JPH08258860A - Hermetically sealed container and its production - Google Patents

Abstract

PURPOSE: To eliminate a troublesome job of fitting a gasket between joined parts in each use, by integrating an elastic member, made of thermoplastic elastomer, with parts of a container main body, near its side-wall tops, or with parts of a cover which come into contact with that parts, or with both thereof. CONSTITUTION: In a contact part between a container main body 1 and a cover 2, an elastic member 4 made of thermoplastic elastomer is embedded and integrated into the surfaces of the side-wall tops of the container main body 1, or into both the side-wall tops of the container main body 1 and parts of the cover 2 which come into contact with the tops. Alternatively, the elastic member 4 is integrally embedded inside the side-wall tops of the container main body 1, or it is embedded and integrated into the side-wall tops of the container main body 1 with a recess left in it and another elastic member 4 is integrally embedded into the cover 2 with a projection left on it. Further the elastic member 4 in the form of a projection is integrated with parts of the container main body 1, near the side-wall tops, and the sides of the cover 2 are brought into contact with the elastic member 4. Thus, this eliminates the need to fit a gasket between the joined parts in each use, which is troublesome.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hermetically sealed container, and more particularly to a hermetically sealed container in which a container body and a lid are in close contact with each other, a liquid contained therein is not leaked, and contamination resistance is excellent.

[0002]

2. Description of the Related Art Conventionally, plastic, which is one kind of synthetic resin, is used for manufacturing various containers because it is inexpensive, easy to mold, has no corrosiveness, and has excellent coloring properties. Has been done. Among these containers, a box-shaped container such as a lunch box or a lunch box usually requires a lid that fits the container body, and various measures are taken so that the lid can be easily attached and detached. It has been subjected.

For example, in the case of a lunch box, as shown in FIGS. 4a and 4b, the container body 1 and the lid are completely sealed so that food containing liquid substances such as broth and seasonings can be stored. An endless belt-shaped gasket 5 made of silicone rubber or the like is fitted in the contacting portion with 2, while the lid 2 is tightened to the lid 2 and the container body 1 as necessary in order to tighten the lid 2 and the container body 1.
Is provided and the abutting portion between the container body 1 and the lid 2 is brought into close contact with the tightening member 3 to prevent leakage of contents. Also, in closed containers such as water bottles, pots, thermos bottles, cans, etc.
It is usual that an elastic member is provided between the container body and the lid for tightly sealing the both.

[0004]

In the above-mentioned conventional closed container, the endless belt-shaped gasket 5 is made of rubber because it is required to have appropriate elasticity. However, rubber is difficult to integrally mold with a thermoplastic resin. Therefore, it is produced by molding and vulcanizing separately from the molding of the container body 1 or the lid 2, while the groove 6 into which the above-mentioned gasket 5 is fitted is formed in the container body 1 at the top of the side wall of the container body 1. There is a complication that the gasket 5 is molded and fitted into the groove 6 when the container is used. Further, since the gasket 5 is formed to have a diameter slightly smaller than that of the groove 6, food residue remains in the groove 6 and is contaminated, which is unsanitary, and the inside of the contaminated groove is completely cleaned. There is a problem that it is difficult to do. Therefore, an object of the present invention is to provide a closed container which does not have the trouble of fitting a gasket each time it is used and is excellent in stain resistance.

[0005]

The above object can be achieved by the present invention described below. That is, the present invention is a closed container comprising a container body made of a hard material and a lid, in the vicinity of the top of the side wall of the container body, or at the portion of the lid abutting the vicinity of the top, or both parts from a thermoplastic elastomer. An elastic container is integrally formed, and a method for manufacturing the same.

According to the present invention, an elastic member made of a thermoplastic elastomer is formed integrally with the container body or the lid near the top of the side wall of the container body, or at a portion of the lid abutting the vicinity of the top, or at both portions. By doing so, it is possible to provide a closed container which does not have the trouble of fitting a gasket each time it is used and has excellent stain resistance. In particular, by integrally molding the container body and / or the lid from a polypropylene resin and the elastic member from a thermoplastic polyolefin-based elastomer or a thermoplastic styrene-based elastomer,
Adhesion between the container body or the lid and the elastic member is good, and these elastic members are also excellent in hermeticity and stain resistance against the liquid contents.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described more specifically with reference to the accompanying drawings showing one embodiment of the present invention. Figure 1a
Shows a lunch box of one embodiment of the closed container of the present invention, and some examples of the cross section taken along the line AA are shown in FIGS.
The container body 1 of the lunch box of the present embodiment, the lid 2, and the tightening members 3 of both of them provided as necessary are the same as those of the conventional lunch box.
The present embodiment is not limited to the lunch box having the shape shown in the drawing, and an elastic member made of a thermoplastic elastomer is provided near the top of the side wall of the container body, at the portion of the lid that abuts near the top, or at both portions. As long as it is integrally molded, it is not limited to a lunch box, for example, a water bottle, a pot, a thermos bottle, a can, etc.
It may be a container of any shape.

