JPS60193804A - Method of sealing vessel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for sealing a container using a shape memory alloy, and more particularly, to a method for sealing a container using shape memory alloy, and more specifically, using deformation and restoring of a shape memory alloy for pressure sealing and releasing the pressure of the container. The present invention relates to a method for sealing a container, characterized by: In particular, the present invention relates to a novel method capable of forming a strong and uniform sealing structure between the annular surface of the open end of a cylindrical container and the annular rim of the lid.

In recent years, containers that are lightweight and easy to dispose of [7] have been developed.
Containers have come to be used in which a laminate consisting of paper, metal foil, and resin film is formed into a cylindrical shape by forming side seams by heat sealing, and a lid is hermetically engaged with the open end of this annular shape. .

Since this laminated container lacks rigidity, it is difficult to securely seal the lid by double seaming as with metal can bodies. This method relies exclusively on a method in which the annular rim portion of the lid body is heat-sealed under pressure and heat.

However, in this type of container, the laminate contains paper and has elasticity, so wrinkles etc. occur on the heat-sealed surface between the container body and the lid, and the entire heat-sealed surface is not strong. Moreover, there is a problem in that it is difficult to form a uniform sealing structure, especially a pressure-resistant sealing structure. To explain this point L7, in terms of the preservation of the contents (
"The hot filling method, in which the contents are filled into containers at high temperatures, is ideal! - However, when adopting this method, filling, sealing,
After cooling, the pressure inside the container naturally becomes reduced due to volume reduction/4. If there is a heat seal defect or a latent defect on the heat seal surface, leakage may occur from this part (c'h).

Accordingly, it is an object of the present invention to provide a sealing method that utilizes the memorized shape of a shape memory alloy to provide a strong and uniform pressing force at the sealed I-beam interface.

Another object of the present invention (d) is to provide a container sealing method that eliminates the above-mentioned conventional drawbacks.

(Another object of the present invention is to provide a sealing method that effectively eliminates the occurrence of 1-1 cracks on the heat sealing surface in the combination of the container body and the rosette. Z).

The present invention will be explained in detail below based on specific examples shown in the accompanying drawings.

In FIG. 1, which shows an exploded view of the container shown in the sealing method of the present invention, the container is composed of a cylindrical container body 11, a top lid member 2, and a bottom lid member 6. Although not shown in the figure, for example, from the outer surface to the inner surface of this container body, a laminate of heat-sealable polyolefin/paper substrate/heat-sealable poly first fin/metal foil/heat-sealable poly first main laminate is formed. The main part is formed from sheet 1, and the edges of the laminated sheet are heat-sealed together (there is a seam 4 on the sides).

The top lid member 2 and the bottom lid member 3 are also formed of the same laminated sheet as the container body 1, or are made of gold foil or metal sheet.
・It is formed of a laminate of heat-sealable resin and
This item consists of a flat center panel part 5 and an annular rim part 6, and the annular rim part 6 and the container body 1.
The size is such that it fits with the annular surface of the open end.

As shown in FIG. 2, the top lid member 2 and the bottom lid member 6 are fitted into the open end of the container body 1, and the fitted parts are heated under pressure (17).
A sealed portion 7.7 is formed by heat sealing.

According to the present invention, the deformation and restoring of the shape memory alloy is utilized for this pressurized sealing and pressurization release.

In the figure showing a preferred example of a pressing device made of this shape memory alloy, this device is made of copper-based (C+]-
A circumferential high-frequency induction heating coil 8 made of a bidirectional shape memory alloy of Zn-*t), both ends 9, 9 of the coil extending radially inward, and a It consists of a high frequency power supply 1D.

The J+V section between the induction heating coil 8 and both ends 9 of the coil is referred to as a power feeding section. Complete insulation must be provided in the power supply section. In FIG. 6, the insulating portion is provided vertically and in a straight line, but in order to obtain a more uniform suppressing surface pressure, the insulating portion may be provided in a so-called interlocking manner.

In FIG. 4, which shows a counter pressure plate 11 used in combination with this pressing device, this plate 11 is provided with a bored hole 12 that approximately corresponds to the outer periphery of the container body 1 shown in FIGS. 1 and 2. There is.

In FIG. 5, for example, the fitting part of the fitting assembly of the container body 1 and the top lid member 2 is
Insert into the hollow hole 12 of the counter pressure plate 11 [~
Then, the coil 8 of the suppression device is fitted into the rt hole 111 of the annular rim portion 6 of the upper lid member 2.

By passing high frequency current through the coil 8, the coil 8
When the temperature of the coil 8 increases and exceeds the set transformation temperature, the shape memory alloy forming the coil 8 transforms from the martensitic phase to the matrix phase. In the present invention, the diameter of the coil 8 in the martensitic phase is set to a thickness that fits completely inside the lid member 2, and the diameter of the coil in the parent phase is set to increase by several φ. (7) Coil 8 is heated to the parent phase.

As a result of this, the diameter of the coil 8 increases and the coil 8
Due to the increase in diameter, a strong and uniform pressing force is exerted over the entire circumference between the annular rim 6 of the lid member 2, which is sandwiched between the coil 8 and the counter pressure plate 11, and the annular surface of the container body. do.

