Fire-extinguishing microcapsule, preparation method thereof and fire-extinguishing tablet

Abstract

The invention discloses a fire extinguishing microcapsule, a preparation method thereof and a fire extinguishing tablet, and belongs to the technical field of fire fighting. Comprising a shell and a core material, and the core material comprises a fire extinguishing agent; the particle size of the fire extinguishing microcapsule is 700-2800mu m, and the fire extinguishing microcapsule is prepared from sodium alginate, an emulsifier, a fire extinguishing agent, polyacrylic resin and a photoinitiator. The shell sequentially comprises an outer shell and an inner shell from outside to inside, the outer shell is formed by exchanging sodium alginate with calcium ions in an emulsifier and polyacrylic acid resin system, and the inner shell is formed by curing polyacrylic acid resin and a photoinitiator under the action of ultraviolet rays; the polyacrylic resin is selected from urethane acrylate, polyester acrylate or polyether acrylate, and the photoinitiator is selected from benzophenone or ethyl 2, 4, 6-trimethylbenzoyl phenyl phosphonate; the wavelength of the ultraviolet rays is 250 to 400 nm.

Description

Technical Field

[0001] The invention belongs to the technical field of fire fighting, and particularly relates to a fire extinguishing microcapsule and a preparation method thereof, and a fire extinguishing sheet. Background Art

[0002] Fire is one of the disasters in people's daily life. If it is not put out in time, it is easy to cause serious damage to people's lives and property. There are many kinds of fire extinguishing media for extinguishing fire sources, and commonly used fire extinguishing media include water, dry ice, etc. Microcapsule fire extinguishing agent, as an emerging fire extinguishing medium, has been gradually widely used in the field of fire protection in recent years. In the prior art, microcapsule active fire extinguishing agent usually uses polymer resin as the shell to encapsulate the fire extinguishing agent inside.

[0003] For example, the application number CN202111679278.2 provides a fire extinguishing microcapsule, characterized in that it includes a core material and a shell layer, wherein the core material is coated in the shell layer; the material of the shell layer is a polymer of methyl methacrylate and N, N-dimethylacrylamide. The particle size of the fire extinguishing microcapsule is 75-200 μm. Monomer methacrylate, N, N-dimethylacrylamide and suspending agent are added to the initiator aqueous solution in sequence, and the core material is added once again. After the polymerization reaction is completed, the microcapsule is filtered, washed and dried to obtain the fire extinguishing microcapsule. The initiator includes one or more of potassium persulfate and ammonium persulfate; and / or the monomer methacrylate includes one or more of methacrylic acid, butyl methacrylate and hydroxyethyl methacrylate; and / or the suspending agent includes polyvinyl pyrrolidone. Among them, the core material of the fire extinguishing microcapsule includes a core material and an outer shell layer; the core material is coated in the outer shell layer; the core material is one or more of perfluorohexanone, perfluorotriethylamine and their homologues; the material of the outer shell layer is chitosan / sodium alginate. The preparation method of the core material of the fire extinguishing microcapsule includes the following steps: S1, mixing and emulsifying a sodium alginate aqueous solution, an emulsifier, a coupling agent and a core material to obtain a core material-sodium alginate emulsion; S2, dropping the core material-sodium alginate emulsion into an acetic acid aqueous solution containing chitosan and calcium chloride, performing a gelation reaction, standing, and obtaining the core material of the fire extinguishing microcapsule. In S1, the concentration of the sodium alginate aqueous solution is 1.0-3.0wt%; the mass ratio of the sodium alginate aqueous solution, the emulsifier, the coupling agent and the core material is 1:0.01-0.1:0.01-0.1:0.01-0.1:1-4.

[0004] There are the following problems in the patent: (1) The particle size of the core material of the fire-extinguishing microcapsule is small; (2) The processing is complicated; (3) The polymerization reaction takes a long time, requiring a temperature of 40°C and a reaction time of 15 hours. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a fire extinguishing microcapsule and a preparation method thereof and a fire extinguishing tablet. The fire extinguishing microcapsule has a large particle size and is simple to prepare and takes a short preparation time. The technical solution is as follows: On the one hand, an embodiment of the present invention provides a fire extinguishing microcapsule, the particle size of which is 700-2800 μm (generally less than 500 μm in the prior art), which includes a shell and a core material, which is made of sodium alginate, an emulsifier, a fire extinguishing agent, a polyacrylic resin and a photoinitiator. The core material includes a fire extinguishing agent; the mass ratio of sodium alginate, emulsifier, fire extinguishing agent, polyacrylic resin and photoinitiator is 1-5: 0.02-0.10: 12-24: 3-8: 0.2-0.8.

