A perfluoromethylcyclohexanone microcapsule fire extinguishing medium and its preparation process

Abstract

The present invention discloses a perfluoromethylcyclohexanone microcapsule fire extinguishing medium and its preparation process, which relates to the field of fire fighting technology. A perfluoromethylcyclohexanone microcapsule fire extinguishing medium is composed of a core material and a shell material. The core material includes perfluoromethylcyclohexanone, silicon dioxide, and azobisisobutyronitrile. The shell material includes modified guar gum, acrylic resin, aluminum hydroxide, potassium nitrate, and an emulsifier. The modified guar gum is prepared by the following method: tetrahydrofuran, guar gum, and triethylamine are sequentially added into a reactor, stirred and mixed evenly, and then a tetrahydrofuran solution of diphenylphosphinyl chloride is added dropwise. After the addition is completed, the temperature is raised to 75-85°C and the reaction is carried out for 10-14 hours, followed by post-treatment to obtain diphenylphosphinyl chloride-modified guar gum. The present invention modifies guar gum with diphenylphosphinyl chloride and then uses the modified guar gum for the shell material of perfluoromethylcyclohexanone microcapsules, improving the fire extinguishing performance, heat resistance, and long-term stability of perfluoromethylcyclohexanone microcapsules.

Description

Technical Field

[0001] The present invention relates to the field of fire protection technology, and particularly to a perfluorohexanone microcapsule fire extinguishing medium and a preparation process thereof. Background Art

[0002] Perfluorohexanone is usually a liquid under normal conditions, with a boiling point of 49°C. It can quickly gasify and volatilize at room temperature, making it difficult to store and apply. Preparing perfluorohexanone into microcapsules and embedding them in polymer materials to form a solid shape is a good solidification and application solution.

[0003] The Chinese invention patent with the publication number CN 116271675 A discloses a perfluorohexanone microcapsule fire extinguishing medium and a preparation method thereof. Although the fire extinguishing time of the perfluorohexanone microcapsule fire extinguishing medium disclosed in this patent can be completed in more than 8 seconds, its heat resistance and long-term stability are poor. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a perfluorohexanone microcapsule fire extinguishing medium and a preparation process thereof.

[0005] To achieve the above purpose, the present invention is realized through the following technical solutions:

[0006] A perfluorohexanone microcapsule fire extinguishing medium is composed of a core material and a shell material. The core material includes perfluorohexanone, silicon dioxide, and azobisisobutyronitrile. The shell material includes modified guar gum, acrylic resin, aluminum hydroxide, potassium nitrate, and an emulsifier;

[0007] The modified guar gum is prepared by the following method:

[0008] Tetrahydrofuran, guar gum, and triethylamine are sequentially added to a reactor, stirred and mixed evenly, and then a tetrahydrofuran solution of diphenylphosphinyl chloride is added dropwise. After the addition is complete, the temperature is raised to 75 - 85°C and the reaction is carried out for 10 - 14 hours. After post-treatment, diphenylphosphinyl chloride-modified guar gum is obtained. The reaction equation is shown as follows:

[0009]

[0010] Among them, Guar Gum-OH represents guar gum, and OH represents the hydroxyl group on guar gum.

[0011] The mass ratio of the guar gum, triethylamine, and diphenylphosphinyl chloride is 100:(10 - 15):(15 - 20).

[0012] The silicon dioxide is porous silicon dioxide, with an average particle size of 400 - 800 nm and a specific surface area of 150 - 200 m² / g.

[0013] The mass ratio of perfluorohexanone, silica, and azobisisobutyronitrile is 10:(2-3):(0.04-0.06).

[0014] The mass ratio of the modified guar gum, acrylic resin, aluminum hydroxide, potassium nitrate, and emulsifier is 100:(6-10):(12-18):(1-2):(8-10).

[0015] A preparation process of a perfluorohexanone microcapsule fire extinguishing medium includes the following steps:

[0016] S1: Add perfluorohexanone, silica, and azobisisobutyronitrile into a reactor, stir and mix evenly to obtain a perfluorohexanone fire extinguishing mixed solution.

[0017] S2: Add deionized water, modified guar gum, and potassium nitrate into a reactor, stir and mix evenly to obtain an aqueous solution of modified guar gum.

[0018] S3: Slowly add the perfluorohexanone fire extinguishing mixed solution, acrylic resin, and emulsifier into the aqueous solution of modified guar gum, and stir to obtain an emulsion.

