Fireproof core material and preparation method thereof, application of fireproof core material and composite board

Abstract

The invention relates to the technical field of building materials, in particular to a fireproof core material, a preparation method of the fireproof core material, application of the fireproof core material and a composite board. S2, under ultrasonic vibration, adding a sodium hydroxide solution into the mixed solution for reaction, and after the reaction is finished, filtering and drying to obtain hollow microspheres loaded with aluminum hydroxide / magnesium hydroxide on the surfaces, and then, carrying out spray drying on the hollow microspheres loaded with the aluminum hydroxide / magnesium hydroxide on the surfaces of the hollow microspheres to obtain the hollow microspheres loaded with the aluminum hydroxide / magnesium hydroxide on the surfaces of the hollow microspheres. And S3, mixing the hollow microspheres loaded with aluminum hydroxide / magnesium hydroxide on the surfaces with a flame retardant, an adhesive and an auxiliary agent to prepare slurry, and pressing and shaping to obtain the fireproof core material. The prepared fireproof core material has the functions of light weight, heat preservation, heat insulation, sound insulation, firmness and fire prevention.

Description

Technical Field

[0001] The present invention relates to the field of building fireproof materials, in particular to a fireproof core material, a preparation method thereof, an application of the fireproof core material, and a composite board. Background Art

[0002] Building fire prevention and heat preservation have become the main concerns in the current construction industry. Due to its dense structure, the traditional inorganic core material has poor heat insulation effect. In order to meet both fire prevention and heat preservation simultaneously, it is necessary to modify the existing inorganic core material. Fly ash cenospheres, as a kind of waste recycling, have a thin-walled hollow structure. The outer shell is composed of oxides, and the core usually contains inert gases such as CO2 and N2. Fly ash cenospheres have a low thermal conductivity and high-temperature heat insulation performance. In addition, due to the high refractive index and large reflection coefficient of the hollow microspheres, they can effectively reduce radiative heat transfer and eliminate convective heat transfer. Moreover, the hollow structure and the internal inert gas can also hinder the transmission of sound waves. Therefore, fly ash cenospheres are a kind of lightweight, economical and effective inorganic core material, which can reduce the density of the inorganic core material and increase its heat preservation and sound absorption effects.

[0003] However, although fly ash cenospheres are currently added to inorganic core materials, their addition amount is usually less than 10%, and it is impossible to effectively achieve the effects of light weight, sound absorption and heat preservation. The reasons for the small addition amount of fly ash cenospheres include that the existing preparation methods cannot effectively combine them with other flame-retardant inorganic substances, which will lead to a reduction in the mechanical properties of the inorganic core material. At the same time, the interfacial problem of poor combination will damage the flame-retardant performance of the core material. For this reason, the present invention proposes a fireproof core material, a preparation method thereof, an application of the fireproof core material, and a composite board. Summary of the Invention

[0004] In order to solve the problems in the prior art, the present invention proposes a fireproof core material, a preparation method thereof, an application of the fireproof core material, and a composite board.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The first aspect of the present invention proposes a preparation method of a fireproof core material, including the following steps:

[0007] S1: Spray-etch the surface of fly ash cenospheres with hydrochloric acid solution, then dry them, and then spray the etched and dried fly ash cenospheres with sodium hydroxide solution to obtain hollow microspheres with in-situ loaded aluminum hydroxide.

[0008] In some embodiments, the fly ash hollow microspheres have an average particle size of 20 - 50 μm, a wall thickness of 2 - 5 μm, a spray etching depth of 100 - 200 nm. The components of the fly ash hollow microspheres include 30 - 45 wt% Al2O3, 50 - 65 wt% SiO2, Fe2O3, MgO and other components, and the oxide components are less than 8%.

[0009] Silicon dioxide is inert and does not react with dilute hydrochloric acid solution. Aluminum oxide can react with dilute hydrochloric acid solution to form aluminum chloride and water. Therefore, selective etching occurs under the action of hydrochloric acid solution spray, and the etching depth is about 100 - 200 nanometers. A relatively dilute and short - term dilute hydrochloric acid spray will not damage the thin wall of the hollow microspheres. Due to the occurrence of the reaction, part of the aluminum oxide on the surface of the hollow microspheres is etched, and at the same time, aluminum chloride is in - situ generated in the etched area, forming aluminum chloride with a rough surface and good bonding with the microspheres. Due to the matching of the droplet spray particle size and the microsphere particle size, the dilute hydrochloric acid spray droplets can wrap the hollow microspheres and etch evenly on the surface.

[0010] After the etching of fly ash is completed, it is dried to remove the moisture on its surface. Then, sodium hydroxide solution is sprayed. The sodium hydroxide droplets can react with the aluminum chloride in - situ generated in the etched area to form aluminum hydroxide precipitate, which is loaded in the etched area, thus precisely forming nano - aluminum hydroxide with a certain bonding strength in - situ on the etched surface of the fly ash hollow microspheres.

