JPH11301715A - Thermal sealing lid material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a lid from being left behind on a spout without any breakage of the lid when unsealed by interposing a polyester film of the specified thickness between an aluminum foil and a polyethylene film in providing a heat-sealed layer on the aluminum foil through the polyethylene film. SOLUTION: Printing is achieved on a surface of an aluminum foil 1 of 20-35 μm in thickness, a printed surface 3 is protected, and an over-print coat 4 is executed to prevent corrosion of the aluminum foil 1. A bi-oriented polyester film 6 of 5-10 μm in thickness is joined with a back side of the aluminum foil 1 through a dry adhesive layer 5, an anchor coat 7 is formed on this polyester film 6, and a low-density polyethylene film 8 of 10-30 μm in thickness is joined therewith. In addition, a hot-melt adhesive 9 is applied to the polyethylene film 8. Since the bi-oriented polyester film 6 is large in elasticity, the resistance against the breakage of a lid when unsealed can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sealing lid material, and more particularly to a heat-sealing lid suitable for forming a heat-sealed lid in a small-sized beverage container made of a synthetic resin having an outer diameter of about 20 to 30 mm. About materials.

[0002]

2. Description of the Related Art Conventionally, as a lid material that is heat-sealed to a lactic acid bacterium beverage or other beverage container made of a synthetic resin, a polyethylene film is bonded to the other surface of a printed aluminum foil, and a heat sealing material is attached to the polyethylene film. A heat sealing material (eg, Japanese Utility Model Publication No. 51-1322) having a basic structure formed by applying a layer (hot melt adhesive layer) is used.

More specifically, as shown in FIG.
An anchor coat 2 made of polyurethane or the like is formed on the surface of the aluminum foil 1 having a thickness of 5 to 35 μm to improve adhesion if necessary, and printing is performed to protect the printing surface 3 and prevent corrosion of the aluminum foil. For this purpose, an overprint coat 4 made of nitrified cotton, epoxy resin, cellulose, melamine resin or the like is applied.

On the other hand, on the back side of the aluminum foil 1, a thickness of 10 to 30 μm is provided via the same anchor coat 7 as described above.
A low-density polyethylene film 8 having a thickness of about m is bonded, and a hot-melt adhesive is applied to the polyethylene film 8 to form a heat sealing layer 9. As the hot melt adhesive, those having an ethylene-vinyl acetate copolymer and a wax as main components are often used, and are applied at an application amount of, for example, 10 to 25 g / m ² . The low-density polyethylene film has a function of increasing the adhesiveness of the hot melt adhesive, giving the lid a cushioning property, and ensuring airtightness.

[0005] The heat sealing material is punched out in a circular shape by a beverage manufacturer and then squeezed into a lid 10 provided with a skirt portion 11 having pleats as shown in FIG. 3 using a molding machine (former). It is molded, fed through a shooter, covered with a container made of synthetic resin, for example, polystyrene filled with the contents, and heat-sealed.

[0006] When drinking a beverage, the heat-sealed lid is opened. However, in the lid made of the above-mentioned conventional heat-sealing lid material, the lid or the shake occurs from the beginning of the opening, and the lid material is placed in the drinking part. There are drawbacks such as lids and shakes occurring during opening and lids remaining around the drinking opening. If the lid material remains in the drinking part, it is difficult to drink the contents, and the drinking opening diameter is 20 to 30 mm
This is particularly problematic for small beverage containers of the order of magnitude. It is not preferable in terms of safety and health.

In order to solve this problem, there has been proposed a method of increasing the strength by increasing the thickness of the aluminum foil or changing the aluminum foil to an aluminum alloy foil containing Fe, Cu or the like. In addition to being changed, the remaining material (skeleton) after punching the lid material contains a large amount of components such as Fe and Cu, so that there is a problem in recycling aluminum. Also, if low-density polyethylene is changed to linear low-density polyethylene or high-density polyethylene, it will be difficult to break, but it is still not a sufficient solution, and a method of reducing the adhesive strength between the hot melt adhesive and the container is Leakage of contents may occur, leaving a problem.

[0008]

SUMMARY OF THE INVENTION The present invention has been made as a result of repeatedly examining the structure of a heat-sealing lid material from various aspects in order to solve the above-mentioned problems in the conventional heat-sealing lid material. An object of the present invention is to provide a heat-sealing lid material in which a lid or a shake does not occur at the time of opening and a lid material does not remain in a drinking mouth.

