JPS5818240A - Manufacture of narrow necked container - Google Patents

Abstract

PURPOSE:To obtain the titled seamless container, by positioning in molds a core that has been made in such a manner that a specified material is injected in a heat-resistant rubber bag, filling an unvulcanized rubber in a space between them, melting the material that forms the core after the vulcanization molding, and removing said material together with the rubber bag. CONSTITUTION:A material 2[e.g. a mixture of sodium nitrate (or nitrite) and potassium nitrite; a readily meltable alloy consisting of Bi, Pb, etc. and; a plastic that will result in stress cracks by solvents such as polycarbonate]having a melting point low enough not to deteriorate the bag material and solidifiable at room temperature is forced in the melted state into the heat-resistant rubber (e.g. silicone rubber, fluorine rubber, etc.) bar 1 via an inlet 31 in the center of a bar 3, and is cooled and solidified. Then it is positioned in the upper mold 4 and the lower mold 5, and an unvulcanized rubber compound is filled in the space 6 defined by the rubber bag 1, and the upper and lower molds 4, 5, and is vulcanized by heating and pressing by press heating plates 6, 7. Then the item is removed from the molds 4, 5, and the core material 2 is dissolved and removed together with the rubber bag to obtain the intended product.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing narrow-mouth containers, particularly seamless bladders. The method for manufacturing a bladder with a narrow mouth compared to the body is to first create a pair of molded products that are divided into upper and lower halves at the body of the bladder, and then cut the body of the molded product into two halves. Glue the
It is generally manufactured as a seamed bladder. This is because if the bladder is to be manufactured seamlessly, there is no suitable means for removing the molding core from the narrow mouth of the bladder. Seamless bladders, on the other hand, are also manufactured in a very special way. The method is to first create a core as a hollow body with a thick wall (approximately 101 IP) using aluminum, manufacture a bladder, and then dissolve the core inside the bladder with a caustic soda solution and remove it from the bladder. be.

However, this method basically has the following drawbacks.

1) It takes a very long time to melt the aluminum, so it takes too long to remove the core from the bladder. For example, it takes several days to melt an aluminum core with a thickness of ID mm.

2) It is necessary to always maintain the caustic soda solution above a certain value, and the operation for this is troublesome.

3) The melting aluminum core has a habit of forming sharp protrusions that damage the inner wall of the bladder.
It is necessary to monitor and remove this, but this is a lot of work.

4) Hydrogen gas is generated and must be removed.

The present invention proposes a method for manufacturing a narrow-mouth container devised in view of the above, in which a material that has a low melting point that does not alter the bag material and solidifies at room temperature is injected into a heat-resistant rubber bag. After that, a core is made, the core is placed in a mold, the gap between the core and the mold is filled with unvulcanized rubber, and a narrow-mouth container is manufactured by vulcanization molding. , the core material inside the rubber bag is melted and taken out from the mouth of the container together with the rubber bag. The present invention will be explained based on the drawings.

FIG. 1 is a front sectional view of one embodiment of a press apparatus used in the method of manufacturing a bladder according to the present invention. In the figure, 1 is a heat-resistant rubber bag, 2 is a core material that has a lower melting point than the bag material and solidifies at room temperature, and 3 is a mandrel.

For example, the core is made as follows. That is, the mandrel 3 is inserted from the mouth into a concave part of a mold having a concave part that matches the inner peripheral shape of the bladder, and the rubber bag 1 is arranged, and the molten state is poured from the injection port 31 provided at the center of the mandrel 3. Press-fit the core material.

Reference numeral 52 denotes an exhaust port provided in the mandrel 5, and when the core material flows out from the exhaust port 22, the press-fitting is stopped and sealed, and the core material is cooled and solidified as it is. In addition, only the rubber bag 1 is arranged in the recess of the mold, and the molten core material is first injected to the vicinity of the mouth of the rubber bag 1. After that, the mandrel 5 is inserted into the rubber bag and the core material is poured into the mold. You may overflow a little and cool and solidify in this state. It is preferable that the rubber bag 1 has substantially the same inner peripheral shape as the bladder, but it is also possible to use a smaller one and inflate it to form a core.