[0011] S2: Put the hollow microspheres loaded with aluminum hydroxide into a mixed solution containing Mg 2+ 、Al 3+ Under ultrasonic vibration, preferably, the frequency of ultrasonic vibration is 10000 - 20000 Hz. Add sodium hydroxide solution to the mixed solution for reaction. After the reaction is completed, filter and dry to obtain hollow microspheres with aluminum hydroxide / magnesium hydroxide loaded on the surface. Preferably, the loading thickness is 2 - 5 μm.

[0012] Turn on the ultrasonic vibration and gradually add sodium hydroxide solution to the solution relatively quickly at the same time. Sodium hydroxide will react with Mg 2+ 、Al 3+The reaction produces magnesium hydroxide and aluminum hydroxide. Within the solubility ranges of both, as the reaction progresses, there is a tendency for magnesium hydroxide and aluminum hydroxide precipitates to start appearing in the solution. A nano-scale hydroxide suspension will gradually form in the solution. The surface of the fly ash cenosphere is etched and in-situ loaded with nano-aluminum hydroxide, which provides "crystal nuclei" to guide the positions where magnesium hydroxide and aluminum hydroxide form precipitates. The two nano-scale hydroxides will combine with the nano-aluminum hydroxide formed in-situ and grow. First, they adsorb on the surface of the in-situ etched aluminum hydroxide. As the precipitates are continuously loaded, aluminum hydroxide and magnesium hydroxide extend to the outside of the etched area. The aluminum hydroxide and magnesium hydroxide on the outside of two adjacent etched areas will continuously crystallize and the aluminum hydroxide and magnesium hydroxide will be loaded on the surface of the fly ash cenosphere between them. As the precipitates accumulate, the cenosphere forms a fly ash composite microsphere coated with nano-magnesium hydroxide and nano-aluminum hydroxide. In addition, under the action of ultrasonic vibration, the agglomeration of fly ash cenospheres can be avoided.

[0013] S3: Mix the hollow microspheres with surface-loaded aluminum hydroxide / magnesium hydroxide with a flame retardant, an adhesive, and an additive to form a slurry, and then obtain a fireproof core material through pressing and shaping.

[0014] In some embodiments, in S1, the hydrochloric acid content of the hydrochloric acid solution is 2-4 wt%, the spray droplet diameter of the hydrochloric acid solution is 30-60 μm, the volume of the hydrochloric acid solution sprayed and etched per kilogram of fly ash cenospheres is 0.5-0.6 L, the etching time is 6-10 s; the drying temperature is 50-80 °C, and the drying time is 20-30 min.

[0015] In some embodiments, in S2, the hollow microspheres with in-situ loaded aluminum hydroxide: Mg 2+ : Al 3+ : The mass ratio of sodium hydroxide is: 100: 3-5: 3-5: 25-30. The mass ratio of the mixed solution containing Mg 2+ and Al 3+ to the hollow microspheres with in-situ loaded aluminum hydroxide is 3-5: 1, and the sodium hydroxide content of the sodium hydroxide solution is 40-45 wt%.

[0016] In some embodiments, in S2, the mixed solution containing Mg 2+ and Al 3+ includes Mg 2+ and Al 3+Cl, Br, and / or I salt solution, wherein the solute content of the Cl salt solution is 50 - 55 wt%, and the mass ratio of magnesium chloride to aluminum chloride is 0.4 - 0.6; the sodium hydroxide content of the sodium hydroxide solution is 40 - 45 wt%, the spray droplet size of the sodium hydroxide solution in S1 is 5 - 10 μm, and the spray volume of the sodium hydroxide solution per kilogram of fly ash hollow microspheres is 0.02 - 0.05 L.

[0017] In some embodiments, the flame retardant includes at least one of magnesium hydroxide, aluminum hydroxide, and magnesite powder; the particle sizes of magnesium hydroxide and aluminum hydroxide are 5 - 10 μm, and the particle size of magnesite powder is 80 - 120 μm;

[0018] The binder includes polyurethane glue; the additives include glass fiber, water, and siliceous fossil powder; the length of the glass fiber is less than 20 mm.

