JPH10194309A - Bottle cap - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bottle cap which can maintain the flavor and the taste of contents in a bottle for a long time in a good condition. SOLUTION: This bottle cap is provided with a circular top wall 4, a cylindrical skirt part 5 pendulating from the periphery of the top wall 4 and a tab 8 joined to a part of the bottom end part of the skirt part 5. A seal member 14 is provided at least in the area along the periphery of the inner side of the top wall 4, and the bottom edge part of the skirt part 5 is folded inward in the radius direction to catch a bottle neck. A polyester film 20 covering the seal material 14 for shutting off the seal material 14 from the contents of the bottle is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cap for sealing a bottle filled with juice or alcoholic beverage.

[0002]

2. Description of the Related Art FIGS. 5 and 6 show a conventional wide-mouth bottle cap. In this cap, a top wall 4 is formed by an annular protruding portion 1 at a peripheral edge, a circular central flat portion 2, and an inclined portion 3 connecting the central flat portion 2 and the annular protruding portion 1. A skirt portion 5 hanging down from the periphery of the top wall 4 is formed, and a lower extension portion 6 extending downward from a part of the lower end of the skirt portion 5 and an oblique downward extension extending further obliquely downward therefrom. A tab 8 having a projection 7 is formed integrally with the skirt 5.

The obliquely downwardly extending portion 7 is formed with an oval finger insertion hole 9, and the cut edge on the inner peripheral side is curled toward the lower surface over the entire circumference to form an inner curl. Part 1
0 is formed, and a portion corresponding to the outer periphery of the finger insertion hole 9 in the cut edge portion of the obliquely downward extending portion 7 is curled toward the lower surface to form an outer curl portion 11.

A pair of score lines (weak lines or score lines) 12 are formed so as to extend from the lower end of the skirt portion 5 on both sides of the tab 8 toward the top wall 4, and two pairs of slits (cut lines) are provided. ) 13, 13 in the direction intersecting the opening direction of the tab 8 (or the direction intersecting the straight line connecting the center of the tab 8 and the center of the top wall 4) from the lower end of the skirt portion 5 to the middle thereof. Is formed. A sealing member 14 is provided on the inner surface side of the annular projection 1 of the top wall 4 to ensure sealing with the bottle mouth.

[0005] As a material of the sealing material 14, a compound such as vinyl chloride plastisol is used. In some cases, a plasticizer (dioctyl adipate, diethylhexyl phthalate, acetyltributyl citrate, epoxy soybean oil, etc.), a stabilizer, a foaming agent, a foaming aid, or the like may be added to the vinyl chloride compound. As another example of the sealing material, as shown in FIG. 7, a thermoplastic resin such as polyethylene is molded over almost the entire inner surface side of the central flat portion 2 and the inclined portion 3 including the annular protrusion 1. (Embossing) is known.

As shown in FIGS. 8 and 9, each cap having the above-described structure is formed by bending the lower edge of the skirt portion 5 inward in the radial direction and locking the outer edge of the bottle neck portion 15. Then, it is attached to a jar and shipped as a product. The inside of the bottle is filled with an amount of the content 16 such as juice or alcoholic beverage so as not to come into contact with the inner surface of the cap (filling such that a predetermined amount of head space is secured at the top of the bottle). .

[0007] In each of the conventional caps described above, the sealing material 14 is exposed to the internal space of the bottle. Therefore, the sealing material 14 made of a vinyl chloride compound is used.
In the cap provided with, the flavor of the contents 16 penetrates through the sealing material 14 and leaks to the outside of the bottle, causing a disadvantage that the flavor is impaired. In addition, in the case of this type of cap, when the contents 16 come into direct contact with the sealing material 14 due to, for example, the liquid level of the contents 16 moving up and down due to vibrations during transportation, or the bottle being stored by falling down. An additive such as a plasticizer in the material 14 elutes into the content 16,
There is a problem that the original taste of the contents 16 is impaired.

On the other hand, in the cap in which the sealing material 14 is made of polyethylene, the resin component does not elute into the contents 16, so that the taste of the contents 16 hardly changes. However, flavor may be impaired by flavor leakage because polyethylene has air permeability or flavor permeability.