[0006] Wherein, the shell is an outer shell and an inner shell from outside to inside, the outer shell is formed by sodium alginate and calcium ion exchange in an emulsifier and polyacrylic resin system, and the inner shell is formed by curing polyacrylic resin and photoinitiator under the action of ultraviolet light. Wherein, polyacrylic resin is selected from polyurethane acrylate, polyester acrylate or polyether acrylate, etc., preferably polyester acrylate. Wherein, the photoinitiator is selected from benzophenone or 2,4,6-trimethylbenzoylphenylphosphonic acid ethyl ester, etc., preferably benzophenone. Wherein, the fire extinguishing agent is selected from perfluorohexanone or perfluorotriethylamine, etc., preferably perfluorohexanone. Wherein, the emulsifier is selected from sodium dodecylbenzene sulfonate, sodium dodecyl sulfate or sodium perfluorononyloxybenzene sulfonate, etc., preferably sodium perfluorononyloxybenzene sulfonate. Wherein, the wavelength of ultraviolet light is 250-400nm.

[0007] In this patent, the fire extinguishing agent is dispersed in an aqueous solution of sodium alginate and polyacrylic resin (to make the particles formed by the reaction larger), and then reacts with calcium chloride to form an outer shell; in this process, the outer shell will form particles with larger particle size, but it will be unstable (it will collapse to reduce the particle size to form a stable structure) and the hardness is not enough. The solution in the outer shell includes a fire extinguishing agent, polyacrylic resin and a photoinitiator. During the light curing process, the polyacrylic resin and the photoinitiator undergo a photocuring reaction to form an inner shell. Both the outer shell (a small amount) and the inner shell contain polyacrylic resin to ensure the stability of the connection between the outer shell (a small amount) and the inner shell.

[0008] Among them, sodium alginate is dissolved in deionized water to prepare a sodium alginate solution with a concentration of 1-3wt%, which is consistent with the prior art. Calcium chloride is dissolved in deionized water to prepare a calcium ion solution with a concentration of 1-5wt%, which does not require the addition of acetic acid compared to the prior art.

[0009] Specifically, when the photoinitiator is benzophenone, the wavelength of the ultraviolet light is 365 nm. When the photoinitiator is ethyl 2,4,6-trimethylbenzoylphenylphosphonate, the wavelength of the ultraviolet light is 320 nm.

[0010] Preferably, the outer shell is formed by sodium alginate in sodium perfluorononyloxybenzene sulfonate and polyester acrylate and calcium ion exchange, and the inner shell is formed by polyester acrylate and benzophenone cured under ultraviolet light. The mass ratio of sodium alginate, sodium perfluorononyloxybenzene sulfonate, perfluorohexanone, polyester acrylate and benzophenone is 1-2: 0.04-0.007: 15-20: 4-6: 0.3-0.5, and the wavelength of the ultraviolet light is 365nm.

[0011] On the other hand, the present invention also provides a fire extinguishing sheet, comprising a base material and the aforementioned fire extinguishing microcapsules, wherein the base material is selected from polyurethane resin, etc., and the mass ratio of the base material to the fire extinguishing microcapsules is 1:1-2. The preparation method of the fire extinguishing sheet is: after the base material and the fire extinguishing microcapsules are mixed, they are coated on a release film, and then pressed into shape, and finally dried at 50-65°C for 70-300 minutes.

[0012] In another aspect, the present invention also provides a method for preparing the aforementioned fire extinguishing microcapsules, the method comprising: S1: adding polyacrylic acid resin and photoinitiator to sodium alginate solution according to the ratio to obtain mixed solution A, and mixing evenly; wherein the concentration of sodium alginate solution is 1-3wt%.

[0013] S2: Add emulsifier and fire extinguishing agent to mixed solution A according to the proportion, stir at 1200-2000 rpm / min for 3-10 min to obtain mixed solution B.

[0014] S3: Slowly drip the mixed solution B into the calcium chloride solution, stir at 150-300 rpm / min for 20-50 min, separate the solid and liquid and wash with water to obtain a crude product; wherein the concentration of the calcium chloride solution is 1-5wt%.