[0009]

Means for Solving the Problems To achieve the above object, a heat sealing material according to the present invention is a heat sealing material having a heat sealing material layer provided on an aluminum foil via a polyethylene film. A structural feature is that a polyester film having a thickness of 5 to 10 μm is interposed therebetween.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described with reference to FIG. The same components as those in the related art are denoted by the same reference numerals. An anchor coat 2 is formed on the surface of an aluminum foil 1 having a thickness of 20 to 35 μm and printing is performed in the same manner as in the related art, and a printing surface 3 is protected, and an overprint coat 4 is applied to prevent corrosion of the aluminum foil. The anchor coat 2 may be omitted in some cases.

On the back side of the aminium foil 1, a biaxially stretched polyester film 6 having a thickness of 5 to 10 μm is bonded via a dry adhesive 5, and an anchor coat 7 or a dry adhesive is formed on the polyester film 6. And thickness 10
Bonding a low-density polyethylene film 8 of ３０30 μm,
Further, the same hot melt adhesive 9 as that of the related art is applied and formed on the polyethylene film 8.

The dry adhesive is used to bond an aluminum foil and a biaxially stretched polyester film, and a two-component reaction type in which a curing agent such as isocyanate is added to polyester or polyurethane is often used. As the hot-melt adhesive 9, as in the prior art, an adhesive mainly containing an ethylene-vinyl acetate copolymer and a wax is often used, and is applied at an application amount of 10 to 25 g / m ² .

The biaxially stretched polyester film 6 has a high elastic modulus and a property of generating resistance to bending, tension, etc., so that the aluminum foil 1 and the low-density polyethylene film bonded to the polyester film are used. Interaction with 8 increases the resistance to lids and shakes when opening.

If the biaxially stretched polyester film 6 has a thickness of less than 5 μm, it is difficult to manufacture and it is difficult to obtain it. The formed pleated skirt opens (spring-back phenomenon) and causes a clog in the shooter for feeding the lid. In addition, even if the lid can pass through the shooter, there is a problem that the lid cannot be properly attached to the container when the lid is put on the container. In addition, as for the biaxially stretched polyester film satisfying the above conditions, those having a nominal thickness of 6 μm and 9 μm can be easily obtained.

It is conceivable to provide a biaxially stretched polyester film layer on the surface side of the aluminum foil 1, for example, on the printing surface. In this case, however, the skirt portion of the lid after molding is more easily opened, which is not preferable. .

[0016]

Hereinafter, examples of the present invention will be described in comparison with comparative examples. Example 1 A heat-sealing lid material (test material A) according to the present invention was produced by the following steps. Printing is performed on the surface of an aluminum foil having a thickness of 25 μm, and an overprint coating of cellulose is performed on the printing surface. The film is adhered, and an anchor coat is applied to the polyester film to bond a low-density polyethylene having a thickness of 15 μm.
The coating is formed with a coating amount of m ² .

The obtained heat-sealed lidding material (test material A) is punched, drawn, generally used for filling small beverage containers, fed with a lid formed by a shooter, and attached to the container. The following evaluation was performed using the apparatus for performing heat sealing (CH15: high-frequency heating method manufactured by Shikoku Koki Co., Ltd.).

Punching property: Evaluation of whether or not the test material can be easily punched into a circle at a normal speed. Shooter feedability: Evaluation of whether or not clogging occurs in the shooter. Attaching of lid to container: Evaluation of whether the lid supplied from the shooter is properly attached to the container. Openability: The lid of the heat-sealed container was opened by hand, and the number of the lids remaining in the drinking mouth was evaluated for the lid and the displacement ratio according to the following formula. Lid and blurring rate (%) = Number of lids left in drinking spout / Total number of tests (n = 20 to 25)

The above-mentioned heat-sealing lid material (test material A) produced according to the present invention has a good punching property, does not cause clogging in the shooter, and is properly mounted on the container. The tear rate was 0%, and no lid or tear was observed at the time of opening.

Comparative Examples 1 to 5 The following heat-sealing lids were prepared and used as comparative test materials. Test material B: A conventional general lid material. That is, printing is performed on the surface of an aluminum foil having a thickness of 25 μm, an overprint coating of cellulose is performed on the printing surface, and the same anchor coat as that of Example 1 is applied on the back surface of the aluminum foil, and a low coating having a thickness of 30 μm is formed. The same hot melt adhesive as in Example 1 was bonded to the high-density polyethylene by 15 g / m
Coating is performed with the coating amount of ² .

