A silicone surfactant composite system for foaming and stabilizing foam in foam fire extinguishers

Abstract

The present invention discloses a silicone surfactant composite system for foaming and stabilizing foam in foam fire extinguishers. The optimal concentration ratio of the silicone surfactant composite system is: 0.2% by mass of Dow Corning 0193, 0.4% by mass of silicone 380, 1% by mass of sodium lauryl sulfate, 1.4% by mass of dodecylbenzenesulfonic acid, 0.03% by mass of xanthan gum, and 1% by mass of dodecyl alcohol. At these concentrations, the composite system exhibits a foaming expansion ratio of 8.3 and a 25% liquid separation time of 783 seconds, meeting the foam standards specified in GB 15308-2006. Based on the silicone surfactant composite system, the present invention derives the optimal foam concentration combination for the composite formula. The innovative use of silicone surfactants as the foam surfactant reduces environmental pollution, and the composite system has broad application prospects.

Description

Technical Field

[0001] The invention belongs to the field of fire extinguishing materials and relates to an organic silicon surfactant composite system for foaming and stabilizing foam in foam fire extinguishers. Background Art

[0002] Research on aqueous film-forming foam (AFFF) fire extinguishing agents started relatively late in China. The first generation of AFFF was not successfully developed until 1979, and multi-purpose AFFF was not developed until the 1990s. Thanks to the continuous efforts of Chinese scientists, AFFF fire extinguishing agents have finally become important in the market. However, due to the control of perfluorooctane sulfonic acid (PFOS), the synthesis and production of new foam fire extinguishing agents has become the focus of scientists' efforts.

[0003] In 2018, Meng Yawei, researching key technologies for fluorine-free foams, synthesized a novel fluorine-free synthetic fire extinguishing foam by screening and compounding different components. Performance testing confirmed its potential for commercialization. To facilitate this research, the authors also constructed a foam thermal stability testing platform.

[0004] In 2020, Wu Nan and others selected non-toxic and harmless dodecyl dimethyl beta (BS-12) and dodecyl glycoside (APG) as aqueous film-forming foam fire extinguishing agents in their research on silicone / hydrocarbon surfactants. The environmentally friendly surfactants were compounded, and after testing the compounded foams, it was found that the foam under the BS-12 compounding system had good performance, which was mainly manifested in low surface tension, high viscosity, good foaming ability, foam stability and good burning resistance. The study found that a compounding system of BS-12 and amphoteric hydrocarbon surfactants with a mass fraction of 3% can be used as the core of a good aqueous film-forming foam fire extinguishing agent, but its foaming performance needs further research to improve its foaming performance.

[0005] In 2020, Jiao Jinqing, Ying Weibao and others introduced the hazards of perfluorooctane sulfonic acid (PFOS) in fluorine-containing foam fire extinguishing agents to the environment, the current research status of some alternatives, and the possible emergence of water-forming foam fire extinguishing agents with excellent foam performance in the "Hazards of Perfluorooctane Sulfonic Acid in Foam Fire Extinguishing Agents and the Current Status of Research and Development of Alternatives".

[0006] In 2019, patent CN110523044A was developed to develop a high-performance, environmentally friendly aqueous film-forming foam fire extinguishing agent. The composition, by weight, consists of 8%-20% solubilizer, 3-6% fluorine-based active agent, 3-20% hydrocarbon active agent, 0.1%-2% antimicrobial agent, 3-6% silicon active agent, 0.1%-4% ion complexing agent, 0.1%-4% plant polysaccharide, and the remainder water. The interaction of these components yields excellent fire-extinguishing properties, including superior foam performance, high fire extinguishing efficiency, excellent sealing properties, long shelf life, and strong rekindling resistance. The raw materials are readily available, environmentally friendly, and readily biodegradable. It does not contain PFOS or its salts, and therefore does not cause environmental pollution. Under the condition of a foaming multiple of 7.3 to 8.1, the 25% liquid separation time is 3.4 to 4.1 minutes, and the fire can be extinguished in only 35 to 47 seconds, while the anti-burning time is 13.1 to 17.4 minutes.

[0007] In 2018, in a foam digester experiment based on a composite system of hydrocarbons and silicon surfactants, Sheng Youjie was the first to test the performance of single foams of silicon and hydrocarbon surfactants, foam stabilizers, and foaming agents, and selected the three with the best foam performance as a compound system. He designed experiments and developed foams that meet international standards, paving the way for its commercialization.

