JPS59150089A - Method for preventing corrosion of container of small- sized fire extinguisher - Google Patents

Abstract

PURPOSE:To prevent the corrosion of the container of a small-sized fire extinguished by incorporating a specified polymer having high water absorbing power into the fire extinguisher manufactured by filling a fire extinguishing agent contg. ''Halon'' into an aerosol container made of a thin metallic plate. CONSTITUTION:A small-sized fire extinguisher is manufactured by filling <=500g fire extinguishing agent into an aerosol container made of a thin tin plate or a thin Al plate. ''Halon'' or a mixture thereof with freon, an inorg. fire extinguishing agent or a compressed gas such as CO2, N2 or nitrous oxide is used as the fire extinguishing agent. A small amount of one or more kinds of polymers having high water absorbing power is put in a bag made of nonwoven fabric or the like, and the bag is incorporated into the container of the small-sized fire extinguisher to prevent the corrosion of the container. The polymers include a starch-polyacrylic acid copolymer and a starch-polymethacrylic acid copolymer. Polyvinyl alcohol, methylcellulose or hydroxyethylcellulose may be substituted for the starch.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing corrosion of a container of a small fire extinguisher containing halon as a fire extinguishing agent.

Traditionally, fire extinguishers using halons [dipromotetrafluoroethane (lHalon 2402), 7'lomotrifluoromethane (lHalon 1301), and promochlorodifluoromecne (lHalon 1211)] have been subject to various standard conditions. It is stipulated by the Fire Service Act. Halon, which does not meet the standards stipulated by the Fire Service Law, was not approved as a fire extinguisher because it was filled in an aerosol can-type container.

However, public and private organizations have recently discovered that small fire extinguishers made of caniasol cans filled with halon are very effective in initially extinguishing fires in the event of a misfire in the home, car, camping, etc. It has been confirmed that it will soon be recognized as an initial extinguishing agent or device.

For several years, the inventor of the present application has confirmed that this type of fire extinguisher is effective for early extinguishing, and has conducted intensive research into its formulation. The biggest problem among them was that if a regular aerosol can filled with Halon was stored for a long period of time, the container would corrode.

The reason for this is 1. When a fire extinguisher is made by filling an aerosol can with halon, the halon decomposes in the presence of a small amount of moisture or air, producing corrosive substances that can be used to remove metals such as thin-walled tin containers or light metals such as aluminum. Containers corrode during storage,
It turned out to be of no use in any case.・Current aerosol containers have a wall thickness of 0.21~Q for tin cans and 0.21~Q for 3 mm 1 aluminum cans, with a wall thickness of 5 mm. The minimum thickness regulation has been abolished.

It is certain that the wall thickness will be reduced in the economically most advantageous direction within the range that provides the necessary withstand pressure, and it goes without saying that corrosion becomes even more of a problem when filled with halon.

The present invention was completed as a result of intensive research with the aim of improving the above-mentioned drawbacks.In other words, the present invention specifically aims at improving the above-mentioned drawbacks by using steel or light metal with a wall thickness of less than 8 mm. is a tin plate or aluminum aerosol filled with Halon 2402, Halon 1301, Halon 1211 and Halon 1301, etc., and the so-called extinguishing agent is halon, or not only the above extinguishing agent, but also Halon and Freon. Mixtures of halon and inorganic fire extinguishing agents, mixtures of nitrogen and inorganic or organic powders, mixtures of halon and compressed gases (carbon dioxide, nitrogen, laughing gas, etc.), and other compounds such as those mentioned above. In order to prevent corrosion of the container that occurs when the contents are a mixture of three or more ingredients and contain NO-RON, the above-mentioned container can be prevented by having a super absorbent polymer coexist in the container. They have discovered that corrosion can be prevented and have completed the present invention.

This super absorbent polymer has the ability to hold water tens to hundreds of times its own weight, and these include, for example, saponified starch-polyacrylonitrile graft copolymers, starch-polymethacrylic Saponified product of nitrile graft copolymer, starch-polyacrylic acid (and its salt) graft copolymer (and its crosslinked product), starch-polyacrylic acid ester graft copolymer hydrolyzate, starch-polyacrylic acid ester graft copolymer Examples include hydrolyzates of methacrylic acid ester graft copolymers. Instead of starch, starch derivatives such as hydroxyethyl starch and oxidized starch, cellulose derivatives such as cellulose, methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose, or polysaccharides having hydroxyl groups can also be used. Other highly absorbent polymers include polyvinyl alcohol-polyacrylic acid graft copolymers, crosslinked polyacrylic acids, self-crosslinked polyacrylic acids, and reaction products (and salts) of polyvinyl alcohol 5 and maleic anhydride. , polyvinyl alcohol sulfonate, and the like.

Most of the above-mentioned superabsorbent polymers that can be applied to the present invention also have the property of being freely processable into spherical, crushed, powder, film, or fibrous forms. Various methods can be considered for coexisting with a fire extinguisher. The object of the present invention is to provide a small aerosol can-type fire extinguisher filled with 500 g or less of fire extinguishing agent, etc., which requires halon to be one of the constituents of the contents. However, the purpose of a fire extinguisher is to extinguish fires, and it is not the intention of the present invention to undermine this purpose.

It must be added in a form that has an anticorrosive effect without reducing fire extinguishing ability.