Test material C: 25 μm thick Fe: 2% by weight
Is printed on the surface of an aluminum alloy foil containing Al and impurities, the overprint coating of cellulose is performed on the printed surface, and the same anchor coat as in Example 1 is applied to the back surface of the aluminum foil to form a thick layer. 15
A low-density polyethylene having a thickness of μm is joined, and the same hot melt adhesive as in Example 1 is applied and formed at an application amount of 15 g / m ² .

Test material D: Printing was performed on the surface of an aluminum foil having a thickness of 25 μm, an overprint coating of cellulose was performed on the printing surface, and the same anchor coating as in Example 1 was applied on the back surface of the aluminum foil. A 30 μm-thick linear low density polyethylene (LLDPE) is joined, and the same hot melt adhesive as in Example 1 is applied and formed at an application amount of 15 g / m ² .

Test material E: Printing was performed on the surface of an aluminum foil having a thickness of 25 μm, a biaxially stretched polyester film having a thickness of 9 μm was adhered to the printed surface, and the same anchor coat as in Example 1 was formed on the back of the aluminum foil. And apply a thickness of 20
A low-density polyethylene having a thickness of μm is joined, and the same hot melt adhesive as in Example 1 is applied and formed at an application amount of 15 g / m ² .

Test Material F: Printing on the surface of an aluminum foil having a thickness of 25 μm, overprint coating of cellulose on the printing surface, and adding a curing agent to the polyester on the back surface of the aluminum foil as in Example 1. A biaxially stretched polyester film having a thickness of 12 μm was adhered via the two-liquid reaction type dry adhesive thus obtained, and the same anchor coat as in Example 1 was applied to the polyester film to form a low-density polyethylene having a thickness of 15 μm. After joining, the same hot melt adhesive as in Example 1 is applied and formed at an application amount of 15 g / m ² .

The obtained test material was evaluated in the same manner as in Example 1 for punching performance, shooter feeding performance, mounting of a lid on a container, and openability. Table 1 shows the evaluation results together with the evaluation results of the test material A. As shown in Table 1, when the test material B (conventional product) was opened, the lid remained at the mouth of the container. Test material C used an aluminum alloy foil containing Fe, and test material D used linear low-density polyethylene instead of low-density polyethylene. The rate is large.

Test material E is obtained by bonding a biaxially stretched polyester film to the printing surface side of an aluminum foil.
Although the punching property was good, clogging in the shooter occurred due to the opening of the skirt portion of the lid, and the lid was not properly mounted. Test material F has a large thickness of the biaxially stretched polyester film, so the elasticity of the film is high, and the opening of the skirt portion of the lid causes clogging in the shooter, and the mounting of the lid is appropriately performed. Not done,
I couldn't punch everything.

[0027]

[Table 1] << Table Notes >> (1) ○: good △: problematic ×: inferior (2) The surface of Al foil means the printed surface.

[0028]

According to the present invention, there is provided a heat-sealing lid material which is free from lids and shakes when opened and does not leave a lid material at the mouth of a beverage container. Since the lid material of the present invention is not easily broken, the residual material (skeleton) generated by punching during lid molding is not cut by the winder, so that the residual material can be easily wound and collected. In addition, it is possible to improve the lid and runout without changing the current conditions of equipment operation such as punching and filling.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing a configuration of a heat sealing material according to the present invention.

FIG. 2 is a partial cross-sectional view showing a configuration of a conventional heat sealing material.

FIG. 3 is a schematic perspective view of a stamped and formed lid.

[Explanation of symbols]

 Reference Signs List 1 aluminum foil 2 anchor coat 3 printing surface 4 overprint coat 5 dry adhesive 6 biaxially stretched polyester film 7 anchor coat (or dry adhesive) 8 low density polyethylene film 9 hot melt adhesive 10 lid 11 skirt

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akio Komori 1-9-13 Uchikanda, Chiyoda-ku, Tokyo Sumitomo Aluminum Foil Co., Ltd. (72) Inventor Toshihiro Uchiyama 1-9-9 Uchikanda, Chiyoda-ku, Tokyo 13 Sumi Light Aluminum Foil Co., Ltd. (72) Inventor Chiaki Kunitake 1-9-13 Uchikanda, Chiyoda-ku, Tokyo Sumi Light Aluminum Foil Co., Ltd.

Claims (1)

[Claims] 1. A cover material comprising a heat sealing material layer provided on an aluminum foil via a polyethylene film, wherein a polyester film having a thickness of 5 to 10 μm is interposed between the aluminum foil and the polyethylene film. Sealing material.