An example of a cap for solving the above-mentioned inconvenience is described in Japanese Patent Application Laid-Open No. 61-259,963. In the cap described in this publication, a sealing material is applied to the inner surface of the top wall, and a coating film of a coating material is provided on the surface of the sealing material so as to cover the sealing material. That is, the sealing material is covered with the coating film of the coating material. As a material of the coating material, PVDC or straight vinyl is used.

[0010]

Incidentally, since the sealing material is for maintaining the airtightness in contact with the opening of the bottle, the sealing material is conventionally generally formed of a material having a certain degree of elasticity.

However, in the cap having the structure described in the above publication, the coating material is formed of a coating film made of PVDC or straight vinyl, and the coating film is formed on the surface of the elastic sealing material. Therefore, for example, when an excessive external force is applied to the cap, there is a possibility that the coating material may be damaged by being pinched between the neck of the bottle mouth and the inner surface of the cap. In particular, the above-mentioned conventional coating material is a resin-coated material and lacks denseness and continuity as a film, and thus is easily damaged by crushing and deformation due to crushing.

If the coating material breaks in this way, the sealing material is partially exposed to the contents,
Alternatively, since the contents penetrate into the sealing material, the flavor is impaired by the flavor penetrating the sealing material and leaking to the outside of the bottle, and the additives in the sealing material are eluted into the contents and the taste is impaired. Would. Thus, even with the cap described in the above-mentioned publication, there is a possibility that the flavor and taste originally contained in the contents cannot always be maintained reliably.

It is an object of the present invention to provide a bottle cap that can maintain the original flavor and taste of the contents of the bottle.

[0014]

In order to achieve the above-mentioned object, the invention according to claim 1 comprises a circular top wall, a cylindrical skirt portion hanging down from the periphery of the top wall. A tab connected to a part of the lower end of the skirt, and a sealing material is provided at least along a peripheral edge of the inner surface of the top wall, and a lower edge of the skirt is provided. Is bent inward in the radial direction to lock the bottle with the bottle neck, and a polyester film covering the seal material is provided so as to shield the seal material from the contents of the bottle. It is assumed that.

Therefore, according to the first aspect of the present invention, at least a portion of the sealing material located inside the bottle is covered with the polyester film, and the polyester film comes into contact with a beverage containing alcohol or the like. Also does not elute the resin component, so that the taste of the contents of the bottle does not change. Polyester film has extremely low gas permeability, so that flavor can be prevented from leaking out of the bottle.Furthermore, since the tear film has high tear resistance, cracking due to crushing deformation hardly occurs. As a result, the taste and flavor of the contents of the bottle are improved. Can be favorably maintained over a long period of time.

According to a second aspect of the present invention, in addition to the configuration described in the first aspect, the sealing material is formed in a circular or annular shape, and the polyester film has an outer diameter larger than the outer diameter of the sealing material by two. It is characterized by being formed in a small circular or annular shape having an outer diameter of up to 6 mm.

Therefore, according to the second aspect of the present invention, the peripheral portion of the polyester film is sandwiched between the top portion of the bottle mouth and the sealing material without largely protruding to the outer peripheral side of the bottle mouth, In addition, since the bottle mouth and the sealing material are in direct close contact with each other outside the peripheral portion of the film, the sealing performance can be improved.

According to a third aspect of the present invention, in addition to the configuration described in the first aspect, a heat-adhesive resin layer is provided on an inner surface of the top wall, and an inner surface of the polyester film on the inner surface side of the top wall is provided. On the surface, a resin layer of the same type or heat-bondable as the resin contained in the heat-bondable resin layer is formed.

Therefore, according to the third aspect of the present invention, the polyester film can be adhered to the inner surface of the cap by pressing the polyester film against the inner surface of the cap in a state where the temperature is increased by heating. improves.