[0015] S4: Immediately after step S3, the crude product is irradiated with ultraviolet light to perform a curing reaction. The wavelength of the ultraviolet light is 250-400 nm, and the curing time is 5-15 minutes.

[0016] S5: drying at 40-60°C to obtain the product.

[0017] The present invention has the following advantages: (1) The particle size of the capsule is relatively large, reaching 700-2800 μm, which is 2-10 times that of the prior art; (2) The product quality is stable, with an encapsulation rate of >85%. At room temperature, the microcapsule retention rate is >92% after one month of storage; at 80°C, the microcapsule retention rate is >93% after 3 hours of storage. (3) The capsule particles have a rounded surface and regular shape; (4) Good fire extinguishing effect; (5) The preparation method is simple, and only requires stirring and irradiation; (6) Short preparation time. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a physical picture of the fire extinguishing microcapsules produced in Example 1; Figure 2 yes Figure 1 Microscopic morphology of fire-extinguishing microcapsules observed under a scanning microscope. 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] Example 1 Embodiment 1 provides a method for preparing fire extinguishing microcapsules, characterized in that the method comprises: S1: Add 5 kg of polyester acrylate and 0.5 kg of benzophenone to 200 kg of sodium alginate solution to obtain a mixed solution A, and mix well. The concentration of the sodium alginate solution is 2 wt %.

[0021] S2: 0.04 kg of sodium perfluorononyloxybenzenesulfonate and 20 kg of perfluorohexanone were added to the mixed solution A, and the mixture was stirred at 1500 rpm / min for 5 min to obtain a mixed solution B.

[0022] S3: Slowly drip the mixed solution B into the calcium chloride solution, stir at 200 rpm / min for 30 min, separate the solid and liquid and wash with water to obtain a crude product. The concentration of the calcium chloride solution is 2 wt%.

[0023] S4: Immediately irradiate the crude product with ultraviolet light to perform a curing reaction. The wavelength of the ultraviolet light is 365 nm and the curing time is 10 minutes.

[0024] S5: drying at 50°C to obtain the product.

[0025] The particle size of the fire extinguishing microcapsules was tested to be 900-1650μm, with an average particle size of 1310μm. The encapsulation rate was 93.1%, and the retention rate was 99.5% at 25℃ for 30 days and 98.1% at 80℃ for 3h.

[0026] Example 2 Embodiment 2 provides a method for preparing fire extinguishing microcapsules, characterized in that the method comprises: S1: 4 kg of polyester acrylate, 2 kg of polyether acrylate and 0.6 kg of benzophenone were added to 300 kg of sodium alginate solution to obtain a mixed solution A, and the mixture was mixed evenly. The concentration of the sodium alginate solution was 1 wt %.

[0027] S2: 0.04 kg of sodium dodecyl sulfate and 18 kg of perfluorotriethylamine were added to the mixed solution A, and the mixture was stirred at 1500 rpm / min for 6 min to obtain a mixed solution B.

[0028] S3: Slowly drip the mixed solution B into the calcium chloride solution, stir at 200 rpm / min for 30 min, separate the solid and liquid and wash with water to obtain a crude product. The concentration of the calcium chloride solution is 2.5 wt%.

[0029] S4: The crude product is irradiated with ultraviolet light to perform a curing reaction, the wavelength of the ultraviolet light is 365 nm, and the curing time is 10 minutes.

[0030] S5: drying at 50°C to obtain the product.

[0031] The particle size of the fire extinguishing microcapsules was tested to be 1100-2030μm, with an average particle size of 1780μm. The encapsulation rate was 92.9%, and the retention rate was 99.3% at 25℃ for 30 days and 97.7% at 80℃ for 3h.

[0032] Example 3 Embodiment 3 provides a method for preparing fire extinguishing microcapsules, characterized in that the method comprises: S1: Add 7.5 kg of polyurethane acrylate and 0.5 kg of ethyl 2,4,6-trimethylbenzoylphenylphosphonate to 150 kg of sodium alginate solution to obtain a mixed solution A, and mix well. The concentration of the sodium alginate solution is 2.5 wt%.

[0033] S2: 0.05 kg of sodium perfluorononyloxybenzene sulfonate, 0.02 kg of sodium dodecylbenzene sulfonate and 15 kg of perfluorohexanone were added to the mixed solution A, and the mixture was stirred at 1800 rpm / min for 6 min to obtain a mixed solution B.