[0019] In some embodiments, in S3, the preparation steps of the slurry include, by weight, first mixing 40 - 60 parts of hollow microspheres with aluminum hydroxide / magnesium hydroxide loaded on the surface with 10 - 20 parts of magnesium hydroxide, 10 - 20 parts of aluminum hydroxide, and 8 - 15 parts of magnesite powder to obtain a mixture, and then taking 50 parts of the mixture and mixing it evenly with 1 - 2.5 parts of siliceous fossil powder, 22.5 - 27.5 parts of polyurethane glue, 22.5 - 27.5 parts of water, and 9 - 11 parts of glass fiber to obtain the slurry;

[0020] The pressing and shaping process includes extruding the slurry and the non - woven fabric from the roller at the same time, covering the non - woven fabric on the upper and lower surfaces of the slurry, then keeping it warm at 150 °C under the pressure of 2 - 5 MPa of the pressing roller for 10 - 20 minutes, removing the surface non - woven fabric to obtain the shaped fire - proof core material, and finally continuously pressing it 8 - 10 times at 100 - 130 °C to obtain the fire - proof core material with the required thickness.

[0021] In the second aspect of the present invention, a fire - proof core material prepared according to the above - mentioned preparation method is proposed. The fly ash hollow microspheres in the fire - proof core material have a hollow structure inside and are loaded with magnesium hydroxide / aluminum hydroxide precipitate on the outer surface.

[0022] In the third aspect of the present invention, the application of the fire - proof core material in the construction field and the field of fire - proof materials is proposed.

[0023] In the fourth aspect of the present invention, a composite board including the above - mentioned fire - proof core material is proposed.

[0024] In the fifth aspect of the present invention, a preparation method of a composite board is proposed. The steps include: shaping the fire - proof core material into a fire - proof core material board with a predetermined size, placing metal laminates or wooden boards on both sides of the fire - proof core material board, placing a polymer bonding film between the fire - proof core material board and the metal laminate, and pressing and compounding them at 110 - 130 °C to obtain the composite board.

[0025] Advantages of the present invention:

[0026] 1. By means of dilute hydrochloric acid spray etching and solution co-precipitation, nano magnesium hydroxide and aluminum hydroxide layers are in-situ generated on the surface of fly ash hollow microspheres, thereby increasing the bonding strength between the hollow microspheres and inorganic substances during the subsequent mixing and pressing processes of the core material, and obtaining a lightweight sound-absorbing, heat-insulating and fire-proof core material with good performance;

[0027] 2. After etching and reaction modification of the surface of fly ash hollow microspheres, magnesium hydroxide and aluminum hydroxide are loaded on the surface of fly ash hollow microspheres. There is a strong bonding force between the crystallized magnesium hydroxide and aluminum hydroxide, enhancing the firmness of fly ash hollow microspheres. The bonding strength between the aluminum hydroxide and magnesium hydroxide loaded on the surface of fly ash hollow microspheres and other flame-retardant inorganic substances is high. Therefore, a large amount of fly ash hollow microspheres can be added, up to 60%. Compared with the prior art, in the case of the same volume, the present invention significantly reduces the density of the fire-proof core material, making the weight of the fire-proof core material lower and achieving the purpose of light weight;

[0028] 3. The present invention increases the dosage of fly ash hollow microspheres. Compared with the prior art, in the case of the same volume, the content of other inorganic flame retardants in the core material is reduced, but the fire-proof performance of the core material does not decline and still reaches Class A2. Because there is also a layer of nano magnesium hydroxide and aluminum hydroxide on the surface of the hollow microspheres, and the hollow microspheres have good heat resistance, the hollow microspheres also become effective flame-retardant inorganic substances;

[0029] 4. The fly ash hollow microspheres of the present invention always maintain an internal hollow sealed structure, and there are also CO2 and N2 gases inside. The flame-retardant effect is excellent, blocking the transfer of heat, having a heat-insulating and heat-preserving effect. The fly ash hollow microspheres have the characteristic of low thermal conductivity, and the addition of a high content thereof significantly reduces the thermal conductivity of the fire-proof core material, thereby improving the heat preservation and effect of the core material;

[0030] 5. As the addition amount of fly ash hollow microspheres in the fire-proof core material increases, the proportion of porous materials in the fire-proof core material increases. The internal pore structure of the fly ash hollow microspheres can hinder the propagation of sound, and the transition of its surface nano-structure can also reduce sound through resonance effect, having a sound-absorbing and noise-proof effect. Brief description of the drawings

[0031] Figure 1 It is a scanning photograph of fly ash hollow microspheres with nano aluminum hydroxide and magnesium hydroxide loaded on the surface of the present invention.

[0032] Figure 2 It is a cross-sectional view of fly ash hollow microspheres with nano aluminum hydroxide and magnesium hydroxide loaded on the surface. Detailed implementation manners

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Apparently, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0034] For the test materials, reagents, etc. used in the following embodiments, unless otherwise specified, they are all existing and can be obtained from commercial channels. For those not indicating specific technologies or conditions in the embodiments, they can all be carried out according to the conventional technologies or conditions disclosed in the art.