Moreover, since the coil 8 made of this shape memory alloy naturally functions as a high frequency induction heating coil,
Naturally, the metal foil portions of the lid member 2 and the container body 1 are heated by induction, and as the heat-sealable resin layer comes off, the heat-sealable resin layer is heated and melted 7, and the heat-seal adhesion at the interface is completed.

Next, the current supply to the coil 8 is cut off (-1) If necessary, the temperature of the coil 8 is lowered by cooling with air cooling etc., and when the transformation from the parent phase to the martensitic phase occurs again, the diameter of the coil 8 decreases. The coil 8 can be easily removed from the annular rim portion 6 of the lid member 2.

In the case of sealing by heat sealing, the heat sealing resin returns from the melted state to the completely assimilated state.
It is desirable to continue applying pressing force.

The suppression time is equal to the time during which the shape memory alloy of the coil is in the matrix state.The time interval in which the coil is in the matrix state is controlled by the transformation temperature of the coil, the state of self-heating of the coil, and the state of its forced cooling. can.

Therefore, it is possible to continue pressing until the temperature of the thermoplastic resin on the heat-sealed surface drops to a temperature sufficiently lower than its melting point or softening point, for example, 50C or lower.

In the present invention, by setting the length of the shape memory alloy coil to be several inches wider, the suppression device can be used repeatedly.

A significant advantage of the sealing system of the present invention is that the occurrence of L7 warps in solid seals is completely suppressed, allowing the formation of sealing structures free of defects or potential defects.

Conventionally, the method used to seal this type of container is as shown in FIG.
is fitted inside the annular rim 6 of the lid member 2 and pressed from the outer periphery of the container body 1 with a pressing Φ die 14 to fuse the heat-sealable resin under pressure.

[7] In this sealing method, as shown in the cross-sectional view of Figure 7-A, the pressing force is applied from the outside of the container, and a compressive force acts on the wall of the container, resulting in In cases 1- and 1-, wrinkles are unavoidable, and this is a major cause of poor sealing or poor sealing during storage. Against this 1. According to the present invention, as shown in FIGS. 7-8,
Pressure is applied so that the pressure L7 filter wall is expanded by pressure I2, and the result and 1. 2. [7] The occurrence of worms was completely suppressed.

It is.

That is, in FIGS. 7-A and 7-8, if the diameter of the outer suppressing member is DC, and the diameter of the inner suppressing member is /')C1, the outer diameter of the annular rim of the lid member 2 is l)h. , these are related to the following inequality (%). In the conventional method, Dc is constant, and as DC is small, Dh is also reduced accordingly."1. In contrast, according to the above-described method of the present invention, DC is constant, DC increases, and Db increases accordingly, and pressure sealing is performed. However, the principle of pressure sealing is also fundamentally different.

In the specific example described above, a two-way shape memory alloy is used to perform pressurized sealing according to the memorized shape and pressurization release according to the memorized shape. For example, a ring made of a one-way shape memory alloy Or, by using the 411 combination of the coil and the overhanging 11-split mold located inside the ring, use the overhanging force of the split mold (C) for pressure sealing, and adjust the diameter according to the memorized shape to release the pressure. Contraction can be used.

Shape memory alloy and 1. Let's start with example 1. In addition to the
Cu-IVi-AL, 7'i-Ni, Au-C'd
A variety of books can be used, such as those for which the alloy is used only for pressure sealing and/or depressurization, and the heating of the heat sealant is
This can be done by any heating mechanism known per se.

For chewing, the container main body and lid body are as shown in the example 1 above. For example, a plastic container body formed by any method such as plastic injection molding, extrusion molding, or plug-assisted molding, and a metal lid body coated with a heat sealing material. The sealing system of the present invention is equally applicable to the purpose of sealing engagement.

In addition, the cross-sectional shape of the container is not limited to a circular one; even containers with an oval, polygonal, or even complicated cross-section can be sealed with strong, uniform pressure. Furthermore, it is possible to perform a strong and uniform pressurized seal even in areas where there is a step, such as a seam that is constantly used for containers.

The invention is illustrated by the following example.

Example A composite material consisting of paper, polyethylene, and aluminum foil was used as a cylindrical body member (1.
/Polyethylene (Oli) /Soft F7J1 Aluminum foil (15μ) /Low density polyethylene (5 () Not) was cut out into a piece of 134mm x 172rnm, rounded into a cylindrical shape and the end was heat sealed with hot air to hide the can. A cylindrical body member with a diameter of 134 mm and an inner diameter of 523 cm was used (Fig. 1-1), and then the lid member shown in Fig. 1-2 and B was coated with a coating film (4μ)/soft anno foil (100μ)/ It was drawn and formed using a laminate material of low density polyethylene (5 [3μ)]. It goes without saying that the polyethylene layer should be located on the convex side at this time. The outer diameter of this lid member rim is φ52
．． 1+nm and depth is 6fi. FIG. 2 shows the state in which this member 1.2 and the filter are fitted together.

