JPH0333031B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a fire extinguishing foam, and more particularly to a fire extinguishing foam containing a reaction product of a protein hydrolysis product and a ferrous salt. [Prior technology] Currently, the foam extinguishing agent used in petroleum fires is made by partially hydrolyzing keratin protein powder from cow and horse hoofs and horns with strong alkalis such as sodium hydroxide and calcium hydroxide. However, a ferrous salt such as ferrous sulfate or ferrous chloride is added to this hydrolysis product as a foam stabilizer. Such foam fire extinguishers have excellent heat resistance and foam film stability, and have the advantage of being highly oil resistant at high oil temperatures, but since they contain iron salts, they do not absorb water during storage. Insoluble decomposed proteins - iron compounds, ferric hydroxide, and decomposed proteins that co-precipitate by adsorbing on ferric hydroxide precipitate, and this precipitate reduces the fire extinguishing ability, making it difficult to use as a fire extinguishing foam. The drawback is that it is only valid for about 3 to 4 years. On the other hand, the partial hydrolyzate of keratin protein and the
It is also known to produce a fire extinguishing foam with improved durability and fire extinguishing performance by reacting it with an iron salt at 90-100°C (Japanese Patent Publication No. 11879/1983). However, the fire extinguishing agent produced in this way also produces precipitates during storage, resulting in a decrease in fire extinguishing ability, and cannot be said to be a satisfactory foam fire extinguishing agent. [Problems to be Solved by the Invention] Therefore, in order to obtain a fire extinguishing foam that has high heat resistance, foam film stability, and particularly maintains fire extinguishing performance over a long period of time, various additives have been added to the keratin protein partial hydrolysis product. Long-term shelf life has been improved through processing and addition of second components, but even by reacting the protein hydrolysis product with ferrous salts, long-term shelf life, It was insufficient as a high-performance fire extinguishing foam. Further, no attempt has been made to further examine the reaction product itself between the proteolytic product and the ferrous salt. However, the present inventor has repeatedly researched this reaction product and found that under certain reaction conditions, the protein hydrolysis product and the first
It was found that iron ions combine to form a water-soluble chelate compound. They also discovered that this chelate compound contains a long-life, high-performance fire extinguishing agent component. [Means/Actions for Solving the Problems] The present inventor uses a partial hydrolysis product of keratin protein and a ferrous salt to induce precipitation of ferric hydroxide and isoelectric precipitation of protein degradation products. By reacting under conditions that do not cause proteolysis, the proteolytic products and the first
A special chelate compound with iron ions was obtained. Although this chelate compound is considered to be a novel compound that has not been previously known, we have completed the present invention by discovering that some of these chelate compounds are extremely excellent as active ingredients for fire extinguishers. It was also found that the molecular weight cut-off of this chelate compound has a large effect on the fire extinguishing effect. That is, according to the present invention, keratin protein is hydrolyzed with an alkali, a ferrous salt is added to the obtained protein hydrolysis product, and ferric hydroxide precipitation and isoelectric precipitation of the protein hydrolysis product are performed. A chelate compound of a proteolytic product and ferrous ion was obtained by reacting the product under conditions that do not cause ferrous ions. From this chelate compound, a molecular weight cutoff of 30 was obtained by ultrafiltration.
A new chelate compound having a long life of less than 10,000 yen, high performance and excellent fire extinguishing action can be obtained. It goes without saying that, for example, chelate compounds with a molecular weight cut-off of 100,000 or less or 50,000 or less also have long life, high performance, and excellent fire extinguishing power. Ferrous salts, which are normally added as stabilizers to fire extinguishing foams, are oxidized in the fire extinguishing agent to produce a precipitate of ferric hydroxide and adsorbed protein hydrolysis products; Isoelectric precipitation is also likely to occur,
