Aerogel composite insulation board and preparation method thereof

Abstract

The invention discloses an aerogel composite thermal insulation board and a preparation method thereof, belonging to the technical field of thermal insulation boards. The preparation method comprises the following steps: step S1, adding polyvinyl pyrrolidone to anhydrous ethanol, stirring and dissolving, then adding modified silica aerogel for ultrasonic dispersion, then adding a styrene monomer mixed solution, stirring and microwave heating for 1.5-2h, cooling to room temperature, centrifugally separating and washing with deionized water for 2-3 times, and vacuum drying to obtain composite microspheres; step S2, stirring and mixing the composite microspheres and a foaming agent, adding the mixture to a mold, and mixing the mixture under a molding pressure of 200-220kg / cm 2 , heat preservation and foaming at a temperature of 120-130°C for 20-30min, and then demolding after cooling to room temperature to obtain an aerogel composite insulation board; the present invention modifies the silica aerogel and uses it to prepare composite microspheres, so that the finally prepared aerogel composite insulation board has both good mechanical properties and thermal insulation properties.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal insulation boards, and in particular relates to an aerogel composite thermal insulation board and a preparation method thereof. Background Art

[0002] Existing insulation boards for building exterior walls are mainly divided into organic, inorganic and composite materials; organic insulation boards mainly include extruded polystyrene foam boards, molded polystyrene foam boards, phenolic foam boards, polyurethane foam boards, etc. The thermal conductivity of organic insulation boards is low, but the flame retardant performance is poor, and it is easy to cause fire when encountering open flames; inorganic insulation boards mainly include rock wool boards, glass wool boards, foamed cement boards, etc. Inorganic insulation boards have good flame retardancy, but their thermal conductivity is high, the thermal insulation effect is general, and their weight is large and it is inconvenient to transport and install; composite insulation boards are usually composited with organic and inorganic materials to have good thermal insulation effect and flame retardant performance; in the prior art, silica aerogel powder is introduced into polystyrene foam insulation boards. On the one hand, it can be used as an inorganic flame retardant material to improve the fire retardant performance of polystyrene foam insulation boards, and on the other hand, it can reduce the thermal conductivity and improve the thermal insulation performance of polystyrene foam insulation boards.

[0003] However, silica aerogel powder is easy to agglomerate in polystyrene particles, resulting in the silica aerogel being distributed in the gaps and bonding interfaces of the polystyrene particles after foaming, causing the strength of the polystyrene foam board to be significantly reduced. Summary of the invention

[0004] The object of the present invention is to provide an aerogel composite thermal insulation board and a preparation method thereof, so as to solve the problems in the background technology.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A method for preparing an aerogel composite insulation board comprises the following steps:

[0007] Step S1, adding polyvinyl pyrrolidone to anhydrous ethanol and stirring to dissolve, then adding modified silica aerogel, ultrasonically dispersing for 15-20 minutes, then adding styrene monomer mixed solution, heating with microwave at a speed of 400-500 r / min for 1.5-2 hours, cooling to room temperature, centrifuging and washing with deionized water for 2-3 times, and vacuum drying to obtain composite microspheres with modified silica aerogel as core and polystyrene as shell;

[0008] Step S2: Mix the composite microspheres and the foaming agent and add them into the mold. 2 , heat preservation and foaming at a temperature of 120-130°C for 20-30 minutes, water cooling to room temperature and then demolding to obtain an aerogel composite insulation board.

[0009] Furthermore, the modified silica aerogel is prepared by the following steps:

[0010] Add anhydrous ethanol to the autoclave, then add silica aerogel powder, azobisisobutyronitrile and silane coupling agent, stir and react for 8-10 hours under 1MPa nitrogen protection and 60-70°C, cool to room temperature, filter out the material, wash and dry to obtain modified silica aerogel. Through the above treatment, part of the azobisisobutyronitrile is impregnated into the pores inside the silica aerogel for storage, which is used to initiate the subsequent surface coating of the modified silica aerogel with polystyrene, and can also act as a foaming agent when the composite microspheres are foamed.