[0008] Internationally, research on foam fire extinguishing agents has been conducted since 1877. In the 1960s, Richard L. Tuve, under an order from the U.S. Military Research Institute, began to research aqueous film-forming foam fire extinguishing agents and successfully applied for a patent in 1966.

[0009] In 2008, Shaefer et al. compared the fuel vapor containment capabilities of three fluorine-free and aqueous film-forming foams. The results showed that commercially available AFFFs, while offering many advantages, generally performed worse than fluorine-free foams in sealing fuel vapor. Fluorine-free foams also have weaker fire-extinguishing capabilities, and Solberg's RF6 fluorine-free foam fire extinguishing agent can serve as an alternative to AFFF.

[0010] In 2011, Australian researcher Hagenarrae studied a long-chain fluorocarbon surfactant alternative developed by DuPont and found it to be harmful to the environment. Wialliams also studied the fire-extinguishing and burn-resistance capabilities of fluorinated and fluorinated-free foams, both in film-forming and non-film-forming states. The results showed that RF6 was more stable than AFFF. RF6 lacks a film-forming structure on the fuel surface, making it more effective at extinguishing octane fires. Meanwhile, it was less effective than AFFF at extinguishing heptane and gasoline fires, but the two had similar burn-resistance capabilities.

[0011] In 2014, German researchers Hetzer and others developed a fluorine-free AFFF, replacing the fluorocarbon surfactant with a glycosylated silicon surfactant. This new glycosylated silicon surfactant outperforms commercially available silicon surfactants, forming a water film on the fuel surface. However, its fire extinguishing performance is still weaker than that of AFFF.

[0012] Literature research and analysis reveals that research on aqueous film-forming foam fire extinguishing agents has been ongoing both domestically and internationally. Various approaches have been attempted to identify novel aqueous film-forming foam fire extinguishing agents that can replace fluorocarbon surfactants, but most have reduced the amount of fluorocarbon surfactant used. For example, in patent CN110523044A, the amount has been reduced to 3%. While the use of fluorocarbon surfactants has been reduced, it is still essentially a fluorocarbon surfactant. Coupled with the rapid development of the domestic aviation industry, the demand for aqueous film-forming foam fire extinguishing agents is increasing. This has resulted in the continued high use of fluorocarbon surfactants, which still pose significant environmental risks. Literature research reveals that there are few studies that directly seek alternatives to fluorocarbon surfactants and then modify them. While several promising surfactant substitutes have been identified in existing research, their foam performance has failed to meet market requirements and requires further research and optimization. Furthermore, the high production costs have prevented large-scale promotion and use. Summary of the Invention

[0013] The present invention provides a silicone surfactant composite system for foaming and stabilizing foam in foam fire extinguishers. The optimal concentration ratio of the silicone surfactant composite system is: 0.2% by mass of Dow Corning 0193, 0.4% by mass of silicone 380, 1% by mass of sodium lauryl sulfate, 1.4% by mass of sodium dodecylbenzenesulfonate, 0.03% by mass of xanthan gum, and 1% by mass of dodecyl alcohol. At these concentrations, the composite system exhibits a foam expansion ratio of 8.3 and a 25% liquid separation time of 783 seconds, meeting the foam standards specified in GB 15308-2006. Based on the silicone surfactant composite system, the present invention derives the optimal foam concentration combination for the composite formula. The innovative use of silicone surfactants as the foam surfactant reduces environmental pollution, and the composite system has broad application prospects.

[0014] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0015] The invention discloses an organosilicon surfactant composite system for foaming and stabilizing foam in foam fire extinguishers, which comprises Dow Corning 0193, organosilicon 380, sodium lauryl sulfate, sodium dodecylbenzene sulfonate, xanthan gum, lauryl alcohol and deionized water.

[0016] Furthermore, the mass ratio of the composite system is:

[0017] Dow Corning 0193 with a mass concentration of 0.2%, silicone 380 with a mass concentration of 0.4%, sodium lauryl sulfate with a mass concentration of 1%, sodium dodecylbenzene sulfonate with a mass concentration of 1.4%, xanthan gum with a mass concentration of 0.03%, dodecanol with a mass concentration of 1%, and deionized water as the rest.

[0018] Furthermore, the foaming multiple of the composite system is 8.3.

[0019] Furthermore, the 25% drainage time of the composite system is 783 s.