These precipitates cause deterioration of the life of the extinguishing agent. According to the present invention, reaction conditions in which these precipitations do not occur are obtained by maintaining the pH between 7.0 and 7.5. As the raw material for the protein hydrolysis product used in the present invention, any keratin protein source of animal or plant origin may be used, such as powder of cow and horse hooves, horns, blood, etc., microbial protein, seed powder, etc. be able to. Protein hydrolysis is carried out under conventional conditions, such as by heating in water at a temperature of about 100 DEG C. for about 1 hour or more using sodium hydroxide or calcium hydroxide at a concentration of 5 to 10% by weight. After the hydrolysis is completed, the mixture is neutralized with an inorganic acid such as hydrochloric acid or sulfuric acid, or an organic acid such as acetic acid, and then fine precipitates and the like present are removed using paper. The protein hydrolysis product obtained in this way has a pH of
Ferrous salt was added under conditions of 7.0 to 7.5, and the added ferrous salt was
All of the iron ions are reacted with the protein hydrolysis product to form a chelate compound of the protein hydrolysis product and ferrous ions. The chelate compound thus obtained is concentrated by ultrafiltration using a membrane with a molecular weight cutoff of 300,000, and those with a molecular weight cutoff of 300,000 or less are completely recovered in the liquid. The liquid can be further concentrated by reverse osmosis, heating or freeze drying, but the molecular weight of approximately
It is preferable to use reverse osmosis, which can exclude less than 1000 components, such as lower peptides and amino acids. The residue with a molecular weight cut-off of 300,000 or more remaining on the membrane can be hydrolyzed again to reduce the molecular weight. Examples of the ferrous salt to be reacted with the protein hydrolysis product having a molecular weight cut-off of 300,000 or less obtained as described above include ferrous sulfate and ferrous chloride. The reaction of protein hydrolysis products with ferrous salts according to the invention is carried out under conditions such that precipitation of ferric hydroxide and isoelectric precipitation of protein hydrolysis products do not occur. In order to prevent oxidation of ferrous ions, stirring is performed at a temperature below 20° C. for about 3 hours. Since the PH decreases due to the reaction between the protein hydrolysis product and ferrous ions, a sodium hydroxide solution is added to bring the PH to 7.0 to 7.5, and the mixture is further stirred. When the reaction between the protein hydrolysis product and the ferrous ions is almost completed, the mixture is further stirred at 50 to 60°C for 30 minutes or more. If the pH drops below 7.0 at this point, add sodium hydroxide solution again until the pH reaches 7.0 to 7.5, and further heat and stir. By continuing such operations and finally confirming that the pH becomes constant, a chelate compound of protein hydrolysis product and ferrous ion can be obtained. FIG. 1 is a visible spectrum diagram of a protein hydrolysis product-iron () chelate compound having a molecular weight cut-off of 300,000 or less according to the present invention. In the figure, the solid line is the wavelength-absorbance curve of a protein hydrolysis product with a molecular weight cut-off of 300,000 or less [no iron () ions, nitrogen concentration 0.125 g/dl (0.09 mol)], and the chain line is the molecular weight cut-off Protein hydrolysis products below 300,000 - iron ()
Chelate compound [iron () ion concentration 0.0125g/
dl (0.0022 mol)], nitrogen concentration 0.125 g/dl]. In addition, the visible spectrum of a chelate compound with a molecular weight cut off of 300,000 or less has a higher absorption over the entire visible region compared to the visible spectrum of a protein hydrolysis product with a molecular weight cut off 300,000 or less and the visible spectrum of ferrous sulfate ion alone. An increase is observed. This increase in absorption is apparently due to the novel chelate compound formed by the reaction of protein hydrolysis products with a molecular weight cutoff of less than 300,000 with ferrous sulfate ions. Further, in the aqueous solution of ferrous sulfate ions, absorption in the visible region is not observed. The increase in absorption in the visible region is caused by the fact that an aqueous solution of protein hydrolysis products with a molecular weight cut-off of 300,000 or less before reaction is a dark brown transparent liquid, but when it reacts with ferrous salts to form chelate compounds. This corresponds well to the reaction solution turning reddish brown. This solution containing a chelate compound with a molecular weight cut-off of 300,000 or less can be used as it is, or after precipitation if precipitation occurs, add additives commonly used in fire extinguishing foams, such as antifreeze agents, such as ethylene glycol.
Glycols such as propylene glycol, viscosity-lowering agents such as urea, preservatives such as water-soluble salts of trichlorophenol, foam flow agents such as saponin, etc. can be added. In particular, fluorosurfactants such as N, M, N-trimethyl, N-3-(perfluorooctylsulfonylamino)propylammonium aniodide [C ₈ F ₁₇ SO ₂ NH(CH ₂ ) ₃ N ⁺ (CH ₃ ) ₃ I ^- ], potassium perfluorooctyl sulfonate [C ₈ F ₁₇ SO ₃ K],
