Disclosure of Invention
In order to solve the technical problems in the prior art, the invention provides an aerogel coating, an aerogel coating and a method for preparing the aerogel coating from the aerogel coating. The aerogel coating disclosed by the invention has the advantages of good dispersibility and good stability; the aerogel coating disclosed by the invention has the advantages of good high-temperature resistance, low density, low heat conductivity coefficient and the like; the method is simple, simple and convenient to operate, easy to implement and low in environmental pollution.
In order to achieve the above object, the present invention provides, in a first aspect, an aerogel coating including, by mass, 35 to 90% of a coating base, 5 to 45% of a functional filler, and 5 to 50% of an auxiliary agent; the coating matrix is selected from the group consisting of epoxy modified resin, phenolic modified resin, organic silicon modified resin and organic silicon rubber; the functional filler comprises aerogel particles; the auxiliary agent is selected from the group consisting of toluene, cyclohexane, polyethylene glycol, polyvinyl alcohol, sodium polyacrylate, acetone and ethanol.
Preferably, the functional filler further comprises a reinforcing filler.
Preferably, the mass ratio of the reinforcing filler to the aerogel particles is (0.1-1): 1.
Preferably, the reinforcing filler is selected from the group consisting of hollow glass microspheres, high silica fibers, glass fibers, quartz fibers, alumina fibers and carbon fibers.
Preferably, the aerogel particles are selected from the group consisting of silica aerogel particles, alumina aerogel particles, zirconia aerogel particles, and titania aerogel particles.
The present invention provides, in a second aspect, a method of preparing an aerogel coating from the aerogel coating of the present invention described in the first aspect, the method comprising the steps of:
(1) uniformly mixing 35-90% of a coating matrix, 5-45% of a functional filler and 5-50% of an auxiliary agent in percentage by mass to obtain the aerogel coating;
(2) coating the aerogel coating on the surface of a substrate;
(3) and sequentially performing a drying step and a curing step on the substrate coated with the aerogel coating, thereby preparing the aerogel coating on the substrate.
Preferably, the drying temperature is 20-120 ℃, and the drying time is 0.1-24 h.
Preferably, the curing temperature is 50-200 ℃, and the curing time is 1-72 hours.
Preferably, the method further comprises the step of cleaning the surface of the substrate before performing step (2).
In a third aspect, the present invention provides an aerogel coating made from the aerogel coating of the first aspect of the present invention or the method of the second aspect of the present invention.
Compared with the prior art, the invention at least has the following beneficial effects:
(1) the aerogel coating comprises, by mass, 35-90% of a coating matrix, 5-45% of a functional filler and 5-50% of an auxiliary agent, and by reasonable proportioning of the components and selection of the types of the coating matrix and the auxiliary agent, the problem that the heat insulation performance of a coating is poor due to poor dispersibility, compatibility and stability between a liquid organic coating and aerogel particles can be effectively avoided, and the problem that the heat insulation performance of an aerogel coating made of the aerogel coating is reduced due to the fact that the liquid organic coating is easily immersed into nano holes of the aerogel can be effectively avoided; the aerogel coating disclosed by the invention has the advantages of good dispersibility, good stability and the like.
(2) The method can directly adopt the aerogel coating to directly coat on the substrate to prepare the aerogel coating, and has the advantages of simple preparation method, simple and convenient operation, easy implementation, small environmental pollution and the like; the method can be used for preparing aerogel heat-insulating coatings on component products with various shapes and specifications, and has wide application prospect in the environments requiring high temperature resistance and high-efficiency heat insulation, such as aerospace and the like.
