JPS6059519B2 - Method for manufacturing thin-walled flammable containers and equipment used therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a thin-walled combustible container and an apparatus used therein, and more particularly to a method for manufacturing a thin-walled flammable container by integrating the containers without deformation and an apparatus used therefor.

Conventionally, combustible cartridges have been used as one type of flammable container, and this production method consists of a casting process, a suction dehydration molding process, and a drying process using a slurry in which combustible fibers are suspended and dispersed in water. It is known that there is.

This manufacturing method will be explained using the apparatus shown in FIG. 1. First, the slurry is charged into a tank 1, the cylindrical body 2 is placed in the tank 1, and then the inside of the cylindrical body 2 is reduced in pressure using a suction dewatering pipe 3. By discharging moisture out of the system, a fibrous solid layer 4 is formed on the outer surface of the cylindrical body 2, and then this solid layer 4 is removed from the cylindrical body 2.
The method was to dry the cartridges in a drying chamber and then process them into predetermined dimensions to obtain combustible cartridges.

However, this manufacturing method is suitable for thick-walled and relatively simple-shaped combustible containers, and the combustible fibers used for this purpose require relatively long fibers mixed in from the viewpoint of mechanical strength. It was used.

In addition, in order to mold thick-walled combustible containers in a relatively short period of time, slurry with a high concentration of about 1 slag weight has been used. Furthermore, the drying process takes time because the flammable containers are thick, so in order to improve drying efficiency, multiple molded containers were placed in a drying chamber and dried at the same time. On the other hand, a method for manufacturing a thin-walled combustible container having a relatively complicated shape as shown in FIG. 2 is also known.

The manufacturing method for this horseshoe-shaped drug package is to first form half of the container using a suction dehydration molding method, then dry-mold the formed half-container using a heating and pressurizing press method, and then combine the two dry-formed half-containers. The method involved facing them and joining them with adhesive to integrate them.

Although this method can produce relatively thin-walled combustible containers without deformation, it is difficult to manufacture them in one piece without a bonding process, and it is economically disadvantageous because it requires a bonding process using an adhesive. Not only that, but the porous parts of the joints had to be filled with adhesive, which could create combustion residue when fired.

As a result of intensive research to improve the shortcomings of conventional methods, the inventors of the present invention have developed a thin-walled easily combustible container that does not deform even in complex shapes and does not produce combustion residue by improving the conventional manufacturing method of combustible cartridges. The present invention has been completed by discovering a method of manufacturing the product by integrating it into a chair using an adhesive.

That is, the first aspect of the present invention is an invention of a manufacturing method, which
In method 4 for producing a flammable container by a casting process, a suction dehydration molding process, and a drying process using a slurry in which combustible fibers are mainly suspended and dispersed in water, the combustible fibers are short fibers, The method for producing a thin-walled combustible container is characterized in that the slurry concentration is low, and the drying step is a step of sending hot air directly to a mold after suction dehydration molding.

The second aspect of the present invention is an invention of an apparatus used in the manufacturing method, which includes: a mold having a slurry injection inlet and a hot air inlet and having many pores communicating from the inside to the outside; This is a manufacturing device for a thin-walled combustible container, which comprises a decompression chamber arranged around the outside of a mold and having a suction/dehydration port and a hot air exhaust port, and a mesh body arranged around the inside of the mold. . The present invention will be explained in detail below. The slurry used in the present invention is prepared by suspending or dissolving combustible fibers, a binder, additives, etc. in water.

Examples of combustible fibers include nitrocellulose,
Vegetable fibers such as seed fibers, fruit fibers, stem fibers, and wood fibers, or their derivatives, and animal/physical fibers such as wool, etc., and when used, one type or a mixture of two or more selected from these is used. It will be done.

In addition, in order to make the wall thickness of the combustible container thin and uniform, the combustible fibers must be short fibers, for example, 10 to 5
It is preferable that it is about 00IL. fiber length is 1
If it is less than 0p, it may flow out into the suction/dehydration port/hot air exhaust port, which is undesirable.If it exceeds 500μ, the slurry will quickly sink when poured into a mold, resulting in uneven wall thickness, so it is not preferable. do not have. The binder is used to bond the contact points between the fibers that are entangled and formed into layers by suction dehydration molding, and includes, for example, starch, carboxymethyl cellulose, vinyl acetate, and polyvinyl alcohol. be.

The additives include stabilizers for nitrocellulose, such as diphenylamine and ethyl central.

Further, a waterproofing agent such as a wax emulsion or a silicone emulsion can be used as an additive if necessary.
A slurry in which the above substances are suspended or dissolved in water has a concentration (solid content/aqueous solution) of 0.25 to 1% by weight.
It is preferable that The reason for this is to manufacture a flammable container with a uniform thickness by suspending the solid matter in the aqueous solution as uniformly as possible for a long period of time. Next, the drying process in the present invention is a process different from the drying process in conventional methods, and does not require a special drying room or a press.

