High-stability fire extinguishing microcapsule and preparation method thereof

Abstract

The invention discloses a high-stability fire extinguishing microcapsule and a preparation method thereof, and belongs to the technical field of fire fighting. Comprising a shell and a core material, the core material comprises a fire extinguishing agent and a nano modified material, and the shell is made of cation modified amino resin; the particle size of the nano modified material is 30-200nm, the mass ratio of the nano modified material to the fire extinguishing agent is 1: (5-20), and the mass ratio of the shell to the core material is 1: (1.5-3.0); the nano modified material is selected from hydrophobic modified aerogel or a hydrophobic modified molecular sieve. According to the invention, the special nano modified material is added into the core material, so that the perfluorohexanone is easier to emulsify, and meanwhile, the perfluorohexanone interacts with the shell formed by the cation modified amino resin, so that the empty coating condition is reduced, and the stability of the product is improved. The packaging rate of the product is greater than 95%, and the retention rate is greater than 99% after 30 days at 25 DEG C; and the retention rate is greater than 97.5% after 30 days under the condition of 60 DEG C.

Description

Technical Field

[0001] The invention belongs to the technical field of fire fighting, and particularly relates to a high-stability fire-extinguishing microcapsule and a preparation method thereof, and more particularly to a fire-extinguishing microcapsule that is stable at high temperatures. Background Art

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

[0003] For example, the patent application number CN201010230643.7 discloses a method for cationizing the surface of microcapsules with urea-formaldehyde resin as the capsule wall, which method includes the following steps: a. At room temperature, add microcapsules with urea-formaldehyde resin as capsule wall, NaOH and glycidyl trimethyl ammonium chloride into a dispersing solvent and stir evenly to obtain a mixed system, wherein the added dispersing solvent is 88-98 parts by weight, the added microcapsules with urea-formaldehyde resin as capsule wall are 2-4.5 parts by weight, the added NaOH is 0.01-0.9 parts by weight, and the added glycidyl trimethyl ammonium chloride is 0.3-6 parts by weight. b. The reaction system of step a is heated to 60-70° C. and reacted for 60-120 min to obtain a crude product of surface cationized microcapsules.

[0004] c. Wash the crude surface cationized microcapsules in anhydrous ethanol and filter them, then replace with new ethanol solution for washing and filtering, repeat several times, and dry them in a vacuum dryer for 8-15 hours to obtain the finished surface cationized microcapsules.

[0005] The applicant found that perfluorohexanone is difficult to emulsify, which may lead to empty packages and instability in the product (especially at high temperatures). Summary of the invention

[0006] In order to solve the above problems, the present invention provides a high-stability fire-extinguishing microcapsule and a preparation method thereof, wherein a special nano-modified material is added to the core material to make perfluorohexanone easier to emulsify, and at the same time interact with the shell composed of a cationic modified amino resin to reduce the empty package situation and improve the stability of the product. The technical solution is as follows: On the one hand, an embodiment of the present invention provides a high-stability fire-extinguishing microcapsule, comprising a shell and a core material. The core material comprises a fire extinguishing agent and a nano-modified material, the shell is a cation-modified amino resin, and the mass ratio of the shell to the core material is 1:1.5-3.0. Among them, the fire extinguishing agent is perfluorohexanone, the particle size of the nano-modified material is 30-200nm, and the mass ratio of the nano-modified material to the fire extinguishing agent is 1:5-20; the nano-modified material is selected from hydrophobic modified aerogel or hydrophobic modified molecular sieve, etc., preferably hydrophobic modified aerogel. Among them, the preparation method of the cation-modified amino resin is: in the process of preparing the amino resin, under alkaline conditions, a cationic modifier is added to modify the amino resin. The cationic modifier is selected from a modifier containing hydrocarbon groups and methyl groups such as choline chloride, betaine or polyquaternary ammonium salt (reacting with the amino resin and having an appropriate charge at the same time), and the molar ratio of the cationic modifier to melamine is 0.01-0.05:1.

[0007] In this patent, the nano-modified material adsorbs the fire extinguishing agent, making it easy to emulsify the fire extinguishing agent, making it easier for the shell to be coated on the surface of the core material. The cationic modified amino resin is more stable as a shell material, and the shell material formed by it carries an electric charge; this charge stabilizes the viscosity and fluidity of the entire system during the mixing process of the shell liquid and the core liquid, and ensures that the product has no empty bags. At the same time, the cationic modifier can enhance the adsorption capacity of the nano-modified material.

