Coating composition, application of coating composition, aerogel felt with coating and preparation method of aerogel felt

Abstract

The invention relates to the technical field of aerogel felt coatings, and discloses a coating composition and application thereof, an aerogel felt with a coating and a preparation method of the aerogel felt, and the coating composition comprises polysilazane and a silane coupling agent. When the obtained coating composition is used for coating the surface of the aerogel felt, the coating composition has very good hydrophobic performance, heat insulation performance and temperature resistance and low powder falling rate.

Description

Technical Field

[0001] The invention relates to the technical field of aerogel felt coatings, and in particular to a coating composition and application thereof, and an aerogel felt with a coating and a preparation method thereof. Background Art

[0002] At present, the traditional materials used for thermal insulation of petrochemical pipelines mainly include calcium silicate, composite silicate, rock wool, etc. The thermal conductivity of these insulation materials will increase significantly with the increase of ambient temperature and humidity. In order to meet the requirement of not exceeding the maximum allowable heat loss, it is necessary to increase the thickness of the insulation material. The use of a thicker insulation layer will have a greater impact on the transportation, construction, and use space of the material. Silica aerogel has a continuous, three-dimensional, skeleton-connected network structure. It is a low-density nanoporous amorphous insulation material with a skeleton size of nanometers and a skeleton thickness of no more than 100nm. This makes the heat flow in the aerogel skeleton produce a unidirectional transmission similar to one-dimensional heat conduction, and the volume occupied by solids in the aerogel structure is usually less than 5%, which also greatly reduces the proportion of solid-state heat transfer in the internal heat transfer mode. Replacing the traditional insulation materials on petrochemical pipelines with aerogel materials can not only reduce the thickness of the insulation layer, but also reduce the heat loss of the pipeline, which is an important part of the general trend of carbon emission reduction.

[0003] However, the inorganic nano-skeleton structure of silica aerogel itself also makes it brittle, with poor bending and friction resistance, making it difficult to achieve industrial application. The strength of aerogel felt prepared by composite fiber materials has been significantly improved. However, the addition of fiber materials also makes the silica aerogel on the surface of aerogel felt more likely to fall off, which not only affects the thermal insulation performance after long-term use, but also generates dust pollution during the construction process, which is unfriendly to the environment and the health of the installers. Therefore, it is extremely important to improve the powder shedding of aerogel materials.

[0004] In order to solve this problem, CN112060719A prevents the aerogel felt from losing powder on the surface by coating each surface of the aerogel felt with high-silica glass fiber cloth, and then sews or bonds the coated package with high-silica thread. However, the products produced in this way have reduced flexibility, are difficult to curl and bend, and are not suitable for use in thermal insulation materials that require flexibility. CN109400105A prepares a coating to improve the powder loss problem of aerogel-based materials. This method uses an aqueous film-forming substance, which has obvious hydrophilicity after being applied to the surface of the aerogel. When stored and constructed for a long time in a humid environment, water vapor or water droplets in the air are easily adsorbed on the coating surface and gradually enter the aerogel pores, resulting in a decrease in the stability of the aerogel. At the same time, in actual high-temperature use environments, this type of film-forming substance tends to decompose when the temperature is greater than 200°C, which not only causes pollution but also affects the performance of the aerogel felt.

[0005] In view of the problems of poor hydrophobicity, poor temperature resistance and high powder loss rate of the coating used on the surface of aerogel felt in the prior art, it is urgent to develop a coating for the surface of aerogel felt with excellent comprehensive performance. Summary of the invention

[0006] The purpose of the present invention is to overcome the problems of poor hydrophobicity, poor thermal insulation performance, poor temperature resistance and high powder loss rate of the coating used on the surface of aerogel felt in the prior art, and to provide a coating composition and its application, a coated aerogel felt and a preparation method thereof.

[0007] In order to achieve the above object, the first aspect of the present invention provides a coating composition, wherein the coating composition comprises polysilazane and a silane coupling agent.

[0008] The second aspect of the present invention provides use of the coating composition described in the first aspect in improving the hydrophobic properties of aerogel felt.

[0009] The third aspect of the present invention provides a method for preparing a coated aerogel felt, wherein the preparation method comprises the following steps: coating the coating composition on the surface of the aerogel felt, and then curing it.