[0019] S4: Add aluminum hydroxide to the emulsion, stir and mix evenly, stand for 2-6 h, filter, wash with water, and freeze-dry to obtain the perfluorohexanone microcapsule fire extinguishing medium.

[0020] Due to the above technical solutions, the beneficial effects of the present invention include:

[0021] (1) In the present invention, guar gum is modified by diphenylphosphinyl chloride, so that the guar gum is grafted with diphenylphosphine oxide groups. The diphenylphosphine oxide groups are flame retardant groups. Using the modified guar gum as the shell material of the perfluorohexanone microcapsule, on the one hand, the sealing effect of the shell material is improved, and the shell material itself has the performance of a flame retardant, improving the fire extinguishing performance, heat resistance, and long-term stability of the perfluorohexanone microcapsule.

[0022] (2) By using porous silica with an average particle size of 400-800 nm and a high specific surface area as the carrier of the perfluorohexanone fire extinguishing medium core material, its porous pore structure can carry perfluorohexanone and serve as its storage space, reducing the external contact area of perfluorohexanone. During storage, the volatilization of perfluorohexanone can be reduced. Therefore, the perfluorohexanone microcapsule prepared in this application has excellent heat resistance and long-term stability. Specific Embodiments

[0023] The following is further described in conjunction with embodiments, but the present invention is not limited to these embodiments.

[0024] Example 1 Preparation of modified guar gum:

[0025] Add 200 g of tetrahydrofuran, 100 g of guar gum, and 10 g of triethylamine into the reactor in sequence, stir and mix evenly, then dropwise add a tetrahydrofuran solution of diphenylphosphinyl chloride (dissolve 15 g of diphenylphosphinyl chloride in 60 g of tetrahydrofuran, complete all dropwise addition, and the dropping time is 30 min). After the dropping is completed, raise the temperature to 75 °C and react for 14 h; filter to remove insoluble salts, and perform vacuum distillation at 60 °C to obtain diphenylphosphinyl chloride-modified guar gum.

[0026] Example 2 Preparation of modified guar gum:

[0027] Add 200 g of tetrahydrofuran, 100 g of guar gum, and 12 g of triethylamine into the reactor in sequence, stir and mix evenly, then dropwise add a tetrahydrofuran solution of diphenylphosphinyl chloride (dissolve 18 g of diphenylphosphinyl chloride in 70 g of tetrahydrofuran, complete all dropwise addition, and the dropping time is 30 min). After the dropping is completed, raise the temperature to 80 °C and react for 12 h; filter to remove insoluble salts, and perform vacuum distillation at 60 °C to obtain diphenylphosphinyl chloride-modified guar gum.

[0028] Example 3 Preparation of modified guar gum:

[0029] Add 200 g of tetrahydrofuran, 100 g of guar gum, and 15 g of triethylamine into the reactor in sequence, stir and mix evenly, then dropwise add a tetrahydrofuran solution of diphenylphosphinyl chloride (dissolve 20 g of diphenylphosphinyl chloride in 80 g of tetrahydrofuran, complete all dropwise addition, and the dropping time is 30 min). After the dropping is completed, raise the temperature to 85 °C and react for 10 h; filter to remove insoluble salts, and perform vacuum distillation at 60 °C to obtain diphenylphosphinyl chloride-modified guar gum.

[0030] Example 4 Preparation of perfluoromethyl isopropyl ketone microcapsule fire extinguishing medium:

[0031] S1: Add 300 g of perfluoromethyl isopropyl ketone, 60 g of porous silica (average particle size is 780 nm, specific surface area is 158 m² / g), and 1.2 g of azobisisobutyronitrile into the reactor, stir and mix evenly to obtain a perfluoromethyl isopropyl ketone fire extinguishing homogeneous liquid;

[0032] S2: Add 250 g of deionized water, 100 g of modified guar gum (prepared in Example 1), and 1 g of potassium nitrate into the reactor, stir and mix evenly to obtain an aqueous solution of modified guar gum;

[0033] S3: Slowly add 250 g of the perfluoromethyl isopropyl ketone fire extinguishing homogeneous liquid, 6 g of acrylic resin, and 8 g of emulsifier (SR-10) to the aqueous solution of modified guar gum in step S2, and stir at high speed to obtain an emulsion;

[0034] S4: Add 12 g of aluminum hydroxide to the emulsion in step S3, stir and mix evenly, let it stand for 2 h, filter by suction, wash the filter cake with 100 g of deionized water, and freeze-dry for 12 h to obtain the perfluoromethyl isopropyl ketone microcapsule fire extinguishing medium.

