JPH08323848A - Hermetically sealed hollow member and production thereof - Google Patents

Abstract

PURPOSE: To obtain a hermetically sealed hollow member capable of perfectly closing a blow hole and excellent with respect to appearance and sanitation. CONSTITUTION: A hollow member is produced by the blow molding of a thermoplastic resin and equipped with a hollow container main body consisting of a body part 2 and the mouth part 3 connected to the body part 2 and the expanded part 4 connected to the mouth part 3 through a cutting part 8. A stepped recessed part 7 consisting of a recessed part 5 depressed into the chamber of the expanded part 4 and the sealing recessed part 6 further stepwise depressed into the chamber from the recessed part 5 is formed to the expanded part 4 and the blow hole 9 opened to the almost central part of the sealing recessed part 6 is perfectly sealed by a closing resin 10b formed by cooling and solidifying the molten sealing resin charged in the sealing recessed part 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed hollow body used as a container for storing foods, pharmaceuticals, cosmetics, industrial chemicals and the like, and a method for producing the same.

[0002]

2. Description of the Related Art Heretofore, methods (a) to (c) described below have been proposed as methods for manufacturing a sealed hollow body of this type.

(A) After the hollow body is blow-molded, the communicating portion into which the pressurized fluid has been introduced is cut by a heating blade, and at the same time, the cut portion of the communicating portion is heated and melted to seal (JP-A-59-178225). Issue).

(B) When the hollow body is blow-molded, a thin piece for closing is formed in the hollow body, and after the completion of blow molding, the thin piece for closing is melted by heating to seal the blow hole ( JP-B-54-37636).

(C) As shown in FIG. 7, a hollow container body composed of a body portion 102 and a mouth portion 103 having a screw portion 103a connected to the body portion 102, and a cutting portion 105 in the mouth portion 103. Blow-hole formed by introducing a pressurized fluid after blow molding a hollow body having a bulging portion 104 continuously provided and a concave portion 106 in which an appropriate portion of the bulging portion 104 is recessed toward the inside of the chamber. 107 is a rivet-shaped closing resin 1
By inserting and closing 08, the sealed hollow body 10
No. 1 (Japanese Patent Application Laid-Open No. 6-286741).

[0006]

However, in the above-mentioned conventional techniques (a) and (b), since the blow hole is sealed by heating and melting the resin around the blow hole, the blow hole is sealed. The amount of resin that can be supplied is limited, and the blow hole tends to be incompletely sealed. Further, when the resin around the blow hole is heated and melted by the heating blade, the resin attached to the heating blade is carbonized and attached to the hollow body, which not only impairs the appearance but is also not preferable from the viewpoint of hygiene. There is a problem.

The remaining (c) can solve the problems of the above (a) and (b), but since the rivet-like blocking resin is inserted into the blow hole to close it, the resin is fitted in the blow hole in an airtight manner. It is necessary to prepare in advance a rivet-shaped closing resin, but there is a problem that the blow hole cannot be closed completely unless the tip of the rivet-shaped closing resin is surely inserted into the blow hole.

The present invention has been made in view of the problems of the above-mentioned prior art, and it is possible to completely close the blow hole and also to provide a sealed hollow body which is excellent in appearance and hygiene. The purpose is to realize the manufacturing method.

[0009]

In order to achieve the above object, the hermetically sealed hollow body of the present invention is formed by blow molding from thermoplastics, and comprises a hollow container body and an opening portion of the hollow container body. And a stepped recess formed of a recess recessed toward the inside of the recess and a sealing recess recessed further toward the inside of the recess from the recess. And a blow hole formed in the sealing recess is closed by a sealing resin that is filled with molten sealing resin in the sealing recess and is cooled and solidified. It is what

According to the method for producing a sealed hollow body of the present invention, a hollow container body, a bulging portion connected to a portion to be an opening of the hollow container body, and the bulging portion recessed toward the inside of the chamber. A mold of a split type having a cavity for restricting the outer surface of a hollow body provided with a concave portion and a stepped concave portion which is further stepwise recessed from the concave portion toward the indoor side is used, and the mold is opened. After arranging a molten parison made of a thermoplastic between molds, the mold is closed, and then a blowing means is inserted from a portion of the parison which will be the recess for sealing to introduce a pressurized fluid into the cavity. After blow-molding the hollow body by expanding along with it, the sealing resin is filled with molten sealing resin in the sealing recess, and the sealing resin is cooled and solidified. Recess It is characterized in that for closing the formed blown hole.

The sealing resin has substantially the same composition as the thermoplastic resin forming the parison, and the difference between the melting point and the heat distortion temperature is within 100 ° C., or
It is effective that the area of the open surface of the sealing recess is within the range of 3 to 20 times the opening area of the blow hole.

