JPH0446914Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The invention relates to an easy-to-open sealed container.
More specifically, it has a significantly high pressure-resistant sealing force when opened from the inside of the container, and when opened from one end of the cap, it can be opened easily with finger force, and it is difficult to reseal. Therefore, the present invention relates to a sealed container having a function of guaranteeing the quality of the contents.

(Prior Art) Conventionally, a container called an easy-to-open container is known in which a peelable lid (an easily peelable lid) is heat-sealed to the opening of the container. This container has a protective resin coating on the outer surface of metal foil such as aluminum, and a heat-sealable resin layer on the inner surface.
It is adjusted to a range of 0.05 to 2 kg/15 mm width.

(Problems to be solved by the invention) However, the above-mentioned peelable lid is flexible and the mechanical strength of the lid material itself is not sufficient, so when trying to protect it from external destructive force, There is the inconvenience of having to cover the outer lid separately.

In addition, the seal strength between the container mouth and the lid changes depending on the heat sealing temperature, and when heat sterilizing the contents, the seal strength also fluctuates due to the heat sterilization. There is a problem that it is difficult to obtain a seal strength (opening force) of .

In particular, for heat-sealed packages whose contents are subjected to retort sterilization, 2.3Kg/15mm from the inside
Peelable lids that meet these requirements are required to have a seal strength (peel strength) greater than the width, but peelable lids that can be opened by breaking the heat-sealed part are still not practical. It has not yet reached the point where it can be done.

Therefore, there is a great need in the industry for an easy-to-open sealed container that is equipped with a rigid shell and has a cap applied to the mouth of the container so that it can be sealed by heat sealing and can be easily opened with one's fingers. It is rare.

The purpose of this invention is to prevent opening from the inside of the container when opening a sealed container whose mouth is heat-sealed with a cap equipped with a heat-sealed laminate bonded to the inner surface of a rigid shell. It has an extremely high pressure-resistant sealing force, and can be opened easily with finger force from one end of the cap.
Furthermore, since resealing is difficult, it is desirable to provide an easily openable sealed container that also has a quality assurance function for the contents.

(Means for Solving the Problems) According to the present invention, an outer layer of propylene resin, a metal foil, an inner layer of propylene resin, a blend layer of propylene homopolymer and propylene copolymer, and a heat seal layer of propylene copolymer are used. A cap with a laminate bonded to the inner surface prepared for this order and with the thickness of each layer in the order of inner layer > blend layer > heat seal layer, and a container whose heat seal surface is made of propylene resin, Provided is an easily openable sealed container characterized by being sealed by heat sealing.

(Function) In FIG. 1 showing an example of an easily openable sealed container of the present invention, a container B has a cylindrical body 1, a bottom 2 at the lower end, a shoulder 3 and a neck 4 at the upper end. The upper open end of the neck portion 4 is a sealing mouth portion 5, and heat sealing is performed between this mouth portion 5 and the laminated body 6 of the cap C covered thereon to seal the container. It will be done.

In FIGS. 2 and 3, which show enlarged cross-sectional structures of the heat-sealed portion of this container, the laminate 6 of the cap C and the opening 5 have a heat seal made of propylene copolymer over the entire surface of their engagement. Heat sealing is performed via the sealing layer 7.

The cap C has a rigid shell 8, and the shell 8 has a top plate portion 9, a peripheral portion 10, and an opening flange or tab 11 provided on at least a portion of the peripheral portion. (Figure 1 is an example of a flange). A laminate 6 is bonded to the inner surface of the top plate 9 of the shell 8.

This laminate 6 is arranged from the shell side to the container side,
Outer layer 12 of propylene resin, metal foil 13, inner layer 14 of propylene resin, blend layer 15 of propylene homopolymer and propylene copolymer
and a heat sealing layer 7 of a propylene copolymer, and it is important that the thickness of each layer is in the order of inner layer 14≧blend layer 15>heat sealing layer 7.

The reason why the blend layer 15 of propylene homopolymer and propylene copolymer is provided is that this part has a structure weakened by the blend.
This is to cause cohesive failure to occur selectively in this portion.

This blend layer 15 is provided with a heat sealing layer 7 of propylene copolymer in the container B.
This is to ensure that a large heat sealing strength can be obtained at the heat sealing interface with the mouth part 5.
Also, by using propylene copolymer,
Heat sealing can be performed reliably even at relatively low heat sealing temperatures. Moreover, since the thickness of the heat seal layer 7 is made thinner than that of the blend layer 15, the heat seal layer 7 is easily broken in response to a peeling force (moment) from one end of the cap.

Note that the inner layer 14 of propylene resin located on the blend layer 15 prevents cohesive failure of the blend layer 15 from spreading to other parts of the laminate 6.

The laminate 6 is bonded to the inner surface of the top plate 9 of the shell 8 of the cap C via the outer layer 12, and is bonded to the top plate 9 of the shell 8 of the cap C on the inner side via the heat-sealing layer 7 of propylene copolymer to the container B.
It is joined to the mouth part 5 of.

When opening the sealed container of the present invention, an extremely large opening force of 10 kg or more is required to pull the cap uniformly around the entire circumference and open the cap. In this way, an extremely high pressure-resistant sealing force can be obtained against opening from the inside of the container.

On the other hand, as shown in FIGS. 4 and 5 (enlarged views), when you place your finger on the opening flange 11 of the cap and push the cap upward, the heat seal layer 7 on the opening side first Fracture occurs from the container side toward the shell side, then cohesive failure of the blend layer 15 occurs, and finally, the heat seal layer 7 fractures again from the shell side toward the container side, causing the cap and the mouth of the container to break. A separation occurs. Since the cap shell 8 is made of a rigid material, the heat-sealed portion is destroyed all at once over the entire circumference of the mouth portion 5. Further, since the heat-sealed portion is destroyed in the above-described order, an advantage is achieved in that the cap can be opened easily with fingers.