[0035] In the following embodiments, the mixed solution containing Mg 2+ , Al 3+ is a mixed solution of magnesium chloride and aluminum chloride. The solute content in the mixed solution is 10 - 25 wt%, and the mass ratio of magnesium chloride to aluminum chloride is 0.8; the sodium hydroxide content in the sodium hydroxide solution is 40 wt%, and the droplet size of the sodium hydroxide spray is 5 - 10 μm; the average particle size of the fly ash cenospheres is 20 - 50 μm, and the wall thickness is 2 - 5 μm. The components of the fly ash cenospheres include 30 - 45 wt% Al2O3, 50 - 65 wt% SiO2, Fe2O3, MgO and other components, and the oxide components are less than 8%; the hydrochloric acid content in the dilute hydrochloric acid solution is 3 wt%, and the droplet size of the hydrochloric acid solution spray is 30 - 60 μm.

[0036] Example 1

[0037] S1. Dilute hydrochloric acid spray etching: Spread 100 parts of fly ash cenospheres flatly under the spray equipment, and uniformly spray-etch the fly ash cenospheres with dilute hydrochloric acid according to the ratio of 0.5 L of hydrochloric acid solution per kilogram of fly ash cenospheres for spray etching, and the spray etching time is 6 s;

[0038] Drying: Place the fly ash cenospheres after dilute hydrochloric acid spray etching in an oven, set the temperature to 50 °C, and dry for 20 min;

[0039] Sodium hydroxide solution surface spray precipitation: Spread the dried fly ash cenospheres flatly under the spray equipment, and spray the sodium hydroxide solution according to the ratio of 0.02 L of sodium hydroxide solution per kilogram of fly ash cenospheres for 1 min to obtain hollow microspheres with in-situ loaded aluminum hydroxide by etching.

[0040] S2. Surface loading of aluminum hydroxide / magnesium hydroxide: Put the hollow microspheres loaded with aluminum hydroxide into 270 parts of a mixed solution of 20 wt% magnesium chloride and aluminum chloride. Turn on the ultrasonic vibration, set the frequency of the ultrasonic vibration to 15,000 Hz, add 75 parts of a 40 wt% sodium hydroxide solution to the mixed solution, react for 2 minutes, filter, and put the filter residue into an oven. Set the temperature to 50 °C and dry for 20 minutes to obtain hollow microspheres with aluminum hydroxide / magnesium hydroxide surface loaded.

[0041] S3. Preparation of the core material:

[0042] Slurry preparation: Take 40 parts of the hollow microspheres with aluminum hydroxide / magnesium hydroxide surface loaded and first mix them evenly with 10 parts of magnesium hydroxide, 10 parts of aluminum hydroxide, and 8 parts of magnesite powder to obtain a mixture. Take 50 parts of the mixture and mix it evenly with 1 part of siliceous fossil powder, 22.5 parts of polyurethane glue, 22.5 parts of water, and 9 parts of glass fiber to obtain a slurry;

[0043] Pressing and shaping: Extrude the slurry and non-woven fabric from the roller at the same time, cover the upper and lower surfaces of the slurry with non-woven fabric, then keep it warm for 10 minutes under the action of a temperature of 150 °C and a pressure roller pressure of 2 MPa, remove the surface non-woven fabric to obtain a shaped fireproof core material, and finally continuously press it 8 times in the pressure roller at 100 °C to obtain a fireproof core material with the required thickness.

[0044] Example 2

[0045] S1. Dilute hydrochloric acid spray etching: Spread 100 parts of fly ash hollow microspheres flat under the spray equipment, and uniformly spray-etch the fly ash hollow microspheres with dilute hydrochloric acid according to the ratio of 0.5 L of hydrochloric acid solution per kilogram of fly ash hollow microspheres for spray etching, and the spray etching time is 8 s;

[0046] Drying: Place the fly ash hollow microspheres after dilute hydrochloric acid spray etching in an oven, set the temperature to 60 °C, and dry for 25 minutes;

[0047] Sodium hydroxide solution surface spray precipitation: Spread the dried fly ash hollow microspheres flat under the spray equipment, spray the sodium hydroxide solution according to the ratio of 0.03 L of sodium hydroxide solution per kilogram of fly ash hollow microspheres for spray, and the reaction time is 3 minutes to obtain hollow microspheres with in-situ loaded aluminum hydroxide by etching.

[0048] S2. Surface loading of aluminum hydroxide / magnesium hydroxide: Put the hollow microspheres loaded with aluminum hydroxide into 270 parts of a mixed solution of 20 wt% magnesium chloride and aluminum chloride. Turn on the ultrasonic vibration, set the frequency of the ultrasonic vibration to 15000 Hz, add 75 parts of a 40 wt% sodium hydroxide solution to the mixed solution, react for 2 min, filter, and put the filter residue into an oven. Set the temperature to 50 °C and dry for 20 min to obtain hollow microspheres with aluminum hydroxide / magnesium hydroxide surface-loaded.