[0011] Furthermore, the usage ratio of the anhydrous ethanol, the silica aerogel powder, the azobisisobutyronitrile and the silane coupling agent is 100 mL: 5-10 g: 1-3 g: 0.2-0.4 g.

[0012] Furthermore, the styrene monomer mixed solution is composed of a mixture of pretreated styrene monomer and ethanol aqueous solution in a volume ratio of 1:2-3, and the volume fraction of the ethanol aqueous solution is 85-90%.

[0013] Furthermore, the pretreated styrene monomer is obtained by repeatedly washing the styrene monomer 3-4 times with a 5% by mass sodium hydroxide solution and deionized water.

[0014] Furthermore, the usage ratio of the polyvinyl pyrrolidone, anhydrous ethanol, modified silica aerogel and styrene monomer mixed solution is 10-14g:80-100mL:10g:700-800g.

[0015] Furthermore, the microwave power of the microwave heating is 500W, and the heating temperature is 70-80°C.

[0016] Furthermore, the mass ratio of the composite microspheres to the foaming agent is 20-22:1.

[0017] Furthermore, the foaming agent is a mixture of azobisisobutyronitrile and ammonium bicarbonate in a mass ratio of 2:1-1.2; ammonium bicarbonate can generate gas at a relatively low temperature, which is beneficial to the formation of initial microbubbles in the foaming process of the composite microspheres, and can be used in combination with azobisisobutyronitrile to ensure the foaming stability of the composite microspheres during the heating process of the mold.

[0018] An aerogel composite thermal insulation board is prepared by the above preparation method.

[0019] Beneficial effects of the present invention:

[0020] The invention uses hot pressing treatment to impregnate azobisisobutyronitrile into the interior of a silica aerogel for storage, and simultaneously grafts a silane coupling agent on the surface of silica aerogel particles to obtain a modified silica aerogel with good dispersibility; then, using the modified silica aerogel as a core, a part of the azobisisobutyronitrile in the modified silica aerogel is slowly released through a dispersion polymerization method under microwave heating conditions, and styrene monomers are induced to polymerize only on the surface of the modified silica aerogel to form a polystyrene shell, thereby avoiding the polymerization of styrene monomers alone in a dispersed system, and obtaining composite microspheres with better coating effect;

[0021] The present invention mixes composite microspheres with a foaming agent and then performs high-temperature and high-pressure foaming, thereby preventing the silicon dioxide aerogel from being distributed in the gaps and bonding interfaces of polystyrene particles, and obtaining a polystyrene foam board with better strength; the foaming agent composed of azobisisobutyronitrile and ammonium bicarbonate can make the foaming of the composite microspheres more stable, and in the foaming process, the azobisisobutyronitrile of the remaining part of the modified silicon dioxide aerogel is decomposed by heat to generate gas, so that there is enough gas inside the composite microspheres for foaming, which solves the problem that the foaming gas is difficult to enter the interior of the composite microspheres, improves the foaming uniformity of the aerogel composite thermal insulation board, and significantly improves the mechanical properties and thermal insulation properties of the aerogel composite thermal insulation board. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Example 1

[0024] The modified silica aerogel is prepared by the following steps:

[0025] Add 100 mL of anhydrous ethanol to the autoclave, then add 5 g of silica aerogel powder, 1 g of azobisisobutyronitrile and 0.2 g of silane coupling agent, stir and react for 8 h under 1 MPa nitrogen protection and 60 ° C. After cooling to room temperature, filter the material, wash and dry to obtain modified silica aerogel.

[0026] Example 2

[0027] The modified silica aerogel is prepared by the following steps:

[0028] Add 100 mL of anhydrous ethanol to the autoclave, then add 8 g of silica aerogel powder, 2 g of azobisisobutyronitrile and 0.3 g of silane coupling agent, stir and react for 9 h under 1 MPa nitrogen protection and 65 ° C. After cooling to room temperature, filter the material, wash and dry to obtain modified silica aerogel.

