Perfluoro-hexanone microcapsule fire extinguishing medium and preparation method thereof
Technical Field
The invention belongs to the technical field of fire control, and particularly relates to a perfluoro-hexanone microcapsule fire extinguishing medium and a preparation method thereof.
Background
The perfluoro-hexanone is liquid under the normal condition, the boiling point is 49 ℃, the perfluoro-hexanone can be gasified and volatilized rapidly at normal temperature, and is difficult to preserve and apply, the perfluoro-hexanone is prepared into microcapsules, and the microcapsules are embedded in a high polymer material to form solid molding, so that the perfluoro-hexanone is a good curing and application scheme.
In the prior art, the perfluorohexanone is made into capsules (comprising a capsule shell and a capsule core), and capsule bodies with different trigger temperatures can be obtained by adjusting the formula (the particle size of the capsule bodies is usually changed along with the adjustment of the formula). The applicant found that the stability and fire extinguishing effect of the perfluorinated hexanone are also related to the particle size, and that the stability and fire extinguishing effect of the product can be ensured by round particles, capsule shells with certain hardness and relatively stable particle size.
Disclosure of Invention
In order to solve the problems, the invention provides the perfluorinated hexanone microcapsule fire extinguishing medium and the preparation method thereof, products with different trigger temperatures can be obtained by adjusting the proportion of aluminum hydroxide and potassium nitrate, the particle size change is small under different formulas, and the perfluorinated hexanone microcapsule fire extinguishing medium has the advantages of round molding, good wrapping effect and the like. The technical scheme is as follows:
on one hand, the embodiment of the invention provides a perfluorinated hexanone microcapsule fire extinguishing medium, which comprises a capsule shell and a capsule core, wherein the mass ratio of the capsule core to the capsule shell is 40-65:30-45. Wherein the capsule core comprises perfluoro-hexanone, silicon dioxide, azodiisobutyronitrile and the like, and the mass ratio of the perfluoro-hexanone to the silicon dioxide to the azodiisobutyronitrile is 100:1.0-3.5:0.1-0.3. The capsule shell is prepared from chitosan, acrylic resin, aluminum hydroxide, an emulsifier, potassium nitrate and the like, wherein the mass ratio of the chitosan to the acrylic resin to the aluminum hydroxide to the emulsifier to the potassium nitrate is 125-160:8-14:20-50:7-15:10-30. Wherein, silicon dioxide and azodiisobutyronitrile are used as stabilizing agents for improving the stability of the capsule core. Chitosan is the main component of the capsule shell. The addition of a small amount of acrylic resin can improve the hardness of the capsule shell and ensure that the capsule shell is more round and the particle size distribution is more stable. The potassium nitrate is used as an oxidant, the triggering temperature can be increased by increasing the dosage, and the triggering temperature can be reduced by reducing the dosage. The role of aluminum hydroxide is several: firstly, as a lifting trigger regulator, the use amount can be increased to reduce the trigger temperature, and the use amount can be reduced to lift the trigger temperature; secondly, as a filler, the hardness of the capsule shell is improved; thirdly, the product is precipitated faster as a flocculating agent, and the precipitation temperature is controllable.
Wherein the particle size of the perfluoro-hexanone microcapsule fire extinguishing medium is 40-100 mu m, the ratio of less than 40 μm and more than 100 μm is less than 5%, and aluminum hydroxide is adjusted (by reasoning, aluminum hydroxide as a flocculant and filler, the effect of which on particle size should be large, in practice very small) and the effect of potassium nitrate on particle size should be very small.
The triggering temperature of the perfluorinated hexanone microcapsule fire extinguishing medium is 135-150 ℃, and the triggering temperature can be realized by adjusting the dosage of aluminum hydroxide and potassium nitrate so as to adapt to different scenes.
Wherein, the emulsifier in the embodiment of the invention is selected from SR-20, ER-30 or ER-10, etc. Preferably, the emulsifier comprises SR-20 and ER-10, and the mass ratio of SR-20 to ER-10 is 1:1-3. More preferably, the emulsifier comprises SR-20 and ER-10, and the mass ratio of SR-20 to ER-10 is 1:2. wherein SR-20 is an anionic emulsifier, and ER-30 or ER-10 is a nonionic emulsifier.
