JPS5818241A - Manufacture of narrow necked container - Google Patents

Abstract

PURPOSE:To obtain the titled seamless container safely and inexpensively, by positioning a core of a readily meltable alloy in a mold, filling an unvulcanized rubber in a space between them, heating the core to be melted after the vulcanization molding of the unvulcanized rubber, and removing the core. CONSTITUTION:For example, the spherical core 1 made of a readily meltable alloy (e.g. an alloy of 52.0wt% Bi, 31.7wt% Pb, 15.3% Sn and 1% Cd and having melting temperature of 83-92 deg.C) attached around one end of a bar 2 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 core 1, the bar 2, and the upper and lower molds 4, 5 and is vulcanized by heating and pressing by press heating plates 6, 7 to obtain the molded item. The the vulcanized and molded item is removed from the molds 4, 5 and the core 1 is melted by a sheathed heater 3 in the bar 1, and is removed from the opening of the obtained product.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing narrow-mouth containers, particularly seamless plugs.

The method for manufacturing a plug with a narrow mouth compared to the body is to first create a pair of molded products that are divided into two halves at the body of the plug, and then divide the body of the molded product into two halves. It is common to glue and manufacture a plug with a seam. This is because if the plug is to be manufactured seamlessly, there is no suitable means for removing the molding core from the narrow mouth of the plug. On the other hand, seamless plugs are also manufactured using a very special method. The method is to first create a core as a thick-walled (about 10 mm) hollow body using aluminum, manufacture a plug, and then dissolve the core in the bladder with caustic soda solution and remove it from the plug. be. However, this method basically has the following drawbacks.

l) It takes a very long time to melt the aluminum, so it takes too long to remove the core from the plug. For example, it takes more than 10 days to melt an aluminum core with a thickness of 10 m.

2) It is necessary to keep the caustic soda solution above a certain level at all times, and the operation for this is troublesome.

3) The melting aluminum core may form sharp protrusions that may damage the inner wall of the plug, so it is necessary to constantly monitor and remove these protrusions, which is time-consuming.

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 core made of a molded and easily melted metal is placed in a mold, and a gap between the core and the mold is provided. The narrow-mouthed container is manufactured by filling the gap with unvulcanized rubber and vulcanizing it, and then the core inside the container is melted by heating and taken out from the mouth of the container. The present invention will be explained based on the drawings.

FIG. 1 is a front sectional view of an embodiment of a hot press apparatus used in the plug manufacturing method according to the present invention. In the figure, l is a core formed into a spherical shape using an easily fusible metal centered at one end of the mandrel 2. Mandrel 20 Outside core part 2
1 is provided with a collar portion 211. A sheathed heater 3 is inserted into a hole 22 provided at the center of the mandrel 2, and is used to melt the core 1 after plug molding. 4
．． 5 are an upper mold and a lower mold, respectively, and the core outer portion 21 of the mandrel 2 is held by the recess 41.51 provided between both molds, and the core l is held at a predetermined position in the mold. do. 6 is the core l.

This is a plug product-shaped void formed by the mandrel 2, upper and lower molds 4.5. The void 6 is preformed into a shape similar to that of a plug product using an unvulcanized rubber compound.
Further, a preformed product divided into halves at the large diameter portion is loaded, and then pressurized and heat-vulcanized by press hot plates 7 and 8 to produce a plug product. When filling the void 6 with a rubber compound, it is not always necessary to preform a half-molded product as described above; for example, a sheet or block of unvulcanized rubber compound may be used in the filling. It may be loaded between the child and the mold. However, if preforming is not performed in this way, when the rubber compound is pressurized by press hot plates 7 and 8 and molded into a plug shape, the rubber compound is unevenly distributed within the gap 5 and the core 1 is not evenly pressurized. Otherwise, the appearance of the product may deteriorate or the thickness may become uneven. 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 pattern void 6 and post-vulcanized. At this time, Suga 41
．． It is desirable to set the mold so that the part 51 is at the top, and if room temperature vulcanized rubber is used, part 7.8 is unnecessary. The plug product thus vulcanized and molded is taken out of the molds 4 and 5, and then the core l is melted by the heater 3 provided in the mandrel 2 and taken out from the mouth of the plug. The operation is complete.

The core material used in the present invention is an easily melted alloy, and for example, alloys having the compositions shown in the table below can be used. The time it takes for the core to melt is approximately 0.5 to 3 hours, depending on the size of the bladder and the capacity of the material heater used.

Since rubber buddhas are generally vulcanized at 130 to 180° C. for 0.5 to 1 hour, it is preferable that the core material does not melt at this vulcanization temperature. Furthermore, if the melting temperature of the core material is too high, there is a risk that the rubber material will deteriorate when the core is melted after manufacturing the plugder. From this point of view, it is preferable that the easily fusible alloy used as the material for the core has a melting temperature of 130 to 200°C. However, when used as room temperature vulcanized rubber, low temperature vulcanized rubber, or plug material, the melting temperature of the easily fusible alloy may be low.

Further, it is more preferable to use a core formed by injecting the easily fusible metal into a thin metal hollow body or a heat-resistant rubber bag, since the easy-to-fusible metal can be operated without coming into contact with the inner wall of the plug. The thin metal hollow body is made of, for example, aluminum, copper, or an alloy thereof, and has a thickness of 0.2 to 2 fl.
Use something that can be easily crushed to a size that can be removed from the mouth of the plug. As the heat-resistant rubber bag, for example, those made of silicone rubber, fluororubber, fluorinated silicone rubber, phthyl rubber, or ethylene propylene rubber can be used.

As detailed above, since the method for manufacturing a narrow-mouth container according to the present invention uses an easily melted metal as the core material, it has the following effects compared to the conventional method of using aluminum and dissolving it in a caustic soda solution. play.

1) The time required to melt the core is extremely short, so the manufacturing time of the plug can be extremely shortened.

2) Since the melting temperature of the material for the core is relatively low, it is easy to manufacture the core.

3) When melting the core, no sharp protrusions are formed, so there is no force to damage the inner surface of the plug.

4) Dangerous gas such as hydrogen gas; it is safe and does not generate it.

5) There is no need to use dangerous alkaline or acid solutions to dissolve the core.

As described above, according to the present invention, a brush can be manufactured safely and inexpensively, and its economic value is high.

It goes without saying that the present invention is useful not only in the manufacture of plugs but also in the manufacture of containers whose mouths are narrower than their bodies.

[Brief explanation of the drawing]

This is a z diagram. In the figure, 1-.-core, 2-, thread/bar,
3- Sheathed heater, 4.5- Mold, 6-・Gap 7.
8-m-press hot plate.

Claims (1)

[Claims] A core molded from an easily fusible metal is placed in a mold, the gap between the core and the mold is filled with unvulcanized rubber, and the narrow-mouthed container is manufactured by vulcanization molding. A method for manufacturing a narrow-mouth container, characterized in that the core inside the container is melted by heating and taken out from the mouth of the container.