Furthermore, the inner diameter of the peripheral part 10 of the shell 8 of the cap C is manufactured to be larger than the outer diameter of the mouth part 5 of the container, and this cap C cannot be resealed after being opened. Since the facts become clear, a guarantee function will be given as to whether or not the contents have been touched.

(Example) In the present invention, as long as the shell 8 of the cap C is made of a rigid material,
It can be made of any material such as rigid resin such as polypropylene or polyethylene, ceramic, or metal. The rigidity of the cap refers to a property that allows the cap to be lifted all at once without substantially bending when opened. In terms of heat sealability,
The shell is made of isotactic polypropylene,
It is preferably made of synthetic resin such as high-density polyethylene or propylene-ethylene copolymer.

The cap shell can be manufactured by injection molding or press molding. The thickness of the top plate is generally 0.5 to
The diameter is preferably in the range of 3.0 mm, and the diameter is between 10 and 200 mm.
A range of mm is desirable from the viewpoint of ease of opening. Also, the height of the peripheral part of the cap shell varies depending on the diameter of the top plate, but it is 0.1 to 0.1 of the diameter of the top plate.
It is desirable to have a height of 0.3 times.

As the heat seal layer of the laminate, propylene-ethylene copolymer, acid-modified propylene resin, etc. can be used. The heat-sealing layer should have a thickness as thin as possible in order to be opened by the mechanism described above, and generally preferably has a thickness of 2 to 30 μm, particularly 3 to 10 μm.

The base material of the laminate consists of an outer layer of propylene resin, a metal foil, and an inner layer of propylene resin. The inner layer adheres the blend layer and facilitates the breakage of the heat-sealed layer from the outer shell side to the container side when the package is opened. The heat seal layer remains in the form of a film at the mouth of the container. The thickness of the inner layer is generally preferably in the range from 10 to 80 μm, particularly from 15 to 50 μm.

The metal foil acts as a heating element when high-frequency induction is heated during heat sealing, and also provides the cap with barrier properties against gases, scents, and the like. As the metal foil, aluminum foil, steel plate, iron foil, tin foil, etc. are used, and the thickness thereof is 5 to 5.
Preferably it is 50 μm, particularly in the range 7 to 30 μm.

The outer layer is used to bond the laminate to the shell, and can be bonded by thermal bonding, urethane adhesive, or epoxy adhesive.

The blend layer used in the present invention is made of a blend of propylene homopolymer and propylene copolymer, and by using this blend, the resin layer itself is weakened and peelable compared to when using a single resin. Cohesive failure easily occurs during this process.

The blend ratio of propylene copolymer ( _PC ) and propylene homopolymer ( _PH ) is desirably _Pc : _PH =20:80 to 60:40, particularly 30:70 to 45:55.

The thickness of the blend layer should generally be in the range 5 to 40 μm, especially 10 to 20 μm.

Also, the thickness ratio of the inner layer _C1 : blend layer _C2 : heat seal layer _C3 is approximately (2-20):(1.2-3):1 to give the most desirable results. In addition, the seal strength F of each layer is determined by the formula F _C1-C2 ＞F _C2-C3 ……(1) F _C3-C4 ＞F _C2-C3 ……(2) F _C1-C2 F _C3-C4 ……(3) In the formula, F _C1-C2 represents the seal strength between the C ₁ and C ₂ layers, and the same applies below, and F _C3-C4 represents the seal strength between the C ₃ layer and the mouth of the container.
It is desirable that the strength T of each layer satisfies the formula T _C3 > T _C1 (4) T _C2 > T _C1 (5), which represents the seal strength with _C4 .

To seal a container with a cap, the laminate is punched out into the shape of a disk, fitted into the shell of the cap, and this assembly is placed over the container mouth, and the container is sealed with a constant pressing force. This is done by high-frequency induction heating in a pressed state. The pressing force is generally
A range of 0.5 to 2 kg is appropriate, and heat sealing is performed at a temperature higher than the melting point or softening point of the resin.

In FIG. 2, small protrusions 16 provided on the inner periphery of the shell of the cap prevent the laminate from coming off.

(Effects of the Invention) The easy-to-open sealed container according to the present invention has a rigid outer shell and a cap with a heat-sealing function tightly attached to the inside of the outer shell, which is heat-sealed to the mouth of the container. It has a significantly high pressure-resistant sealing force against opening of the cap, and since it can be easily opened using finger force from one end of the cap, and it is difficult to reseal, it also has a quality assurance function for the contents. The advantage of having is achieved.

This sealed container is useful as a container for soft drinks, alcoholic drinks, milk drinks, fruit-filled containers, infusion containers, and the like.

[Brief explanation of the drawing]

Figure 1 is a front view of the present invention, Figures 2 and 3 are sectional views and enlarged views of the main parts of Figure 1, and Figures 4 and 5 are cross-sections of the main parts showing the cap being opened. FIG. B... Container, C... Cap, 5... Mouth, 6
... Laminated body, 7 ... Heat seal layer, 8 ... Shell body, 11 ... Flange, 14 ... Inner layer, 15 ...
Blend layer.

Claims (1)

[Scope of utility model registration request] An outer layer of propylene resin, a metal foil, an inner layer of propylene resin, a blend layer of a propylene homopolymer and a propylene copolymer, and a heat seal layer of a propylene copolymer are provided in this order, and the thickness of each layer is such that the inner layer≧the blend layer> An easy-to-open hermetic seal characterized by being formed by heat-sealing a cap to which a laminate in the order of heat-sealing layers is bonded to the inner surface, and a container whose heat-sealing surface is made of propylene resin. container.