The container body 1, the lid 2 and the tightening member 3 of the lunch box are preferably made of hard plastic by injection molding. The feature of this embodiment is that the elastic member 4 is integrally formed at the contact portion between the container body 1 and the lid 2 as shown in FIGS. In the example shown in FIG. 1b, the elastic member 4 is embedded and integrally molded in the top surface of the side wall of the container body 1.
In the example shown in FIG. 1c, the elastic member 4 is integrally formed on the top of the side wall of the container body 1. In the example shown in FIG. 1d, the elastic member 4 is formed on both the top of the side wall of the container body 1 and the portion of the lid 2 that abuts on the top. 1e is an example in which the elastic member 4 is embedded and formed integrally inside the side wall top of the container body 1, and the example shown in FIG. 1f is recessed in the side wall top of the container body 1. This is an example in which the elastic member 4 is embedded and integrally molded in the state, and the convex elastic member 4 is embedded and integrally formed in the portion of the lid 2 that abuts on the elastic member 4. The example shown in FIG. In this example, the convex elastic member 4 is integrally formed near the top of the side wall, and the side surface of the lid 2 contacts the elastic member 4. In any of the examples, when the lid 2 is overlaid on the container body 1 and the two are united by the tightening member 3 as needed, the boundary between the two is sealed by the elastic force of the elastic member 4 to completely prevent the liquid leakage of the stored items. It can be prevented.

The embodiment shown in FIG. 2 is an example in which the present invention is applied to a tea-cylinder-shaped container with a lid. In this container, a container body 21 is a metal cylindrical body, and a metal plate is provided inside the cylinder top. Is formed with a convex portion 22 in which the top of the is rounded inward.
On the other hand, the lid 23 is a lid body 24 made of hard plastic.
And an elastic member 25 made of thermoplastic elastomer integrally formed inside the lower portion of the lid. When the lid 23 is put on the container body 21, the elastic member 25 is pushed into the container body 21 and comes into contact with the convex portion 22 formed on the top of the container body 21, and the elasticity of the elastic member 25 causes the container to completely move. Sealed. Although the above example is an example of a cylindrical container, for example, even in a container having a screwable lid such as a thermos, conventionally, the thermos body is sealed under the screwed lid for sealing. A rubber gasket having an O-ring shape similar to that shown in FIG. 4 is fitted in the above, but by applying the present invention to such a thermos,
Similarly to the above, the lid main body and the gasket can be integrally molded.

The hard member used in the present invention may be, for example, metal, porcelain, earthenware, ceramics or the like, but at least one of the container body and the lid integrally forming the elastic member is made of hard plastic. Is preferred. As the hard plastic, general-purpose hard plastics such as polyethylene, polypropylene, polystyrene, polyester and polyamide can be used, but polypropylene resin is particularly preferable. The polypropylene resin used in the present invention is a polymer mainly composed of a propylene monomer and may contain a small amount of other copolymerizable olefin as a copolymerization component, and has been conventionally used for various fibers and various molded products. It is widely used as a raw material for the above, and any of these conventionally known polypropylene resins can be used as they are in the present invention.

The thermoplastic elastomer used in the present invention has elasticity similar to that of rubber at room temperature,
A material that is softened by heating and exhibits fluidity, that is, thermoplasticity. For example, a polyolefin-based rubber (mainly EPR-EPDM) is used as a soft segment and a polyolefin-based resin (mainly P is used as a hard segment).
P), a crosslinked structure in which both are chemically bonded, a thermoplastic polyolefin-based elastomer such as a polypropylene / ethylene / propylene rubber blend, a block polymer of a styrene polymer and a polybutadiene (or polyisoprene) polymer, and a block copolymer thereof. Hydrogenated compounds, polystyrene-poly (ethylene-butylene) -polystyrene thermoplastic elastomers such as polystyrene block copolymer (SEBS), polyester-based and polyurethane-based block copolymers, etc., and all of these materials are available from the market. It is a possible material.