(3) The aerogel coating disclosed by the invention is good in high-temperature resistance, adjustable in use temperature and capable of being used for a long time at the temperature of 400-800 ℃; the aerogel coating has low heat conductivity, and the heat conductivity coefficient is 0.02-0.1W/m.K; the aerogel coating prepared by the invention has the advantages of smooth and clean surface and beautiful appearance.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
The invention provides an aerogel coating in a first aspect, the aerogel coating (aerogel thermal insulation coating) comprises, by mass percent, 35-90% (e.g., 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or 90%) of a coating matrix, 5-45% (e.g., 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, or 45%) of a functional filler, and 5-50% (e.g., 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50%) of an auxiliary agent; the coating matrix is selected from the group consisting of epoxy modified resins (e.g., glycidyl ethers, glycidyl esters, glycidyl amines or aliphatic epoxy modified resins), phenolic modified resins (e.g., borophenolic modified resins, barium phenolic modified resins, polyvinyl acetal phenolic modified resins or polyamide phenolic modified resins), silicone modified resins (e.g., alkyd modified silicone resins, epoxy modified silicone resins, acrylic silicone resins) and silicone rubbers; the functional filler comprises aerogel particles; the auxiliary agent is selected from the group consisting of toluene, cyclohexane, polyethylene glycol, polyvinyl alcohol, sodium polyacrylate, acetone and ethanol. The coating substrate in the present invention is a liquid coating substrate (liquid organic coating); according to the aerogel coating disclosed by the invention, through reasonable proportioning of the components and selection of the coating matrix and the types of the additives, the problems of poor dispersibility, compatibility and stability between the liquid organic coating and aerogel particles can be effectively avoided, and the problem that the heat insulation performance of an aerogel coating prepared from the aerogel coating is reduced due to the fact that the liquid organic coating is easily immersed into nano holes of the aerogel can be effectively avoided; the aerogel coating disclosed by the invention has the advantages of good dispersibility, good stability and the like, and can effectively improve the comprehensive performance of the aerogel coating prepared from the aerogel coating, so that the prepared aerogel coating has the advantages of low density, low heat conductivity coefficient (good heat insulation performance) and good high temperature resistance, and can be applied to a high-temperature environment for a long time (good stability).
According to some preferred embodiments, the aerogel coating comprises, by mass, 35 to 50% (e.g., 35%, 40%, 45%, or 50%) of a coating matrix, 15 to 35% (e.g., 15%, 20%, 25%, 30%, or 35%) of a functional filler, and 30 to 45% (e.g., 30%, 35%, 40%, or 45%) of an auxiliary agent, so that uniform dispersibility of the aerogel coating can be effectively ensured and coating is facilitated (good coatability) and comprehensive performance of the aerogel coating made of the aerogel coating can be further ensured.
According to some preferred embodiments, the auxiliary agent consists of a first auxiliary agent selected from the group consisting of polyethylene glycol (polyethylene glycol-based dispersing agent), polyvinyl alcohol (polyvinyl alcohol-based dispersing agent), and sodium polyacrylate salt (sodium polyacrylate-based dispersing agent), and a second auxiliary agent selected from the group consisting of toluene, cyclohexane, acetone, and ethanol; in the invention, preferably, the auxiliary agent is composed of a first auxiliary agent and a second auxiliary agent, so that the aerogel particles can be dispersed more uniformly in the liquid organic coating, the stability of the aerogel coating is better, and more importantly, the liquid organic coating can be more effectively prevented from being immersed into nano holes of the aerogel particles, so that the comprehensive properties of the aerogel coating made of the aerogel coating, such as heat insulation property, high-temperature stability, high-temperature resistance, and the like, can be further ensured.
According to some preferred embodiments, the volume ratio of the first auxiliary agent to the second auxiliary agent is (0.5-1: 1) (e.g., 0.5:1, 0.55:1, 0.6:1, 0.65:1, 0.7:1, 0.75:1, 0.8:1, 0.85:1, 0.9:1, 0.95:1, or 1: 1).
According to some preferred embodiments, the functional filler further comprises a reinforcing filler; the addition of the reinforcing filler can enhance the strength and the wear resistance of the aerogel coating in the process of preparing the aerogel coating by adopting the aerogel coating, and can further ensure the stability of the aerogel coating in the using process.
According to some preferred embodiments, the mass ratio of the reinforcing filler to the aerogel particles is (0.1 to 1:1) (e.g., 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1, 0.5:1, 0.55:1, 0.65:1, 0.7:1, 0.75:1, 0.8:1, 0.85:1, 0.9:1, 0.95:1, or 1:1), preferably (0.3 to 0.8): 1 (e.g., 0.3:1, 0.35:1, 0.4:1, 0.45:1, 0.5:1, 0.55:1, 0.65:1, 0.7:1, 0.75:1, or 0.8: 1). In the invention, the mass ratio of the reinforcing filler to the aerogel particles is preferably (0.1-1): 1, the content of the reinforcing filler cannot be too high, and the addition of too much reinforcing filler is not beneficial to forming the aerogel coating with good dispersibility, good compatibility and good stability.