[0029] Example 3

[0030] The modified silica aerogel is prepared by the following steps:

[0031] Add 100 mL of anhydrous ethanol to the autoclave, then add 10 g of silica aerogel powder, 3 g of azobisisobutyronitrile and 0.4 g of silane coupling agent, stir and react for 10 h under 1 MPa nitrogen protection and 70 ° C. After cooling to room temperature, filter the material, wash and dry to obtain modified silica aerogel.

[0032] Example 4

[0033] The styrene monomer mixed solution is prepared by the following steps:

[0034] The styrene monomer was first added into a 5% by mass sodium hydroxide solution and stirred and mixed. After standing for 5 minutes, the lower water layer was filtered out and the upper layer was washed with deionized water. The above operation was repeated 3 times to obtain the pretreated styrene monomer. The pretreated styrene monomer was uniformly mixed with an 85% by volume ethanol aqueous solution in a volume ratio of 1:3 to obtain a styrene monomer mixed solution.

[0035] Example 5

[0036] The styrene monomer mixed solution is prepared by the following steps:

[0037] The styrene monomer was first added into a 5% by mass sodium hydroxide solution and stirred and mixed. After standing for 5 minutes, the lower water layer was filtered out and the upper layer was washed with deionized water. The above operation was repeated 4 times to obtain the pretreated styrene monomer. The pretreated styrene monomer was uniformly mixed with a 90% by volume ethanol aqueous solution in a volume ratio of 1:2 to obtain a styrene monomer mixed solution.

[0038] Example 6

[0039] An aerogel composite thermal insulation board is prepared by the following steps:

[0040] Step S1, adding 10g of polyvinyl pyrrolidone to 80mL of anhydrous ethanol and stirring to dissolve, then adding 10g of modified silica aerogel, ultrasonically dispersing for 15min, then adding 700g of styrene monomer mixed solution, stirring at a speed of 400-500r / min, heating to 70°C with a power of 500W for insulation reaction for 1.5h, cooling to room temperature, centrifuging and washing with deionized water twice, and vacuum drying to obtain composite microspheres;

[0041] Step S2: The composite microspheres and the foaming agent are mixed in a mass ratio of 20:1 and added into the mold. 2 , heat preservation and foaming for 30 minutes at a temperature of 120°C, wherein the foaming agent is a mixture of azobisisobutyronitrile and ammonium bicarbonate in a mass ratio of 2:1, and the aerogel composite insulation board is obtained after water cooling to room temperature.

[0042] Example 7

[0043] An aerogel composite thermal insulation board is prepared by the following steps:

[0044] Step S1, adding 12g of polyvinyl pyrrolidone into 90mL of anhydrous ethanol and stirring to dissolve, then adding 10g of modified silica aerogel, ultrasonically dispersing for 18min, then adding 750g of styrene monomer mixed solution, stirring at a speed of 450r / min, heating to 75°C with a power of 500W for insulation reaction for 2h, cooling to room temperature, centrifuging and washing with deionized water for 3 times, and vacuum drying to obtain composite microspheres;

[0045] Step S2: The composite microspheres and the foaming agent are mixed in a mass ratio of 21:1 and added into the mold. 2 , heat preservation and foaming for 25 minutes at a temperature of 125°C, wherein the foaming agent is a mixture of azobisisobutyronitrile and ammonium bicarbonate in a mass ratio of 2:1.1, and the aerogel composite insulation board is obtained after water cooling to room temperature.

[0046] Example 8

[0047] An aerogel composite thermal insulation board is prepared by the following steps:

[0048] Step S1, adding 14 g of polyvinyl pyrrolidone into 100 mL of anhydrous ethanol and stirring to dissolve, then adding 10 g of modified silica aerogel, ultrasonically dispersing for 20 min, then adding 800 g of styrene monomer mixed solution, stirring at a speed of 500 r / min, heating to 80° C. with a power of 500 W for insulation reaction for 2 h, cooling to room temperature, centrifuging and washing with deionized water for 3 times, and vacuum drying to obtain composite microspheres;

[0049] Step S2: The composite microspheres and the foaming agent are mixed in a mass ratio of 22:1 and added into the mold. 2 , heat preservation and foaming for 20 minutes at a temperature of 130°C, wherein the foaming agent is a mixture of azobisisobutyronitrile and ammonium bicarbonate in a mass ratio of 2:1.2, and the aerogel composite insulation board is obtained after water cooling to room temperature.