[0049] S3. Preparation of the core material:

[0050] Slurry preparation: Take 50 parts of the hollow microspheres with aluminum hydroxide / magnesium hydroxide surface-loaded and first mix them evenly with 15 parts of magnesium hydroxide, 15 parts of aluminum hydroxide, and 12 parts of magnesite powder to obtain a mixture. Take 50 parts of the mixture and mix it evenly with 2 parts of siliceous fossil powder, 25 parts of polyurethane glue, 25 parts of water, and 10 parts of glass fiber to obtain a slurry;

[0051] Pressing and shaping: Extrude the slurry and non-woven fabric from the rollers at the same time, cover the upper and lower surfaces of the slurry with non-woven fabric, then keep it warm for 10 minutes under the action of a temperature of 150 °C and a roller pressure of 2 MPa, remove the surface non-woven fabric to obtain a shaped fireproof core material, and finally continuously press it 9 times in the roller at 100 °C to obtain a fireproof core material with the required thickness.

[0052] Example 3

[0053] S1. Dilute hydrochloric acid spray etching: Spread 100 parts of fly ash hollow microspheres flat under the spray equipment, and uniformly carry out dilute hydrochloric acid spray etching on the fly ash hollow microspheres according to the ratio that the volume of the hydrochloric acid solution for spray etching per kilogram of fly ash hollow microspheres is 0.5 L, and the spray etching time is 8 s;

[0054] Drying: Place the fly ash hollow microspheres after dilute hydrochloric acid spray etching in an oven, set the temperature to 60 °C, and dry for 25 min;

[0055] Sodium hydroxide solution surface spray precipitation: Spread the dried fly ash hollow microspheres flat under the spray equipment, carry out sodium hydroxide solution spray according to the ratio that the spray volume of the sodium hydroxide solution per kilogram of fly ash hollow microspheres is 0.03 L, and the reaction time is 3 min to obtain hollow microspheres with aluminum hydroxide etched and in-situ loaded.

[0056] S2. Surface loading of aluminum hydroxide / magnesium hydroxide: Put the hollow microspheres loaded with aluminum hydroxide into 270 parts of a mixed solution of 20 wt% magnesium chloride and aluminum chloride. Turn on the ultrasonic vibration, set the frequency of the ultrasonic vibration to 15000 Hz, add 75 parts of a 40 wt% sodium hydroxide solution to the mixed solution, react for 2 min, filter, and put the filter residue into an oven. Set the temperature to 50 °C and dry for 20 min to obtain hollow microspheres with aluminum hydroxide / magnesium hydroxide surface-loaded.

[0057] S3. Preparation of the core material:

[0058] Slurry preparation: Take 40 parts of the hollow microspheres with aluminum hydroxide / magnesium hydroxide surface-loaded and first mix them evenly with 20 parts of magnesium hydroxide, 20 parts of aluminum hydroxide, and 15 parts of magnesite powder to obtain a mixture. Take 50 parts of the mixture and mix it evenly with 2.5 parts of siliceous fossil powder, 27.5 parts of polyurethane glue, 25 parts of water, and 11 parts of glass fiber to obtain a slurry;

[0059] Pressing and shaping: Extrude the slurry and non-woven fabric from the roller at the same time, cover the upper and lower surfaces of the slurry with non-woven fabric, then keep it warm for 10 minutes under the action of a temperature of 150 °C and a roller pressure of 2 MPa, remove the surface non-woven fabric to obtain a shaped fireproof core material, and finally continuously press it 9 times in the roller at 100 °C to obtain a fireproof core material with the required thickness.

[0060] Example 4

[0061] S1. Dilute hydrochloric acid spray etching: Spread 100 parts of fly ash hollow microspheres flatly under the spray equipment, and uniformly spray-etch the fly ash hollow microspheres with dilute hydrochloric acid according to the ratio that the volume of the hydrochloric acid solution for spray etching per kilogram of fly ash hollow microspheres is 0.6 L. The spray etching time is 10 s;

[0062] Drying: Place the fly ash hollow microspheres after dilute hydrochloric acid spray etching in an oven, set the temperature to 80 °C, and dry for 30 min;

[0063] Sodium hydroxide solution surface spray precipitation: Spread the dried fly ash hollow microspheres flatly under the spray equipment, spray the sodium hydroxide solution according to the ratio that the spray volume of the sodium hydroxide solution per kilogram of fly ash hollow microspheres is 0.05 L, and the reaction time is 3 min to obtain hollow microspheres with aluminum hydroxide etched and in-situ loaded.