[0034] S3: Slowly drip the mixed solution B into the calcium chloride solution, stir at 200 rpm / min for 30 min, separate the solid and liquid and wash with water to obtain a crude product. The concentration of the calcium chloride solution is 2 wt%.

[0035] S4: The crude product is irradiated with ultraviolet light to perform a curing reaction, the wavelength of the ultraviolet light is 320 nm, and the curing time is 10 minutes.

[0036] S5: drying at 50°C to obtain the product.

[0037] The particle size of the fire extinguishing microcapsules was tested to be 1500-2470μm, with an average particle size of 2090μm. The encapsulation rate was 93.0%, and the retention rate was 99.5% at 25℃ for 30 days and 97.9% at 80℃ for 3h.

[0038] Example 4 Embodiment 4 provides a method for preparing fire extinguishing microcapsules, characterized in that the method comprises: S1: 4 kg of polyester acrylate, 0.1 kg of ethyl 2,4,6-trimethylbenzoylphenylphosphonate and 0.2 kg of benzophenone were added to 250 kg of sodium alginate solution to obtain a mixed solution A, and the mixture was mixed. The concentration of the sodium alginate solution was 1.2 wt %.

[0039] S2: 0.05 kg of sodium perfluorononyloxybenzenesulfonate and 20 g of perfluorohexanone were added to the mixed solution A, and the mixture was stirred at 1500 rpm / min for 8 min to obtain a mixed solution B.

[0040] S3: Slowly drip the mixed solution B into the calcium chloride solution, stir at 200 rpm / min for 30 min, separate the solid and liquid and wash with water to obtain a crude product. The concentration of the calcium chloride solution is 2 wt%.

[0041] S4: The crude product is irradiated with ultraviolet light to perform a curing reaction, the wavelength of the ultraviolet light is 320 nm, and the curing time is 10 minutes.

[0042] S5: drying at 50°C to obtain the product.

[0043] The particle size of the fire extinguishing microcapsules was tested to be 820-1630μm, with an average particle size of 1230μm. The encapsulation rate was 92.7%, and the retention rate was 99.2% at 25℃ for 30 days and 98.1% at 80℃ for 3h.

[0044] Comparative Example 1 The process of Comparative Example 1 is basically the same as that of Example 1, except that step S4 is not performed in this comparative example.

[0045] The particle size of the fire extinguishing microcapsules was tested to be 560-1410μm, with an average particle size of 770μm. The encapsulation rate was 75.3%, and the retention rate was 89.5% at 25℃ for 30 days and 71.9% at 80℃ for 3h.

[0046] It can be seen from Comparative Document 1 that if step S4 is not performed, the particle size of the product will be slightly smaller than that of Example 1, and the stability will be significantly reduced.

[0047] Comparative Example 2 The process of Comparative Example 2 is basically the same as that of Example 1, except that: in step S2, benzophenone is not added.

[0048] The particle size of the fire extinguishing microcapsules was tested to be 310-920μm, with an average particle size of 590μm. The encapsulation rate was 77.3%, and the retention rate was 91.9% at 25℃ for 30 days and 71.4% at 80℃ for 3h.

[0049] It can be seen from Comparative Example 2 that no photoinitiator is added; the particle size is smaller than that of Comparative Example 1.

[0050] Comparative Example 3 The process of Comparative Example 3 is basically the same as that of Example 1, except that: in step S1, 1-hydroxy-cyclohexyl phenyl ketone is added as a photoinitiator.

[0051] The particle size of the fire extinguishing microcapsules was tested to be 920-1810μm, with an average particle size of 1280μm. The encapsulation rate was 85.1%, and the retention rate was 93.3% at 25℃ for 30 days and 85.9% at 80℃ for 3h.

[0052] It can be seen from Comparative Example 3 that although the addition of 1-hydroxy-cyclohexylphenyl ketone can obtain capsules with larger particle size, the stability is poor, that is, in the system of this patent, not all photoinitiators can be used; only under specific photoinitiators can the product particle size be larger and good stability be guaranteed.

[0053] Comparative Example 4 The process of Comparative Example 4 is basically the same as that of Example 1, except that: in step S1, 5 kg of polyester acrylate and 0.5 kg of benzophenone are directly added to 200 kg of deionized water to obtain a mixed solution A.

[0054] After testing, it was found that no capsule structure could be formed.

[0055] The fire extinguishing microcapsules of Examples 1-4 and Comparative Examples 1-3 were made into fire extinguishing tablets, and the preparation process was as follows: 7 g of the base material and 10 g of the 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.