[0020]

Next, the present invention will be described in detail with reference to FIGS. The cap 3 of the present invention
0 is the basic configuration shown in FIGS. 5 and 6,
This is an improvement. Therefore, also in the cap 30 shown here, the annular protruding portion 1 at the peripheral edge, the circular central flat portion 2 and the inclined portion 3 connecting the central flat portion 2 and the annular protruding portion 1 are provided. A top wall 4 is formed. The top wall 4 is formed with a skirt portion 5 hanging down from the peripheral edge, and extends downward from a part of the lower end of the skirt portion 5 and further obliquely downward therefrom. A tab 8 having an obliquely downward extension 7 is formed integrally with the skirt 5.

An oblong finger insertion hole 9 is formed in the obliquely downwardly extending portion 7, and the cut edge on the inner peripheral side is curled toward the lower surface over the entire circumference to form an inner curl. Part 1
0 is formed, and a portion corresponding to the outer periphery of the finger insertion hole 9 among the cut end edges of the obliquely downwardly extending portion 7 is curled toward the lower surface to form an outer curl portion 11.

A pair of score lines 12 are formed so as to extend from the lower end of the skirt portion 5 on both sides of the tab 8 toward the top wall 4, and two pairs of slits 13, 13 are provided.
Are formed from the lower end of the skirt portion 5 to the middle thereof in the direction intersecting the opening direction of the tab 8.

The inner and outer surfaces of the cap 30 are each coated. Acrylic resin paint 17 can be used as the coating agent on the outer surface side. On the other hand, the coating on the inner side has a two-layer structure, and the epoxy-
A phenolic resin paint 18 is applied, and this serves as a base coat. Then, a phenol-modified vinyl resin paint 19 in which polyethylene resin powder is dispersed is applied as a top coat on the upper surface of the base coat. As the powder resin to be dispersed, polyethylene oxide or unsaturated carboxylic acid-modified polyethylene can also be used. The particle diameter is not limited, but is preferably about 1 to 80 μm. The amount of the powder resin dispersed in a thermosetting paint such as a phenol-modified vinyl paint is preferably 1 to 15% by weight (total solid content).

As the other resin for the top coat, for example, a polyethylene oxide resin, a modified polyolefin resin modified with an unsaturated carboxylic acid such as acrylic acid or maleic acid, or an ionomer resin, or other heat-resistant resin in place of the polyethylene resin A modified polyolefin resin or the like having excellent adhesiveness can be employed. Further, an epoxy-modified vinyl-based resin, an epoxy-phenol-based resin, an acrylic-based resin, and other thermosetting paints may be used instead of the phenol-modified vinyl-based resin.

On the other hand, a sealing member 14 made of a vinyl chloride compound is provided on the annular projection 1 on the inner surface side of the top wall 4. The sealing material 14 can be formed by heating the entire cap 30 in a state where the vinyl chloride compound is laid thereon in a manner following the annular projection 1, thereby melting the compound and attaching the compound to the cap. In addition, a plasticizer (dioctyl adipate, diethylhexyl phthalate, acetyltributyl citrate, epoxy soybean oil, etc.), a stabilizer, a foaming agent, a foaming aid, etc. are added to the vinyl chloride compound in the same manner as before. You may. Further, in place of the vinyl chloride resin, a soft resin conventionally used for forming an annular sealing material, for example, a low-density polyethylene, an ethylene-vinyl acetate copolymer, a thermoplastic styrene-butadiene copolymer, or the like can also be used. Is applied in the form of a plastisol, organosol, or dispersion containing particles of these resins, and heated to form a sealing material.

Although not particularly shown, the sealing material may be provided on the entire surface of the top wall 4, in which case, for example, soft vinyl chloride resin, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-propylene copolymer, etc. It may be formed by molding using a vinyl acetate copolymer, an ionomer or the like as a material.

On the other hand, on the inner side of the top wall 4, a two-layer film 20 corresponding to the polyester film of the present invention is provided. The two-layer film 20 is, for example, a circular film obtained by laminating a polyester film 21 such as polyethylene terephthalate having a thickness of 12 μm and a polyethylene film 22 having a thickness of 50 μm by a dry lamination method. The outer diameter of the two-layer film 20 may be smaller than the inner diameter of the top wall 4, that is, the outer diameter of the seal member 14 by about 2 to 6 mm.

