JPH0442599B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a porous combustible cylinder, and particularly to a method for manufacturing a porous combustible cylinder with improved fire resistance and moisture resistance without impairing thermal exhaustability. It is something. An example of the combustible cartridge of the present invention will be explained below. Generally, a gun bullet consists of a bullet and a cartridge that fires it. The cartridge consists of a case body, a case base, an igniter, and a propellant loaded within the case. In addition, for large gun shells, a fire tube or cartridge filled with ignition powder that is ignited by a detonator is inserted into the case. Conventionally, metals have been used for the case body, case bottom, fire tube, cartridge body, etc. of such cartridges. However, since the cartridge remains in the turret or gunfire unit after the bullet is fired, there are problems with the disposal of empty cartridges, problems with handling as a heavy object due to metal cartridges, and problems with economical manufacturing. Ta. Recently, it has been proposed to make the shell, fire tube, etc. of this cartridge from a material that can be burned out at the same time as the bullet is fired (Japanese Patent Laid-Open Publication No. 56-49900). However, when these cartridges were placed in humid environmental conditions, the flammable cartridges tended to absorb moisture, resulting in a large amount of combustion residue. Therefore, in order to improve this water resistance and moisture resistance, a method of impregnating the shell with synthetic rubber latex was previously proposed (Japanese Patent Application Laid-open No. 47793/1983). Further, as a result of subsequent research, it was found that after impregnating the shell with synthetic rubber latex, a polyurethane resin paint was applied to the outer surface of the shell to improve water resistance.
It was discovered that it has a moisture-resistant effect. However, if the amount of synthetic rubber latex impregnated and the amount of polyurethane resin paint applied are increased in order to improve water resistance and moisture resistance, there is a problem in that flammability decreases because the porosity of the casing is greatly affected. Ta. Another problem was that the treatment consisted of two steps. Therefore, the inventors of the present invention conducted extensive research to improve the water resistance and moisture resistance through the simplest possible treatment without reducing the flammability of the capsule. Then,
The inventors discovered that the object could be achieved and completed the present invention. That is, the present invention provides a method for producing a porous combustible cylinder by mixing and stirring combustible fibers, a binder, and an additive in water to form a slurry, and then using a dehydration molding method. The outer surface of the cylindrical body is covered with a flammable thermoplastic resin film made of polyethylene or polypropylene whose inner diameter is larger than the outer diameter of the cylindrical body and has a thickness of 15 to 50 μm, and then the heat distortion temperature conditions of the film are determined. It is characterized in that the film is heat-shrinked at the bottom and tightly covers the outer surface of the cylindrical body. Here, the combustible cylinder includes the above-mentioned casing, fire tube, medicine package, and the like. Combustible fibers used in the present invention include conventionally known nitrocellulose, plant fibers such as seed fibers, fruit fibers, stem fibers, wood fibers or derivatives thereof, and animal fibers such as wool. This is a combination of Further, the binder used in the present invention includes conventionally known binders such as vinyl acetate, polyvinyl alcohol, starch, and carboxymethyl cellulose. Furthermore, the additives used in the present invention include conventionally known stabilizers for nitrocellulose, such as diphenylamine and ethyl centralite. If the thickness of the film is less than 15 .mu.m, the water resistance and moisture resistance will be less effective, and if it exceeds 50 .mu.m, the flammability will decrease, which is not preferable. An example of a porous combustible cylinder manufactured by the manufacturing method of the present invention will be explained with reference to the drawings. FIG. 1 is a fragmented cross-sectional view showing an example of a cannonball using a porous combustible cylinder manufactured by the manufacturing method of the present invention, and FIG. FIG. 3 is a fragmentary cross-sectional view showing another example of a cannonball using the shell, and FIG. 3 is a partially enlarged view of FIG. 1. In FIGS. 1 and 2, a shell 1, 1' consists of a bullet 2, 2' and a cartridge case 3, 3'. The cartridge cases 3, 3' further include case bodies 4, 4' which are combustible cylinders, metal case bottoms 5, 5', and igniters 6, 6', and no propellant is provided. In FIG. 1, the surfaces of the casing 4, which is a flammable cylinder, and the fire tube 7 of the igniter 6 are covered with a flammable thermoplastic resin film 9, and in FIG. The capsule body 4' and the ignition device 6,