[0008] The particle size of the high-stability fire-extinguishing microcapsule is 30-200 μm, and the triggering temperature is 100-140° C.

[0009] Preferably, the high-stability fire-extinguishing microcapsules provided in the embodiment of the present invention include a shell and a core material, and the mass ratio of the shell to the core material is 1:1.5-2.0. Among them, the core material includes perfluorohexanone and hydrophobically modified aerogel, the particle size of the hydrophobically modified aerogel is 30-200nm, the mass ratio of the hydrophobically modified aerogel to perfluorohexanone is 1:10-12, and the shell is a cationically modified amino resin. The preparation method of the cationically modified amino resin is: in the process of preparing the amino resin, under alkaline conditions, betaine is added to modify the amino resin; the molar ratio of betaine to melamine is 0.01-0.05:1.

[0010] On the other hand, see Figure 1 The present invention also provides a method for preparing the aforementioned high-stability fire-extinguishing microcapsules, the method comprising: S1: Add the emulsifier into deionized water and add acid to adjust the pH value to 4.5-6.0 to obtain an emulsified solution with a concentration of 1-5wt%.

[0011] S2: Slowly add the nano-modified material into the fire extinguishing agent according to the proportion, and stir to obtain the core material liquid.

[0012] S3: Mix melamine, formaldehyde and cationic modifier, add alkali to adjust pH value to 8.0-8.5, react at 70-85°C for 1-3h, and obtain shell liquid after the reaction is completed. The molar ratio of melamine, formaldehyde and cationic modifier is 1:3-5:0.01-0.05.

[0013] S4: Add the core material liquid to the emulsified solution, disperse at 25-50°C for 10-30 min, and obtain the core material emulsion after dispersion. The amount of the emulsifier is 1-5% of the mass of the core material liquid. The emulsifier is selected from sodium dodecylbenzene sulfonate, styrene-maleic anhydride, sodium dodecyl sulfate or sodium perfluorononyloxybenzene sulfonate.

[0014] S5: adding the shell liquid to the core material emulsion according to the ratio and adding acid to adjust the pH value to 3-4, reacting at room temperature for 6-12 hours, and obtaining the capsule emulsion after the reaction is completed.

[0015] S6: solid-liquid separation, drying at 40-60°C for 12-24h to obtain the product.

[0016] Wherein, in step S1, the acid is selected from acetic acid, citric acid or acrylic acid, etc.; in step S3, the base is selected from sodium carbonate, triethylamine or potassium carbonate, etc.; in step S5, the acid is selected from acetic acid or hydrochloric acid, etc.

[0017] The present invention has the following advantages: (1) The empty package rate is low, the encapsulation rate is greater than 95%, the prepared microcapsule shell material has good density and the particles are round; (2) Good stability: the retention rate is greater than 99% after 30 days at 25°C and greater than 97.5% after 30 days at 60°C. (3) Good fire extinguishing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a flow chart of a method for preparing high-stability fire-extinguishing microcapsules provided by an embodiment of the present invention; Figure 2 This is the SEM image of the fire extinguishing microcapsules prepared in Example 1; Figure 3 This is the SEM image of the fire extinguishing microcapsules prepared in Comparative Example 1. DETAILED DESCRIPTION

[0019] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings.

[0020] Embodiment 1: Example 1 provides a method for preparing high-stability fire-extinguishing microcapsules, comprising the following steps: S1: In a beaker, sodium dodecyl sulfate was added to deionized water and citric acid was added to adjust the pH to 5.5 to obtain an emulsified solution with a concentration of 2 wt%.

[0021] S2: In a beaker, add 10 g of hydrophobically modified aerogel (particle size of 100 nm) into 90 g of perfluorohexanone and slowly stir to obtain a core material liquid.

[0022] S3: In a beaker, melamine, formaldehyde (37%) and betaine were mixed in a molar ratio of 1:4:0.02, triethylamine was added to adjust the pH value to 8.2, and the mixture was reacted at 80°C for 2.5 hours. After the reaction was completed, a shell liquid was obtained.