In the combination of the thermoplastic elastomer and the hard plastic as described above, a particularly preferable combination is a polypropylene resin as the hard plastic and a polyolefin thermoplastic elastomer as the thermoplastic elastomer (for example, JSR Thermolane: made by Nippon Synthetic Rubber, Mirastomer: Mitsui Petrochemical,
Santoprene: manufactured by Monsanto, Tuffmer: manufactured by Mitsui Petrochemical, elastomer AR: manufactured by Aron Kasei), or a thermoplastic polystyrene-based elastomer such as polystyrene-
Polybutadiene-polystyrene block copolymer (for example, JSR TR: Nippon Synthetic Rubber, Clayton or Califlex TR: Shell Chemical, Toughprene, Sorprene, Asaprene, Toughtech: Asahi Kasei, Electric STR: Electrochemical, Europrene SOL T: Tosoh Etc.), polystyrene-poly (ethylene-butylene)
-Polystyrene block copolymer (SEBS) (for example, Kraton G: Shell Chemical, Lavalon: Mitsubishi Yuka, Sumitomo TPE-SB: Sumitomo Chemical, Tuftec: Asahi Kasei, Septon: Kuraray, Elastomer AR: Aron Kasei) Etc. are combined.

The sealed container of the present invention as described above can be manufactured by conventionally known insert molding and two-color molding. The molding conditions themselves may be the same as the conventional general insert molding or two-color molding conditions as described in, for example, "Recent Injection Molding Technology-Their Actual and Application-" (Sanko Publishing Co., Ltd.). In both cases of insert molding and two-color molding of the sealed container of the present invention, the thermoplastic elastomer may be molded first, and then the hard plastic may be molded, but preferably the hard plastic is molded first, and then the hard plastic is molded. Mold the thermoplastic elastomer. In insert molding, first, hard plastic, for example,
1b to g, a container body and a lid are formed by melt injection molding in a mold having a cavity having a shape without the elastic member 4, and the molded product is shown in FIGS. 1b to g. It is preferable that the elastic member 4 is integrally melt-molded by being inserted into a mold having the above, and the thermoplastic elastomer is melt-injected into the space portion (portion of the elastic member 4).

In the case of two-color molding, for example, it is integrally molded as shown in FIG. The example shown in FIG. 3a shows a first mold 31.
The second mold 32 and the second mold 32 are detachably attached to each other at the parting line 33. The first mold 31 has a concave portion shown by a curve 34, while the lower surface of the second mold 32 has a convex portion shown by a curve 35, and the first mold 31 and the second mold 32 The cavity 36 having the same shape as the outer surface shape of the molded product is formed by the butting with the mold 32.
The second mold 32 is provided with a resin injection port 37. In this state, as shown in FIG. 3B, molten hard plastic is injected from the injection port 37 to mold the container body 38 in the cavity 36. After the container main body 38 is molded in this manner, the first mold 31 shown in FIGS. 3a and 3b is rotated, and as shown in FIGS. 3c and 3d, another second mold 32 'is formed.
The first die 31 is brought into close contact with. While the molded body made of the hard plastic is cooled and hardened to some extent during the replacement time of the second mold, the length of the replacement time of the mold does not cause any particular problem.

In the state shown in FIG. 3c, a space 39 is formed in the upper end surface of the side wall of the container body 38 made of hard plastic, and as shown in FIG. 3d, the space 39 is filled with the thermoplastic elastomer from the injection port 40. The melt is injected to mold the elastic member 41 and integrate it with the container body 38. Next, after cooling the molding die to a required temperature, the molded product is released from the mold, whereby a desired molded product in which the elastic member 41 is integrally molded on the upper end surface of the side wall of the container body 38 is obtained. The above example is one example of the core rotation system, and it goes without saying that any other two-color molding system such as the core back system is also useful in the present invention. Further, in the above example, the molding was performed in the order of hard plastic → thermoplastic elastomer,
There is no problem even if the order of molding is the reverse.

[0016]

EXAMPLES Next, the present invention will be described more specifically with reference to examples. Example 1 A DC100-200 type two-color molding machine (manufactured by Nissei Plastic Industry Co., Ltd.) was used as an injection molding machine, and a polypropylene resin was melted at a temperature of 200 to 230 ° C. It was injection-injected into the temperature mold A (the combination of the first mold 31 and the second mold 32 shown in FIG. 3a). As a result, the container body 38 of the lunch box made of polypropylene resin is molded. Next, by rotating the mold 31 with the molded container body still inside,
The mold B is moved and brought into close contact with another mold 32 'to form the mold B in the state shown in Fig. 3c, and SEBS is injected from the injection port 40 of the mold 32'.
(Asahi Kasei, trade name Tuftec, block copolymer of styrene polymer and ethylene-butylene random copolymer) is melted at a temperature of 180 ° C. to 240 ° C. and injected into the cavity 39 at the top of the side wall of the lunch box container body 38. The elastic member 41 is integrally molded. Next, after cooling to a constant temperature in the mold B, the mold was opened to obtain a container body 1 of a lunch box having a side wall structure as shown in FIG. 1c.