The resin film to be laminated on the polyester film 21 may be any resin having good thermal adhesiveness to the inner surface of the cap. Particularly, the resin film may be applied to the top coat when the sealing material is formed in an annular shape, or to the entire surface of the top wall 4. When the sealing material is provided, a material having good thermal adhesion to the sealing material is preferable. Good thermal adhesiveness means, in addition to the same resin, for example, when one is polyethylene, the other is a combination of polyethylene oxide, unsaturated carboxylic acid-modified polyethylene, ethylene-vinyl acetate copolymer, ionomer, etc. In the case where one of them is polypropylene, it is a combination of ethylene-propylene copolymer, unsaturated carboxylic acid-modified polypropylene, ethylene-vinyl acetate copolymer and the like. Note that, instead of the two-layer film, a film made of only polyester can be adopted. As for the film thickness of the film, it is necessary to prevent the additives of the sealing material from being eluted, and to have a certain rigidity in handling the film. ~ 25
It is preferably set to μm.

The two-layer film 20 is heat-bonded to the top coat with the polyethylene film 22 facing upward in FIG. 3, that is, toward the central flat portion 2 and the center points of the two are almost aligned. You. Therefore, the sealing material 1
A part on the inner peripheral side of the surface of the film 4 is covered with the peripheral portion of the two-layer film 20.

As shown in FIG. 4, the lower end of the skirt portion 5 is bent inward in the radial direction, and the cap 30 is locked on the outer periphery of the bottle neck portion 24, thereby opening the open end of the bottle. Seal. Therefore, in that case, the bottle mouth neck 24
The peripheral portion of the two-layer film 20 is sandwiched between the top of the film and the sealing material 14. That is, the polyester film 21 shields the sealing material 14 from the inner space of the bottle neck 24. In addition, inside the bottle,
A content 25 such as juice or alcoholic beverage is injected in an amount that does not touch the cap 30 in a steady state.

Therefore, according to the cap 30 constructed as described above, even if the liquid level of the contents 25 fluctuates due to the transportation or storage of the bottle filled with the contents 25, the sealing material 14 is made of the polyester film. It is not interrupted by 21 and does not contact the contents 25. That is, the additive such as the plasticizer contained in the sealing material 14 does not elute into the content 25, so that the original taste can be maintained without impairing the taste of the content 25.

The sealing material 14 is made of a polyester film 21 having a lower gas permeability than that of the sealing film 14 so that the contents 25 are formed.
Content 25
Is shielded by the polyester film 21 and does not leak out of the bottle. Furthermore, since the polyester film 21 has high density and continuity as a film and high tear strength, even if it deforms following the elastic deformation of the sealing material 14, no damage such as a crack occurs. Also in this respect, elution of additives and leakage of flavor can be effectively prevented.

Here, the procedure for manufacturing the cap 30 having the above-described configuration will be described. First, as an example, a plate thickness of 0.2
An aluminum alloy plate of mm is prepared. Then, an acrylic resin paint is applied to the surface of the aluminum alloy plate that is to be the outer surface side of the cap 30, and dried. Next, an epoxy-phenol-modified vinyl resin paint is applied to the surface on the opposite side of the aluminum alloy plate, that is, the surface on the inner surface side of the cap 30, and dried. Thereafter, a coating material in which a polyethylene resin powder is dispersed in a phenol-modified vinyl resin coating material (the polyethylene resin powder is 13% by weight in the solid content of the coating material) is further applied thereon, and dried.

Next, a cap 30 having the shape shown in FIG. 1 is formed by stamping out an aluminum alloy plate coated on both sides and pressing. Furthermore, the inner surface side of the cap 30 is arranged facing upward, and while rotating around the center point of the top wall 4, a compound of vinyl chloride is applied to the peripheral portion on the inner surface side of the cap 30. By heating, the compound of vinyl chloride is heated and melted to form an annular sealing material 14. Many such caps 30 are manufactured.