[0056] 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

[0057] 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 fire extinguishing microcapsule, comprising a shell and a core material, wherein the core material comprises a fire extinguishing agent; characterized in that: The particle size of the fire extinguishing microcapsule is 700-2800 μm and it is made of sodium alginate, emulsifier, fire extinguishing agent, polyacrylic resin and photoinitiator, and the mass ratio of the sodium alginate, emulsifier, fire extinguishing agent, polyacrylic resin and photoinitiator is 1-5: 0.02-0.10: 12-24: 3-8: 0.2-0.8; The shell is composed of an outer shell and an inner shell from the outside to the inside, wherein the outer shell is formed by sodium alginate exchanged with calcium ions in an emulsifier and polyacrylic resin system, and the inner shell is formed by curing polyacrylic resin and a photoinitiator under the action of ultraviolet rays, wherein the polyacrylic resin is selected from polyurethane acrylate, polyester acrylate or polyether acrylate, and the photoinitiator is selected from benzophenone or ethyl 2,4,6-trimethylbenzoylphenylphosphonate; Wherein, the wavelength of the ultraviolet rays is 250-400nm.

2. The fire extinguishing microcapsule according to claim 1, characterized in that: The fire extinguishing agent is selected from perfluorohexanone or perfluorotriethylamine.

3. The fire extinguishing microcapsule according to claim 1, characterized in that: The emulsifier is selected from sodium dodecylbenzene sulfonate, sodium dodecyl sulfate or sodium perfluorononyloxybenzene sulfonate.

4. The fire extinguishing microcapsule according to claim 1, characterized in that: Sodium alginate is dissolved in deionized water to prepare a sodium alginate solution with a concentration of 1-3wt%; calcium chloride is dissolved in deionized water to prepare a calcium ion solution with a concentration of 1-5wt%.

5. The fire extinguishing microcapsule according to claim 1, characterized in that: When the photoinitiator is benzophenone, the wavelength of the ultraviolet light is 365 nm; when the photoinitiator is ethyl 2,4,6-trimethylbenzoylphenylphosphonate, the wavelength of the ultraviolet light is 320 nm.

6. The fire extinguishing microcapsule according to claim 1, characterized in that: The outer shell is formed by sodium alginate being exchanged with calcium ions in sodium perfluorononoxybenzene sulfonate and polyester acrylate, and the inner shell is formed by polyester acrylate and benzophenone being cured under the action of ultraviolet rays; the mass ratio of the sodium alginate, sodium perfluorononoxybenzene sulfonate, perfluorohexanone, polyester acrylate and benzophenone is 1-2: 0.04-0.007: 15-20: 4-6: 0.3-0.5, and the wavelength of the ultraviolet rays is 365nm.

7. A fire extinguishing sheet, characterized in that: It comprises a base material and the fire extinguishing microcapsules as described in any one of items 1-6, wherein the base material is selected from polyurethane resin, and the mass ratio of the base material to the fire extinguishing microcapsules is 1:1-2.

8. The fire extinguishing sheet according to claim 7, characterized in that: The preparation method of the fire extinguishing sheet is as follows: the base material and the fire extinguishing microcapsules are mixed evenly, coated on a release film, pressed into shape, and finally dried at 50-65° C. for 70-300 minutes.

9. The method for preparing the fire extinguishing microcapsules according to any one of claims 1 to 6, characterized in that: The method comprises: S1: adding polyacrylic acid resin and photoinitiator to sodium alginate solution according to the ratio to obtain mixed solution A, and mixing evenly, wherein the concentration of the sodium alginate solution is 1-3wt%; S2: Add emulsifier and fire extinguishing agent to mixed solution A according to the proportion, stir at high speed for 3-10 minutes to obtain mixed solution B; S3: slowly dripping the mixed solution B into the calcium chloride solution, stirring at a low speed for 20-50 minutes, solid-liquid separation and washing with water to obtain a crude product, wherein the concentration of the calcium chloride solution is 1-5wt%; S4: Immediately after step S3, the crude product is irradiated with ultraviolet light to perform a curing reaction, the wavelength of the ultraviolet light is 250-400nm, and the curing time is 5-15min; S5: Drying to obtain the product.

10. The method for preparing fire extinguishing microcapsules according to claim 9, characterized in that: In step S2, the rotation speed of the high-speed stirring is 1200-2000 rpm / min; in step S3, the rotation speed of the low-speed stirring is 150-300 rpm / min.

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