JP3597599B2 - Sealed hollow body and method for producing the same - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a hermetically sealed hollow body used as a storage container for foods, pharmaceuticals, cosmetics, industrial chemicals, and the like, and a method for producing the same.
[0002]
[Prior art]
Conventionally, as a method for producing this kind of sealed hollow body, the following methods (a) to (c) have been proposed.
[0003]
(A) After the hollow body is blow-molded, the communicating portion into which the pressurized fluid is introduced is cut by a heating blade, and at the same time, the cut portion of the communicating portion is melted by heating and sealed (JP-A-59-178225). .
[0004]
(B) When blow molding a hollow body, a thin piece for closing is formed in the hollow body, and after the completion of blow molding, the thin piece for closing is heated and melted to seal a blow hole (Japanese Patent Publication No. Sho 54). -37636).
[0005]
(C) As shown in FIG. 7, a hollow container body including a body portion 102 and a mouth portion 103 having a screw portion 103a connected to the body portion 102, and a hollow container body connected to the mouth portion 103 via a cutting portion 105. After blow molding a hollow body having the bulged portion 104 and a concave portion 106 in which an appropriate portion of the bulged portion 104 is recessed toward the inside of the room, the blow hole 107 generated by the introduction of the pressurized fluid is riveted. A method of producing a sealed hollow body 101 by inserting a block-shaped closing resin 108 and closing the same (JP-A-6-286741).
[0006]
[Problems to be solved by the invention]
However, in the above prior arts (a) and (b), since the blowhole is sealed by heating and melting the resin around the blowhole, the amount of resin that can be used for sealing the blowhole is limited. In addition, the sealing of the blow holes tends to be incomplete. In addition, 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 adheres to the hollow body. There is a problem.
[0007]
The remaining (C) is a rivet having a shape that fits tightly into the blow hole because the problem of (A) and (B) can be solved, but the rivet-shaped plugging resin is inserted into the blow hole and closed. However, there is a problem that the blow hole cannot be completely closed unless the tip is securely inserted into the blow hole.
[0008]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the related art, and is capable of completely closing a blow hole, and is excellent in appearance and hygiene, and a method of manufacturing the same. It is intended to realize.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the sealed hollow body of the present invention is blow-molded from thermoplastic plastic, and has a hollow container main body and a bulge connected to a portion to be an opening of the hollow container main body. And a stepped recess formed of a recess recessed toward the indoor side of the bulging portion and a sealing recess further recessed from the recess toward the indoor side in a stepwise manner. A blow hole formed in the stop recess is filled with a sealing resin melted into the sealing recess and closed by cooling and solidifying the sealing resin.
[0010]
The method for producing a sealed hollow body according to the present invention includes a hollow container body, a bulging portion connected to a portion to be an opening of the hollow container body, a concave portion recessed toward the indoor side of the bulging portion, and Using a divided mold having a cavity that regulates the outer surface of a hollow body having a stepped recess formed of a sealing recess recessed stepwise from the recess toward the indoor side, and between the opened molds The mold is closed after disposing a molten parison made of a thermoplastic plastic, and then blowing means is inserted from a portion of the parison serving as the sealing concave portion to introduce a pressurized fluid to expand along the cavity. After blow molding the hollow body, the sealing recess is filled with a molten sealing resin, and the sealing resin is cooled and solidified. The sealing resin is formed in the sealing recess by introducing the pressurized fluid. Was done It is characterized in that for closing the low hole.
[0011]
It is also effective if 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]
[Action]
Since the present invention is configured as described above, the sealing recess is filled with a molten sealing resin and cooled and solidified to fill the sealing recess. Is completely closed. Further, since the resin is not carbonized and adheres to the sealed hollow body and does not fall into the inside, it is superior in appearance and hygiene.
[0013]
In the present invention, the heat deformation temperature is defined in ASTM D648, and the load is 1.8 MPa.
[0014]
【Example】
An embodiment of the present invention will be described with reference to the drawings.
[0015]
An embodiment of the sealed hollow body of the present invention will be described.
