JPH022080B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of manufacturing a combustible cylinder for a burnt-out cartridge, and more particularly to a method of manufacturing a combustible cylinder for a burnt-out cartridge, and in particular to a manufacturing method in which the suction molded body is dehydrated by pressurizing it through a flexible membrane envelope after suction molding. Conventionally, the method for manufacturing combustible cylinders for burnout cartridges is as follows:
It is known that this manufacturing method consists of a suction molding step and a drying step using a slurry in which combustible fibers and the like are suspended or dispersed in water. This manufacturing method will be explained using the apparatus shown in FIG. 1. First, slurry is charged into a tank 1, a cylindrical body 2 is placed in the tank 1, and then the inside of the cylindrical body 2 is brought into a reduced pressure state using a suction pipe 3. By discharging moisture out of the system, a fibrous combustible cylinder 4 is formed on the outer surface of the cylinder body 2.
After that, the combustible cylinder 4 is removed from the cylindrical body 2, and the combustible cylinder 4 is dried in a drying chamber, and then processed to a predetermined size to obtain a combustible cylinder for burnout cartridges. It was a method. However, this manufacturing method has the disadvantage that the combustible cylinder undergoes significant deformation during drying due to the influence of moisture in the combustible cylinder after suction, and there is a limit to the mechanical strength of the combustible cylinder after drying. . In order to eliminate this drawback, a method of pressurizing the combustible cylinder using a mold is considered, but in this method, each time a combustible cylinder with a different shape is pressurized, a corresponding mold is prepared. There is an inconvenience to doing so. In order to improve the shortcomings of the conventional method and the inconvenience of the method using a mold, the present inventors have conducted extensive research and have found that by improving the conventional manufacturing method of combustible cylinders, there is less deformation and the machine We have discovered a method for manufacturing a combustible cylinder with high mechanical strength without using a mold, and have completed the present invention. That is, the present invention mainly relates to the process of manufacturing a combustible cylindrical body through a suction molding process and a drying process using a slurry in which combustible fibers are suspended or dispersed in water. A method for producing a combustible cylindrical body, which includes a pressurizing step that covers the combustible cylindrical body and pressurizes the combustible cylindrical body to dehydrate it with a fluid pressurized from the outside of the envelope. . The present invention will be explained in detail below. The flexible membrane envelope used in the present invention is a bag-shaped envelope whose main constituent material is rubber, synthetic resin, or the like. A combustible cylinder containing moisture formed in the suction molding process is covered with a flexible membrane envelope, and pressure is applied from the outside of the envelope.
For example, by applying pressure such as air pressure, the envelope is contracted and the combustible cylinder is compressed, then the pressure is returned to atmospheric pressure, the combustible cylinder is taken out and dried in a dryer, and then processed to the specified dimensions. This is a method to obtain a combustible cylindrical body. Next, the method of the present invention will be specifically explained with reference to explanatory diagrams. FIG. 2 is an explanatory diagram showing an example of the method of the present invention. In FIG. 2, a combustible cylinder 11 is shown on the outer surface.
The cylindrical body 12 in which the combustible cylindrical body 11 is formed is fixed to a pedestal 13 having a drainage hole 17, and then the open end of the flexible membrane envelope 14 formed to enclose the combustible cylindrical body 11 is attached to the inner wall surface. A container 15 that is sealed and provided with a conduit 16 through which a pressurized fluid can pass is fixed to a pedestal 13 so that the pressurized fluid does not leak. Thereafter, a pressurized fluid such as pressurized air is sent from the conduit 16 between the container 15 and the flexible membrane envelope 14 to deform the flexible membrane envelope 14 and compress the combustible cylinder 11. do. The water exuding from the combustible cylindrical body 11 is passed through the small hole of the cylindrical body 12 and drained from the water drain pipe 1 of the pedestal 13.
7 to be discharged from the system. Here, since the flexible membrane envelope 14 is designed to be deformable, it can sufficiently expand and contract to respond to changes in the shape of the combustible cylinder 11. Cylindrical body 11
Therefore, the combustible cylinder 11 has a uniformly compressed and dehydrated shape regardless of its shape. Next, the pressurized fluid is drained out of the system through the conduit 16 of the container 15 and returned to atmospheric pressure, and the container 15 and the pedestal 13 are
After releasing the fixation, the combustible cylinder 11 is taken out and dried in a dryer or the like, and then processed to a predetermined size to obtain the combustible cylinder of the present invention. The features and effects of the method for manufacturing a combustible cylinder according to the present invention as described above are as follows. (b) In the method of the present invention, the suction-molded combustible cylinder is further compressed and dehydrated, so compared to the conventional method that does not compress it, the amount of water contained is small, so it can be used in the subsequent drying process. A combustible cylinder with little deformation and little dimensional variation can be obtained. (b) Since the method of the present invention further compresses the suction-molded combustible cylinder, it is possible to increase the density of the combustible cylinder compared to conventional methods that do not compress it. Mechanical strength can be improved. (c) In the method of the present invention, the flexible membrane envelope is used to compress the combustible cylinder, so the flexible membrane envelope changes depending on the change in the shape of the combustible cylinder. It can be deformed and the combustible cylinder can be compressed uniformly. Therefore, there is no need to prepare a mold corresponding to the shape and dimensions of the combustible cylinder. Next, the manufacturing method and effects of the present invention will be specifically explained with reference to Examples and Comparative Examples. Example 1 A mixture of 50 parts of nitrocellulose, 50 parts of kraft pulp, and 900 parts of kraft pulp was sufficiently stirred to form a slurry mixture. A cylindrical body with an outer diameter of 145 mm and a length of 500 mm was covered with a furnace cloth, and the above slurry mixture was mixed. The cylinder was immersed in a bath and the pressure inside the cylinder was reduced using conventional suction techniques to form a combustible cylinder on the outer surface. Ten combustible cylinders were molded in the same manner, and five were dried at 60°C as usual. Each of the remaining five pieces was covered with a rubber jacket 5 mm thick, compressed for 5 minutes at an air pressure of 7 kg/ ^cm2 , and heated to 60°C.
It was dried. Both were then immersed in vinyl acetate emulsion for 20 minutes to impregnate the vinyl acetate resin, dried again, and machined. The combustible cylinders made by the conventional manufacturing method and the combustible cylinders manufactured by the manufacturing method including the pressurization process of the present invention were impregnated with moisture before drying, variations in the inner diameter after drying, and vinyl acetate and dried. Measuring the mechanical strength of a sample taken from a combustible cylindrical body revealed that
It was as shown in Table-1. Example 2 A cylindrical body was made using the method of Example 1 with an outer diameter of 80 mm and a length of 100 mm.
Five combustible containers were manufactured using the manufacturing method including the pressurization process of the present invention, and the moisture content, inner diameter variation, and mechanical strength were measured in the same manner as in Example 1. Table 1 It was as described in .