For example, the powdered or granular material of the superabsorbent polymer used in the present invention may be placed in a non-woven bag, and may be encapsulated as a fine powder to the extent that it does not clog the pulp or radiation button. , pulp dip tube Vr
There is a method of C-molding and sealing it in a container.

The above-mentioned superabsorbent polymer that can be used in the present invention has chemical water absorption and water retention abilities, but these functions cannot be achieved by conventional inorganic desiccants that have physical water absorption and adsorption abilities, such as silica gel. , activated zeolite, etc.

In this way, chemical water absorption and water retention ability suppresses the increase in moisture inside the container, and in addition, it prevents the decomposition of halon, which is a constituent component of the contents, and suppresses the generation of corrosive substances, thereby preventing corrosion and pitting of the container. By doing so, we will have reliable fire extinguishing capabilities in the event of an emergency, and at the same time reduce the damage caused by approximately 60,000 fires and approximately 2,000 deaths per year in our country. This was our main objective, and we completed the development of this new method after confirming that this corrosion prevention method is extremely important both socially and economically.

Various natural increases in water are known in aerosols that do not contain water, and the same is true for small aerosol can-type fire extinguishers that contain halon. In most cases, this moisture reaches the inside of the container mainly through the pulp portion, and there are also cases where the content to be filled contains a large amount of moisture.

For example, a surfactant is used when inorganic fine powder is dispersed in halon as shown in Special Bulletin 1975-75667, but since the water content of the surfactant is very high, In sharp cutting dies, Halon becomes extremely unstable and corrosion becomes severe. It has also been found that very good results can be obtained by coexisting the superabsorbent polymer of the present invention in such a system.

The amount of super absorbent polymer used in the present invention added to the small aerosol can type fire extinguisher is 0.1% based on the content.
Effects can be recognized if the concentration is further north, but in terms of economy and long-term effects, a concentration of about 0.4% to 3% is most preferable.Next, some embodiments of the present invention will be shown.

Example 1 3g of powder of polyvinyl alcohol-polyacrylic acid gshift copolymer was put into a non-woven bag and mixed with Tamoto and Halon 2.
402 (392 g) and Halon 1301 (85 g) were placed in a tin aerosol can, and an aerosol can type small fire extinguisher pulp 2 and a radiation button were attached to obtain a small fire extinguisher containing 480 g.

Example 2 Starch-polyacrylic late graft mixture τl'f, 2 g of crushed grains of the compound were placed in a non-woven bag and placed in a pulp dip tube. f fixed, Halon 1301 50g,
Put 438g of Halon 1211 into an aluminum can - Lam air sheet, attach the burlap and radiation button using the usual method, and fill with 490 g.
i Example 3.1 Starch-polyacrylonitrile graft [Fine powder of polymer compound 4. =,,...n2402'
A small aerosol F5 pear fire extinguisher containing 400 g was obtained by placing 320 g and 76 g of Halon 1301' in a tin aerosol can using a conventional method.

Example 4.

Halon 1301 40g, Halon 1211 379g,
25 g of fine powder of sodium bicarbonate, 2.5 g of fine powder of pycnide of droxyethylcellulose-polymethacrylonitrile gram copolymer, and 3.5 g of polyoxyethylene alkyl phenyl ether were placed in an aluminum aerosol container and prepared in a conventional manner. A small aerosol can type fire extinguisher containing 450F was obtained.

Next, some of the experimental results that led to the present invention will be shown.

Table - ■ Effects of outdoor storage avoiding rainwater each IC, n
``' Tested in 5, Container: Tin can Pulp: Pesbag type, Filling amount: 400g Additive: Crushed granules directly sealed in the container.

*1: A gun compound of a de-embun-polyacrylonitrile graphite copolymer.

*2: Crosslinked product of descipne-polyacrylic acid graft copolymer.

*3: Hydrolyzate of starch-polyacrylic acid ester graft copolymer *4: Polyvinyl alcohol-polyacrylic acid graft copolymer.

*5: Methylcellulose-polyacrylonitrile graft copolymer.

*6: Hydroxyethylcellulose-polyacrylic acid graft polymer.

*7: Reactant table of polyvinyl alcohol and maleic anhydride - ■ Effective person if when storing water-added products at 45°C
Tested at n = 5, Container Nialuminum can Bulk: Bessback type, Filling amount: 450g Additive: Crushed granules or powder were placed in a non-woven bag and fixed by welding to the pulp dip tube *1 to *5: Same as *1 to *5 of ER-I experimental example.

As is clear from the above Tables I and I, the effects of superabsorbent polymers are very excellent, and aerosols made by filling tin cans or aluminum cans with a wall thickness of 0.8 mm or less with halon, etc. It can be said that it is an essential substance for the long-term stability of small can-shaped fire extinguishers.

Claims (1)

[Scope of Claims] A method for preventing corrosion of a small fire extinguisher container filled with 500 g or less of a fire extinguisher, characterized in that a highly water-absorbing polymer coexists in the container. 2. The superabsorbent polymer is a starch-polyacrylic acid copolymer or a starch-borimecacrylic acid polymer, or the starch is replaced with polyvinyl alcohol, methyl cellulose, or hydroxyethyl cellulose. The container corrosion prevention method for a small fire extinguisher according to claim 1, characterized in that one or more types selected from these are used.