[0012]

Since the present invention is configured as described above, the sealing resin is filled with the molten sealing resin, and the sealing resin is cooled and solidified.
The blow hole formed in the sealing recess is completely closed. Further, since the resin is not carbonized and attached to the sealed hollow body or dropped inside, it is excellent in appearance and hygiene.

In the present invention, the heat distortion temperature means AST.
It is specified in MD648 and the load is 1.8M.
Pa.

[0014]

Embodiments of the present invention will be described with reference to the drawings.

An embodiment of the sealed hollow body of the present invention will be described.

As shown in FIG. 1, the hollow body 1 is formed by blow molding from thermoplastics, and has a mouth portion 3 having a body portion 2 and a screw portion 3a connected to the body portion 2.
And a bulging portion 4 connected to the mouth portion 3 via a cutting portion 8 serving as an opening, and the bulging portion 4 has a recessed portion 5 recessed toward the inside thereof and A stepped recess 7 is provided, which is composed of a sealing recess 6 that is further recessed inward from the recess 5 in a stepwise manner. The blow hole 9 that opens at approximately the center of the sealing recess 6 is shown in FIG. As shown, the sealing recess 6 is completely blocked by the sealing resin 10b shown in FIG. 6, which is filled with the molten sealing resin 10a and cooled and solidified.

Next, a method for manufacturing the above-mentioned sealed hollow body will be described.

First, the metal mold used in this embodiment will be described. As shown in FIG. 2, the metal mold is of a split type and has a protrusion 23a protruding toward the other metal mold 22. One mold 2 in which the core mold 23 is installed
1 and the other die 22 opposite thereto, and when the die is closed, the above-mentioned body portion 2, the mouth portion 3 having the screw portion 3a connected to the body portion 2 and the opening portion in the mouth portion 3 are formed. And a recessed portion 5 recessed toward the indoor side of the swollen portion 4 and a sealing recessed portion further recessed toward the indoor side in stages from the recessed portion 5. 6 is formed so as to form a cavity 24 that regulates the outer surface of the hollow body 1 in which the stepped recessed portion 7 formed of 6 is formed. An insertion hole 26 for inserting a blowing needle 25 or the like, which is a blowing means, which is opened on a surface that regulates the recess 6 for use is provided.
The steps of the method for manufacturing a sealed hollow body using this split type mold will be described below.

One mold 21 and the other mold 22
After the mold is opened, a molten parison made of a thermoplastic is extruded from an extruding head of an extruder (not shown) and placed between the molds 21 and 22, and then the mold is closed to sandwich the parison.

After the above, the blow-in needle 25 is thrust into the interior of the chamber 4a corresponding to the bulging portion 4 from the substantially central portion of the portion corresponding to the sealing recess 6 of the parison to pressurize compressed air or the like. The hollow body 1 is blow-molded by introducing a fluid to expand it along the cavity 24.

After the above, the hollow body 1 is cooled in a mold, and then the mold is opened to take out the hollow body 1.

After the above, as shown in FIG. 3, the hollow body 1 is placed on a workbench (not shown) such that the stepped recess 7 of the bulging portion 4 faces upward.

After the above, if necessary, as shown in FIG. 4, hot air is blown toward the stepped recess 7 by the hot air nozzle 11 or the like, and the sealing recess 6 and its peripheral portion form a hollow body. Preheating to a predetermined temperature below the heat distortion temperature of the thermoplastic resin.

Then, the sealing recess 6 is filled with the molten sealing resin 10a by dropping or injecting the molten sealing resin 10a as shown in FIG. 5 by a plasticizing device (not shown). The amount of the molten sealing resin 10a filled is set to a level slightly higher than the open surface 6a of the sealing recess 6.

After the above, as shown in FIG. 6, before the sealing resin 10a is cooled and solidified, the tip end face is pressed by the flat pressing member 12 and shaped so as to enter the blow hole 9 and then cooled. By solidifying, the sealing hollow body in which the blow hole 9 is closed by the closing resin 10b filled in the sealing recess 6 is produced.

In the present invention, the sealing resin used to close the blow hole has a composition substantially the same as that of the thermoplastic resin forming the parison, that is, the hollow body, and has a melting temperature M and thermal deformation of the sealing resin. Difference from temperature T is 1
Those having a temperature of 00 ° C. or lower are preferable. When the difference between the melting temperature M and the heat deformation temperature T is larger than 100 ° C., the heat shrinkage amount of the sealing resin due to the temperature difference between the molten sealing resin for closing the blow hole and the hollow body is large. There is a risk that the occlusivity will be impaired due to excessive aging. Examples of thermoplastics that satisfy this condition include ethylene-vinyl acetate copolymer, high-pressure low-density polyethylene, high-density polyethylene, polypropylene, and polyoxymethylene.