[0035] Example 5 Preparation of perfluorohexanone microcapsule fire extinguishing medium:

[0036] S1: Add 300 g of perfluorohexanone, 75 g of porous silica (average particle size of 640 nm, specific surface area of 182 m² / g), and 1.5 g of azobisisobutyronitrile into a reactor, stir well and mix evenly to obtain a perfluorohexanone fire extinguishing mixed solution;

[0037] S2: Add 250 g of deionized water, 100 g of modified guar gum (prepared in Example 2), and 1.5 g of potassium nitrate into a reactor, stir and mix evenly to obtain an aqueous solution of modified guar gum;

[0038] S3: Slowly add 270 g of the perfluorohexanone fire extinguishing mixed solution, 8 g of acrylic resin, and 9 g of emulsifier (SR-20) into the aqueous solution of modified guar gum in step S2, and stir at high speed to obtain an emulsion;

[0039] S4: Add 15 g of aluminum hydroxide into the emulsion in step S3, stir and mix evenly, let it stand for 5 h, filter by suction, wash the filter cake with 90 g of deionized water, and freeze-dry for 12 h to obtain the perfluorohexanone microcapsule fire extinguishing medium.

[0040] Example 6 Preparation of perfluorohexanone microcapsule fire extinguishing medium:

[0041] S1: Add 300 g of perfluorohexanone, 90 g of porous silica (average particle size of 410 nm, specific surface area of 197 m² / g), and 1.8 g of azobisisobutyronitrile into a reactor, stir well and mix evenly to obtain a perfluorohexanone fire extinguishing mixed solution;

[0042] S2: Add 250 g of deionized water, 100 g of modified guar gum (prepared in Example 3), and 2 g of potassium nitrate into a reactor, stir and mix evenly to obtain an aqueous solution of modified guar gum;

[0043] S3: Slowly add 280 g of the perfluorohexanone fire extinguishing mixed solution, 10 g of acrylic resin, and 10 g of emulsifier (SR-20) into the aqueous solution of modified guar gum in step S2, and stir at high speed to obtain an emulsion;

[0044] S4: Add 18 g of aluminum hydroxide into the emulsion in step S3, stir and mix evenly, let it stand for 6 h, filter by suction, wash the filter cake with 80 g of deionized water, and freeze-dry for 12 h to obtain the perfluorohexanone microcapsule fire extinguishing medium.

[0045] Comparative Example 1

[0046] The preparation process of the perfluorohexanone microcapsule fire extinguishing medium is basically the same as that of Example 5, the difference is that 100 g of modified guar gum in step S2 is replaced by: 85 g of guar gum and 16 g of diphenylphosphinic chloride.

[0047] Comparative Example 2

[0048] The preparation process of the perfluoroketone microcapsule fire extinguishing medium is basically the same as that of Example 5, except that 100 g of modified guar gum in Step S2 is replaced with: 100 g of guar gum.

[0049] Comparative Example 3

[0050] The preparation process of the perfluoroketone microcapsule fire extinguishing medium is basically the same as that of Example 5, except that the modified guar gum in Step S2 is replaced with an equal weight of modified chitosan. The preparation method of the modified chitosan is basically the same as that of Example 2, except that 100 g of guar gum is replaced with 100 g of chitosan.

[0051] Comparative Example 4

[0052] The preparation process of the perfluoroketone microcapsule fire extinguishing medium is basically the same as that of Example 5, except that the porous silica in Step S1 is replaced with an equal weight of porous silica with an average particle size of 190 nm and a specific surface area of 219 m² / g.

[0053] Comparative Example 5

[0054] The preparation process of the perfluoroketone microcapsule fire extinguishing medium is basically the same as that of Example 5, except that the porous silica in Step S1 is replaced with an equal weight of porous silica with an average particle size of 980 nm and a specific surface area of 68 m² / g.

[0055] Comparative Example 6

[0056] The perfluoroketone microcapsule fire extinguishing medium prepared by the method of Example 2 of the Chinese invention patent with the publication number of CN 116271675 A.

[0057] In the process of preparing the perfluoroketone microcapsule fire extinguishing medium in Examples 4 - 6 and Comparative Examples 1 - 5 of the present application, Steps S1 - S4 are all prepared at room temperature, where room temperature refers to 25°C. The rotation speed of high - speed stirring in Step S3 is 1500 rmp, and the stirring time is 30 min.