On the other hand, as an example, a two-layer film 20 composed of a polyester film 21 and a polyethylene film 22 laminated by a dry lamination method is punched out in a circular shape. In addition, as a manufacturing method of each film, a conventionally known inflation method, a T-die method, a stretching method, or the like can be adopted.

Next, the cap 30 provided with the sealing material as described above is placed on the heating plate with its inner surface facing upward. This heating plate is kept at about 200 ° C. Then, the circular two-layer film 20 prepared in advance is placed inside each cap 30 one by one with the polyethylene film 22 facing downward, that is, facing the top coat. In that case, the center point of the two-layer film 20 and the center point of the cap 30 are made to substantially match. As a result, a part of the sealing material 14 is covered by the peripheral portion of the two-layer film 20.

In this state, the pressing plate heated and heated to about 200 ° C. is pressed from above the two-layer film 20 (the polyester film 21 side), and the two-layer film 20 is thermally bonded to the inner surface of the cap 30. In this case, since the polyethylene resin powder is dispersed in the phenol-modified vinyl-based coating film serving as the top coat, and the thermal bonding temperature of polyethylene is in the range of about 121 to 155 ° C., the polyethylene film 22 is Good adhesion to the inner surface. By performing a normal cleaning / inspection step and the like together with the above steps, the cap 3 shown in FIG.
0 is produced.

Next, examples of the present invention and comparative examples will be described.

[0039]

Example 1 An aluminum alloy plate having a thickness of 0.2 mm was used as a material for a cap, and an acrylic resin coating film was formed on the outer surface thereof. Further, an epoxy-phenol-based resin coating was formed as a base coat on the inner surface side, and a vinyl-based resin coating in which a polyethylene resin having an average particle diameter of 29 to 34 μm was dispersed was formed as a top coat. This aluminum alloy plate was punched out and formed into a cap having the configuration shown in FIG. 1 by press working.

Next, with the inner surface of the cap facing upward, a vinyl chloride compound is placed along the annular projection while rotating about the center axis thereof. The compound was heated and melted by heating for 2 minutes to form a sealant on the top surface of the top coat. In addition, ATBC (acetyl tributyl citrate) was used as a plasticizer of the vinyl chloride compound.

A circular two-layer film obtained by laminating a 50 μm-thick polyethylene film (PE film) and a 12 μm-thick polyester film (PET film) by a dry lamination method, with the polyethylene film facing the top coat. Was heat bonded. The procedure of the heat bonding operation is as follows. Each cap provided with the sealing material is placed in a state in which the inner surface thereof faces upward for about 2 hours.
The film was placed on a heating plate maintained at 00 ° C., and the two-layer films were placed one by one in the cap with the polyethylene film facing downward. In that case, the center point of the two-layer film and the center point of the cap almost coincided. From this state, the pressing plate heated and heated to about 200 ° C. was pressed from the polyester film side to thermally bond the two-layer film to the inner surface of the cap. The double-layer film is φ4
Eight levels in 1 mm increments were set in the range of 9 to 56 mm.

[0042]

COMPARATIVE EXAMPLE Example 1 was repeated except that no coating film was formed on the inner and outer surfaces of the cap and that no two-layer film was provided.
The same configuration was used.

Table 1 shows the dimensions of Example 1 and Comparative Example, and the dimensions of the bottle neck to which they are attached. The shape of the mouth and neck of the bottle used is as shown in FIG.

[0044]

[Table 1] A sample was filled in a bottle under the following conditions, and a test for confirming the sealability and a long-term dissolution test were performed using the samples sealed with the caps of Example 1 and Comparative Example.

1. Filled sample ・ Pure water: distilled water for high performance liquid chromatography ・ Ethanol: special grade ethanol for precision analysis Filling conditions (1) Pure water-filled sample-Contents: pure water-Filling temperature and storage condition: Invert the filled product at 95 ° C and allow it to cool down-Contents: Fill a 180-ml capacity bottle with 60 ml (2) Alcohol 2. Water-filled sample-Contents: 20% solution of ethanol-Filling temperature and storage state: Filled at 70 ° C for 15 seconds, inverted and allowed to cool.-Contents: 60 ml. Test method (1) Sealing test (single inverted drop test) ・ On a steel plate inclined at 15 °, from 50 cm in height to the diagonal of the tab (annular protrusion opposite to the tab side across the center of the cap)
And leave it for a day and night to measure the degree of vacuum.

