JPH066049Y2 - Film cap for cans - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a film cap used for a beverage such as canned beer or canned juice.

[Prior Art] Generally, a beverage can, for example, a beverage can such as beer or juice has a structure in which a metal ring is attached to a canopy, and when the ring is lifted with a finger, a metal plate of the canopy is torn and opened. , I often drink by mouth directly at this opening.

Among them, there is a beer can, which has a shape in which the bottom of the can fits just above the other cans and is convenient for stacking, displaying and packing.

In this case, since it is unknown to the consumer what kind of contamination the opening has been subjected to after being manufactured and before being used for drinking, there is a drawback that it gives anxiety when drinking the can.

In the beverage can as described above, it is sanitary to cover the canopy and its upper edge portion just before drinking and remove the cover before drinking.

As such a sanitary cover for a can, a plastic thick cap is already used for a small part of the can. This is simply covered with a thick sheet plastic lid that fits over the top edge of the can.

However, such lids may fall off, and in the storage and transportation of large numbers of beverage cans, such as vending machines, cooling in ice water, etc. It is difficult to directly adapt to the usage method of.

In addition, in the case of commercially available beer cans, the bottom of other cans are fitted on top of the lid of the can, and the structure is such that the cans are stacked, but using the above lid increases the dimensions of the fitting part. , It will be necessary to change other standards for box packaging in the distribution form.

[Problems to be Solved by the Invention] An object of the present invention is to provide a film cap for a can, which is simple, hygienic, and can be applied to the conventional sales and distribution form without any trouble.

[Means for Solving the Problem] The present inventor assumes that it is indispensable to use a thin film cover in order to solve the above problems by adapting to the current distribution form, and As a result, a heat-shrinkable film is used, and the heat-shrinkage rate is changed according to the specific shape of the film cap and the function of the constituent parts of the film cap.

That is, the present invention is a substantially disc-shaped thermoplastic resin film having a circular inner lid portion 3, a convex ring inner side surface portion A around the outer periphery of the inner lid portion, and the convex ring portion outer surface portion. A skirt portion 1 composed of B and a flange portion C around the outside thereof is a constituent portion, and the diameter of the apex of the convex ring portion 2 is made to coincide with the diameter of the upper edge of the can, and the height of the inner side surface of the convex ring is increased. Film having a heat shrinkage of 15% or more, and a heat shrinkage of the collar having a peak of a convex ring portion. 5 from the heat shrinkage rate
The film cap for a can is characterized by having a high content of at least%.

Any material can be used as the material of the film used in the present invention as long as it is a thermoplastic resin. For example, vinyl chloride resin, polyethylene, polypropylene,
Heat-shrinkable films such as polystyrene, polyethylene terephthalate, polybutylene terephthalate, and polyamide can be used.

In the case of the present invention, since the heat shrinkage is not anisotropic, the heat shrinkage manufactured by biaxial stretching is 15 to 60%, preferably,
It is more preferable to use a 30 to 50% heat-shrinkable film.

The thickness of the film used in the present invention is not particularly limited,
Usually, about 10 to 200 μm can be used.

When the thickness of the film is less than 10 μ, the film has no strength and is 200
If it exceeds μ, heat shrinkage becomes difficult.

[Operation and Embodiment] The present invention will be described in more detail with reference to the drawings of the embodiment.

In the film caps of the embodiments shown in FIGS. 1 and 2, a narrow groove ring 4 is provided on the peripheral edge of the central circular lid portion 3, and the convex ring 2 is continuously provided outside the ring of the groove portion 4. It is provided, and further, a flange portion C is provided outside thereof. The skirt portion 1 is composed of an outer side surface B of a convex ring and a collar portion C, and the skirt 1 is fixed in close contact with the upper side surface of the can by heat shrinking treatment.

When this film cap is used for a beer can, for example, as shown in FIGS. 3 and 4, the film cap is placed on the beer lid, and the convex ring 2 is fitted to the convex edge of the peripheral edge of the can. Then, heat is applied to the skirt portion 1 by hot air or infrared rays to cause heat shrinkage, and the film cap is fixed to the upper lid of the can by the shrinking force.

Then, when drinking beer, the film cap can be easily removed by holding and peeling the knob piece 5.

The once removed film cap can no longer be covered and fixed again.

The feature of the present invention resides in the shape of the film cap, and firstly, in that the collar portion is provided as the outer peripheral portion of the skirt portion.

That is, as a common sense, when designing a film cap to be fitted on the upper edge of the can, it is a normal shape to punch out the convex ring up to the outer side surface B.