According to some preferred embodiments, the reinforcing filler is selected from the group consisting of hollow glass microspheres, high silica fibers, glass fibers, quartz fibers, alumina fibers and carbon fibers.
According to some preferred embodiments, the aerogel particles are selected from the group consisting of silica aerogel particles, alumina aerogel particles, zirconia aerogel particles, and titania aerogel particles. In the present invention, the porosity of the aerogel particles may be, for example, 50 to 99%, and the particle size of the aerogel particles may be, for example, 0.0001 to 0.2 mm.
The present invention provides, in a second aspect, a method of preparing an aerogel coating from the aerogel coating of the present invention described in the first aspect, the method comprising the steps of:
(1) uniformly mixing 35-90% of a coating matrix, 5-45% of a functional filler and 5-50% of an auxiliary agent in percentage by mass to obtain the aerogel coating; for example, the coating matrix, the functional filler and the auxiliary agent are stirred, dispersed and uniformly mixed to prepare the aerogel coating (slurry);
(2) coating the aerogel coating on the surface of a substrate;
(3) the substrate coated with the aerogel coating is sequentially subjected to a drying step and a curing step, thereby producing the aerogel coating (aerogel thermal barrier coating) on the substrate.
In the present invention, the aerogel coating can be applied to the surface of the substrate by, for example, conventional brushing or conventional spraying, which can be performed by using, for example, an existing brushing tool or an existing spraying device, and the thickness of the aerogel coating can be determined according to the needs of the use environment; the substrate can be, for example, a component product for which a thermal barrier coating is to be prepared, such as a component product for use in an environment requiring high temperature resistance and high thermal insulation, such as aerospace and the like. According to the invention, the aerogel coating with good dispersibility and stability is adopted to prepare the aerogel coating, so that the uniformity of the dispersion of the coating matrix, the functional filler and the residual auxiliary agent in the aerogel coating can be effectively ensured, and the comprehensive performances of the aerogel coating, such as high temperature resistance, heat insulation performance, high temperature stability and the like, can be favorably ensured. The method can directly adopt the aerogel coating to directly coat on the substrate to prepare the aerogel coating without special treatment, and has the advantages of simple preparation method, simple and convenient operation, easy implementation, small environmental pollution and the like; the method can be used for preparing the aerogel coating on component products with various shapes and specifications, and has wide application prospect in the environments requiring high temperature resistance and high-efficiency heat insulation, such as aerospace and the like.
In the invention, the aerogel coating comprises, by mass, 35-90% of a coating matrix, 5-45% of a functional filler and 5-50% of an auxiliary agent, and within the range of the mixture ratio and the range of the types of the components, the aerogel coating prepared from the aerogel coating can have different densities, different tolerance to use environment temperatures, different heat insulation properties and the like under the combined action of the components in different types and different proportions.
According to some preferred embodiments, the drying is at a temperature of 20 to 120 ℃ (e.g., 20 ℃, 25 ℃, 30 ℃, 35 ℃, 40 ℃, 45 ℃, 50 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃, 95 ℃, 100 ℃, 105 ℃, 110 ℃, 115 ℃ or 120 ℃), and the drying is for a time of 0.1 to 24 hours (e.g., 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 hours).
According to some preferred embodiments, the curing temperature is 50 to 200 ℃ (e.g., 50 ℃, 60 ℃, 70 ℃, 80 ℃, 90 ℃, 100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃ or 200 ℃) and the curing time is 1 to 72 hours (e.g., 1, 3, 5, 6, 8, 10, 12, 15, 20, 24, 30, 36, 40, 48, 54, 58, 60, 65, 70 or 72 hours).
In the invention, the drying step is preferably carried out at the temperature of 20-120 ℃ for 0.1-24 h, and the curing step is preferably carried out at the temperature of 20-200 ℃ for 1-72 h, so that the uniformity of the dispersion of the coating matrix, the functional filler and the residual auxiliary agent in the aerogel coating can be further ensured, and the comprehensive performances of the aerogel coating, such as high-temperature resistance, heat insulation performance, high-temperature stability and the like, are better.
According to some preferred embodiments, the method further comprises the step of cleaning the surface of the substrate prior to performing step (2). In the present invention, for example, 400#, 800#, 1200# sandpaper may be used to abrade the surface of a substrate in sequence, and then the abraded surface of the substrate may be washed with clean water or ultrasonically cleaned with an acetone solution according to the size of the substrate.