[0064] S2. Surface loading of aluminum hydroxide / magnesium hydroxide: Put the hollow microspheres loaded with aluminum hydroxide into 270 parts of a mixed solution of 20 wt% magnesium chloride and aluminum chloride. Turn on the ultrasonic vibration, set the frequency of the ultrasonic vibration to 15,000 Hz, add 75 parts of a 40 wt% sodium hydroxide solution to the mixed solution, react for 2 minutes, filter, and put the filter residue into an oven. Set the temperature to 50 °C and dry for 20 minutes to obtain hollow microspheres with aluminum hydroxide / magnesium hydroxide surface loaded.

[0065] S3. Preparation of the core material:

[0066] Slurry preparation: Take 60 parts of the hollow microspheres with aluminum hydroxide / magnesium hydroxide surface loaded and first mix them evenly with 20 parts of magnesium hydroxide, 20 parts of aluminum hydroxide, and 15 parts of magnesite powder to obtain a mixture. Take 50 parts of the mixture and mix it evenly with 2.5 parts of silicified stone powder, 27.5 parts of polyurethane glue, 27.5 parts of water, and 11 parts of glass fiber to obtain a slurry;

[0067] Pressing and shaping: Extrude the slurry and non-woven fabric from the roller at the same time, cover the upper and lower surfaces of the slurry with non-woven fabric, then keep it warm for 20 minutes under the action of a temperature of 150 °C and a roller pressure of 5 MPa, remove the surface non-woven fabric to obtain a shaped fireproof core material, and finally continuously press it 10 times in the roller at 130 °C to obtain a fireproof core material with the required thickness.

[0068] Example 5

[0069] Composite board preparation: Arbitrarily take the fireproof core materials of Examples 1-4, shape the fireproof core materials into fireproof core boards of a predetermined size, place metal laminates or wooden boards on both sides of the fireproof core boards, place a polymer bonding film between the fireproof core boards and the metal laminates, and press and compound them at 110-130 °C to obtain a composite board.

[0070] Comparative Example 1 (compared with Example 1, compare the differences between hydrochloric acid spray etching and excessive hydrochloric acid immersion etching, that is, the differences between surface etching and penetration etching of fly ash hollow microspheres)

[0071] The thickness of the fireproof core materials in Examples 1-4 and the comparative example is 4 mm, and the metal laminates (aluminum alloy plates) on both sides are 0.5 mm.

[0072] S1. Dilute hydrochloric acid immersion etching: Put 100 parts of fly ash hollow microspheres in an excessive 3 wt% hydrochloric acid solution and soak for 5 minutes, filter, and dry the filter residue in an oven. Set the temperature to 50 °C and dry for 50 minutes;

[0073] Spray precipitation on the surface of sodium hydroxide solution: Spread the dried fly ash hollow microspheres flat under the spraying equipment, and spray the sodium hydroxide solution according to the ratio of 0.02 L of sodium hydroxide solution sprayed per kilogram of fly ash hollow microspheres, with a reaction time of 1 min, to obtain hollow microspheres with in-situ loaded aluminum hydroxide by etching.

[0074] Steps S2 and S3 are the same as the subsequent steps of Example 1 to prepare the fireproof core material.

[0075] Comparative Example 2 (compared with Example 1, comparing the difference between generating in-situ sodium hydroxide precipitation on the hollow microspheres by sodium hydroxide spraying first, then impregnating the surface of the hollow microspheres with solution to load precipitation and directly impregnating the surface of the hollow microspheres with solution to load precipitation)

[0076] S1. Dilute hydrochloric acid spray etching: Spread 100 parts of fly ash hollow microspheres flat under the spraying equipment, and uniformly spray-etch the fly ash hollow microspheres with dilute hydrochloric acid according to the ratio of 0.5 L of hydrochloric acid solution sprayed per kilogram of fly ash hollow microspheres for spray etching, with a spray etching time of 6 s;

[0077] Drying: Place the fly ash hollow microspheres after dilute hydrochloric acid spray etching in an oven, set the temperature to 50 °C, and dry for 20 min. (Do not perform sodium hydroxide spray precipitation)

[0078] S2: Put the dried fly ash hollow microspheres into 270 parts of a mixed solution of 20 wt% magnesium chloride and aluminum chloride, turn on the ultrasonic vibration, set the frequency of the ultrasonic vibration to 15000 Hz, add 75 parts of 40 wt% sodium hydroxide solution to the mixed solution, react for 2 min, filter, put the filter residue into the oven, set the temperature to 50 °C, and dry for 20 min to obtain hollow microspheres with aluminum hydroxide / magnesium hydroxide loaded on the surface.

[0079] Step S3 is the same as S3 of Example 1.