Preferably, the embodiment of the invention provides a perfluorinated hexanone microcapsule fire extinguishing medium, which comprises a capsule shell and a capsule core, wherein the mass ratio of the capsule core to the capsule shell is 50:33. wherein the capsule core comprises perfluoro-hexanone, silicon dioxide and azodiisobutyronitrile, and the mass ratio of the perfluoro-hexanone to the silicon dioxide to the azodiisobutyronitrile is 100:2:0.2. wherein the capsule shell is prepared from chitosan, acrylic resin, aluminum hydroxide, an emulsifier and potassium nitrate, and the mass ratio of the chitosan to the acrylic resin to the aluminum hydroxide to the emulsifier to the potassium nitrate is 150:10:20-50:12:10-30. Wherein the emulsifier comprises SR-20 and ER-10, and the mass ratio of SR-20 to ER-10 is 1:2.
on the other hand, the invention also provides a preparation method of the perfluorinated hexanone microcapsule fire extinguishing medium, which comprises the following steps:
(1) And uniformly mixing the perfluoro-hexanone, the silicon dioxide and the azodiisobutyronitrile according to the proportion at room temperature to obtain the fire extinguishing agent liquid, wherein the stirring speed is 2000-3000r/min, and the stirring time is more than 1h.
(2) At room temperature, potassium nitrate is dissolved in chitosan acetic acid aqueous solution according to the proportion to prepare a water phase; wherein the concentration of the acetic acid is 1-2% (volume concentration), and the concentration of the chitosan is as high as possible.
(3) Slowly adding fire extinguishing agent liquid, acrylic resin and emulsifying agent into water phase at 20-45deg.C, and emulsifying at high speed to obtain emulsion; the stirring speed is more than 3500r/min, and the emulsifying time is 2.0-3.5h.
(4) Adding aluminum hydroxide according to a proportion under the condition of 20-45 ℃, stirring for 30-60min at the stirring speed of 200-500r/min, and standing for 1-2h.
(5) Filtering (specifically, suction filtration), washing with water and vacuum drying (the temperature is preferably less than 40 ℃) the product of the step (4) to obtain the perfluorinated hexanone microcapsule fire extinguishing medium.
The invention has the following advantages:
(1) The triggering temperature can be adjusted by adjusting aluminum hydroxide and potassium nitrate, for example, the triggering temperature can be adjusted to 140 ℃ and 150 ℃, and the aluminum hydroxide and potassium nitrate are mainly used for fireproof patches;
(2) The product quality is stable, the storage temperature is between minus 30 ℃ and 60 ℃, and the effective time is 60 months after installation;
(3) The capsule particles have stable size (are too large to be broken and unstable in forming, are too small to be hardened and have larger wall thickness to influence the fire extinguishing effect), moderate hardness and round surface, and ensure the fire extinguishing effect and stability;
(4) The fire extinguishing effect is good, and the fire extinguishing time is less than 10s under the recommended use amount.
Drawings
FIG. 1 is an electron microscopic view of the perfluoro-hexanone microcapsule fire extinguishing medium produced in example 1;
fig. 2 is a partial enlarged view of fig. 1.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings, for the purpose of making the objects, technical solutions and advantages of the present invention more apparent.
Example 1
The embodiment 1 provides a preparation method of a perfluorinated hexanone microcapsule fire extinguishing medium, which comprises the following steps:
(1) At room temperature, 490 parts by weight of perfluorinated hexanone, 10 parts by weight of silicon dioxide and 1 part by weight of azodiisobutyronitrile are uniformly mixed according to the proportion to obtain the fire extinguishing agent liquid, the stirring speed is 2500r/min, and the stirring time is 2h.
(2) At room temperature, potassium nitrate is dissolved in chitosan acetic acid aqueous solution according to the proportion to prepare a water phase; wherein the amount of potassium nitrate was 42 parts by weight, the amount of chitosan was 225 parts by weight, and the amount of acetic acid was small, and the present example did not include the amount of acetic acid.
(3) Slowly adding 15 parts by weight of the fire extinguishing agent liquid obtained in the step (1), 15 parts by weight of the acrylic resin, 6 parts by weight of SR-20 and 12 parts by weight of ER-10 into the water phase obtained in the step (2) at the temperature of 30 ℃ and emulsifying at a high speed to obtain an emulsion; the stirring speed is 4000r/min, and the emulsifying time is 3h.
(4) At 30 ℃, 30 parts by weight of aluminum hydroxide is added according to the proportion, and the mixture is stirred for 50min at the stirring speed of 300r/min and then is kept stand for 2h.
(5) And (3) carrying out suction filtration, water washing and vacuum drying (the temperature is 30 ℃) on the product of the step (4) to obtain the perfluoro-hexanone microcapsule fire extinguishing medium.
Example 2
The embodiment 2 provides a preparation method of a perfluorinated hexanone microcapsule fire extinguishing medium, which comprises the following steps:
(1) At room temperature, 490 parts by weight of perfluorinated hexanone, 10 parts by weight of silicon dioxide and 1 part by weight of azodiisobutyronitrile are uniformly mixed according to the proportion to obtain the fire extinguishing agent liquid, the stirring speed is 2500r/min, and the stirring time is 2h.