In this plastic container body, the polypropylene resin portion and the SEBS portion were melt-bonded together and completely integrated, and thus could not be peeled off. In addition, the cooked fish was put into the lunch box body obtained as described above, and the lid was closed and sealed with a tightening member.
In this state, no liquid leakage occurred in any way. Also, when the elastic member part of the container body was soaked in the simmered simmered food for one week, then taken out and wiped with a wet cloth, the stain was completely removed and the simmered liquid also appeared on the boundary between the side wall material and the elastic member. No trace of soaking in was observed.

Example 2 In the case of insert molding, a general injection molding machine (KC-140 type A manufactured by Kawaguchi Iron Works) was used, and the first molds 31 and 32 of FIG. A, polypropylene resin, which is a hard plastic, is melted at a temperature of 180 to 250 ° C., the mold A is held at a temperature of 50 ° C., and an injection pressure of 40 to 100 kg / in the cavity 36 of the mold A.
The container body 38 is molded by injection injection at cm ² . When the molded product solidifies to a temperature that does not deform when taken out, mold A
Open, the molded product 38 is taken out from the mold A, and the container body 3
The molding of No. 8 is completed.

Next, in a general injection molding machine (KC-140 type B manufactured by Kawaguchi Iron Works Co., Ltd.), the molds 31 and 32 'of FIG. 3c are used.
, And insert the molded container body 38 into the recess of the mold 31 and combine it with the mold 32 'to mold B.
And seal SEBS (Sumitomo TPE-S
B) is melted at a temperature of 180 ° C to 250 ° C and the injection pressure is 3
The elastic member 41 was molded by injection injection into the cavity 39 at 0 to 80 kg / cm ² . After the integrally molded product was solidified in the mold B, the mold B was opened and the integrally molded product was taken out. In this plastic container body and lid, the polypropylene resin portion and the SEBS portion were both melt-bonded together and completely integrated, and could not be peeled off. This lunch box was also excellent in hermeticity and stain resistance as in Example 1. The SEB in Examples 1 and 2
Similar results were obtained by using a thermoplastic polyolefin elastomer (trade name) Mirastomer: manufactured by Mitsui Petrochemical Co., Ltd. instead of S.

[0020]

According to the present invention as described above, an elastic member made of a thermoplastic elastomer is provided near the top of the side wall of the container body, or at a portion of the lid abutting the vicinity of the top portion, or at both portions of the container body or the lid. By integrally molding with, it is possible to provide a closed container which does not have the trouble of fitting a gasket each time it is used and has excellent stain resistance. Particularly, by integrally molding the container body and / or the lid from the polypropylene resin, and the elastic member from the polyolefin-based thermoplastic elastomer or the styrene-based thermoplastic elastomer, good adhesion between the container body or the lid and the elastic member,
In addition, these elastic members are also excellent in the hermeticity and stain resistance against the liquid contents.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing an example of a closed container of the present invention.

FIG. 2 is a diagram schematically showing an example of a closed container of the present invention.

FIG. 3 is a diagram illustrating a manufacturing method of the present invention.

FIG. 4 is a diagram schematically showing a conventional closed container.

[Explanation of symbols]

 1: Container body 2: Lid 3: Tightening member 4: Elastic member 5: Gasket 6: Groove

Claims (5)

[Claims] 1. A closed container comprising a container body made of a hard material and a lid, comprising a thermoplastic elastomer in the vicinity of the top of the side wall of the container body, in the portion of the lid abutting the top, or in both portions. An airtight container characterized in that an elastic member is integrally molded. 2. The plastic closed container according to claim 1, wherein the elastic member is formed by insert molding or two-color molding. 3. The closed container according to claim 1, wherein the container body and / or the lid is made of polypropylene resin, and the elastic member is made of a thermoplastic polyolefin-based elastomer or a thermoplastic styrene-based elastomer. 4. The closed container according to claim 1, which is a food container. 5. A closed container comprising a container body made of a hard material and a lid, wherein the container body and / or the lid is injection-molded from hard plastic, and an elastic member is insert-molded at the abutting portion of the container body and / or the lid. Alternatively, the method for manufacturing a closed container is characterized by integrally molding by two-color molding.