JPH089012Y2 - Molding lid for sealing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial field of application The present invention relates to a molding lid for sealing, which is particularly suitable for high temperature filling and heat sterilization, which is applied to a packaging container made of glass, ceramics, plastic, metal or the like.

Conventional technology and its problems Conventionally, contents such as jam and juice are put in a container made of glass, ceramics, plastic, metal, etc. at 80 ° C to 98 ° C.
When the lid material made of aluminum foil provided with a heat sealing agent layer is sealed by heat sealing, the heat of the contents and the heat from the heat sealing hot plate cause
The air in the headspace is heated and expands, pushing up the lid material. At this time, since the heat-sealed portion has a high temperature and thus has a weak adhesive force, it is often impossible to seal due to partial peeling. In order to solve this problem, methods such as lowering the filling temperature, lowering the heat sealing temperature, and reducing the head space have been carried out, but the conditions are limited and it is not practically sufficient. On the other hand, instead of a flat lid, a molding lid in which the central portion is formed into a concave shape has been proposed (see FIGS. 3 and 4). This molding lid has an effect of reducing the head space and suppressing an increase in internal pressure, and even if the internal pressure rises and the lid is pushed up, it is absorbed by the deformation of the molding portion and no force is applied to the seal portion. However, the shape of the molding is trapezoidal in cross section, and is formed in a concave shape, but only a stepwise shape is proposed. For this reason, it is not possible to mold deep enough, breakage occurs at the corners, and when finished after cooling after filling and sealing, this molding shape has wrinkles and corner lines remain. The appearance becomes unsightly. In extreme cases, the corners are repeatedly bent, which may cause pinholes in the aluminum foil.

Further, even when heat sterilization is performed after the filling and sealing, it is necessary to absorb the pushing force of the lid due to the increase in the internal pressure by deforming the lid. In the case of retort sterilization, an external pressure (counter pressure) is applied according to the internal pressure to achieve balance, but it is unavoidable that an imbalance will occur on the way. In such a case, the same thing can be said as in the case of high temperature filling.

Means for Solving Problems As a result of various studies on the problems of the prior art as described above, when a molding lid having a new molding shape is used,
It has been found that these problems are virtually eliminated or greatly reduced. That is, the present invention comprises an aluminum foil having a flexible resin layer on the front side and a heat sealant layer for the container to be sealed on the back side,
In a planar circular sealing molding lid in which a molding part is formed in the central part excluding the heat-sealing part of the peripheral side part, the molding part is composed of a spherical concave recess bulging downward. The present invention relates to a characteristic molded lid for sealing.

In the present invention, the lid material needs to have moldability, flexibility enough to cope with deformation, and heat sealability as in the conventional product. Such a lid material is obtained by laminating a flexible resin layer on one side, preferably the front side, of a metal foil such as an aluminum foil, and a heat sealing agent layer on the back side. Laminating means of the resin layer is optional,
Various known means such as resin paste printing, resin liquid coating and film sticking can be adopted, but especially when sticking a resin film such as a polyester film to form a resin layer, it can withstand repeated bending. Obtained,
It is preferable because no pinhole is generated.

The downwardly bulging spherical concave portion forming the molding portion is molded in the central portion of the lid member, for example, the entire central portion excluding the heat seal portion on the peripheral side portion. The spherical concave portion may have a single-step configuration with the same curvature, or may have a multi-step configuration such as a two-step configuration in which the upper and lower steps have different curvatures.
Cold pressing means, for example, is suitable as a means for forming the spherical concave portions.

Effect In the molding lid according to the present invention, since the spherical concave recessed portion which bulges downward is molded in the central portion, the head space is reduced, and the bulging of the lid immediately after high temperature filling sealing or during heat sterilization can be reduced. . Further, even if the molding lid receives a deformation force, the spherical concave portion is deformed to absorb and relieve it, and the adverse effect on the heat seal portion can be reduced or eliminated.
Furthermore, since the molded part is composed of spherical concave parts, it is more durable against repeated bending than conventional products, and it is less likely to cause pinholes, and wrinkles and ring-shaped lines are formed. Difficult to obtain a good finished appearance.