In a third aspect, the present invention provides an aerogel coating made from the aerogel coating of the first aspect of the present invention or the method of the second aspect of the present invention. The aerogel coating disclosed by the invention is good in high-temperature resistance, adjustable in use temperature and capable of being used for a long time at the temperature of 400-800 ℃ (good in high-temperature stability); the aerogel coating has low heat conductivity, and the heat conductivity coefficient is 0.02-0.1W/m.K; the aerogel coating prepared by the invention has the advantages of smooth and clean surface and beautiful appearance.
The present invention will be further described with reference to the following examples. These examples are merely illustrative of preferred embodiments of the present invention and the scope of the present invention should not be construed as being limited to these examples.
The raw materials involved in the embodiments of the present invention are all commercially available.
Example 1
Preparing an aerogel coating by adopting the aerogel coating: the aerogel coating comprises a coating matrix, a functional filler, an auxiliary agent and a coating additive, wherein the coating matrix is organic silicon modified resin (epoxy resin modified organic silicon resin), the functional filler is silica aerogel particles and quartz fibers in a mass ratio of 1:0.5, and the auxiliary agent is polyethylene glycol, polyvinyl alcohol, sodium polyacrylate and toluene in a volume ratio of 0.3:0.3:0.3: 1; the preparation steps of the aerogel coating are as follows:
firstly, uniformly dispersing and mixing a coating matrix, a functional filler and an auxiliary agent according to the mass percent of 45 percent to 15 percent to 40 percent to prepare the aerogel coating (slurry).
Secondly, spraying the aerogel coating on the surface of the base material, drying at 50 ℃ for 60min, and curing at 150 ℃ for 3h to obtain the aerogel coating.
The performance of the aerogel coating in this example was tested: the sample can resist 500 ℃ (500 ℃ for 1h without shrinkage) and has density of 0.4g/cm3(GB/T6343-1995), the thermal conductivity at room temperature is 0.085W/m.K (GB/T10295-2008); the temperature resistance of the aerogel coating refers to the highest temperature which can be endured when the aerogel coating is subjected to high-temperature treatment for 1 hour and the sample of the aerogel coating is not shrunk, namely the enduring temperature.
Example 2
Preparing an aerogel coating by adopting the aerogel coating: the aerogel coating comprises a coating matrix which is organic silicon rubber, functional fillers which are silicon dioxide aerogel particles and hollow glass microspheres in a mass ratio of 1:0.5, and auxiliaries which are polyethylene glycol, polyvinyl alcohol, sodium polyacrylate and cyclohexane in a volume ratio of 0.3:0.3:0.3: 1; the preparation steps of the aerogel coating are as follows:
firstly, dispersing and mixing a coating matrix, a functional filler and an auxiliary agent uniformly according to the mass percentage of 40 percent to 25 percent to 35 percent to prepare the aerogel coating (slurry).
Secondly, spraying the aerogel coating on the surface of the base material, drying at 80 ℃ for 30min, and curing at 80 ℃ for 6h to obtain the aerogel coating.
The performance of the aerogel coating in this example was tested: the sample can resist 600 ℃ (600 ℃ for 1h without shrinkage) and has density of 0.35g/cm3(GB/T6343-1995) and the room-temperature thermal conductivity coefficient of 0.05W/m.K (GB/T10295-2008).
Example 3
Example 3 is essentially the same as example 1, except that:
the coating matrix is phenolic modified resin (boron phenolic modified resin); the auxiliary agent is polyethylene glycol, polyvinyl alcohol, sodium polyacrylate and ethanol with the volume ratio of 0.3:0.3:0.3: 1; 35 percent to 30 percent to 35 percent of the mass percentage of the coating substrate, the functional filler and the auxiliary agent; ②, the drying temperature is 80 ℃, the drying time is 60min, the curing temperature is 180 ℃, and the curing time is 6 h.
The properties of the aerogel coatings prepared in this example are shown in table 1.
Example 4
Example 4 is essentially the same as example 2, except that:
the functional filler is silicon dioxide aerogel particles, hollow glass microspheres and high silica fibers in a mass ratio of 1:0.25: 0.25; the mass percentage of the coating substrate, the functional filler and the auxiliary agent is 35 percent to 30 percent to 35 percent.
