JPS5818239A - Manufacture of narrow necked container - Google Patents

Abstract

PURPOSE:To obtain the titled seamless container safely and inexpensively, by positioning a core of a nitrate and/or a nitrite in a mold, filling an unvulcanized rubber in a space between the core and the mold, dissolving or melting the core after the vulcanization molding, and removing the core. CONSTITUTION:For example, the spherical core 1 made of a mixed salt of nitrates and nitrites attached around one end of a bar 2 is positioned in the upper mold 3 and the lower mold 4, an unvulcanized rubber compound is preformed in the space 5 in the shape of a bladder and defined by the core 1, the bar 2, and the upper and lower molds 3, 4 into a shape similar to a bladder, and it is vulcanized by heating and pressing by press heating plates 6, 7. The vulcanized and molded item is removed from the molds 3, 4, and after the bar 2 is withdrawn from the core 1, water is introduced in the space left by the withdrawing of the bar 2 so that the core 1 is dissolved and removed to obtain the intended product. It is also possible that a sheet, block or the like of an unvulcanized rubber compound without being preformed is filled in the space 5.

Description

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

An example of a method for manufacturing a bladder with a narrow mouth compared to the body is to create a pair of molded products that are vertically divided into two parts at the body of the skinless bladder, and then remove the body of the molded product. It is common to manufacture a bladder with gaps by gluing the sections together. This is because even if an attempt is made to manufacture the bladder seamlessly, it is difficult to remove the molding core from the narrow mouth of the molded bladder.

- On the other hand, as an example of a method for manufacturing a seamless bladder, a hollow core is made of thick-walled (about 10 nm) aluminum, and after the bladder is manufactured, the core inside the bladder is dissolved in a caustic soda solution and removed from the bladder. Although a method for extracting it is well known, this method has the following disadvantages.

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 more than 10 days to melt an aluminum core with a thickness of 101 m+1.

2) It is necessary to always maintain the concentration of caustic soda above a certain value.

3) Melting aluminum has sharp protrusions that tend to damage the inner wall of the bladder, so it is necessary to constantly monitor and remove any protrusions.

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 nitrate and/or nitrite is placed in a mold, and the core and the metal are placed in a mold. After a narrow-mouthed container is manufactured by filling the void in a mold with unvulcanized rubber and vulcanizing it, the core inside the container is melted with water and/or heat and removed from the mouth of the container. Features. The invention will be explained below with reference to the drawings.

FIG. 1 is a front sectional view of an embodiment of a hot press apparatus used in the method of manufacturing a bladder according to the present invention. In the figure, 1 is a core formed into a spherical shape from a mixed salt 5 of nitrates and nitrites with one end of the mandrel 2 as the center. Mandrel 2
A collar portion 211 is provided on the outer portion 21 of the core 1, and a portion 22 covered with the core 1 is used to attach the mandrel 2 to the core 1 after bladder molding.
In order to make it easier to pull out, the tip becomes thinner as it goes 12 times. 3.4 are an upper mold and a lower mold, respectively, and the mandrel 2 is
The outer portion 21 of the core 1 is clamped to hold the core 1 in a fixed position within the mold. 5 is core 1, mandrel 2,
This is a void in the shape of a bladder product formed by upper and lower molds 3.4, and the void 5 is preformed into a shape similar to the bladder product using an unvulcanized rubber compound, and is further filled with a portion at the large diameter part. The resulting half-split preform is filled, and then heated and pressure vulcanized by press hot plates 6 and 7 to form a bladder product. When filling the void 5 with a rubber compound, it is neither necessary nor necessary to preform a half-molded product as described above; for example, a sheet or block of unvulcanized rubber compound can be used to It may be loaded between the core and the mold. However, when preforming is not performed in this way, when the rubber compound is pressurized from the north of the press hot plate 6.7 and molded into a tephrata shape, the rubber compound is unevenly distributed within the gap 5, and the core 1 is not evenly applied. There is a risk that the core 1 will be broken depending on the material strength of the core 1 without being pressed. On the other hand, the method using the half-split preform mentioned above is preferable because it does not have this problem. Alternatively, liquid rubber may be injected into the void 5 and post-vulcanized. In this case, it is desirable to set the mold so that the 31°41 part is at the top, and if room temperature vulcanized rubber is used, 6.7 is unnecessary.