(2) Dissolution test: The substance stored in an inverted room at 35 ° C. for 3 months is subjected to gas chromatography to examine the dissolution.

4. Test Results First, the results regarding the sealing properties are shown in Table 2.

[0048]

[Table 2] As can be seen from Table 2, in any of the samples of Example 1, no defective product was generated as in the conventional case, and the sealing property was good.

Table 3 shows the results of the dissolution test.

[0050]

[Table 3] As can be seen from Table 3, in the comparative example, a large amount of the plasticizer in the vinyl chloride compound forming the sealing material was eluted into the content regardless of the type of the content, which adversely affected the taste of the content. It is presumed to occur.

On the other hand, in the first embodiment, φ50 to φ50
In each two-layer film up to 56 mm, elution of a plasticizer or the like was hardly recognized irrespective of the type of the contents because the sealing material was completely covered. However, in the first embodiment, φ
In the two-layer film of 49 mm, since a part of the sealing material was not completely shielded, a large amount of the plasticizer was eluted, and a substance other than the plasticizer was also detected. Therefore, the smallest dimension that can prevent the dissolution of plasticizer and the like is φ
50 mm is appropriate.

In order to confirm the tightness of the bottle mouth for each cap in Example 1, the amount of decrease in the content was examined under the following conditions. The dimensions of the bottle mouth and the dimensions of the two-layer film are as described above.

1. Filled sample ・ Pure water: distilled water for high performance liquid chromatography 2. 2. Filling conditions-Sample filled with pure water-Contents: pure water-Filling temperature and storage condition: Filled at 95 ° C, inverted and allowed to cool-Contents: 60 ml Test method ・ Measure the amount of decrease by measuring the weight ・ Hold the filled product at room temperature and measure the weight change over time.

4. Test results The results shown in Table 4 were obtained. In addition, ND in Table 4 shows the amount of decrease 0.

[0055]

[Table 4] As can be seen from Table 4, there was no leakage of the contents in each of the two-layer films of φ49 to 54 mm. On the other hand, in the example using the φ55 mm and φ56 mm two-layer films, the content was reduced. This is presumably because the two-layer film has wrinkles and the like, and the adhesiveness of the film to the opening end of the bottle opening has deteriorated. Therefore, from the viewpoint of the tightness of the bottle mouth, the outer diameter of the polyester film is preferably φ54 mm or less. In addition, φ52m
FIG. 11 shows a state in which a cap using a polyester film of m is attached to the bottle mouth. The numbers in the figure are dimensions in mm units. After all, considering the results shown in Table 3, it is appropriate that the outer diameter of the polyester film is smaller by 2 to 6 mm than the outer diameter of the sealing material 14. Even if the bottle diameter changes, this relationship holds because the thickness of the neck portion of the bottle mouth is almost the same.

[0056]

Embodiment 2 A predetermined amount of molten polyethylene resin is supplied to a cap placed on a heating plate with its inner surface facing upward, in place of an annular sealing material made of a vinyl chloride compound provided on an annular projection. Then, the polyethylene resin is extruded by stamping with a mold to form a sealing material in which the entire inner surface of the top wall is covered with the polyethylene resin, and a two-layer film is thermally bonded to the sealing material. did. Other configurations were the same as those of the first embodiment.

Even when the sealing material is formed on the entire inner surface of the cap, the taste and flavor of the contents can be maintained well over a long period of time by sticking the polyester film on the surface of the sealing material. It was confirmed that it was possible. It was also confirmed that the original sealing property or the sealing property was good. Further, the outer diameter of the polyester film is the same as that of Example 1, and is 2 to 2 times larger than the outer diameter of the sealing material.
It is preferable that the diameter is small by 6 mm.
It was confirmed that the content was effective in retaining the taste and flavor.