The properties of the aerogel coatings prepared in this example are shown in table 1.
Example 5
Example 5 is essentially the same as example 1, except that:
the mass percentage of the coating substrate, the functional filler and the auxiliary agent is 60 percent to 15 percent to 25 percent.
The properties of the aerogel coatings prepared in this example are shown in table 1.
Example 6
Example 6 is essentially the same as example 1, except that:
the mass percentage of the coating substrate, the functional filler and the auxiliary agent is 30 percent to 40 percent to 30 percent.
The properties of the aerogel coatings prepared in this example are shown in table 1.
Example 7
Example 7 is essentially the same as example 1, except that:
the auxiliary agent is toluene.
The properties of the aerogel coatings prepared in this example are shown in table 1.
Comparative example 1
Preparing an organic heat-insulating coating: the coating comprises organic silicon modified resin (epoxy resin modified organic silicon resin), quartz fiber as a filler, polyethylene glycol with the volume ratio of 0.3:0.3:0.3:1 as an auxiliary agent, polyvinyl alcohol, sodium polyacrylate and toluene; the preparation steps of the organic heat-insulating coating are as follows:
firstly, uniformly dispersing and mixing 45 mass percent of organoalkoxysilane resin, 15 mass percent of quartz fiber and 40 mass percent of auxiliary agent to prepare slurry.
Secondly, spraying the coating on the surface of the substrate, drying at 50 ℃ for 60min, and curing at 150 ℃ for 3h to obtain the organic heat-insulating coating.
The performance of the organic thermal barrier coating in this comparative example was tested: the sample can resist 500 ℃ (500 ℃ for 1h without shrinkage) and has a density of 1.0g/cm3(GB/T6343-1995) and the room-temperature thermal conductivity coefficient of 0.2W/m.K (GB/T10295-2008).
Comparative example 2
Preparing an organic heat-insulating coating: the coating comprises organic silicon rubber, filler which is hollow glass microspheres, and auxiliary agent which is polyethylene glycol, polyvinyl alcohol, sodium polyacrylate and cyclohexane with the volume ratio of 0.3:0.3:0.3: 1; the preparation steps of the organic heat-insulating coating are as follows:
firstly, uniformly dispersing and mixing organic silicon rubber, hollow glass microspheres and an auxiliary agent according to the mass percentage of 40 percent to 25 percent to 35 percent to prepare slurry.
Secondly, spraying the coating on the surface of the substrate, drying at 80 ℃ for 30min, and curing at 80 ℃ for 6h to obtain the organic heat-insulating coating.
The performance of the organic thermal barrier coating in this comparative example was tested: the sample can resist 350 ℃ (350 ℃ for 1h without shrinkage) and has a density of 0.6g/cm3(GB/T6343-1995) and the room-temperature thermal conductivity coefficient is 0.15W/m.K (GB/T10295-2008).
Comparative example 3
Weighing 50% of hydrophobic silica aerogel particles, 49.5% of powdered epoxy resin and 0.5% of acrylic flatting agent according to volume percentage, adding into a high-speed mixer, and premixing for 3min at 1000 r/min.
And feeding the mixed materials into a melt extruder for melt extrusion at the temperature of 90 ℃.
And thirdly, pressing the mixture into slices by a cooling tablet press, wherein the cooling temperature is 40 ℃.
And fourthly, crushing the cooled sheet into small sheets with the size of 1-2 mm by a roller mill.
Fifthly, feeding the small flaky material in the fourth step into air classification grinding equipment to be ground into powder with the particle size of 0.01-0.08 mm, and screening to obtain the powder coating with the particle size of 0.04-0.08 mm.
Spraying the prepared powder coating containing the aerogel on a metal sheet with the thickness of 0.16mm by adopting an electrostatic spraying process and the thickness of 100 multiplied by 100mm, and curing for 10min at the temperature of 200 ℃; and repeatedly spraying and curing for 5 times to obtain the heat-insulating coating.
The performance of the thermal barrier coating of this comparative example was tested: the sample can resist 300 ℃ (treated at 300 ℃ for 1h without shrinkage) and has density of 0.65g/cm3(GB/T6343-1995) and the room-temperature thermal conductivity coefficient of 0.1W/m.K (GB/T10295-2008).
Finally, the description is as follows: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the embodiments can still be modified, or some technical features can be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the present invention in its spirit and scope.