These advantages are that, in a sealed container that is cooled by hot filling and sealing, the pressure inside the container is reduced, the external pressure is higher, the lid receives the same pressure from all directions, and the lid is Due to its flexibility, it can be transformed into a spherical shape. Therefore, it is considered that the molded lid of the present invention, which is molded in the same spherical shape in advance, has a beautiful finish, does not have wrinkles, and is difficult to form pinholes.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an example of the molding lid of the present invention which is applied for sealing a glass container having an inner diameter of 55 mmφ and an outer diameter of 62 mmφ.

The lid material (1) consists of 12μPET / urethane adhesive / 50μ aluminum foil / urethane adhesive / heat sealant layer (modified polyolefin resin layer for glass), excluding the heat seal part (2) on the peripheral side. In the central portion, a downwardly bulging spherical concave portion (3) is formed by applying cold pressing means. The size and shape of each part of this molding lid are as follows.

Outer diameter of heat seal part (2) …… 63mmφ Inner diameter of heat seal part (2) …… 56mmφ Curvature of spherical concave part (3) …… 60mmR Center depth of spherical concave part (3) …… 8mm FIG. 2 shows another embodiment of the present invention, which is substantially the same as that of FIG. 1 except that the spherical concave portion (3) has a two-tiered structure. The size and shape of the concave portion (3) are as follows.

Curvature of the upper concave depression (3a) …… 85mmR Curvature of the lower concave depression (3b) …… 17mmR Central depth of the entire concave depressions (3a) (3b) …… 8mm Shown in Figs. 1 and 2. The molded lid of the present invention is placed in a container of the above size and shape filled with hot water at 85 ° C, and 240 ° C × 4 kg / cm ²
When heat-sealed and hermetically sealed under a heat-sealing condition of × 2 sec and cooled, the molding lid was tightly tensioned without wrinkles. In addition, the swelling of the lid immediately after the sealing was small and, of course, no sealing failure occurred.

Even when this 85 ° C-filled product was immersed in 70 ° C hot water and sterilized by boiling, there was no puncture and the finished product after cooling was beautiful.

Further, when the product filled with 85 ° C was subjected to retort sterilization at 120 ° C for 30 minutes, there was no puncture and no pinhole was generated in the lid, which was a good result.

 The following is a comparative example.

Comparative Example 1 The same test as in Example 1 was performed except that only the shape of the lid was molded into the shape shown in FIGS. 3 and 4. As a result, a part of the seal failure occurred when filling hot water at 85 ° C.
Even if no sealing failure occurred, wrinkles remained on the lid material and it was unsightly. Some punctures occurred in the boil sterilized by immersion in hot water at 70 ° C, and wrinkles and the like occurred even in the non-punctured ones. The product subjected to retort sterilization at 120 ° C for 30 minutes had wrinkles and pinholes at the corners.

Effect Since the molding lid of the present invention has a molding portion composed of a downwardly bulging spherical concave portion, it can sufficiently withstand high temperature filling of the contents and heat sterilization after filling, and in the finish. It is beautiful without wrinkles and can provide a sealing molding lid suitable for high temperature filling and heat sterilization applications.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention, FIG. 2 is a vertical sectional view showing another embodiment, and FIGS. 3 and 4 are vertical sectional views showing a conventional example. In the figure, (1) is a cover material, (2) is a heat seal part,
(3) is a spherical concave portion.

Claims (1)

[Scope of utility model registration request] 1. An aluminum foil having a flexible resin layer on the front surface side and a heat sealant layer for the container to be sealed on the back surface side, and in the central portion excluding the heat seal portion on the peripheral side portion. A sealing molding lid having a flat circular shape in which a molding portion is formed, wherein the molding portion is formed of a spherical concave recess that bulges downward.