[0058] Preparation Example 1 of Porous Silica: Preparation of Silica (with an average particle size of 640 nm and a specific surface area of 182 m² / g):

[0059] (1) Take fumed silica (with an average particle size of 1000 nm) and add it to a sand mill for grinding. Control the rotation speed of the sand mill at 8000 rmp and the grinding time at 50 min. Then dry the ground fumed silica in an 80°C oven for 7 h to form a powder;

[0060] (2) Weigh 50 g of formaldehyde solution (35 wt%) and 44 g of urea, and stir evenly.

[0061] (3) Weigh 100 g of the ground fumed silica powder and add it to the mixed solution in step (2), and stir evenly.

[0062] (4) Add 1500 g of deionized water to the system in step (3) to dilute the solid content, then adjust the pH of the system to 1.0 with hydrochloric acid (2 M), and let it stand at room temperature for 24 h to obtain urea-formaldehyde resin-fumed silica composite nanospheres.

[0063] (5) Filter the urea-formaldehyde resin-fumed silica composite nanospheres, and then wash them repeatedly 4 times with anhydrous ethanol (50 g each time) and deionized water (50 g each time), and dry them at 120 °C for 8 h to obtain urea-formaldehyde resin-fumed silica composite powder.

[0064] (6) Calcinate the urea-formaldehyde resin-fumed silica composite powder in a muffle furnace at 600 °C for 6 h to obtain porous silica.

[0065] Preparation Example 2 of Porous Silica: Preparation of Silica (average particle size is 780 nm, specific surface area is 158 m² / g):

[0066] It is basically the same as the steps of Silica Preparation Example 1, the difference is that in step (1), the rotation speed of the sand mill is 6000 rmp and the grinding time is 40 min.

[0067] Preparation Example 3 of Porous Silica: Preparation of Silica (average particle size is 410 nm, specific surface area is 197 m² / g):

[0068] It is basically the same as the steps of Silica Preparation Example 1, the differences are that in step (1), the rotation speed of the sand mill is 10000 rmp and the grinding time is 60 min; in step (2), it is calcined at 600 °C for 5 h.

[0069] Preparation Example 4 of Porous Silica: Preparation of Silica (average particle size is 190 nm, specific surface area is 219 m² / g):

[0070] It is basically the same as the steps of Silica Preparation Example 1, the differences are that in step (1), the rotation speed of the sand mill is 10000 rmp and the grinding time is 70 min; in step (6), it is calcined at 600 °C for 4.5 h.

[0071] Preparation Example 5 of Porous Silica: Preparation of Silica (average particle size is 980 nm, specific surface area is 68 m² / g):

[0072] It is basically the same as the steps of Preparation Example 1 of silicon dioxide, except that in step (1), the rotation speed of the sand mill is 2000 rmp and the grinding time is 20 min.

[0073] The guar gum used in this application is the building material grade guar gum produced by Beijing Guarelun Technology Co., Ltd.

[0074] The perfluoromethylcyclohexanone microcapsule fire extinguishing media prepared in Examples 4 - 6 and Comparative Examples 1 - 6 were made into fire extinguishing patches, and the fire extinguishing performance and storage stability of the prepared fire extinguishing patches were tested.

[0075] Method for making the fire extinguishing patch: Add 80 g of microcapsules to 76 g of water-soluble melamine - formaldehyde resin, stir for 10 minutes, pour into a mold, and dry and form at 40 °C to obtain a perfluoromethylcyclohexanone fire extinguishing sheet (size: 34 mm × 24 mm × 3 mm); scrape a layer of about 50 μm of polydimethylsiloxane on the surface of the fire extinguishing sheet, cover a double-sided adhesive film on the back of the fire extinguishing sheet, and then cover an iron sheet, and suck a circular magnet on the iron sheet to make a perfluoromethylcyclohexanone microcapsule fire extinguishing patch.

[0076] Method for testing the fire extinguishing performance: Use an 800 °C flame as the fire source, measure the temperature with an infrared thermometer, measure the fire extinguishing time with a stopwatch. The fire extinguishing patch is fixed on the surface of a stamping steel plate, with the sheet facing down and placed 1.5 cm away from the outer flame of the fire, and measure the fire extinguishing time and the temperature difference before and after fire extinguishing at the upper part of the sheet. The fire extinguishing performance is characterized by the fire extinguishing time and the temperature difference.

[0077] Test on the storage stability of the perfluoromethylcyclohexanone microcapsule fire extinguishing media: Place 100 g of the perfluoromethylcyclohexanone microcapsule fire extinguishing media in an 80 °C oven and dry for 12 h, and calculate the weight retention rate of the perfluoromethylcyclohexanone microcapsule fire extinguishing media.