[0050] Comparative Example 1

[0051] Compared with Example 7, this comparative example uses an equal amount of unmodified silica aerogel to replace the modified silica aerogel, and then adds a proper amount of initiator azobisisobutyronitrile to the styrene monomer mixture, and the other raw materials and steps are the same.

[0052] Comparative Example 2

[0053] Compared with Example 7, this comparative example uses ordinary water bath heating instead of microwave heating, and the other raw materials and steps are the same.

[0054] Comparative Example 3

[0055] Compared with Example 7, this comparative example uses a single azobisisobutyronitrile as a foaming agent, and the other raw materials and steps are the same.

[0056] The density and compressive strength of the composite insulation boards prepared in Examples 6 to 8 and Comparative Examples 1 to 3 were tested for performance, and the thermal conductivity of the composite insulation boards was tested according to GB / T 10294-2008. The results of the composite insulation boards were shown in Table 1.

[0057] Table 1

[0058]

[0059] It can be seen from the data in Table 1 that the composite insulation boards prepared in Examples 6 to 8 have lower density, higher compressive strength and lower thermal conductivity, and therefore when applied to building exterior walls, they are not only convenient to transport and install, but also have better use effects.

[0060] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0061] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an aerogel composite insulation board, It is characterized in that The following steps are involved: Step S1, adding polyvinyl pyrrolidone to anhydrous ethanol and stirring to dissolve, then adding modified silica aerogel, ultrasonically dispersing for 15-20 minutes, then adding styrene monomer mixed solution, heating with microwave at a speed of 400-500 r / min for 1.5-2 hours, cooling to room temperature, centrifuging and washing with deionized water for 2-3 times, and vacuum drying to obtain composite microspheres; Step S2: Mix the composite microspheres and the foaming agent and add them into the mold. 2 , heat preservation and foaming at a temperature of 120-130°C for 20-30 minutes, cooling to room temperature with water and then demolding to obtain an aerogel composite insulation board; the foaming agent is a mixture of azobisisobutyronitrile and ammonium bicarbonate in a mass ratio of 2:1-1.2; The modified silica aerogel is prepared by the following steps: Anhydrous ethanol was added to the autoclave, followed by silica aerogel powder, azobisisobutyronitrile and silane coupling agent. The mixture was stirred and reacted for 8-10 hours at 60-70°C under 1MPa nitrogen protection. After cooling to room temperature, the material was filtered, washed and dried to obtain modified silica aerogel.

2. A method for preparing an aerogel composite insulation board according to claim 1, It is characterized in that The usage ratio of the anhydrous ethanol, the silicon dioxide aerogel powder, the azobisisobutyronitrile and the silane coupling agent is 100 mL: 5-10 g: 1-3 g: 0.2-0.4 g.

3. The method for preparing an aerogel composite insulation board according to claim 1, It is characterized in that The styrene monomer mixed solution is composed of a mixture of pretreated styrene monomer and ethanol aqueous solution in a volume ratio of 1:2-3, and the volume fraction of the ethanol aqueous solution is 85-90%.

4. The method for preparing an aerogel composite insulation board according to claim 3, It is characterized in that The pretreated styrene monomer is obtained by repeatedly washing the styrene monomer 3-4 times with a sodium hydroxide solution and deionized water.

5. The method for preparing an aerogel composite insulation board according to claim 1, It is characterized in that The dosage ratio of the polyvinyl pyrrolidone, anhydrous ethanol, modified silica aerogel and styrene monomer mixed liquid is 10-14g:80-100mL:10g:700-800g.

6. The method for preparing an aerogel composite insulation board according to claim 1, It is characterized in that The microwave power of the microwave heating is 500W, and the heating temperature is 70-80°C.

7. The method for preparing an aerogel composite insulation board according to claim 1, It is characterized in that The mass ratio of the composite microspheres to the foaming agent is 20-22:

1.

8. An aerogel composite insulation board, It is characterized in that Prepared by the preparation method according to any one of claims 1 to 7.

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