[0023] S4: In a beaker, add 100 g of the core material liquid to the emulsified solution and disperse at high speed at 40°C for 20 min. After dispersion, a core material emulsion is obtained. The amount of emulsifier used is 1.5 g.

[0024] S5: In a beaker, add the shell liquid to the core material emulsion and add hydrochloric acid to adjust the pH value to 3.3. React at room temperature for 10 hours. After the reaction is completed, a capsule emulsion is obtained, and the mass ratio of the shell to the core material is 1:2.

[0025] S6: Filter and dry in an oven at 45°C for 24 hours to obtain the product.

[0026] Products such as Figure 2 As shown, the emulsification is easy, the product is round, and there are few empty packages. The encapsulation rate is 95.3%, and the retention rate is 99.6% at 25℃ for 30 days and 97.9% at 60℃ for 30 days.

[0027] Embodiment 2: Example 2 provides a method for preparing high-stability fire-extinguishing microcapsules, comprising the following steps: S1: In a beaker, styrene-maleic anhydride was added to deionized water and citric acid was added to adjust the pH value to 5.4 to obtain an emulsified solution with a concentration of 3 wt%.

[0028] S2: In a beaker, add 6 g of hydrophobically modified molecular sieve (particle size 80 nm) into 94 g of perfluorohexanone and slowly stir to obtain a core material liquid.

[0029] S3: In a beaker, melamine, formaldehyde (37%) and betaine were mixed in a molar ratio of 1:4:0.05, sodium carbonate was added to adjust the pH value to 8.0, and the mixture was reacted at 80°C for 2.5 hours. After the reaction was completed, a shell liquid was obtained.

[0030] S4: In a beaker, add 100 g of the core material liquid to the emulsified solution and disperse at high speed at 45°C for 20 min. After dispersion, a core material emulsion is obtained. The amount of emulsifier used is 2.7 g.

[0031] S5: In a beaker, add the shell liquid to the core material emulsion and add hydrochloric acid to adjust the pH value to 3.5. React at room temperature for 9 hours. After the reaction is completed, a capsule emulsion is obtained, and the mass ratio of the shell to the core material is 1:2.2.

[0032] S6: Filter and dry in an oven at 45°C for 24 hours to obtain the product.

[0033] Emulsification is easy, and the viscosity of the solution in step S4 is stable. The finished product is round and has few empty packages. The encapsulation rate is 94.9% at room temperature, and the retention rate is 99.2% after 30 days at 25°C; and the retention rate is 97.7% after 30 days at 60°C.

[0034] Embodiment 3: Example 3 provides a method for preparing high-stability fire-extinguishing microcapsules, comprising the following steps: S1: In a beaker, sodium dodecyl sulfate was added to deionized water and acetic acid was added to adjust the pH to 5.5 to obtain an emulsified solution with a concentration of 3.5 wt%.

[0035] S2: In a beaker, add 15 g of hydrophobically modified aerogel (particle size 150 nm) into 85 g of perfluorohexanone and slowly stir to obtain a core material liquid.

[0036] S3: In a beaker, melamine, formaldehyde (37%) and polyquaternium salt are mixed in a molar ratio of 1:3.7:0.03, sodium carbonate is added to adjust the pH value to 8.5, and the mixture is reacted at 75°C for 2.5 hours. After the reaction is completed, a shell liquid is obtained.

[0037] S4: In a beaker, add 100 g of the core material liquid to the emulsified solution and disperse at high speed at 25°C for 25 minutes. After the dispersion is completed, the core material emulsion is obtained. The amount of emulsifier used is 2.5 g.

[0038] S5: In a beaker, add the shell liquid to the core material emulsion and add hydrochloric acid to adjust the pH value to 3.5. React at room temperature for 12 hours. After the reaction is completed, a capsule emulsion is obtained, and the mass ratio of the shell to the core material is 1:2.

[0039] S6: Filter and dry in an oven at 45°C for 24 hours to obtain the product.

[0040] Emulsification is easy, and the viscosity of the solution in step S4 is stable. The product is round and has few empty packages. The encapsulation rate is 95.0%, and the retention rate is 99.3% at 25°C for 30 days and 97.7% at 60°C for 30 days.

[0041] Embodiment 4: Example 4 provides a method for preparing high-stability fire-extinguishing microcapsules, comprising the following steps: S1: In a beaker, sodium dodecylbenzene sulfonate was added to deionized water and acetic acid was added to adjust the pH value to 5.6 to obtain an emulsified solution with a concentration of 2 wt%.