[0016]
As shown in FIG. 1, a hollow body 1 is blow-molded from a thermoplastic plastic and includes a body portion 2 and a hollow container body 3 having a mouth portion 3 having a screw portion 3 a connected to the body portion 2. And a bulging part 4 connected to the mouth part 3 via a cutting part 8 serving as an opening part. Is provided with a stepped recess 7 formed of a sealing recess 6 which is further recessed toward the indoor side, and a blow hole 9 opening at a substantially central portion of the sealing recess 6 is sealed as shown in FIG. The filling recess 6 is filled with a molten sealing resin 10a and is completely closed by a closing resin 10b shown in FIG. 6 which is cooled and solidified.
[0017]
Next, a method for producing the sealed hollow body will be described.
[0018]
First, the mold used in this embodiment will be described. As shown in FIG. 2, the mold is of a split type, and has a protruding portion 23a protruding toward the other mold 22. A mold 23 includes one mold 21 provided therein and the other mold 22 opposed thereto. When the mold is closed, a mouth having the above-mentioned body portion 2 and the screw portion 3a connected to the body portion 2 is provided. A bulging portion 4 connected to the portion 3 and the mouth portion 3 via a cutting portion 8 serving as an opening, and the bulging portion 4 is provided with a concave portion 5 recessed toward the indoor side and a stepped portion from the concave portion 5. Further, a cavity 24 is formed to regulate the outer surface of the hollow body 1 in which the stepped recess 7 composed of the sealing recess 6 recessed toward the indoor side is formed. An opening is formed on the distal end surface of the protruding portion 23a, that is, a surface that regulates the sealing recess 6. Insertion holes 26 for inserting the blow needle 25, etc. is feed means is provided. The steps of the method for manufacturing a sealed hollow body using the divided mold will be described below.
[0019]
{Circle around (1)} One mold 21 and the other mold 22 are opened, and a molten parison made of a thermoplastic plastic is extruded from an extrusion head of an extruder (not shown) and arranged between the molds 21 and 22. Thereafter, the mold is closed to hold the parison.
[0020]
{Circle around (2)} After the above {circle around (1)}, the blowing needle 25 is inserted into the room 4a of the part to be the bulging part 4 from the substantially central part of the part to be the sealing concave part 6 of the parison, and pressurized air or the like. Then, the hollow body 1 is blow-molded by introducing the pressurized fluid to expand the cavity body 24 along the cavity 24.
[0021]
{Circle around (3)} After the above {circle around (2)}, the hollow body 1 is cooled in a mold, the mold is opened, and the hollow body 1 is taken out.
[0022]
(4) After the above (3), as shown in FIG. 3, the hollow body 1 is placed on a work table (not shown) such that the stepped recess 7 of the bulging portion 4 faces upward.
[0023]
(5) After the above (4), if necessary, as shown in FIG. 4, hot air is blown toward the recessed step 7 by a hot air nozzle 11 or the like, so that the sealing recess 6 and its peripheral portion are hollow. Is preheated to a predetermined temperature equal to or lower than the heat deformation temperature of the thermoplastic resin constituting the above.
[0024]
{Circle around (6)} Next, as shown in FIG. 5, the molten sealing resin 10a is dropped or injected into the sealing recess 6 by a plasticizing device (not shown) to fill the sealing recess 6. The filling amount of the molten sealing resin 10a is set so as to slightly rise above the open surface 6a of the sealing concave portion 6.
[0025]
(7) After the above (6), as shown in FIG. 6, before the sealing resin 10a is cooled and solidified, the front end face is pressed by the flat pressing member 12 and shaped so as to enter the blow hole 9. Thereafter, by cooling and solidifying, a sealed hollow body in which the blow holes 9 are closed by the closing resin 10b filled in the sealing recesses 6 is produced.
[0026]
In the present invention, the sealing resin used for closing the blow holes has substantially the same composition as that of the parison, that is, the thermoplastic plastic constituting the hollow body, and has a melting temperature M and a heat deformation temperature T of the sealing resin. Is preferably 100 ° C. or less. When the difference between the melting temperature M and the heat deformation temperature T is larger than 100 ° C., the heat shrinkage of the sealing resin due to the temperature difference between the molten sealing resin for closing the blow holes and the hollow body is large. There is a possibility that obstruction may be impaired due to too much. Thermoplastics satisfying this condition include ethylene-vinyl acetate copolymer, high-pressure low-density polyethylene, high-density polyethylene, polypropylene, and polyoxymethylene.