[0080] Comparative Example 3 (compared with Example 1, comparing the difference between not performing hydrochloric acid solution etching, not performing sodium hydroxide spray precipitation, not growing and loading hydroxides on the surface of the hollow microspheres and directly using fly ash to make the fireproof core material)

[0081] S1 Core material preparation:

[0082] Slurry preparation: Take 40 parts of fly ash hollow microspheres and first mix them evenly with 10 parts of magnesium hydroxide, 10 parts of aluminum hydroxide, and 8 parts of magnesite powder to obtain a mixture. Take 50 parts of the mixture and mix it evenly with 1 part of silica powder, 22.5 parts of polyurethane glue, 22.5 parts of water, and 9 parts of glass fiber to obtain a slurry;

[0083] Pressing and shaping: The slurry and non-woven fabric are simultaneously extruded from the rollers. The non-woven fabric is coated on the upper and lower surfaces of the slurry. Then, after heat preservation for 10 minutes at 150°C under the pressure of 2 MPa of the pressure roller, the surface non-woven fabric is removed to obtain the shaped fireproof core material. Finally, at 100°C, it is continuously pressed 8 times in the pressure roller to obtain the fireproof core material with the required thickness.

[0084] Comparative Example 4 (compared with Example 1, replacing fly ash hollow microspheres with magnesium hydroxide and aluminum hydroxide, the difference without fly ash hollow microspheres)

[0085] S1 Core material preparation:

[0086] Slurry preparation: Take 30 parts of magnesium hydroxide, 30 parts of aluminum hydroxide, and 12 parts of magnesite powder and mix them evenly to obtain a mixture. Take 50 parts of the mixture and mix it evenly with 1 part of siliceous fossil powder, 22.5 parts of polyurethane glue, 22.5 parts of water, and 9 parts of glass fiber to obtain the slurry;

[0087] Pressing and shaping: The slurry and non-woven fabric are simultaneously extruded from the rollers. The non-woven fabric is coated on the upper and lower surfaces of the slurry. Then, after heat preservation for 10 minutes at 150°C under the pressure of 2 MPa of the pressure roller, the surface non-woven fabric is removed to obtain the shaped fireproof core material. Finally, at 100°C, it is continuously pressed 8 times in the pressure roller to obtain the fireproof core material with the required thickness.

[0088] Test example

[0089] The fireproof core materials prepared in Examples 1-4 and Comparative Examples 1-4 were subjected to performance tests according to the following test methods:

[0090] 1. Density test: Cut fireproof core materials with the same volume of 0.4 cm × 20 cm 2 for weighing, density = weight / volume;

[0091] 2. Tensile strength test of the core material: Test according to the standard GB / T 228.1-2021;

[0092] 3. Measure the thermal conductivity of the fireproof core material: Test according to the standard GB / T 10295-2008;

[0093] 4. Fireproof performance test: Test according to the standard GB / T 8624-2012;

[0094] 5. Sound insulation effect test: Test according to the standard GB / T 6881.2-2017.

[0095] The above test results are as follows:

[0096] Table 1. Test data of the fireproof core materials prepared in Examples 1-4 and Comparative Examples 1-4

[0097]

[0098]

[0099] As can be seen from Table 1, the density of the fireproof core material obtained by adding fly ash cenospheres in the present invention is significantly reduced (1.08 - 1.21 g / cm 3 ), much lower than that of the conventional core material (Comparative Example 4, 1.8 g / cm 3 ). Moreover, the greater the addition amount of fly ash cenospheres, the smaller the density of the core material. Due to the addition of cenospheres, the thermal conductivity of the core material is significantly reduced compared with Comparative Examples 1 - 4, the sound insulation effect is enhanced, and the fire protection grade remains A2. It can be seen that the lightweight fireproof core material obtained in the present invention has good heat preservation and sound insulation effects. In Comparative Example 1, due to soaking in hydrochloric acid solution, a large number of cenospheres were corroded and perforated, so the structure of the cenospheres was damaged and the bonding performance was worse (the lowest strength), and the density of the obtained core material increased, and the heat preservation and sound insulation performance was hardly improved. In Comparative Example 2, the cenospheres were directly impregnated with sodium hydroxide solution, and in Comparative Example 3, the cenospheres were not modified. The combination of cenospheres and other inorganic substances was not improved. Although the thermal conductivity and sound insulation performance were improved to some extent, the tensile strength of the core material was relatively low (significantly lower than that of Comparative Example 4).