[0042] S2: In a beaker, add 10 g of hydrophobically modified aerogel (particle size 120 nm) into 90 g of perfluorohexanone and slowly stir to obtain a core material liquid.

[0043] S3: In a beaker, melamine, formaldehyde (37%) and choline chloride were mixed in a molar ratio of 1:3.7:0.03, sodium carbonate was added to adjust the pH value to 8.1, and the mixture was reacted at 80°C for 1.5 hours. After the reaction was completed, a shell liquid was obtained.

[0044] S4: In a beaker, add 100 g of the core material liquid to the emulsified solution and disperse at high speed at 30°C for 25 minutes. After the dispersion is completed, the core material emulsion is obtained. The amount of emulsifier used is 2.5 g.

[0045] S5: In a beaker, add the shell liquid to the core material emulsion and add hydrochloric acid to adjust the pH value to 3.2. React at room temperature for 8 hours. After the reaction is completed, a capsule emulsion is obtained, and the mass ratio of the shell to the core material is 1:2.5.

[0046] S6: Filter and dry in an oven at 45°C for 24 hours to obtain the product.

[0047] Emulsification is easy, and the viscosity of the solution in step S4 is stable. The product is round and has few empty packages. The encapsulation rate is 95.1%, and the retention rate is 99.1% at 25°C for 30 days and 97.5% at 60°C for 30 days.

[0048] Comparative Example 1 Comparative Example 1 is basically the same as Example 1, except that: in step S2, no hydrophobic modified aerogel is added. Emulsification is difficult. The product is as follows Figure 3 As shown, there are a few empty packages. The encapsulation rate is 93.2%, and the retention rate is 98.7% at 25°C for 30 days and 95.3% at 60°C for 30 days.

[0049] It can be seen from Comparative Example 1 and Example 1 that without adding the hydrophobically modified aerogel, the encapsulation rate, room temperature stability and high temperature stability are all significantly reduced.

[0050] Comparative Example 2 Comparative Example 2 is basically the same as Example 1, except that: in step S2, unmodified aerogel is added. Emulsification is difficult. There are a small number of empty packages. The encapsulation rate is 91.4%, and the retention rate is 98.5% at 25°C for 30 days; the retention rate is 94.3% at 60°C for 30 days.

[0051] It can be seen from Comparative Example 2 and Example 1 that the encapsulation rate is significantly reduced when unmodified aerogel is added; the room temperature stability is slightly reduced, and the high temperature stability is significantly reduced.

[0052] It can be seen from Comparative Example 2 and Comparative Example 1 that adding unreasonable nano powder will reduce the performance of the product.

[0053] Comparative Example 3 Comparative Example 3 is basically the same as Example 1, except that: in step S2, aluminum oxide powder of equal weight and particle size is added. Emulsification is difficult. There are a small number of empty packages. The encapsulation rate is 90.9%, and the retention rate is 98.3% at 25°C for 30 days; the retention rate is 91.3% at 60°C for 30 days.

[0054] It can be seen from Comparative Example 3 and Example 1 that the encapsulation rate is significantly reduced by adding alumina powder; the room temperature stability is slightly reduced, and the high temperature stability is significantly reduced.

[0055] It can be seen from Comparative Example 3 and Comparative Example 1 that adding unreasonable nano powder will reduce the performance of the product.

[0056] Comparative Example 4 Comparative Example 4 is basically the same as Example 1, except that betaine is not added in step S3. Emulsification is easy, and the viscosity of the solution in step S4 is unstable. The encapsulation rate is 90.2%, and the retention rate is 99.1% at 25°C for 30 days; the retention rate is 96.5% at 60°C for 30 days.

[0057] It can be seen from Comparative Example 4 and Example 1 that without modifying the shell, the encapsulation rate is significantly reduced; and the stability is slightly lower than that of Comparative Example 1.

[0058] The fire extinguishing microcapsules of Examples 1-4 and Comparative Examples 1-4 were made into fire extinguishing tablets, and the preparation process was as follows: 10 g of polyurethane resin and 15 g of fire extinguishing microcapsules were mixed, coated on a release film, pressed into shape, and finally dried at 55° C. for 150 min to obtain a fire extinguishing sheet.