(2) At room temperature, potassium nitrate is dissolved in chitosan acetic acid aqueous solution according to the proportion to prepare a water phase; wherein the amount of potassium nitrate was 15 parts by weight, the amount of chitosan was 225 parts by weight, and the amount of acetic acid was small, and the present example did not include the amount of acetic acid.
(3) Slowly adding 15 parts by weight of the fire extinguishing agent liquid obtained in the step (1), 15 parts by weight of the acrylic resin, 6 parts by weight of SR-20 and 12 parts by weight of ER-10 into the water phase obtained in the step (2) at 25 ℃ and emulsifying at a high speed to obtain an emulsion; the stirring speed is 4000r/min, and the emulsifying time is 3h.
(4) 58 parts by weight of aluminum hydroxide is added according to the proportion under the condition of 25 ℃, stirred for 50min at the stirring speed of 300r/min, and then kept stand for 2h.
(5) And (3) carrying out suction filtration, water washing and vacuum drying (the temperature is 35 ℃) on the product of the step (4) to obtain the perfluoro-hexanone microcapsule fire extinguishing medium.
Example 3
Embodiment 3 provides a preparation method of a perfluorinated hexanone microcapsule fire extinguishing medium, which comprises the following steps:
(1) At room temperature, 490 parts by weight of perfluorinated hexanone, 10 parts by weight of silicon dioxide and 1 part by weight of azodiisobutyronitrile are uniformly mixed according to the proportion to obtain the fire extinguishing agent liquid, the stirring speed is 2500r/min, and the stirring time is 2.5h.
(2) At room temperature, potassium nitrate is dissolved in chitosan acetic acid aqueous solution according to the proportion to prepare a water phase; wherein the amount of potassium nitrate was 27 parts by weight, the amount of chitosan was 225 parts by weight, and the amount of acetic acid was small, and the present example did not include the amount of acetic acid.
(3) Slowly adding 15 parts by weight of the fire extinguishing agent liquid obtained in the step (1), 15 parts by weight of the acrylic resin, 6 parts by weight of SR-20 and 12 parts by weight of ER-10 into the water phase obtained in the step (2) at 40 ℃ and emulsifying at a high speed to obtain an emulsion; the stirring speed was 4200r/min and the emulsification time was 2.5h.
(4) 45 parts by weight of aluminum hydroxide is added according to the proportion under the condition of 30 ℃, stirred for 50min at the stirring speed of 200r/min, and then kept stand for 1.5h.
(5) And (3) carrying out suction filtration, water washing and vacuum drying (the temperature is 30 ℃) on the product of the step (4) to obtain the perfluoro-hexanone microcapsule fire extinguishing medium.
Comparative example 1
Comparative example 1 is substantially the same as example 1 except that: 225 parts by weight of chitosan was directly added without adding acrylic resin.
Comparative example 2
Comparative example 2 is substantially the same as example 2 except that: 225 parts by weight of chitosan was directly added without adding acrylic resin.
Comparative example 3
Comparative example 3 is substantially the same as example 1 except that: in the step (4), 30 parts by weight of alumina was added and left standing for 5 hours.
Particle size ratio test, the results are shown in table 1:
TABLE 1
It can be seen from examples 1-3 and comparative examples 1-2 that the particle size in this example is not substantially affected by the amount of aluminum hydroxide used; as can be seen from comparative examples 1 and 2, the particle size variation was large without adding acrylic resin; as can be seen from comparative example 3, without adding aluminum hydroxide, the size distribution range of the particles is large and the particle diameter is small. From fig. 1-2 (processed to make the image more clear), the particles prepared in this example had round surfaces and were substantially free of broken particles.
Fire extinguishing test
The product was made into a fire extinguishing patch with dimensions 34mm 24mm 3mm, a protective volume 70L, and a weight of 60g. The results are shown in Table 2:
TABLE 2
It can be seen from table 2 that in this patent, since the particle size is stable, adjusting the ratio can adjust the trigger temperature, but the effect on fire extinguishing is not much. It can be seen from examples 1-2 and comparative examples 1-2 that the addition of the acrylic resin has an effect on the trigger temperature and the extinguishing effect, and that the trend of the trigger temperature is changed and the extinguishing effect is changed due to the difference in the capsule particle size from example 1 to comparative example 1 and from example 2 to comparative example 2. As can be seen from comparative example 3, the particle distribution is very dispersed due to the very poor flocculation effect of alumina, and the applicant suspects that part of the capsules are broken, resulting in a higher trigger temperature and a poor fire extinguishing effect.
The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the precise form disclosed, and any such modifications, equivalents, and alternatives falling within the spirit and scope of the invention are intended to be included within the scope of the invention.