Reference numeral 53 denotes a collar provided at the left end of the mandrel 5, and by holding the collar between the recesses 41 and 51 provided between the upper and lower molds 4 and 5, the core is fixed in the mold. hold in position. 6
is a gap in the shape of a bladder product formed by the rubber bag 1, upper and lower molds 4.5. The void 6 is filled with a preformed product that has been preformed into a shape similar to a bladder product using an unvulcanized rubber compound, and is further divided into 90/50 parts at the large diameter portion, and is then filled with a press hot plate 7. Bladder products are manufactured by pressurizing and heating vulcanization according to step 8. When filling an empty PJ6 with a rubber compound, it is not always necessary to preform a half-molded product as described above; for example, it is not necessary to use a sheet or block of unvulcanized rubber compound as a core. It may also be loaded between the molds.

However, if preforming is not performed in this way, when the rubber compound is pressurized with the press hot plate 7.8 and molded into a bladder shape, the rubber compound will be unevenly distributed in the air space 16, and the core will not be evenly pressurized. It is common for the core material 2 to break due to failure. On the other hand, the method using the above-mentioned half-split preform is free from this concern and is preferable. Alternatively, liquid rubber may be injected into the void 6 and then vulcanized. The bladder product thus vulcanized and molded is removed from the mold 4.5, and then the core material 2 is melted and removed from the mouth of the bladder, thus completing the operation.

The material for the heat-resistant rubber bag used in the present invention may be any material as long as it can withstand the vulcanization temperature of the bladder, which is generally 130 to 180°C, or the melting temperature of the core material, whichever is higher, such as silicone rubber, Fluororubber, fluorinated silicone rubber, butyl rubber, and ethylene propylene rubber can be used. Various materials can be used as the core material, as long as they solidify at room temperature and have a melting point low enough not to alter the rubber bag material. For example, salts containing at least - potassium nitrate, sodium nitrite, and sodium nitrate (formulation examples are shown in Table 1), easily melted metals (formulation examples are shown in Table 2), and plastics that develop stress cracks due to solvents (formulation examples are shown in Table 2). shown in Table 5) can be used. The salt is dissolved by applying water or heat, the easily fusible metal is melted by heating, and the plastic is broken into small pieces with a solvent and each piece is taken out of the container.

Table 1 Table 2 (% by weight) (°C) Table 5 As mentioned above, in the present invention, the heat-resistant rubber bag has a melting point low enough not to change the quality of the bag material, and does not solidify at room temperature. The material is injected to create the core, and after the bladder is manufactured, the molten core material is taken out of the bladder along with the rubber bag, so the core material can be removed without adhering to the bladder product. As well as making work easier,
Materials that alter the quality of the bladder when it comes into contact with the bladder can also be used as core materials, and have high practical value.

It goes without saying that the present invention is useful not only for bladders but also for manufacturing containers whose mouths are narrower than their bodies.

[Brief explanation of the drawing]

1 is a front sectional view of one embodiment of a press device used in the method for manufacturing a narrow-mouth container according to the present invention. In the figure, 1
...Heat-resistant rubber bag, 2. Core material, 3. Mandrel, 4. Upper mold, 5. Lower mold, 6. Gap, 7.
．． 8...Press hot plate. Patent applicant Dainichi Nippon Electric Cable Co., Ltd. Representative Director Yukio Aoyama Figure

Claims (1)

[Claims] A core is made by injecting a material that has a low melting point that does not alter the bag material and solidifies at room temperature into a heat-resistant rubber bag, and the core is placed in a mold. After filling the gap between the molds with unvulcanized rubber and vulcanizing it to manufacture a narrow-mouthed container,
A method for manufacturing a narrow-mouth container, characterized in that the core material in the rubber bag is melted and taken out from the mouth of the container together with the rubber bag.