The parts 1.2.3 thus obtained are thermally bonded using a pressing device made of a shape memory alloy according to the invention. This heat suppression device had the shape I7 shown in FIG. 6, and was manufactured using a brass-based two-way shape memory alloy (SMA).

The physical properties and shape memory characteristics of the shape memory alloy used in this example are listed in Section 1 and Table 2.

Table 1 Physical Properties Table 2 Shape Memory Characteristics As is clear from the fact that this heating/suppressing device uses high-frequency induction heating for heating, it also functions with an induction heating coil. The outer periphery of this heating/suppression coil is coated with 0.5 mm of silicone rubber. The coil made of this shape memory alloy has a transformation temperature (7''Z) set at 60C, and is processed to have an outer diameter of 50.5 mm in the martensitic phase and 51.8 mm in the parent phase. This coil is constantly cooled by cold air.

On the other hand, the counter-pressure plate 11 shown in FIG.
is a Teflon plate (<6rrrrrn thickness) with a hole 12 of φ53.1 mm. First, the fitted top cover and the upper end of the body are inserted into the hollow hole 12 of the counter pressure plate 11. Next, a shape memory alloy coil is fitted inside the annular rim on the top cover side (see Figure 5). In this state, a high frequency current is applied to the coil to raise the temperature of the seal interface to 180C.
I made it so that The coil generates heat due to electric bending caused by this current (~60C, which is the transformation temperature (Tz), and transforms from the martensitic phase to the parent phase.The counter pressure plate that regulates the increased outer diameter of the coil and the outer circumference of the can is sealed. A pressing force of 20 kg/crA is applied to the interface.At the same time, the aluminum foil on the rim of the lid is heated by the induced current, melting the polyethylene layer at the joint.Even after the current is cut off, the temperature of the coil remains at the transformation temperature. The pressing force is maintained until it decreases to 60 tl.In the case of this embodiment, after the current is cut off, the pressing force is maintained at 0.
It transformed in 5 seconds. Due to transformation, the outer diameter of the coil is φ50, 5
The coil is removed from the inside of the rim of the lid.

The bottom lid can also be heat sealed in the same way. In this example, hot water of 95 iC was poured.

Comparative Example The lid member and body member, which were exactly the same as those used in the example, were joined and sealed using a conventional method. This method, as shown in FIGS. 6 and 7-A, comprises a cylindrical die 1.6 which also serves as a seal heating mechanism and a grating die 14 which presses the seal from the outer periphery. In this comparative example, a high frequency induction heating coil was used as the heating mechanism. 3rd-A
A schematic diagram of an apparatus according to this method is shown in FIG. Using this device, heat sealing (~
is. This method packs 95C hot water [7].

A comparison was made between 60 composite cans that were hot-filled with water using the sealing method of the present invention and 60 composite cans that were hot-filled with water using the conventional sealing method.

A cut 12 was made 2 runs from the hermetically sealed end of the can body on a plane parallel to the lid panel, and this cut was observed using a stereomicroscope (magnification: 25x). At this time, 15 in Figure 9
A pinhole appeared at the position shown in . Table 6 shows the rate at which pinholes appear. Table 6: Rate at which pinholes appear Table 3 shows that according to the sealing method of the present invention, the appearance of pinholes, which could not be prevented using conventional methods, can be completely prevented. I found out that there are 6 things.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the container components, the second tooth is a perspective view of the completed container, Fig. 6 is an example of a suppression device made of a shape memory alloy, Fig. 4 is a counter pressure plate, and Fig. 5 is a counter pressure plate. FIG. 6 is a schematic diagram of the situation when sealing according to the present invention, FIG. 6 is a schematic diagram of the state of sealing according to the conventional method, FIG. BB' sectional view, FIG. 8-A and B-s are schematic diagrams of a device according to a conventional method, and FIG. 9 is a sectional view of the seal portion of the can body and lid. Reference number 1 is the container body 1.2 and 3 lid members, 4 is the side seam, 5 is the center panel, 6 is the annular rim, 7 is the sealing part, 8 is the shape memory alloy coil, 9 is both ends of the coil ,
10 is a high-frequency power supply, 11 is a counter pressure plate, 12 is a hole, 13 is a circumferential guide, 14 is a grating guide, 15 is a through hole, 16 is a body member, 17 is a polyethylene layer, and 18 is a lid member. . Patent applicant Akira Kishimoto Agent Patent attorney Iku Suzuki Male lineage 3 Figure 4 Figure 5 Figure 6 Figure 7-A Figure 7-8 Figure 8-A Figure 8-8

Claims (4)

[Claims] (1) A method for sealing a container, characterized in that deformation and/or restoring of a shape memory alloy is used for pressure sealing and/or pressure release of the container. (2) The method according to claim 1, wherein pressure sealing is performed using the memorized shape of the shape memory alloy, thereby defining the sealed shape of the container. (3) The method according to claim 1, wherein the pressure is released using the memorized shape of the shape memory alloy. (4) The container includes a container body having a circumferential open end and a lid that engages with the open end, and the shape memory alloy is engaged with the open end or the lid that engages with the open end. 2. The method according to claim 1, wherein the sealing is performed by