[0010] A fourth aspect of the present invention provides a coated aerogel felt, wherein the coated aerogel felt comprises an aerogel felt and a coating attached to the surface of the aerogel felt, wherein the coating is obtained by curing the coating composition.

[0011] Through the above technical scheme, the coating composition provided by the present invention has a very good effect when applied on the surface of the aerogel felt, as follows:

[0012] (1) The main components of the coating are Si-O and Si-O-Si generated by the hydrolysis reaction of Si-N bonds in polysilazane, which are similar to the main components of silica aerogel felt and can better adhere to the surface of aerogel felt; polysilazane is rich in active Si-N bonds and has a high cross-linking density after curing. The coating is dense and has good toughness, which can effectively prevent the silica aerogel from falling off during surface processing, transportation, and bending of the aerogel felt.

[0013] (2) The silane coupling agent in the coating can couple the polymer with the inorganic material, promote the fusion of the organic-inorganic interface, and thus improve the bonding between the coating and the substrate.

[0014] (3) The silicon-oxygen-carbon-nitrogen network structure contained in the coating can improve the hydrophobic properties of the coating surface, which is beneficial to the storage and use of aerogel felt in a humid environment.

[0015] (4) The overall coating is a SiOCN structure with good temperature resistance, which enables the aerogel felt to maintain its complete morphology under high-temperature use environments, thereby ensuring the long-term performance of the material.

[0016] (5) The coating has little effect on the aerogel felt. After being coated on the surface of the aerogel felt and dried, the thermal conductivity coefficient is increased by no more than 20% compared with the untreated aerogel felt, and the thermal insulation performance is good. DETAILED DESCRIPTION

[0017] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0018] A first aspect of the present invention provides a coating composition, wherein the coating composition comprises polysilazane and a silane coupling agent.

[0019] In the present invention, the coating composition formed by the polysilazane and the silane coupling agent has good hydrophobicity, heat resistance and low powder loss rate. The reason may be that during the curing process, NH, CH and Si-H in the polysilazane undergo dehydrogenation coupling reaction to generate a cured product with Si-N, Si-C, Si-O and Si-O-Si network structures. The schematic diagram of the reaction process is shown in formula (1), which has good uniformity and film-forming properties. The overall structure of the coating is SiOCN, which has good heat resistance and can keep the aerogel felt intact in a high-temperature use environment, thereby ensuring the long-term use performance of the material. At the same time, the silicon oxygen carbon nitrogen network structure contained in the coating can improve the hydrophobicity of the coating surface, which is beneficial to the storage and use of the aerogel felt in a humid environment. The obtained coating composition has very good hydrophobicity, good thermal insulation, heat resistance and low powder loss rate when applied on the surface of the aerogel felt.

[0020]

[0021] In some specific embodiments of the present invention, the polysilazane and the silane coupling agent are stored separately and then mixed when used.

[0022] In some specific embodiments of the present invention, polysilazane is a polymer composed of silicon and nitrogen atoms alternately forming a basic skeleton, with a molecular formula of [R 1 R 2 Si-NR 3 ] n Indicates that R 1 -R3 It can be a hydrogen atom or an organic substituent. If all substituents are hydrogen atoms, the polymer is called perhydropolysilazane [H 2 Si-NH] n If the hydrocarbon substituent is connected to the silicon atom, it is called an organic polysilazane. The polysilazane is selected from one or more of methyl polysilazane, phenyl polysilazane, vinyl polysilazane, propenyl polysilazane and perhydropolysilazane, preferably perhydropolysilazane.

[0023] In some specific embodiments of the present invention, the weight average molecular weight of the polysilazane is 500-1500 g / mol.

[0024] In some specific embodiments of the present invention, the coating composition further contains an organic solvent, and the organic solvent is selected from C 1 -C 12 Alkanes, C 6 -C 10 Aromatics and C 4 -C 8 One or more of the alkyl ethers of , preferably one or more selected from n-hexane, xylene, anisole, decalin, cyclohexane, cyclohexene, methylcyclohexane, ethylcyclohexane, limonene, octane, nonane and decane.