[Table] However, in Table 1, the moisture before drying is determined by subtracting the weight after drying from the weight before drying of the combustible cylindrical body manufactured by each method to calculate the moisture content per gram of combustible cylindrical body. The converted value is shown. The variation in the inner diameter after drying was expressed as a value of 3S (3 times the standard deviation) when the inner diameter was measured at three locations on each combustible cylinder produced by each method. The tensile strength is the average value of the maximum breaking strength when three test pieces were cut out from each combustible cylinder that had been immersed in vinyl acetate emulsion and then re-dried and subjected to a tensile test. As is clear from the results of the above examples, the combustible cylinder obtained by the manufacturing method of the present invention is
Compared to conventional manufacturing methods, it was shown that the variation in inner diameter was small, that is, deformation was small, and the tensile strength, that is, mechanical strength was high and excellent. Furthermore, it can be seen that even if combustible cylinders of different shapes are manufactured using the same flexible membrane envelope, combustible cylinders with approximately the same size variation and mechanical strength can be obtained. Therefore, it was shown that in the method of the present invention, when producing combustible cylinders of different shapes and dimensions, it is not necessary to prepare molds according to the respective dimensions.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional explanatory view of a suction dehydration molding apparatus for explaining an example of a suction dehydration molding method, and FIG. 2 is a cross-sectional explanatory view of a pressure dehydrating apparatus for explaining an example of the present invention. . 1... Tank, 2... Cylindrical body, 3... Pipe, 4...
... Combustible cylinder body, 11 ... Combustible cylinder body, 12 ... Cylindrical body, 13 ... cradle, 14 ... Flexible membrane envelope,
15... Container, 16... Conduit, 17... Water drain pipe.

Claims (1)

[Claims] 1. In the process of manufacturing a combustible container by suction molding using a slurry in which combustible fibers are mainly suspended or dispersed in water, after suction molding, the molded body is covered with a flexible membrane envelope. A method for manufacturing a combustible cylindrical body for a burnt-out cartridge, characterized in that a pressurized fluid is sent to the outside of the envelope to pressurize and dehydrate the molded body.