The present invention is characterized in that the collar portion C of the shrink film is purposely provided on the outer peripheral edge of the outer side surface B thereof.

The outer side surface B of the convex ring 2 is inevitably heated in a preheating step in a forming process such as vacuum forming, and therefore the high heat shrinkage ratio of the heat shrinkable film as a raw material is lowered.

On the other hand, the collar C as described above can be operated so as not to be heated in the vacuum forming process for forming the convex ring.

Therefore, the heat shrinkage rate of the heat shrinkable film of the raw material is maintained as it is after the molding, and the diameter of the outer periphery of the collar portion C becomes large, and the gap with the diameter of the can becomes large. It turns out that I can austerate.

That is, the flange-shaped portion that does not receive the heat of the forming process is left specially on the outer side of the outer side surface B of the convex ring, and the high heat-shrinkability that the original material film has from the beginning is provided on the outermost periphery of the film cap. The fixing force is increased.

As a second feature, the height of the inside of the convex ring 2 is adjusted according to the length from the top surface of the can to the top surface of the inside lid,
The beer cans are set to be the same or substantially equal to each other, and it is possible to stack and stack other beer cans on the beer cans equipped with the film cap of the present invention.

Further, the diameter of the apex of the convex ring 2 is made to coincide with the diameter of the upper peripheral edge of the can.

Therefore, the line of the apex of the convex ring of the film and the apex of the convex portion of the upper edge of the can are not wrinkled, and the airtightness can be maintained.

The groove portion 4 inside the convex ring 2 shown in the drawings of the embodiment is
Although not always necessary, it is convenient because the bottom of the cans fits into the groove when the cans are stacked to improve the stability of stacking.

The width of the collar portion C of the film cap of the present invention is appropriately selected and determined according to the shape of the side surface of the upper portion of the can. If the width is too narrow, the fixing force will be reduced, and if it is too wide, the films in the skirt portion will overlap and the appearance will be poor. .

Usually, a collar portion having a width of 2 to 30 mm, preferably 3 to 15 mm can be suitably used.

Further, it is desirable that the height of the outer side surface B of the convex ring 2 is about 1 to 3 times that of the inner side surface A.
By drawing deeper than the inner height, the film may be stretched, and if the conditions are selected, the heat shrinkage reduced by the preheating of the molding is recovered to some extent, which is desirable.

Another feature of the present invention resides in that the collar portion C is left with a large heat shrinkability, while the apex portion of the convex ring 2 is reduced in heat shrinkability.

That is, the thermal contraction rate of the collar portion C is 15% or more, preferably 20% or more, more preferably 30% or more,
Moreover, it is desirable that the thermal shrinkage of the collar portion be maintained at 5% or more higher than the thermal shrinkage of the apex of the convex ring.

If the thermal contraction rate of the collar portion C is less than 15%, the fixing force of the film cap due to the contracting force of the skirt portion 1 is weak, and the film cap easily falls off, and the capping step takes a long time, which is inconvenient.

Further, if the difference in the heat shrinkage rate at the apex of the convex ring is less than 5%, the apex of the convex ring 2 is likely to contract when heat is applied to the skirt portion 1, and the apex of the can has a convex shape. If the film is displaced from the apex of the edge or wrinkles are formed on the film on the apex, the airtightness is impaired and the appearance as a product is deteriorated.

In the film cap of the present invention, the heat shrinkage rate of the intermediate portion from the collar portion C to the apex of the convex ring 2 gradually changes from the heat shrinkage rate of the collar portion C to the heat shrinkage rate of the apex of the convex ring 2. .

The intermediate portion and the brim portion, which are the outer side surfaces of the convex ring, are heated in the capping step and heat-shrinks to adhere to the side surface of the can, but this contact surface often causes wrinkles on the film, , Airtightness is not good.

According to the present invention, since the diameter of the apex of the convex ring 2 is matched with the edge of the can and the heat shrinkability is reduced, the film at the apex does not have wrinkles, and thus the airtightness and The appearance will improve.

The heat shrinkage rate of each part of the film cap of the present invention is measured by the following method.

i) Measurement of heat shrinkage rate of the collar portion C A film having a length of 20 mm and a width of 2 mm is cut from four symmetrical points along the outer circumference of the collar portion C, and the heat shrinkage temperature is determined by the material of the film. The film was immersed in a maintained glycerin bath for 20 minutes, the film was stretched without tension, and the longest length was measured.
m) was calculated and the heat shrinkage was calculated by the following formula.