[0025] In some specific embodiments of the present invention, the weight ratio of the polysilazane to the organic solvent is 0.1-5: 1, preferably 3.5-4.5: 1, and more preferably 4-4.5: 1. Within the weight ratio / type range of the polysilazane to the organic solvent, the obtained coating composition has better hydrophobicity, temperature resistance and low powder loss rate when applied on the surface of the aerogel felt.

[0026] In some specific embodiments of the present invention, the silane coupling agent is selected from one or more of alkyl silanes, amino silanes, epoxy silanes and acyloxy silanes, preferably selected from one or more of ethyl triethoxy silane, octadecyl triethoxy silane, trifluoropropyl trimethoxy silane, γ-aminopropyl triethoxy silane, γ-glycidyloxypropyl trimethoxy silane, γ-methacryloxypropyl trimethoxy silane.

[0027] In some specific embodiments of the present invention, the weight ratio of the polysilazane to the silane coupling agent is 10-40: 1, preferably 20-30: 1, and more preferably 26-30: 1. Within the weight ratio / type range of the polysilazane to the silane coupling agent, the obtained coating composition has better hydrophobicity, temperature resistance and low powder loss rate when applied on the surface of the aerogel felt.

[0028] According to a particularly preferred embodiment of the present invention, the coating composition comprises polysilazane and a silane coupling agent, wherein the polysilazane is selected from perhydropolysilazane, the solvent is selected from n-hexane, the silane coupling agent is selected from γ-methacryloxypropyltrimethoxysilane, and the weight ratio of the polysilazane to the silane coupling agent is 20-30:1.

[0029] The second aspect of the present invention provides use of the coating composition described in the first aspect in improving the hydrophobic properties of aerogel felt.

[0030] The third aspect of the present invention provides a method for preparing a coated aerogel felt, wherein the preparation method comprises the following steps: coating the coating composition on the surface of the aerogel felt, and then curing it.

[0031] In some specific embodiments of the present invention, the coating composition is prepared in the following steps:

[0032] (1) mixing polysilazane with an organic solvent to obtain a mixed solution;

[0033] (2) adding a silane coupling agent to the mixed solution to obtain the coating composition;

[0034] Wherein, the polysilazane, organic solvent and silane coupling agent are the same as those in the coating composition described above.

[0035] In some specific embodiments of the present invention, the coating is selected from one or more of spray coating, brush coating and spin coating.

[0036] In some specific embodiments of the present invention, the curing temperature is 60-120° C., and the curing time is 8-12 hours.

[0037] In some specific embodiments of the present invention, the amount of the coating composition applied is 200-500 g / m 2 .

[0038] According to a particularly preferred embodiment of the present invention, a method for preparing a coated aerogel felt comprises the following steps:

[0039] Perhydropolysilazane (weight average molecular weight of 500-1500 g / mol) was dissolved in n-hexane, the mass ratio of perhydropolysilazane to n-hexane was 4-4.5:1, and stirred for 1 hour to obtain a mixed solution. Then, γ-methacryloxypropyltrimethoxysilane was added to the mixed solution and stirred evenly again, wherein the mass ratio of perhydropolysilazane to γ-methacryloxypropyltrimethoxysilane was 26-30:1, and the coating composition was obtained. The coating composition was evenly scraped on the surface of the aerogel felt, and the amount of the coating composition was 300 g / m 2, and then the aerogel felt with coating is obtained after constant temperature curing at 80°C for 8 hours, and the thickness of the coating is 50-200nm.

[0040] In some specific embodiments of the present invention, the material of the aerogel felt is silica aerogel felt. The hydrolyzed groups of polysilazane in the coating composition of the present invention are similar to the main components of silica aerogel felt, can better adhere to the surface of the aerogel felt, and have a better effect on improving the hydrophobicity and powder loss performance of the silica aerogel felt.

[0041] A fourth aspect of the present invention provides a coated aerogel felt, wherein the coated aerogel felt comprises an aerogel felt and a coating attached to the surface of the aerogel felt, wherein the coating is obtained by curing the coating composition.

[0042] In some specific embodiments of the present invention, the room temperature thermal conductivity of the aerogel felt is 0.021-0.025 W / m·K, the powder loss rate is 0.2-1.1%, and the hydrophobicity is 96-99.8%.

[0043] In some specific embodiments of the present invention, the thickness of the coating is 50-200 nm.