The medicine package 8 is coated with a combustible thermoplastic resin film 9'. FIG. 3 is an enlarged view of section A in FIG. Unlike the conventional method of moistening the shell or applying a paint on it, the porosity of the capsule is not inhibited, so it has excellent burnout properties. Next, the present invention will be specifically explained with reference to Examples. Note that all parts in each example are based on weight. Example 1 A mixture consisting of 50 parts of nitrocellulose (nitrogen content 13.3%), 50 parts of kraft pulp from wood fibers, and 900 parts of water was beaten with a beater for about 2 hours, and then mixed and stirred with a stirrer. 15 parts (external) of vinyl acetate was added to the slurry, and then 1.1 parts (external) of finely powdered ethyl centralite was added as a stabilizer and thoroughly stirred to obtain a slurry mixture. Next, a cylindrical body was molded from this slurry mixture by a suction dehydration molding method. This cylindrical body was dried at 60°C and left to cool to obtain a cylindrical body with an outer diameter of 140 mm, a flow rate of 500 mm, and a thickness of 6 mm. This cylinder has an outer diameter of 141 mm, a length of 510 mm, and a thickness of
A flammable cylindrical body was produced by covering the tube with a 20 μm polyethylene film and uniformly heating the top of the film with hot air at 50°C to bring the film into close contact. A combustible cylindrical body with an outer diameter of 44 mm, a length of 140 mm, and a thickness of 6 mm was also produced in the same manner. Using these flammable cylindrical bodies, the following moisture resistance test and radioactivity test were conducted. The results are shown in Table 1. [Moisture Resistance Test] The above-mentioned flammable cylinder having an outer diameter of about 140 mm was used, and the upper and lower ends of the cylinder were adhesively sealed with synthetic rubber plates to prepare a sample. Place this sample in a constant temperature bath, and keep the temperature inside the bath at 20℃.
The temperature was set to 40°C and the humidity was 95% for 4 hours, the temperature was kept under these conditions for 6 hours, and then the temperature was set to 21°C.
℃ and 100% humidity for 10 hours and held under these conditions for 4 hours is one cycle.After repeating this for 3 cycles, the sample was weighed and the moisture absorption was determined from the difference in weight from the weight before the test. The percentage was calculated. [Flammability test] The flammable cylinder with an outer diameter of 44 mm was placed in a sealed pump, ignited and burned with 5 g of black powder, and the combustion residue in the sealed pump was weighed and divided by the weight of the sample before the test. Example 2 of determining the percentage of residue: 20μ thick combustible thermoplastic resin film
Each combustible cylindrical body was manufactured according to Example 1, except that a polypropylene film with a thickness of 50 μm was used instead of the polyethylene film with a thickness of 50 μm. The same test as in Example 1 was conducted using the cylinder. The results are shown in Table 1. Comparative Example 1 A flammable cylindrical body was manufactured according to Example 1, except that 0.5 part (external portion) of a polyurethane resin paint was applied to the cylindrical body instead of using a flammable thermoplastic resin film. The same test as in Example 1 was conducted using this cylinder. The results are shown in Table 1. Comparative Example 2 Same as Example 1 except that instead of using a flammable thermoplastic resin film, the cylinder body was moistened with synthetic rubber latex at 7.6% by weight, and 1.5 parts (external portion) of polyurethane resin paint was applied. A flammable cylinder was manufactured. The same test as in Example 1 was conducted using this cylinder. The results are shown in Table 1. 【table】

[Brief explanation of drawings]

FIG. 1 is a fragmented cross-sectional view showing an example of a cannonball using a porous combustible cylinder manufactured by the manufacturing method of the present invention, and FIG. FIG. 3 is a fragmented sectional view showing another example of the shell used, and FIG. 3 is a partially enlarged view of FIG. 1. 1... Artillery shell, 3... Cartridge casing, 4, 4'... Case body which is a flammable cylinder, 7... Fire tube which is a combustible cylinder,
8...Medicine package which is a flammable cylinder, 9,9'...Flammable thermoplastic resin film.

Claims (1)

[Claims] 1. In a method of manufacturing a porous combustible cylinder by mixing and stirring combustible fibers, a binder, and additives in water to form a slurry, and using a dehydration molding method, after forming the cylinder, The outer surface is covered with a flammable thermoplastic resin film made of polyethylene or polypropylene whose inner diameter is larger than the outer diameter of the cylinder and has a thickness of 15 to 50 μm, and then the film is heated under the conditions of the heat deformation temperature of the film. A method for manufacturing a porous combustible cylinder, characterized in that the porous combustible cylinder is heat-shrinked and coated in close contact with the outer surface of the cylinder.