[A / 20] × 100 (%) ii) Measurement of heat shrinkage rate at the apex of the convex ring 20 mm from the four inner positions corresponding to the test piece of the flange along the apex of the convex ring 2. The length was cut into a width of 2 mm, and the heat shrinkage rate was obtained by the same method as the heat shrinkage test of the collar portion.

The heat shrinkage temperature adopted in this test was carried out at the following temperature with respect to the working temperature range adopted in the normal shrinkage process.

Vinyl chloride resin 120 ° C (heat shrinking working temperature 65 to 150 ° C) Polyfropylene 135 ° C (heat shrinking working temperature 105 to 165 ° C) Polyethylene 115 ° C (heat shrinking working temperature 105 to 120 ° C) The film cap of the present invention is manufactured. Can be produced using a conventional vacuum forming or pressure forming method.

For example, as a raw material, using a biaxially stretched thermoplastic heat-shrinkable film, with the periphery of the molded portion fixed,
Preheat the portion corresponding to the convex ring so that the temperature of the collar does not rise as much as possible during this heating. For example, the temperature of the collar part should be kept by surrounding the heat source for preheating so that heat does not hit in the outer circumferential direction, by locally heating only the molding part with an infrared lamp, or by locally contacting the heat source body. Can be prevented from rising.

By doing so, the molecular orientation of the film in the heated portion is disrupted during the preheating period, and the heat shrinkage rate is partially reduced.

On the other hand, the thermal contraction rate of the collar portion is almost the same as that of the original material, and a strong contraction force is exerted by the thermal contraction.

Further, in order to improve the airtightness of the film cap of the present invention, it is preferable to apply an adhesive having good adhesiveness to metal to the inner surface of the film cap.

In this case, as the adhesive, a heat-sensitive adhesive is easier to perform the capping operation, and for example, an ethylene-vinyl acetate copolymer-based adhesive, a copolymer polyester-based adhesive, a polyamide-based adhesive, an atactic polypropylene adhesive , Ethylene-ethyl acrylate copolymer-based adhesives, polyurethane-based adhesives and tackifiers such as petroleum resin, rosin and pinene-based resin can be preferably used.

[Advantage of the Invention] The film cap of the present invention can seal the opening portion of a beer can or the like just before the opening, and once opened, it cannot be fixed again by covering the opening with the film cap. The person can identify whether the film cap is opened or not, and can confirm that there is no contamination, which is an advantage of giving a sense of security.

When the film cap of the present invention is used, wrinkles do not occur at the apex of the convex ring during the fixing operation due to the heat shrinkage of the flange portion on the outer periphery, so the airtightness between the film and the can at the apex of this ring Even if the can with the film cap is cooled by immersing it in ice water, it is difficult for water to enter the space between the can lid and the film cap.

The presence of such infiltrating water may make the consumer feel unclean, but in the case of the present invention, there is an advantage that this fear does not occur.

Further, since the shape of the film cap of the present invention is set so that the lid film is almost in contact with the lid surface of the can when the film cap is covered, the cans can be stacked as usual. In addition, when the film cap is in contact with the can like a drop lid, there is an advantage that the film cap is much less likely to be soiled even if it is pierced with a pin or the like, as compared with a state where the film cap is flatly attached to the rim of the can.

[Brief description of drawings]

FIG. 1 is a plan view of a film cap of an embodiment of the present invention, FIG. 2 is a cross-sectional view thereof, and FIG. 3 is a cross-sectional view showing a structure when the film cap is used in a beer can. , FIG. 4 is a perspective view thereof. The symbols in the figure are
1; skirt part, 2; convex ring part, 3; inner lid part, 4;
Groove part, 5; Knob piece, 6; Can, 7; Can bottom, 8; Opening metal,
A: convex ring inner side surface, B: convex ring outer side surface,
C: It is Tsubabe.

Claims (2)

[Scope of utility model registration request] 1. A substantially disc-shaped thermoplastic resin film comprising a circular inner lid portion 3, an inner side surface portion A of a convex ring around the outer side of the inner lid portion and an outer surface portion B of the convex ring portion. And a skirt portion 1 composed of a collar portion C on the outside of the convex ring portion 2 as a constituent portion, and the diameter of the apex of the convex ring portion 2 is made to coincide with the diameter of the upper edge of the can. Is set according to the height of the lid surface and the upper edge of the can, and the film of the collar portion has a heat shrinkage rate of 15% or more, and the heat shrinkage rate of the collar portion of the film at the apex of the convex ring portion is A film cap for a can, which has a heat shrinkage ratio of 5% or more. 2. The film cap for a can according to claim 1, wherein the height of the outer side surface of the convex ring is 1 to 3 times the height of the inner side surface.