[0020] Furthermore, the preparation method of the composite system is:

[0021] 0.2 g of an organosilicon surfactant, Dow Corning 0193, 0.4 g of organosilicon 380, 1.0 g of sodium lauryl sulfate, 1.4 g of sodium dodecylbenzenesulfonate, 0.03 g of xanthan gum, and 1.0 g of dodecanol were weighed and mixed with deionized water to prepare a 1000 mL solution to obtain an organosilicon surfactant composite system for foaming and stabilizing foam in a foam fire extinguisher.

[0022] Furthermore, the composite system is used in water-based foam fire extinguishers.

[0023] Beneficial effects:

[0024] 1. Using silicone surfactant as the surfactant of the foam reduces pollution to the environment; using two surfactants, foaming agent and foam stabilizer to conduct orthogonal experiments simplifies the experimental steps and optimizes the compounding effect;

[0025] The optimal concentration ratio for the silicone surfactant composite system is: 0.2% Dow Corning 0193, 0.4% silicone 380, 1% sodium lauryl sulfate, 1.4% sodium dodecylbenzenesulfonate, 0.03% xanthan gum, and 1% dodecanol. The composite system achieved a foam expansion ratio of 8.3 and a 25% liquid extraction time of 783 seconds, meeting the foam standards specified in GB 15308-2006. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the structure of a fully automatic foam analyzer in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0028] Example 1:

[0029] This example uses an automated foam property analysis platform to test foam foaming and stability:

[0030] In this embodiment, 8 ml of the compound liquid is introduced into the glass tube of the fully automatic foam analyzer through a glass rod, and the inflation tube, air compressor, computer and equipment of the fully automatic foam analyzer are connected. A 100 mm sieve is selected, and the test is started after the inflation is connected. The height reading of the foam in the glass tube of the fully automatic foam analyzer is the foaming multiple of the foam. Introduce 10 ml of the compound liquid into a hand-cranked test tube and shake it up and down. The shaking time is at least 1 minute. Immediately after the shaking is completed, press the stopwatch to record the time when the foam precipitates to the 2.5 ml scale line as 25% precipitate time. After the experiment is completed, record and organize the data. See the experimental equipment structure diagram for details. Figure 1 .

[0031] In this example, a compounding experiment was conducted using the organosilicon surfactants Dow Corning 0193 and Organosilicon 380, the foaming agents sodium lauryl sulfate and sodium dodecylbenzene sulfonate, and the foam stabilizers xanthan gum and lauryl alcohol. These surfactants were renamed A, B, C, D, E, and F, respectively.

[0032] The experimental results are shown in Tables 1 and 2 below.

[0033] Table 1. Levels of surfactant compounding experiments (concentration)

[0034]

[0035] Table 2 Surfactant compounding experiment

[0036]

[0037]

[0038] Range analysis of compounding experiments

[0039] After obtaining the experimental data, the following two tables, Table 3 and Table 4, performed range analysis on the experimental foaming rate and 25% drainage time.

[0040] Table 3 Analysis of the range of foaming multiples

[0041]

[0042] Table 4 Analysis of the range of 25% drainage time

[0043]

[0044]

[0045] The data in the table are all tested at 23℃.

[0046] As can be seen above, the compounding experiments in Table 2 used expansion ratio and 25% drainage time as reference and reference indicators, respectively. Range analysis was used as the primary analysis method, and the main process and steps for applying this method are as follows. First, the primary and secondary relationships of each factor were determined. As can be clearly seen from Table 3, the ranges of A, B, C, D, E, and F are 2.2, 3.4, 3.9, 3.8, 3.3, and 1.0, respectively. Therefore, the primary and secondary relationship affecting the expansion ratio is C > D > B > A = E > F. Second, the optimal level of each factor was determined. The average value of the different levels of different factors is called the optimal level. As can be clearly seen from Table 4, the optimal levels of expansion ratio are A3 B2 C2 D2 E2 F3. Similarly, Table 4 shows that the priority order affecting the 25% drainage time is A > E > D > B > C > F, with the optimal level being A2 B2 C3 D3 E2 F3.

[0047] For factor A, the optimal level is either A2 or A3. If A is A2, the 25% drainage time is 377.3 seconds, and the foaming rate is 8.9. When A is A3, the foaming rate is 9.5, and the 25% drainage time is 170.8 seconds. Compared to A3, A2 decreases the foaming rate by 0.6%, a 6% decrease; while the drainage time increases by 206.5 seconds, a 54% increase. Overall, A2 should be selected.

[0048] For the B factor, the optimal level of B is only B2. When B is selected as B2, the foaming rate is 10.5 and the drainage time is 295s.