Potassium = N-propyl, N-perfluorooctylsulfonyl-glycinate [C ₈ F ₁₇ SO ₂ N
( _{C3H7 ) CH2COOK} ], N-propyl, N _- polyoxyethylene, perfluorooctylsulfonamide [ _C8F17SO2N ( _{C3H7 ) ( CH2CH2O )} nH],
Sodium = 3-{N-methyl-N-[3-(perfluorohexylsulfonylamino)propyl]
_amino }-1- _{propanesulfonate [C6F13SO2NH ( CH2 ) 3N} ( _CH3 )( _CH2 ) _3SO3Na ],
Sodium = 2-{ _N- [2-(perolohepticarbonamido)amino}-1-ethanecarboxylate [ _C7F15CONH ( _CH2 ) _2NH
(CH ₂ ) ₂ COONa] has the effect of significantly improving the extinguishing action of the fire extinguisher of the present invention against petroleum, alcohol, etc. The present invention will be explained in more detail with reference to the following examples. Example: Put 100 g of mixed powder of cow and horse horns and hooves passed through a Tyler sieve with a mesh size of about 1 mm into a 2-necked flask with a reflux condenser, add 400 c.c. of distilled water, and add 20 g of sodium hydroxide. , boiled at 90°C for 90 min. After hydrolysis is complete, neutralize with concentrated hydrochloric acid so that the pH becomes 7.5, filter through No. 2 paper, and remove coexisting fine precipitates with a 5 μm (micron) membrane filter. The hydrolysis product thus obtained has a ferrous iron concentration.
Powdered ferrous sulfate is added to give a concentration of 1.0 to 1.5% by weight. Next, in order to prevent oxidation of ferrous sulfate ions, the mixture is stirred at 20°C or lower for about 3 hours. Since the PH decreases due to the reaction between protein hydrolysis products and ferrous ions, a concentrated sodium hydroxide solution is added while stirring to prevent the PH from decreasing, and the temperature is 20°C.
Keep the pH between 7.0 and 7.5. When the reaction between the protein hydrolysis product and ferrous ions was almost completed, the mixture was stirred at 50 to 60°C for 30 minutes or more to promote the reaction, and then cooled to room temperature. If the pH drops below 7.0 after cooling, add more concentrated sodium hydroxide solution.
Add until the pH reaches 7.0 to 7.5, and further heat and stir. Finally, after confirming that the pH has become constant, it is applied to an ultrafiltration device (UHP-150, manufactured by Toyo Shi Co., Ltd.) using a membrane with a molecular weight cutoff of 300,000 (manufactured by Amicon) to achieve a molecular weight cutoff of 300,000. The above substances were collected on the membrane, and those with a molecular weight cut-off of 300,000 or less were recovered in the liquid (yield approximately 70,000 or less).
~80%). The obtained liquid was passed through a reverse osmosis device (RO-3 type, manufactured by Albak Service Co., Ltd.) using a reverse osmosis membrane (manufactured by Albak Service Co., Ltd.) with a sucrose rejection rate of 15%.
It was concentrated to a solid content concentration of 20-30%. As a result, a reddish-brown transparent liquid was obtained. This liquid is considered to contain an iron()-protein hydrolysis product chelate compound, which is clearly different from the reaction solution of Japanese Patent Publication No. 11879/1983, which exhibits a dark green color. The performance of the solution containing the iron()-protein hydrolysis product chelate compound thus obtained as a fire extinguishing agent was tested as follows. One side is 70.7cm, height is
Fill a 40cm iron square combustion dish (combustion area ^0.5m2 ) with 50 grams of gasoline as fuel, ignite it, and 5 minutes after ignition, apply a 3% aqueous solution of the sample from a fixed foam discharge nozzle along the wall of the combustion dish. bubble water solution for 1 minute
It was released in the form of bubbles onto the combustion surface at a rate of 2.5%. The results are as follows.

〔Effect of the invention〕

The fire extinguishing agent containing a chelate compound of a protein hydrolysis product and ferrous ion according to the present invention and having a molecular weight cut off of 300,000 or less has excellent foaming properties and extinguishing properties, and has a long shelf life, compared to conventional It retains its fire extinguishing performance for a longer period of time.

[Brief explanation of drawings]

FIG. 1 is a visible spectrum diagram of a protein hydrolysis product-iron () chelate compound having a molecular weight cut-off of 300,000 or less according to the present invention.

Claims (1)

[Claims] 1 Protein hydrolysis product and ferrous salt, pH
After reacting at 20℃ or lower for about 3 hours while maintaining the temperature at 7.0 to 7.5, the mixture is further stirred at 50 to 60℃ for 30 minutes or more to limit the chelate compound of the protein hydrolysis product and ferrous ion. External filtration with a molecular weight cutoff of 30
A method for producing fire extinguishing foam characterized by collecting less than 10,000 yen of fire extinguishing agent and adding ordinary additives as necessary.