JPH02152607A - Sealing of can lid - Google Patents

Abstract

PURPOSE:To permit a continuous sealing of cans with caps free from separation in transit by continuously placing the caps of a heat shrinkable film over the necks of the cans and continuously heat shrinking the cap bodies into close contact with the cans. CONSTITUTION:When a forming die with a heat shrinkable film fed therein and formed into caps 14 is moved into a capping process E and the neck of a can 15 is brought directly below the cap, the cap is separated from the forming die by air pressure transmitted from a pressurizing zone 9 to be placed over the neck of the can. The capped can 16 is transferred from a conveying device 18 to a rotary table and the upper surface of the cap is held down by a hold-down plate 22 to be prevented from shrinking at the time of shrinkage of a sleeve part. The rotary table carrying thereon the can with the bottom supported by a reception plate 26 rotates, while a hot air is being directed against the sleeve part of the cap body 24 from the side or above at an angle to shrink the sleeve part into close contact with the upper wall part of the can and then the upper surface of the cap into a virgin seal in a flat form.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION 1 The present invention relates to a method for continuous virgin sealing of the affected side of a can.

[Prior Art] Canned beer and canned coffee are sold in vending machines because they are easy to drink, but the covered surface of cans with pull tops is prone to dust, dirt, bacteria, etc. Conventionally, capping has been done for hygiene reasons. The method involved vacuum-forming an unstretched thermoplastic resin and simply fitting it over the can. Therefore, during transportation and at stores, these containers may become contaminated with dirt or bacteria entering through the gaps, or the cap may come off, resulting in the loss of virgin tSC.
It had the disadvantage of not having any.

Problems to be Solved by the Invention] It is an object of the present invention to provide a method for continuously sealing a cap body that has virgin sealing properties and does not come off during transportation.

[Means for Solving the Problems] The present invention involves continuously forming a heat-shrinkable film into a cap body of a specific shape, continuously placing the film on the cover surface of a can, and then continuously molding the cap body into a specific shape. This is a series of methods that thermally shrink the material to make it adhere tightly.

That is, the present invention provides a method for virgin-sealing the covered surface of 11 cans, 1) The heat-shrinkable film 1 is made so that the vicinity of both ends in the width direction of the film is approximately the same as the outer circumferential surface of the continuous rotary molding drum 6. The continuous rotary molding drum 6 is pressed with the clamp 4 of the arc-shaped heating device 2 having an inner circumferential surface of 2) a preheating step A in which the molding drum 6 has a flat top wall that opens outward on the peripheral surface of the continuous rotary molding drum 6 and has an inner diameter that is approximately the same as the outer diameter of the lid surface of the can; A forming step B in which a preheated film is brought into close contact with a vacuum forming mold 7 having a vacuum forming mold 7, and vacuum forming is performed continuously by reducing the pressure inside the mold while pressing the vicinity of both ends in the width direction of the film with clamps 4. 3) Then, the heating device is removed from the forming drum 6,
Cutting process C of cutting the formed film into a cap shape
4) A transfer process in which the cut cap body 14 is transferred to the capping process E while being stored in the mold; 5) The can filled with contents and covered is transferred to the capping process E. A capping step E in which the molded cap body is removed from the mold and placed on the cover surface of the transported can using a transport device; It is characterized by combining a shrinking process F in which the top surface is prevented from shrinking while shrinking, and the cap body is shrunk by spraying JP% on the periphery of the sleeve of the cap body, making the top surface flat and the sleeve periphery in close contact with the circumferential wall of the can. A method of sealing the lid of a can.

2. In the shrinking process F, first, the periphery of the sleeve of the cap body is shrunk to bring it into close contact with the peripheral wall of the can, and then the top surface of the cap body is shrunk to make the top surface flat, item 1. How to seal the lid of the can as described.

3. The method for sealing a can lid according to item 1 or 2, which uses a film provided with an adhesive layer on the side facing the can wall as the heat-shrinkable film 1.

The present invention is a method in which a cap body with a flat top surface is formed in advance, and this is attached to the lid of a can and then shrunk to seal the can.

The hot air that is blown onto the sleeve to shrink it is
It may be done from the side, but it may also be done from diagonally above.

In addition, in the process of shrinking the cap body, the presser that presses the top surface of the cap body presses the film against the edge of the can and prevents the top surface from shrinking, and may be a flat plate-shaped body or a metal net or the like. Materials with breathability such as woven fabrics, perforated plates, and plates with slits can also be used.

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

〔Example] 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. 3 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
A thermoplastic resin film of 0 μm and biaxially stretched at a stretching ratio of 1.01 to 10 times is continuously sent to a preheating step A and wound around a rotary molding drum 6.

A plurality of molds 7 for vacuum forming are provided on the circumferential surface of this molding drum and open outward.

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

FIG. 2 is a view of the heating device 2 seen from below.

The flang 4 installed on the arc-shaped heating device 2, which has an inner peripheral surface that is almost the same as the outer peripheral surface of the molding drum 6 that reciprocates along the peripheral surface of the rotary molding drum 6, prevents thermal shrinkage. The rotary molding drum 6 carrying the heat-shrinkable film pressed near both ends in the width direction rotates together with the heating device 2 in the direction of the arrow 20, and is placed on the heating device 2 on the top surface of the pressed heat-shrinkable film. A heating plate 3 having a temperature of 60 to 200° C. is brought close to the film, and the film is preheated while moving together with the heat shrink film, and then the heat shrink film is heated to a temperature at which it can be molded.