[0078] The test results of the fire extinguishing performance and storage stability are shown in Table 1.

[0079] Table 1

[0080]

[0081] It can be seen from Table 1 that for the perfluoromethylcyclohexanone microcapsule fire extinguishing media prepared in Examples 5 - 6 of this application, the fire extinguishing time of the prepared fire extinguishing patch < 6 s, and during the stability test, the weight retention rate of the perfluoromethylcyclohexanone microcapsule fire extinguishing media reaches more than 96.5%.

[0082] Comparative Example 1 and Comparative Example 2 are comparative examples in which the modified guar gum is replaced with guar gum and diphenylphosphinyl chloride, unmodified guar gum respectively. It can be seen from Table 1 that their fire extinguishing time is greater than 8.5 s.

[0083] Comparative Example 3 is a comparative example in which the modified guar gum is replaced with modified chitosan. It can be seen from Table 1 that its fire extinguishing time is 8.6 s.

[0084] Comparative Example 4 and Comparative Example 5 are comparative examples using silica with different particle sizes. It can be seen from Table 1 that their fire extinguishing time > 9 s.

[0085] Comparative Example 6 is a perfluorocyclohexanone microcapsule fire extinguishing medium prepared by the method of Example 2 of the Chinese invention patent with the publication number CN 116271675 A. During the stability test, the retention rate of the weight of the perfluorocyclohexanone microcapsule fire extinguishing medium is only 92.3%, and its storage stability is poor.

[0086] The above is only the preferred embodiment of the present invention and is not used to limit the present invention. However, for those of ordinary skill in the art, without departing from the scope of the technical solution of the present invention, any equivalent changes such as slight modifications, decorations, and evolutions made using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications, and evolutions made to the above embodiments based on the essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A perfluoroketone microcapsule fire extinguishing medium, which is composed of a core material and a shell material, and is characterized in that, The core material includes perfluoromethyl isopropyl ketone, silica, and azodiisobutyronitrile, and the shell material includes modified guar gum, acrylic resin, aluminum hydroxide, potassium nitrate, and emulsifier; The modified guar gum is prepared by the following method: Add tetrahydrofuran, guar gum, and triethylamine into the reactor in sequence, stir and mix evenly, then dropwise add the tetrahydrofuran solution of diphenylphosphinyl chloride. After dropping, raise the temperature to 75 - 85 °C and react for 10 - 14 h, and perform post-treatment to obtain diphenylphosphinyl chloride-modified guar gum.

2. The perfluoroketone microcapsule fire extinguishing medium according to claim 1, characterized in that The mass ratio of the guar gum, triethylamine, and diphenylphosphinyl chloride is 100:(10 - 15):(15 - 20).

3. The perfluoroketone microcapsule fire extinguishing medium according to claim 1, characterized in that, The silica is porous silica with an average particle size of 400 - 800 nm and a specific surface area of 150 - 200 m 2 / g.

4. The perfluoroketone microcapsule fire extinguishing medium according to claim 1, characterized in that, The mass ratio of the perfluoromethyl isopropyl ketone, silica, and azodiisobutyronitrile is 10:(2 - 3):(0.04 - 0.06).

5. A perfluoromethylcyclohexanone microcapsule fire extinguishing medium according to claim 1, characterized in that The mass ratio of the modified guar gum, acrylic resin, aluminum hydroxide, potassium nitrate, and emulsifier is 100:(6 - 10):(12 - 18):(1 - 2):(8 - 10).

6. The perfluoroketone microcapsule fire extinguishing medium according to claim 1, characterized in that, The emulsifier is one of SR-20 and ER-10.

7. A preparation process of the perfluoroketone microcapsule fire extinguishing medium according to any one of claims 1-6, characterized in that, It includes the following steps: S1: Add perfluoromethyl isopropyl ketone, silica, and azodiisobutyronitrile into the reactor, stir and mix evenly to obtain a perfluoromethyl isopropyl ketone fire-extinguishing homogeneous liquid; S2: Add deionized water, modified guar gum, and potassium nitrate into the reactor, stir and mix evenly to obtain an aqueous solution of modified guar gum; S3: Slowly add the perfluoromethyl isopropyl ketone fire-extinguishing homogeneous liquid, acrylic resin, and emulsifier into the aqueous solution of modified guar gum, and stir to obtain an emulsion; S4: Add aluminum hydroxide to the emulsion, stir and mix evenly, stand for 2 - 6 h, filter, wash with water, and freeze-dry to obtain a perfluoromethyl isopropyl ketone microcapsule fire-extinguishing medium.

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