The product thus vulcanized and molded is taken out of the mold 3.4, and then the mandrel 2 is pulled out from the core 1, and water is injected into the hole after the mandrel 2 has been pulled out. The operation is completed by removing the core l dissolved in water from the mouth of the bladder.

The core material used in the present invention is a nitrate and/or a nitrite, and for example, a salt prepared by mixing potassium nitrate, sodium nitrite, and sodium nitrate in an appropriate ratio can be used.

Of course, any two salts may be used, or even one salt can be used.

The following table shows some examples.

(Overlay %) (℃”) Generally, rubber "Terada" is heated at 130-180℃.

The material for the core is preferably not melted at this vulcanization temperature.

Furthermore, if the melting temperature of the core material is too high, handling during core formation is troublesome. If selected from this point of view, 43.4.5 in the table. It is preferable to mix the following.

If you use salt with a lower melting temperature than the example above as a core, the core material will begin to melt due to the vulcanization temperature, making it difficult to handle, but it should be sealed to prevent the molten salt from flowing out of the bladder mouth. It can be used if Furthermore, when room temperature vulcanized rubber or low temperature vulcanized rubber is used as the bladder material, a salt with a low melting temperature can be used.

The salt used for the core material is very easy to handle because it easily dissolves in water in a short time, but if you plan to reuse the salt as the core material, you can also use heated melting that does not mix in any excess salt.

Of course, even if the salt is melted with water, it can be reused if the water is separated and treated. It may be heated or melted while adding water. In addition, if a core is formed by solidifying the mixed salt in a thin metal hollow body containing the inner wall shape of the bladder, or by injecting the mixed salt into a heat-resistant rubber bag, the molten salt can be solidified. This is more preferable because it can be operated without contacting the inner wall of the bladder.

The thin metal hollow body is made of, for example, aluminum, copper, or an alloy thereof, and has a thickness of, for example, 02 to 21111, such that it can be crushed and removed from the mouth of the bladder.

As the heat-resistant rubber, for example, silicone rubber, fluororubber, fluorinated silicone rubber, butyl rubber, and ethylene propylene rubber can be used.

As detailed above, the bladder manufacturing method according to the present invention includes:
Since nitrate and/or nitrite are used as the core material, the following effects are achieved compared to the conventional method of dissolving aluminum with caustic soda.

l) The time required to melt the core is extremely short, so the production time of the bladder can be extremely shortened.

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

3) Since no sharp protrusions are formed when the core is melted, the inner surface of the bladder will not be damaged.

4) It is safe and does not generate dangerous gases such as hydrogen gas.

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 bladder can be manufactured safely and inexpensively, and its economic value is extremely high. It goes without saying that the present invention is useful in manufacturing not only bladders but also containers having a narrow opening relative to the body.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of an embodiment of a hot press apparatus used in the method for manufacturing a narrow-mouth container according to the present invention. In the figure, 1...core, 2...mandrel, 3.4...
・Mold, 5...Gap, 6,7...Press hot plate patent applicant Dainichi Nippon Electric Cable Co., Ltd. Representative Director Yukio Aoyama jXl Figure

Claims (1)

[Claims] 1) A core made of nitrate and/or nitrite is placed in a mold, the gap between the core and the mold is filled with unvulcanized rubber, and vulcanization molding is performed. 1. A method for manufacturing a narrow convex container, characterized in that, after manufacturing the narrow-mouth container, the core inside the container is sealed with water and/or heat and taken out from the mouth of the container. 2) The method for manufacturing a narrow-mouth container according to claim 1, wherein the core material is comprised of at least potassium nitrate, sodium nitrite, and sodium nitrate.