[0044] The present invention will be described in detail below through examples.

[0045] The organic polysilazanes were purchased from Anhui IOTA Silicone Oil Co., Ltd. with the brands of IOTA 9283 (methyl and fluorine modified polysilazane), IOTA OPSZ 9150K, IOTA 9108, IOTA 9118 (vinyl polysilazane), IOTA 9150, and IOTA-PHPS (perhydropolysilazane).

[0046] In the following examples and comparative examples, if no specific conditions are specified, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used, if no manufacturer is specified, are all conventional products that can be obtained through commercial channels.

[0047] Example 1

[0048] A method for preparing a coated aerogel felt comprises the following steps:

[0049] Perhydropolysilazane (weight average molecular weight of 1000 g / mol) was dissolved in n-hexane, the mass ratio of perhydropolysilazane to n-hexane was 1:1, and stirred for 1 hour to obtain a mixed solution. Then, γ-methacryloxypropyltrimethoxysilane was added to the mixed solution and stirred evenly again, wherein the mass ratio of perhydropolysilazane to γ-methacryloxypropyltrimethoxysilane was 20:1, and the coating composition was obtained. The coating composition was evenly scraped on the surface of the aerogel felt, and the amount of the coating composition was 300 g / m 2 , and then the aerogel felt with coating was obtained after constant temperature curing at 80°C for 8 hours, and the thickness of the coating was 65nm.

[0050] Example 2

[0051] A method for preparing a coated aerogel felt comprises the following steps:

[0052] Perhydropolysilazane (weight average molecular weight of 1000 g / mol) was dissolved in n-hexane, the mass ratio of perhydropolysilazane to n-hexane was 3.5:1, and stirred for 1 hour to obtain a mixed solution. Then, γ-methacryloxypropyltrimethoxysilane was added to the mixed solution and stirred evenly again, wherein the mass ratio of perhydropolysilazane to γ-methacryloxypropyltrimethoxysilane was 25:1, and the coating composition was obtained. The coating composition was evenly scraped on the surface of the aerogel felt, and the amount of the coating composition was 300 g / m 2 After constant temperature curing at 80°C for 8 hours, an aerogel felt with a coating is obtained, and the thickness of the coating is 87 nm.

[0053] Example 3

[0054] A method for preparing a coated aerogel felt comprises the following steps:

[0055] Perhydropolysilazane (weight average molecular weight of 1000 g / mol) was dissolved in n-hexane, the mass ratio of perhydropolysilazane to n-hexane was 4.5:1, and stirred for 1 hour to obtain a mixed solution. Then, γ-methacryloxypropyltrimethoxysilane was added to the mixed solution and stirred evenly again, wherein the mass ratio of perhydropolysilazane to γ-methacryloxypropyltrimethoxysilane was 30:1, and the coating composition was obtained. The coating composition was evenly scraped on the surface of the aerogel felt, and the amount of the coating composition was 300 g / m 2 , and after constant temperature curing at 80°C for 8h, an aerogel felt with a coating is obtained, and the thickness of the coating is 98nm.

[0056] Example 4

[0057] A method for preparing a coated aerogel felt comprises the following steps:

[0058] Methylpolysilazane (weight average molecular weight of 900g / mol) was dissolved in n-hexane, the mass ratio of methylpolysilazane to n-hexane was 4.5:1, and stirred for 1 hour to obtain a mixed solution. Then, γ-methacryloxypropyltrimethoxysilane was added to the mixed solution and stirred evenly again, wherein the mass ratio of methylpolysilazane to γ-methacryloxypropyltrimethoxysilane was 30:1, and the coating composition was obtained. The coating composition was evenly scraped on the surface of the aerogel felt, and the amount of the coating composition was 300g / m 2 After constant temperature curing at 80°C for 8 hours, an aerogel felt with a coating is obtained, and the thickness of the coating is 118 nm.