The area S of the open surface 6a of the sealing recess 6 is S.
₁ is preferably within a range of 3 to 20 times the opening area S ₂ of the blow hole 9. Opening surface 6 of the recess for sealing
If the area S _{1 of a} is larger than 20 times the opening area S ₂ of the blow hole 9, the amount of the molten sealing resin 10a consumed is large, but the blocking property of the blow hole 9 is not effective.
On the contrary, if it is less than 3 times, the blocking resin 10b after cooling and solidification may fall off.

The hollow container body is not limited to the shape of the above-mentioned embodiment, but the mouth part has no threaded part, or the bulge part is continuously connected through a cut part which becomes an opening. The shape does not matter.

[0029]

Since the present invention is configured as described above, it has the following effects.

The bulging portion is provided with a stepped recess including a recess recessed toward the inside of the room and a sealing recess recessed further toward the room inward from the recess, and the sealing resin melted in the recess for sealing. It is possible to completely close the blow hole formed in the sealing recess by using the plugging resin that has been filled with and then cooled and solidified, and since the resin does not carbonize, it is also excellent in appearance and hygiene. ing.

Further, since the surface of the blocking resin does not project outward than the open surface of the recess, the blocking resin may come into contact with other members or the like and drop off during transportation or the like. Nor.

[Brief description of drawings]

FIG. 1 is an elevational view showing a hollow body before closing a blow hole in an embodiment of a sealed hollow body of the present invention.

FIG. 2 is a schematic cross-sectional view of a mold main part showing one step of blow molding of the hollow body shown in FIG.

FIG. 3 is an explanatory view showing one step of the method for producing a sealed hollow body of the present invention, in which a main portion of a hollow body having a stepped recess placed upward on a workbench is shown in a partial cross-sectional view. .

FIG. 4 is an explanatory view showing a partial cross-sectional view of a main part of the hollow body, which shows a step of preheating the sealing concave portion and its periphery by blowing hot air to the stepped concave portion after the step shown in FIG. 3; is there.

FIG. 5 is an explanatory view showing a partial cross-sectional view of a main part of the hollow body, showing a step of filling the sealing recess with a molten sealing resin after the step shown in FIG. 4;

FIG. 6 is an explanatory view showing a partial cross-sectional view of a main part of the hollow body, showing a step of shaping the sealing resin filled in the sealing recess after the step shown in FIG. 5;

FIG. 7 is an elevation view showing an example of a conventional sealed hollow body in a partial sectional view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hollow body 2 Body part 3 Mouth part 3a Screw part 4 Swelling part 4a Indoor 5 recessed part 6 Sealing recessed part 6a Open surface 7 Stepped recessed part 8 Cutting part 9 Blow hole 10a Melting sealing resin 10b Closing resin 11 Hot air Nozzle 12 Pressing member

Claims (4)

[Claims] 1. A blow molding from a thermoplastic, comprising: a hollow container body; and a bulging portion connected to a portion that becomes an opening of the hollow container body, and the bulging portion. Has a stepped recess formed of a recess recessed toward the inside of the chamber and a recess recess for sealing recessed further toward the room from the recess, and the blow hole formed in the recess for sealing is formed. A sealed hollow body, characterized in that the sealing recess is filled with a molten sealing resin and is closed by a sealing resin which is cooled and solidified. 2. A hollow container main body, a bulging portion continuously provided in a portion that becomes an opening of the hollow container main body, a recessed portion that is recessed toward the indoor side in the bulging portion, and further stepwise from the recessed portion. A split-type mold having a cavity for controlling the outer surface of a hollow body having a stepped recess formed of a sealing recess that is recessed toward the indoor side is used, and the mold is made of a thermoplastic resin between the molds. After arranging the molten parison, the mold is closed, and then the blowing means is inserted from the portion which becomes the sealing recess of the parison to introduce pressurized fluid to expand along the cavity to expand the hollow body. After the blow molding, the sealing recess is filled with molten sealing resin and then cooled and solidified to block the blow hole formed in the sealing recess by the introduction of the pressurized fluid. To do A method for producing a sealed hollow body, comprising: 3. The sealing resin has substantially the same composition as the thermoplastic resin forming the parison, and the difference between the melting point and the heat distortion temperature is 100 ° C. or less. Method for manufacturing sealed hollow body. 4. The method for producing a hermetically sealed hollow body according to claim 2, wherein the area of the open surface of the sealing recess is within a range of 3 to 20 times the opening area of the blow hole.