When the molding drum 6 rotates and enters the molding process B, the vacuum area 8
The pressure inside the mold was reduced, and the heat-shrinkable film was continuously molded to form the desired cap body.3! ! A follow-up film 10 is provided.

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 to the outside of the system between the cutting process and the gear/Y-bing process.

When the mold housing the cap body 14 is transferred to the capping process, as shown in FIG.
The synchronization is adjusted so that the cover surface of the can 15 that has been conveyed by the can arrives directly below, and the cap body is separated from the mold and placed on the cover surface of the can by the air pressure from the pressurizing area 9. It will be done.

The can 16 with the cap body placed thereon is 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 one shrink device.

The can 16 carrying the cap body is transferred from the conveyor 18 to the rotary table, and the top surface of the cap body is held down by a cap wood board 22 to prevent the top surface from shrinking when the sleeve portion shrinks. The bottom of the can bottom holder is held down by a plate 26, and the sleeve portion of the cap body 24 is shrunk by blowing hot air from the side or diagonally upward while rotating 2 to 4 times per minute. When the seal is brought into close contact with the upper wall and then the upper surface is shrunk, a virgin seal with a flat upper surface is created.

At this time, adhesion can be further improved by using a heat-shrinkable film that does not have a layer of adhesive, such as a hot-melt adhesive such as ethylene-vinyl acetate copolymer resin, on the side facing the can wall. Even if a sealed can is immersed in ice water, the seal will not peel off and water will not enter.

(Effects of the Invention) According to the method of the present invention, since a heat-shrinkable film is used, it can be closely attached to the upper wall of the can and cannot be peeled off from the can without tearing, so the virgin sealing function is extremely high.

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

The method of the present invention is particularly superior in that it is installed in an arc-shaped heating device 2 having an inner circumferential surface that is almost the same as the outer circumferential surface of the continuous rotary molding drum 6, and presses the continuous rotary molding drum 6 with a lamp 4. The heat-shrinkable film is then vacuum-formed to prevent it from shrinking, and then placed on the lid of the can. This means that a series of steps such as pinging and virgin sealing are performed continuously. As a result, productivity has improved several times compared to conventional methods.

[Brief explanation of the drawing]

1 and 3 are a side view and a plan view showing one embodiment of the method of the invention. FIG. 2 is a view of the heating device 2 seen from below. FIG. 4 is a side view showing details of the operation in the shrink process. 1... Heat shrink film, 2... Heating device, 3...
Heating plate, 4... Clamp, 6... Forming drum, 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 with a lid, 16... Can with a cap body placed on it, 17... Can with a shrunk cap body, 1
8... Conveyance device, 19... Shrink device, 20.
...Arrow (rotation direction of forming drum), 21... Rotary table for shrinkage, 22... Cap wood grain board (self-rotating type, 2 to 4 rotations), 24... Cap body, 25...
... Can (self-rotating type, 2 to 4 rotations), 26... Pipe bottom support is a plate, 27... Hot air, 28... Shrinked cap sleeve.

Claims (1)

[Claims] 1. In a method of virgin sealing the covered surface of a can, 1). A heat-shrinkable film 1 is placed so that the vicinity of both ends in the width direction of the film are approximately in contact with the outer circumferential surface of a continuous rotary molding drum 6. The continuous rotary molding drum 6 is pressed with the clamp 4 of the arc-shaped heating device 2 having the same inner circumferential surface, and is preheated while being protected from shrinkage even under the influence of heat, and the molding step B is started. 2) a flat upper wall portion having an inner diameter approximately the same as the outer diameter of the cover surface of the can and opening outward to the circumferential surface of the continuous rotary molding drum 6; A forming process B in which a preheated film is brought into close contact with a vacuum forming mold 7 having a vacuum forming mold 7, and vacuum forming is performed continuously by reducing the pressure inside the mold while pressing the vicinity of both ends in the width direction of the film with clamps 4. 3) Then, the heating device is removed from the forming drum 6,
Cutting process C of cutting the formed film into a cap shape
4) A transfer process D in which the cut cap body 14 is transferred to the capping process E while being stored in the mold; 5) The can filled with contents and covered is transferred to the capping process E. A capping step E in which the molded cap body is removed from the mold and placed on the cover surface of the can being conveyed by the conveyance device; Shrink process F: Shrink the cap body by blowing hot air around the sleeve of the cap body while preventing shrinkage of the top surface during shrinking, making the top surface flat and the sleeve periphery tightly attached to the can peripheral wall.
A method for sealing a can lid, characterized by combining the following. 2. In the shrinking process F, the periphery of the sleeve of the cap body is first shrunk to bring it into close contact with the peripheral wall of the can, and then the top surface of the cap body is shrunk to make the top surface flat. A method for sealing the lid of a can according to scope 1. 3. A method for sealing a lid of a can according to claim 1 or 2, wherein the heat-shrinkable film 1 is a film provided with an adhesive layer on the side facing the can wall.