[0049] For factor C, the optimal level for A is either C2 or C3. When C is C2, the foaming rate is 12.2 and the drain time is 211.6 seconds. When C is C3, the foaming rate is 8.9 and the drain time is 261.6 seconds. Compared to C2 and C3, C3's foaming rate decreases by 3.3, a 27% decrease, while the drain time increases by 50 seconds, a 23% increase. Overall, C3 should be selected.

[0050] Regarding the D factor, the optimal level of D is likely D2 or D3. When D is D2, the foaming rate is 11.1 and the drainage time is 193.3 seconds. When D is D3, the foaming rate is 8.6 and the drainage time is 333 seconds. Compared to D2, the foaming rate of D3 decreases by 2.5, a percentage decrease of 22%, while the drainage time increases by 139.7 seconds, a percentage increase of 41%. In summary, D3 should be selected.

[0051] For the E factor, the optimal level of E is only E2. When E is E2, the foaming rate is 10.1 and the drainage time is 316.2s.

[0052] From the perspective of F factor, the optimal level of F factor is only F3. When F is F3, the foaming multiple is 8.9 and the 25% drainage time is 259.8s.

[0053] In summary, the optimal combination for the compound experiment is A2 B2 C3D3 E2 F3.

[0054] Compound foam experimental verification

[0055] The range analysis of the compounding experiments above revealed that the optimal foam combination is A2 B2 C3 D3 E2 F3. Therefore, the following experimental verification of this optimal foam combination will be conducted. The specific preparation method is to weigh 0.2g of the silicone surfactant Dow Corning 0193, 0.4g of silicone 380, 1.0g of sodium lauryl sulfate, 1.4g of sodium dodecylbenzene sulfonate, 0.03g of xanthan gum, and 1.0g of dodecyl alcohol and mix them with deionized water to make a 1000mL solution. The specific testing instrument is a fully automatic foam analyzer. The foam performance data of the optimal compounding system are shown in Table 5.

[0056] Table 5 Compound foam properties

[0057]

[0058]

[0059] As shown in Table 5, the foam expansion ratio of the composite foam under the optimal combination obtained by orthogonal experiment is 8.3, and the 25% drainage time is 783s, which meets the foam standard specified in GB 15308-2006.

[0060] The present invention discloses a silicone surfactant composite system for foaming and stabilizing foam in foam fire extinguishers. The optimal concentration ratio of the silicone surfactant composite system is: 0.2% by mass of Dow Corning 0193, 0.4% by mass of silicone 380, 1% by mass of sodium lauryl sulfate, 1.4% by mass of sodium dodecylbenzenesulfonate, 0.03% by mass of xanthan gum, and 1% by mass of dodecanol. At these concentrations, the composite system exhibits a foaming expansion ratio of 8.3 and a 25% liquid separation time of 783 seconds, meeting the foam standards specified in GB 15308-2006. Based on the silicone surfactant composite system, the present invention derives the optimal foam concentration combination for the composite formula. The innovative use of silicone surfactants as the foam surfactant reduces environmental pollution, and the composite system has broad application prospects.

[0061] The above description does not limit the present invention in any form. Although the present invention has been disclosed through the above embodiments, it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A silicone surfactant composite system for foaming and stabilizing foam in foam fire extinguishers, characterized in that: The composite system is: Dow Corning 0193, silicone 380, sodium lauryl sulfate, dodecylbenzene sulfonic acid, xanthan gum, lauryl alcohol and deionized water; The mass ratio of the composite system is: 0.2% by mass of Dow Corning 0193, 0.4% by mass of silicone 380, 1% by mass of sodium lauryl sulfate, 1.4% by mass of dodecylbenzenesulfonic acid, 0.03% by mass of xanthan gum, 1% by mass of dodecanol, and the rest is deionized water; The foaming multiple of the composite system is 8.3; the 25% liquid separation time of the composite system is 783 s; The preparation method of the composite system is: 0.2 g of the organosilicon surfactant Dow Corning 0193, 0.4 g of organosilicon 380, 1.0 g of sodium lauryl sulfate, 1.4 g of sodium dodecylbenzene sulfonate, 0.03 g of xanthan gum, and 1.0 g of dodecanol were weighed and mixed with deionized water to prepare a 1000 mL solution to obtain an organosilicon surfactant composite system for foaming and stabilizing foam in foam fire extinguishers.

2. The method for applying the organic silicon surfactant composite system for foaming and stabilizing foam in a foam fire extinguisher as claimed in claim 1, characterized in that: Application of the composite system in water-based foam fire extinguishers.

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