Hot air of 60°C or less is blown into the mold after suction dehydration molding, and the molded product is force-dried while being pressed against the wall of the mold by the pressure of the hot air. Items can be dried without deformation or shrinkage. Furthermore, it is preferable to reduce the pressure on the outside of the mold at the same time, because this allows the molded product to be completely pressed against the wall surface and the drying time can be significantly shortened. This is because warm air is forced to pass between the fiber matrices, and the drying time is usually within one minute. According to the method of the present invention, in addition to thin-walled, easily flammable containers having relatively simple shapes such as bottle shapes, prismatic shapes, and spherical shapes, containers having concave, convex, or uneven parts, such as a horseshoe shape, a donut shape, etc. It is possible to manufacture thin-walled combustible containers with relatively complex shapes.

The method of the present invention and the apparatus used therein will be specifically explained below using a horseshoe-shaped medicine package shown in FIG. 2 as an example of a thin-walled flammable container.

FIG. 2 is a perspective view of a horseshoe-shaped medicine casing, including a partially fragmented cross section.

The horseshoe-shaped cartridge 5 is composed of a thin-walled easily flammable container 6 and a propellant 8 loaded through a charging hole 7.

Figures 3 and 4 are cross-sectional explanatory views showing an example of an apparatus for manufacturing this thin-walled easily combustible container, with Figure 3 showing the suction dehydration molding process and Figure 4 showing the drying process, respectively. .

FIG. 5 is an explanatory view showing how the thin-walled combustible container is removed after the drying process.

First, the apparatus of the present invention will be explained with reference to FIG.

The device of the present invention includes a mold 9 and an outer frame 16 around the outside thereof.
It is composed of a decompression chamber 12 arranged by a vacuum chamber 12 and a mesh body 14 arranged inside the mold 9.

In the case of this example, the mold 9 has a two-part structure, and has a structure in which a recess forming body 15 is combined. In this mold 9, pores 11 communicating from the inside to the outside are arranged throughout the wall surface of the mold 9. The diameter and number of pores 11 are appropriately selected depending on the shape of the molded product, the length of the combustible fibers used, etc., but the pore diameter and number of pores should be increased in locations where it is difficult for solid components to be stacked. It is preferable. A typical pore size is about 0.5 to 1.3 Tfn in diameter. Further, the mold 9 is provided with a slurry inlet and hot air inlet 10 at the upper side. On the other hand, the decompression chamber 12 is provided with a suction/dehydration port/hot air exhaust port 11 at the bottom thereof, and a vacuum pump (not shown) is provided beyond that via a vacuum valve 19 . The mesh member 14 is used to prevent extremely short combustible fibers from flowing out into the decompression chamber 12 through the pores 11, and to facilitate the release of the thin-walled combustible container from the mold 9 after the drying process is completed. For example, wire mesh, door cloth, bamboo paper, etc. are used singly or in combination.

In the case of wire mesh, a wire mesh of about 200 to 300 mesh is used. In the figure, 17 indicates a slurry funnel, and 18 indicates a fixture for fixing the mold 9 having a two-part structure and the outer frame 16, respectively.

Note that the arrow indicates the direction in which the filtered water moves. Next, the manufacturing method of the present invention will be explained using this apparatus.

First, the combustible fiber is beaten using a beating machine, and its length is adjusted to 10 to 500p. Next, the combustible fibers are added to a predetermined amount of water, a binder and additives are added, and the mixture is sufficiently stirred to obtain a slurry. However, the slurry concentration (solid content/aqueous solution) is 0.25 to 1% by weight depending on the thickness and shape of the flammable container, the degree of pressure reduction during the suction dehydration molding process, etc.
so that it is within the range of Next, this slurry is
Fill the slurry funnel 17 up to a certain scale as shown in the figure.

At the same time, the vacuum valve 19 is opened and the vacuum pump is activated.
The degree of pressure reduction at this time is appropriately selected depending on the slurry concentration, suction dehydration molding speed, etc., but is usually around 70 iHg. is the mesh body 14, the pores 11
through the decompression chamber 12 to the suction dehydration port and hot air exhaust port 1.
Water is drained from 3.

The floating fibers in the slurry are filtered through the mesh body 14 and the pores 11, and are uniformly adhered to the inside of the mold 9 and stacked to form a molded article. Adjustment of the wall thickness of this molded product is mainly performed by adjusting the amount of slurry to be cast.

l Next, the drying process will be explained with reference to FIG.

The molded product after the suction dehydration molding contains 90% or more of water. Then, a drying step is carried out to dry the material to an equilibrium moisture content of 3 to 5%. The drying step is carried out by blowing hot air of 600 C or less from the slurry injection port/warm air blowing port 10 immediately after the suction dehydration molding.

If the vacuum pump is operated at the same time, the molded product 20 is pressed against the mold 9, so that the molded product 20 can be dried in a short time without deformation. The drying time depends on the thickness of the molded product 20, but if the thickness is about 1 to 2 Wf1, it is usually 10
Within minutes. In the figure, arrows indicate the direction in which the warm air travels.