[0027]
The area S ₁ of the opening surface 6a of the sealing recess 6, to 3-fold of the opening area S ₂ of the blow hole 9 preferably within a range of 20 times. Effective the area S ₁ of the opening surface 6a of the sealing recess for only obstructive blow hole 9 becomes large consumption of sealing resin 10a melted greater than 20 times the opening area S ₂ of the blow hole 9 If it is less than three times, the plugging resin 10b after cooling and solidification may fall off.
[0028]
The shape of the hollow container body is not limited to the shape of the above embodiment, but may be any shape such as a shape without a screw portion at the mouth or a shape with a bulging portion connected continuously through a cut portion that becomes an opening. Absent.
[0029]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
[0030]
The bulging portion was provided with a concave portion having a concave portion recessed toward the room side and a stepped concave portion including a sealing concave portion further recessed toward the room stepwise from the concave portion, and the sealing concave portion was filled with molten sealing resin. After that, the blowing resin formed by cooling and solidifying the resin can completely close the blow hole formed in the sealing recess, and the resin is not carbonized.
[0031]
In addition, since the surface of the closing resin does not protrude outward from the open surface of the concave portion, the closing resin does not come into contact with other members or the like during transportation or the like and fall off.
[Brief description of the drawings]
FIG. 1 is an elevational view showing a hollow body before closing a blow hole in one embodiment of a sealed hollow body of the present invention.
FIG. 2 is a schematic sectional view of a main part of a mold 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 according to the present invention, and showing a partial cross-sectional view of a main part of the hollow body in which a recess with a step is placed upward on a work table or the like. .
FIG. 4 is an explanatory view partially showing a main part of a hollow body in a step of blowing hot air to the stepped recess and preheating the sealing recess and its periphery after the step shown in FIG. 3; is there.
FIG. 5 is an explanatory view showing a main part of a hollow body in a partial cross-sectional view showing a step of filling the sealing recess with molten sealing resin after the step shown in FIG. 4;
FIG. 6 is an explanatory view showing a main portion of the hollow body in a partial cross-sectional view showing a step of shaping the sealing resin filled in the sealing recess after the step shown in FIG. 5;
FIG. 7 is an elevational view showing an example of a conventional sealed hollow body in a partially sectional view.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 hollow body 2 trunk 3 mouth 3a screw 4 bulge 4a room 5 recess 6 sealing recess 6a open surface 7 stepped recess 8 cutting portion 9 blow hole 10a melted sealing resin 10b closing resin 11 hot air Nozzle 12 pressing member

Claims (3)

The hollow container body, which is blow-molded from a thermoplastic, includes a hollow container body, and a bulging portion connected to a portion to be an opening of the hollow container body, and the bulging portion has an indoor side. A stepped recess formed by a concave recess and a sealing recess further stepwisely recessed from the recess toward the indoor side, and a blow hole formed in the sealing recess is formed by the sealing recess. A sealed hollow body characterized by being filled with a sealing resin melted and cooled and solidified by a sealing resin. A hollow container main body, a bulging portion connected to a portion to be an opening of the hollow container main body, a concave portion depressed toward the indoor side of the bulged portion, and further stepwise depressed toward the indoor side from the concave portion. Using a divided mold having a cavity that regulates the outer surface of a hollow body having a stepped recess formed of a sealing recess, and disposing a molten parison made of thermoplastic plastic between the opened molds. After closing the mold, and then blow-molding the hollow body by expanding along the cavity by introducing a pressurized fluid by inserting blowing means from the portion serving as the sealing concave portion of the parison, The blowhole formed in the sealing recess by the introduction of the pressurized fluid is filled with a closing resin which is filled with a molten sealing resin in the sealing recess and cooled and solidified. You Method for manufacturing a sealed hollow body. 3. The method for producing a 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.

Images