JPH0579585B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <<Industrial Application Field>> The present invention relates to a method for sealing a can with a protective lid obtained from a biaxially oriented thermoplastic resin film or sheet.

<<Prior Art>> Conventionally, top lids for cans having pull-tops and the like have generally been vacuum-formed from non-stretched thermoplastic resin and simply fitted onto the cans. As a result, these containers have the disadvantage that their lids may come off during transportation or at stores, and that they do not have any virgin properties.

In addition, there is a capping method that uses a biaxially stretched thermoplastic resin film or sheet (hereinafter abbreviated as heat-shrinkable film) to create a lid that has adhesive properties, but this is limited to lids with a flat top surface. However, it was difficult to stack them when displaying them in stores.

≪Purpose of the Invention≫ The present invention was completed as a result of various studies into the possibility of creating a protective lid that has virgin sealing properties and can be stacked. By using the molded product for a protective lid, it has been possible to provide a protective lid for cans that has virgin sealing properties, can be stacked, and has a fall-off prevention function.

<<Configuration of the Invention>> The present invention comprises a flat part 2 in contact with the top surface of the can, a projection part 3 having an outer diameter smaller than the inner diameter of the bottom flange part 8 of the can, and a stepped part 4 in contact with the upper flange part 9 of the can.
and a protective lid molding 1 provided with a skirt portion 5,
A heat-shrinkable film is formed at a low temperature without losing its heat-shrinkability, and is placed over the top of the can, and the skirt portion 5 is heated and shrunk with hot air or the like only from the side without applying heat to the top, and the protective lid is formed. This is a method for sealing a protective lid for canned goods, which is characterized in that the protective lid for canned goods is brought into close contact with the upper flange of the can.

This will be explained in detail below with reference to the drawings.

The molded product 1 for the protective lid is made by using a preheating heater built into the upper plate to securely clamp the non-molded part with the upper plate and lower plate to prevent heat shrinkage of the single-layer or multi-layer heat-shrinkable film. Only the part to be molded is preheated and molded into the shape shown in FIGS. 1 and 2 while cooling by vacuum pressure molding or compression molding.

Next, the protective lid molding 1 is placed over the top of the can 6, including the pull-top portion, and the protective lid molding 1, especially the stepped portion 4, is pressed down from the top with a cushioning press plate 10 from the side and diagonally above. The skirt portion 5 is heated using hot air or the like. Since the skirt portion 5 is hardly preheated and shrunk at the stage of the molded product, its heat shrinkage performance is exactly the same as that of the original heat shrinkable film, so it shrinks when heat is applied. At this time, the skirt portion 5 is contracted until it fits over the upper flange portion 9 of the can to form a close contact portion 5'. This adhesive part 5' becomes wrapped around the upper flange part 9 of the can due to the shrinkage force of the heat-shrinkable film, and the protective lid 12 cannot be removed from the can without breaking the adhesive part 5'. It is.

Furthermore, the heat-shrinkable film used is not limited to a single film, and by using a composite film in which a heat-fusible adhesive layer is laminated on the inner surface, it is possible to provide the function of shrinkage force plus adhesive force.

The sealed cans have a virgin sealing function due to the protective lid 12 obtained by the present invention, which is not found in conventional protective lids, and when displayed at a store, the bottom flange of one can 8 fits well with the protrusion 3 and stepped portion 4 of the protective lid of another can, making it possible to stack them in multiple tiers.

Although FIG. 2 shows an example in which there are four protrusions 3, the shape, number, etc. of the protrusions can be selected and determined as appropriate.

<<Effects of the Invention>> In the canned food with a protective lid obtained by the present invention, since the protective lid uses a heat-shrinkable film, the protective lid protects the top pull-top portion of the can, and the protective lid Because it adheres closely to the upper flange of the can and cannot be removed from the can without being broken, it has a virgin seal function and will not fall off during transportation, display, or other factors. In addition, since the bottom flange of the can and the protrusion of the protective lid fit well together, canned goods can be stacked in multiple tiers when displayed at a store.

[Brief explanation of the drawing]

1 and 2 are a cross-sectional view and a plan view of a molded product for a protective lid used in the present invention, FIG. 3 is a cross-sectional view for explaining the sealing method of the present invention, and FIG. FIG. 3 is a cross-sectional view showing a state in which the obtained canned goods with protective lids are stacked.

Claims (1)

[Claims] 1 a flat part 2 in contact with the top surface of the can; a protrusion 3 having an outer diameter smaller than the inner diameter of the bottom flange part 8 of the can;
A protective lid molding 1 having a step portion 4 and a skirt portion 5 in contact with the upper flange portion 9 of the can is molded at low temperature without losing heat shrinkability using a heat-shrinkable film, and is placed over the top of the can. This method of sealing a protective lid for canned goods is characterized in that the skirt part 5 is heated and contracted by hot air or the like only from the side without applying heat to the top surface, and the protective lid 12 is brought into close contact with the upper flange part of the can.