is continuously performed by reducing the pressure in the mold while elastically pressing the presser foot and heating belt from the back side with a presser roller 4;

Next, a cutting step C in which the forming drum is removed from the heating belt and the formed film is cut into a cap shape;
5) A transfer process in which the cut character 7#14 is transferred to the capping process E while being stored in the mold.
, a capping step in which the molded cap body is removed from the mold and placed on the capping surface of the transported can using a conveyance device that transports the filled and capped can to the capping step E; E and 6), a shrinking process in which the upper surface of the cap body is pressed with a presser and at the same time protected from hot air, hot air is blown from around the sleeve of the cap body to shrink the cap body and bring the periphery of the sleeve into close contact with the can peripheral wall. This is a method for sealing a can lid, characterized by bonding F.

The present invention will be explained in detail below with reference to the drawings.

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

Made of a single layer of polyvinyl chloride, polyethylene, polypropylene, polystyrene, polycarbonate, polyester, etc. or a composite using these materials, thickness 15-2
00 μl of a thermoplastic resin film biaxially stretched at a stretching ratio of 1.01 to 10 times is continuously sent to the preheating step A and wound around the rotary molding tram 6.

A mold 7 for vacuum forming is provided on the circumferential surface of this molding drum and is open toward the outside.

This mold for vacuum forming has an inner circumferential surface having substantially the same shape as the cover surface of the stacked cans, and thus exhibits an uneven shape similar to the cover surface of the stacked cans.

The molding drum 6 on which the heat-shrinkable film is mounted, which is not clamped to prevent heat-shrinking, rotates in the direction of arrow 20, and the top surface of the clamped heat-shrinkable film is heated to 60 to 200°C with a heating medium or a casting heater. A heated heat-resistant silicone belt 3 with a thickness of 5 to 15 mm is brought into close contact with the heated heating roll 2, and the film is preheated while moving together with the heat-shrinkable film. The heat-shrinkable film is heated to a temperature at which it can be molded by pressing it against a molding drum.

When the molding drum 6 rotates and enters the molding process B, the vacuum area 8
The pressure inside the mold is reduced, and the heat-shrinkable film is continuously molded to provide a continuous film 10 in which the desired cap body is formed.

When the forming drum 6 further rotates and enters the cutting process C, the cutting device 11 reciprocates along the circumferential surface of the forming drum.
A punching blade 12 attached to the drum cuts off unnecessary portions of the formed film and punches out the cap body while traveling in parallel with the drum.

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

Punched formed film 14, that is, cap body 14
, remains housed in the mold installed in the molding drum,
It is transferred to the capping process E by the rotation of the drum.

On the other hand, the remaining film 13 from which the cap body has been punched out is discharged from the system between the cutting process and the capping process.

When the mold housing the cap body 14 is transferred to the capping process, synchronization is adjusted so that the covering surface of the stacked cans 15 transported by the transport device 18 arrives directly below, and the pressurized area is By the air pressure from 9, the cap body is released from the mold and placed on the cover surface of the stacked cans.

The stacked cans 16 with the cap bodies placed thereon are transferred to a shrink process F and sealed.

The details of the operation in the shrinking process are shown in FIG.

21 is a shrink rotary table attached to the shrink device 19.

The stacked cans 16 carrying the cap bodies are transferred from the conveying device 18 to the rotary table, the upper surface of the cap bodies is held down by a cap body holding plate 22 with cushioning properties, and the bottom of the stacked cans is held by a can bottom support plate 26. 2-4 per minute while being held down
While rotating, the sleeve portion of the cap body 24 is shrunk by blowing hot air from the surface and diagonally above.
Place it in close contact with the earthen wall of the stacked cans.

At this time, since the cooling water 23 is passed through the cap body holding plate 22 for cooling, the molded portion of the cap body is protected from hot air and does not shrink or deform.

In addition, when stacking is not required, the upper surface of the can 71 can also be shrunk to form a flat sealing film on the upper surface of the can.

(Effects of the Invention) According to the method of the present invention, the bottom flange of the stacked cans and the cover are bonded to the bottom flange of the stacked cans for virgin sealing using a cap body which is pre-molded with a heat-shrinkable film to have substantially the same shape as the lidding surface of the stacked cans. Since the protrusions on the parts fit well, they can be stacked in multiple tiers when displayed at a store or the like.

Because it uses heat-shrinkable film, it can be tightly attached to the earthen walls of the can, and it cannot be removed from the can without tearing, so it has an extremely high virgin sealing function.

The particular advantage of the method of the present invention is that it involves a series of steps in which a heat-shrinkable film is vacuum-formed using a heating belt to prevent it from shrinking, and then this is capped on the lid of the stacked cans and virgin-sealed. This means that the process is performed continuously.

As a result, productivity has improved several times compared to conventional methods.

[Brief explanation of the drawing]

1 and 2 are a side view and a plan view showing one embodiment of the method of the present invention. FIG. 3 is a side view showing details of the operation in the shrink process. 1... Heat shrink film, 2... Heating roller, 3...
... Belt, 4... Press roller 5... Belt drive roller, 6... Forming tram, 7... Vacuum forming mold, 8... Vacuum area, 9... Pressure area, 10...
Molded film, 11... Cutting device, 12...
Punching blade, 13... Scrap film, 14...
Cut formed film (cap body), 15... Can covered, 16... Can with cap body mounted, 17...
・Can with a shrink cap body, 18... Conveyance device, 19... Shrink device, 20... Arrow (rotation direction of forming drum), 21... Rotary table for shrinking, 22... Cap Body press plate (self-rotating type, 2 to 4
Rotating), 23... Cooling water, 24... Kya... 21 bodies, 25... Stacking cans (self-rotating type, 2 to 4 rotations) 26...
...Can bottom holder is a plate, 27..Hot air, 28..Sleeve of 71 shrunk cans. Applicant: Engraving of the diagram of Sumitomo Bakelite Co., Ltd. (no change in content) Procedural amendment (method) % formula % Name of the invention Relationship to the case of a person amending the method of sealing the lid of a can Patent applicant address: Tokyo No. 4, 11836-11836, Mita-3-chome, Miyakominato-ku, Amendment order [ ] dated 10/25/1983 (Shipping port) 5゜Drawing subject to amendment 6, Contents of amendment

Claims (1)

[Claims] 1. In a method for virgin sealing the covered surface of stacked cans, 1). heat-shrinkable film 1 is protected from shrinkage even under the influence of heat, while heating belt 3 and 2) A preheating step A in which the cans are brought into close contact with each other and preheated, and then continuously fed into the molding step B; 2) a shape that is approximately the same as the cover surface of the stacked cans, which opens outward on the circumferential surface of the continuous rotary molding drum 6; A preheated film is brought into close contact with a vacuum forming mold 7 having an inner peripheral surface, the top surface of the film is pressed by a heating belt 3, and the inside of the mold is pressed while being elastically pressed by a presser roller 4 from the back side of the heating belt. 3) a forming step B in which vacuum forming is performed continuously under reduced pressure; 3) a cutting step C in which the forming drum is removed from the heating belt and the formed film is cut into a cap shape; 4) the cut film is 5) A transfer step D in which the cap body 14 is transferred to the capping step E while being housed in the mold; capping step E in which the molded cap body is removed from the mold and placed on the cover surface of the can, and 6) the sleeve of the cap body is removed while pressing the top surface of the cap body with a presser and simultaneously protecting it from hot air. A method for sealing a can lid, characterized by combining a shrinking step F in which hot air is blown from the periphery to shrink the cap body and bring the periphery of the sleeve into close contact with the can peripheral wall.