[0059] Test the fire extinguishing effect of the fire extinguishing film: The test process is: cut the fire extinguishing sheet into a size of 5cm*5cm*0.5cm, place it in a 10L box (with an opening on the top), there is burning gasoline in the box, and record the time when the gasoline flame is extinguished. The results are shown in Table 1: Table 1

[0060] As can be seen from Table 1, the fire extinguishing effect of this patent is better. The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-stability fire-extinguishing microcapsule, comprising a shell and a core material, wherein the core material comprises a fire extinguishing agent, and the shell is a cation-modified amino resin; characterized in that: The core material also includes a nano-modified material, the particle size of the nano-modified material is 30-200nm, the mass ratio of the nano-modified material to the fire extinguishing agent is 1:5-20, and the mass ratio of the shell to the core material is 1:1.5-3.0; the nano-modified material is selected from hydrophobically modified aerogel or hydrophobically modified molecular sieve.

2. The high stability fire extinguishing microcapsule according to claim 1, characterized in that: The particle size of the high-stability fire-extinguishing microcapsule is 30-200 μm, and the triggering temperature thereof is 100-140° C.

3. The high stability fire extinguishing microcapsule according to claim 1, characterized in that: The fire extinguishing agent is perfluorohexanone.

4. The high stability fire extinguishing microcapsule according to claim 1, characterized in that: The preparation method of the cation-modified amino resin is as follows: during the preparation of the amino resin, under alkaline conditions, a cationic modifier is added to modify the amino resin; the cationic modifier is selected from choline chloride, betaine or polyquaternium salt, and the molar ratio of the cationic modifier to melamine is 0.01-0.05:

1.

5. The high stability fire extinguishing microcapsule according to claim 1, characterized in that: It comprises a shell and a core material, wherein the mass ratio of the shell to the core material is 1:1.5-2.0; the core material comprises perfluorohexanone and hydrophobically modified aerogel, the particle size of the hydrophobically modified aerogel is 30-200nm, the mass ratio of the hydrophobically modified aerogel to the perfluorohexanone is 1:10-12, and the shell is a cationically modified amino resin; the preparation method of the cationically modified amino resin is as follows: in the process of preparing the amino resin, under alkaline conditions, betaine is added to modify the amino resin; the molar ratio of the betaine to melamine is 0.01-0.05:

1.

6. The method for preparing the high stability fire extinguishing microcapsules according to any one of claims 1 to 5, characterized in that: The method comprises: S1: adding an emulsifier to deionized water and adding acid to adjust the pH value to 4.5-6.0 to obtain an emulsified solution with a concentration of 1-5 wt%; S2: Slowly add the nano-modified material into the fire extinguishing agent according to the ratio, and stir to obtain the core material liquid; S3: mixing melamine, formaldehyde and a cationic modifier, adding alkali to adjust the pH value to 8.0-8.5, reacting at 70-85° C., and obtaining a shell liquid after the reaction is completed, wherein the molar ratio of melamine, formaldehyde and cationic modifier is 1:3-5:0.01-0.05; S4: adding the core material liquid to the emulsified solution and dispersing at 25-50° C. to obtain a core material emulsion, wherein the amount of the emulsifier is 1-5% of the mass of the core material liquid; S5: adding the shell liquid to the core material emulsion according to the ratio and adding acid to adjust the pH value to 3-4, reacting at room temperature, and obtaining a capsule emulsion after the reaction is completed; S6: The product is obtained after solid-liquid separation and drying of the capsule emulsion.

7. The method according to claim 6, characterized in that The emulsifier is selected from sodium dodecylbenzene sulfonate, styrene-maleic anhydride, sodium dodecyl sulfate or sodium perfluorononyloxybenzene sulfonate.

8. The method according to claim 6, characterized in that In step S1, the acid is selected from acetic acid, citric acid or acrylic acid; in step S3, the base is selected from sodium carbonate, triethylamine or potassium carbonate; in step S5, the acid is selected from acetic acid or hydrochloric acid.

9. The method according to claim 6, characterized in that In step S3, the reaction time is 1-3 hours; in step S4, the dispersion time is 10-30 minutes; in step S5, the reaction time is 6-12 hours.

10. The method according to claim 6, characterized in that In step S6, drying is performed at 40-60° C. for 12-24 hours.

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