The polyester film in the present invention does not need to be a two-layer film, but may be a single film or a multilayer film having three or more layers. Further, the polyester film in the present invention is preferably a polyethylene terephthalate film, but is not limited thereto. Further, if the sealing material is annular, the polyester film may be formed in an annular shape accordingly. Further, the cap of the present invention may not include the annular protrusion on the peripheral edge of the top.

[0059]

As described above, according to the first aspect of the present invention, at least a portion of the sealing material located inside the bottle is covered with the polyester film, and the polyester film contains alcohol. The resin component is not eluted even when it comes into contact with beverages, etc., so that the taste of the contents can be prevented from deteriorating and maintained in a good condition. Flavors can be prevented from leaking, and because of their high tear resistance, damage such as cracks due to crushing deformation is unlikely to occur.In this regard, the taste and flavor of the contents of the bottle can be maintained well over a long period of time. it can.

According to the second aspect of the present invention, the peripheral portion of the polyester film is sandwiched between the top portion of the bottle mouth and the sealing material without largely protruding to the outer peripheral side of the bottle mouth, In addition, since the bottle mouth and the sealing material are directly in close contact with each other outside the peripheral portion of the film, the sealing performance can be improved.

According to the third aspect of the present invention, a thermo-adhesive resin layer is provided on the inner surface of the top wall of the cap, and the thermo-adhesive resin layer is formed on the inner surface of the polyester film on the inner surface of the top wall. Since the same type of resin layer as the resin contained in the layer is formed, the polyester film can be adhered to the inner surface of the cap by pressing the polyester film against the inner surface of the cap in a state where the temperature is increased by heating. Manufacturing operability can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a cap according to an embodiment of the present invention, partially broken away.

FIG. 2 is a schematic bottom view showing the inside of the cap.

FIG. 3 is a partially enlarged sectional view of a top wall of the cap according to the present invention.

FIG. 4 is a partial cross-sectional view showing a state where the cap shown in FIG. 1 is attached to a bottle mouth.

FIG. 5 is a schematic view showing a conventional cap with a part cut away.

FIG. 6 is a plan view of a conventional cap.

FIG. 7 is a partial sectional view showing another conventional cap.

FIG. 8 is a partial cross-sectional view showing a state where the cap shown in FIGS. 5 and 6 is attached to the bottle mouth.

FIG. 9 is a partial cross-sectional view showing a state where the cap shown in FIG. 7 is attached to a bottle mouth.

FIG. 10 is a partially enlarged cross-sectional view of the mouth and neck of the bottle used in the sealability test and the long-term dissolution test.

FIG. 11 is a partially enlarged sectional view showing a state in which the cap according to the embodiment of the present invention is attached to the bottle mouth.

[Explanation of symbols]

4 top wall, 5 skirt, 8 tab, 14 sealant, 20 two-layer film, 21 polyester film, 22 polyethylene film, 24 bottle neck and neck, 30 cap.

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[Procedure amendment]

[Submission date] December 18, 1997

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Toshihiro Ueda 4-14-114 Shimohozumi, Ibaraki-shi, Osaka

Claims (3)

[Claims] 1. A top wall having a circular shape, a cylindrical skirt portion hanging down from the periphery of the top wall, and a tab connected to a part of a lower end portion of the skirt portion. A sealing material is provided at least in a range along a peripheral edge of the inner surface side, and a lower cap of the skirt portion is bent inward in a radial direction to be locked on a bottle mouth and neck portion. A bottle cap, wherein a polyester film for covering the sealing material is provided so as to shield from the contents of the bottle. 2. The method according to claim 1, wherein the sealing material is formed in a circular or annular shape, and the polyester film is formed in a circular or annular shape having an outer diameter of 2 to 6 mm smaller than the outer diameter of the sealing material. Claim 1.
A bottle cap according to claim 1. 3. A thermo-adhesive resin layer is provided on an inner surface of the top wall, and a resin of the same or a same type as the resin contained in the thermo-adhesive resin layer is provided on an inner surface of the polyester film on the inner surface side of the top wall. The bottle cap according to claim 1, wherein a resin layer that can be thermally bonded is formed.