[0100] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A preparation method of a fireproof core material, characterized in that: It includes the following steps: S1: Spray-etch the surface of fly ash hollow microspheres with hydrochloric acid solution, then dry them. Subsequently, spray the etched and dried fly ash hollow microspheres with sodium hydroxide solution to obtain hollow microspheres with in-situ loaded aluminum hydroxide; S2: Place the hollow microbeads loaded with aluminum hydroxide into a Mg 2+ 、Al 3+ In the mixed solution, sodium hydroxide solution is added to the mixed solution under ultrasonic vibration to react, and after the reaction is completed, the mixture is filtered and dried to obtain hollow microbeads with aluminum hydroxide / magnesium hydroxide loaded on the surface; S3: Mix the hollow microspheres with surface-loaded aluminum hydroxide / magnesium hydroxide with a flame retardant, an adhesive, and an additive to form a slurry, and then obtain a fireproof core material through pressing and shaping.

2. The preparation method of a fireproof core material according to claim 1, characterized in that, In the above S1, the hydrochloric acid content of the hydrochloric acid solution is 2-4 wt%, the spray droplet size of the hydrochloric acid solution is 30-60 μm, the volume of the hydrochloric acid solution for spray-etching per kilogram of fly ash hollow microspheres is 0.5-0.6 L, the etching time is 6-10 s; the drying temperature is 50-80 °C, and the drying time is 20-30 min.

3. The preparation method of a fireproof core material according to claim 2, characterized in that, The average particle size of the fly ash hollow microspheres is 20-50 μm, the wall thickness is 2-5 μm, the spray-etching depth is 100-200 nm, and the components of the fly ash hollow microspheres include 30-45 wt% Al2O3, 50-65 wt% SiO2, Fe2O3, and MgO.

4. The preparation method of a fireproof core material according to claim 1, characterized in that, In S2, etch the hollow microspheres with in-situ loaded aluminum hydroxide: Mg 2+ : Al 3+ : The mass ratio of sodium hydroxide is: 100: 3 - 5: 3 - 5: 25 - 30, containing Mg 2+ , Al 3+ The mass ratio of the mixed solution and the hollow microspheres with in-situ loaded aluminum hydroxide is 3 - 5: 1, and the sodium hydroxide content of the sodium hydroxide solution is 40 - 45 wt%.

5. The preparation method of a fireproof core material according to claim 1, characterized in that, In S2, the mixture solution containing Mg 2+ , Al 3+ includes the Cl, Br, and / or I salt solutions of Mg 2+ , Al 3+ . The solute content of the Cl salt solution is 10-25 wt%, and the mass ratio of magnesium chloride to aluminum chloride is 0.7-1; the sodium hydroxide content of the sodium hydroxide solution is 40-45 wt%, the spray droplet size of the sodium hydroxide solution in S1 is 5-10 μm, and the spray volume of the sodium hydroxide solution per kilogram of fly ash hollow microspheres is 0.02-0.05 L.

6. The preparation method of a fireproof core material according to claim 1, characterized in that, The flame retardant includes at least one of magnesium hydroxide, aluminum hydroxide, and magnesite powder; the particle sizes of magnesium hydroxide and aluminum hydroxide are 5-10 μm, and the particle size of magnesite powder is 80-120 μm; The adhesive includes polyurethane glue; the additives include glass fiber, water, and siliceous powder; the length of the glass fiber is less than 20 mm.

7. The preparation method of a fireproof core material according to claim 6, characterized in that, In the above S3, the preparation steps of the slurry include, by weight, first mixing 40-60 parts of hollow microspheres with surface-loaded aluminum hydroxide / magnesium hydroxide evenly with 10-20 parts of magnesium hydroxide, 10-20 parts of aluminum hydroxide, and 8-15 parts of magnesite powder to obtain a mixture. Take 50 parts of the mixture and mix it evenly with 1-2.5 parts of siliceous powder, 22.5-27.5 parts of polyurethane glue, 22.5-27.5 parts of water, and 9-11 parts of glass fiber to obtain a slurry; The process of pressing and shaping includes extruding the slurry and non-woven fabric from the roller at the same time, covering the non-woven fabric on the upper and lower surfaces of the slurry. Subsequently, after heat preservation for 10-20 minutes under the action of 150 °C and a roller pressure of 2-5 MPa, remove the surface non-woven fabric to obtain a shaped fireproof core material. Finally, continuously press it 8-10 times at 100-130 °C to obtain a fireproof core material with the required thickness.

8. A fireproof core material prepared by the preparation method of a fireproof core material according to any one of claims 1-7, wherein the fly ash hollow microspheres in the fireproof core material have a hollow structure inside and magnesium hydroxide / aluminum hydroxide precipitates are loaded on the outer surface.

9. The application of the fireproof core material prepared by the preparation method of a fireproof core material according to any one of claims 1-7 or the fireproof core material according to claim 8 in the building field and the fireproof material field.

10. A composite board, comprising the fireproof core material prepared by the preparation method of a fireproof core material according to any one of claims 1-7 or the fireproof core material according to claim 8.

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