After the drying process is completed, remove the fixture (1) as shown in Figure 5.
By removing "and 1", the two-piece outer frame (16'' and 16'') is divided, and by removing the recess forming body 15, the thin-walled combustible container 6 can be easily released from the mold.

In addition, when waterproofing of thin-walled flammable containers is required,
This can be achieved by adding a waterproofing agent into the slurry in advance, or by applying or spraying a waterproofing agent onto the outer surface of the thin-walled combustible container after it has been released from the mold.

As described above in detail, the manufacturing method of the present invention can manufacture a thin-walled combustible container with a complex shape without deformation, compared to the conventional method of manufacturing a combustible cartridge.

In addition, since it is extremely easy to manufacture, it does not require trained workers, and the drying process is extremely short.
Moreover, since the same mold is used for the suction dewatering process, there is a great effect in terms of labor saving and rationalization. On the other hand, compared to the conventional heating and pressurizing press method, the present invention can produce a seamless, integrated, thin-walled, easily flammable container, and since no adhesive or the like is used, it is possible to No combustion residue is produced.

The thin-walled easily flammable container manufactured according to the present invention having the above-mentioned characteristics can be used in addition to the above-mentioned containers for medicine packages, for example, shells for fireworks, extinguishing rocket cases for artificial rain, igniter cases, etc. I can do things.

Next, the present invention will be specifically explained with reference to Examples.

Note that parts and percentages in the examples are based on weight.

Example Using the apparatus shown in FIG. 3, the thin-walled combustible container shown in FIG. 2 was manufactured in the following manner.

First, the slurry was adjusted in the following manner.

8 parts nitrocellulose, 2 parts kraft valve and 10 parts water
The mixture consisting of acetic acid was beaten for 3 hours using a beater to adjust the fiber length to about 50 to 200p, and 19 (1) parts of water was added while stirring with a stirrer, and then 1.0 parts of vinyl acetate was added.
5 parts and 0.2 parts of ethyl central were added and stirred for 1 minute to obtain a slurry.

Next, the slurry was poured into a mold covered with a 200-mesh wire mesh, and at the same time the outer vacuum chamber was heated to 700 mH.
The pressure was reduced and suction dehydration molding was continued for 1 minute. Then,
Slurry inlet and hot air supply loner blows hot air at 60℃.
At the same time, the pressure in the outer vacuum chamber was reduced to 700 TIr 1 ftHg and drying was carried out for 7 minutes.

After drying, the outer frame and mold were divided, and the concave portion forming body was removed to obtain a thin-walled combustible container.

The weight of the obtained thin-walled flammable container was 5.62y, the wall thickness was 1 m, and no deformation was observed.

In addition, an analysis of the components of the thin-walled flammable container revealed that nitrocellulose was 3.84y (68.4%) and Kraft valve was 0.
．． 96y (17.1%), vinyl acetate 0.096y (1
．． 7%).

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional explanatory view for explaining the conventional manufacturing method of combustion cartridges, Fig. 2 is a perspective view of a horseshoe-shaped cartridge including a partially fractured cross section, and Figs. 3 and 4 are FIG. 5 is an explanatory cross-sectional view showing an example of the manufacturing apparatus of the present invention, and FIG. 5 is an explanatory view showing an example of how the thin-walled easily flammable container is taken out after the drying process in the present invention. 9...Molding mold, 10...Slurry inlet/hot air inlet, 11...Pore, 12...
...Decompression chamber, 13...Suction dehydration port and hot air exhaust port,
14...Mesh body, 15...Recess forming body, 16, 16'', 16■...Outer frame.

Claims (1)

[Scope of Claims] 1. A method for producing a flammable container through a casting process, a suction dehydration molding process, and a drying process using a slurry in which combustible fibers are mainly suspended and dispersed in water, is a short fiber, the concentration of the slurry is low, and the drying step is a step of sending hot air directly to a mold after suction dehydration molding. 2. The method for manufacturing a thin-walled combustible container according to claim 1, wherein the combustible fibers have a length of 10 to 500μ and the slurry has a concentration of 0.25 to 1% by weight. 3. The thin wall according to claim 1 or 2, wherein the step of sending warm air is a step of sending warm air to the inside of the mold while reducing pressure around the outside of the mold, and forcibly pressurizing and suctioning the hot air. Method for manufacturing flammable containers. 4 A mold having a slurry inlet and hot air inlet and many pores communicating from the inside to the outside, and a suction dewatering and hot air exhaust port located around the outside of the mold. 1. An apparatus for producing a thin-walled easily flammable container, comprising a reduced pressure chamber having a vacuum chamber and a mesh body disposed around the inside of the mold. 5. The apparatus for producing a thin-walled combustible container according to claim 4, wherein the mold is a mold having a concave portion, a convex portion, or an uneven portion. 6. The apparatus for producing a thin-walled combustible container according to claim 5, which is a mold in which the concave portion, convex portion, or uneven portion and other portions of the mold are not integrally molded but are constructed by combining them. 7. The apparatus for producing a thin-walled flammable container according to claim 5 or 6, wherein the mold having the recessed portion has a horseshoe shape.