[0059] Example 5

[0060] A method for preparing a coated aerogel felt comprises the following steps:

[0061] Dissolve vinyl polysilazane (weight average molecular weight of 1400g / mol) in n-hexane, the mass ratio of vinyl polysilazane to n-hexane is 4.5:1, and stir for 1 hour to obtain a mixed solution. Add γ-methacryloxypropyl trimethoxysilane to the mixed solution and stir evenly again, wherein the mass ratio of vinyl polysilazane to γ-methacryloxypropyl trimethoxysilane is 30:1, to obtain the coating composition. The coating composition is evenly scraped on the surface of the aerogel felt, and the amount of the coating composition is 300g / m 2 , and then the aerogel felt with coating was obtained after constant temperature curing at 80°C for 8 hours, and the thickness of the coating was 150nm.

[0062] Example 6

[0063] A method for preparing a coated aerogel felt comprises the following steps:

[0064] Perhydropolysilazane (weight average molecular weight of 1000 g / mol) was dissolved in n-hexane, the mass ratio of perhydropolysilazane to n-hexane was 2:1, and stirred for 1 hour to obtain a mixed solution. Then, γ-methacryloxypropyltrimethoxysilane was added to the mixed solution and stirred evenly again, wherein the mass ratio of perhydropolysilazane to γ-methacryloxypropyltrimethoxysilane was 30:1, and the coating composition was obtained. The coating composition was evenly scraped on the surface of the aerogel felt, and the amount of the coating composition was 300 g / m 2 After constant temperature curing at 80°C for 8 hours, an aerogel felt with a coating is obtained, and the thickness of the coating is 76 nm.

[0065] Example 7

[0066] A method for preparing a coated aerogel felt comprises the following steps:

[0067] Perhydropolysilazane (weight average molecular weight of 1000 g / mol) was dissolved in n-hexane, the mass ratio of perhydropolysilazane to n-hexane was 4.5:1, and stirred for 1 hour to obtain a mixed solution. Then, γ-methacryloxypropyltrimethoxysilane was added to the mixed solution and stirred evenly again, wherein the mass ratio of perhydropolysilazane to γ-methacryloxypropyltrimethoxysilane was 10:1, and the coating composition was obtained. The coating composition was evenly scraped on the surface of the aerogel felt, and the amount of the coating composition was 300 g / m 2 , and then the aerogel felt with coating was obtained after constant temperature curing at 80°C for 8 hours, and the thickness of the coating was 112nm.

[0068] Example 8

[0069] A method for preparing a coated aerogel felt comprises the following steps:

[0070] Perhydropolysilazane (weight average molecular weight of 1000 g / mol) was dissolved in n-hexane, the mass ratio of perhydropolysilazane to n-hexane was 4.5:1, and stirred for 1 hour to obtain a mixed solution. Then γ-aminopropyltriethoxysilane was added to the mixed solution and stirred evenly again, wherein the mass ratio of perhydropolysilazane to γ-aminopropyltriethoxysilane was 30:1, and the coating composition was obtained. The coating composition was evenly scraped on the surface of the aerogel felt, and the amount of the coating composition was 300 g / m 2 , and after constant temperature curing at 80°C for 8 hours, an aerogel felt with a coating is obtained, and the thickness of the coating is 88nm.

[0071] Test Example 1

[0072] The room temperature thermal conductivity, powder loss rate, water repellency and temperature resistance of the aerogel felt of the embodiment and the untreated aerogel felt were measured according to the following method. The results are shown in Table 1.

[0073] Room temperature thermal conductivity measurement: Tested according to GB / T 10294-2008 method;

[0074] Powder loss rate measurement: tested according to GB / T 34336-2017 method;

[0075] Water repellency: tested according to GB / T 10299-2011 method;

[0076] Temperature resistance: The thermal decomposition temperature of the coating composition obtained by the TGA test method is used as a reference.

[0077] Table 1

[0078]

[0079]

[0080] It can be seen from the results in Table 1 that compared with the untreated aerogel felt, Examples 1-8 of the present invention have significantly better effects on powder loss rate and water repellency, while ensuring that the room temperature thermal conductivity of the aerogel felt is no more than 20% higher than that of the untreated aerogel felt, and the thermal insulation performance is good, among which Examples 1-3 have the best effect.

[0081] By comparing the results of Examples 3-5, it can be seen that the polysilazane selected from perhydropolysilazane has a lower powder loss rate and a higher hydrophobicity, and the aerogel felt has a significantly better effect, while the thermal decomposition temperature of the aerogel felt is higher.

[0082] By comparing the results of Example 3 and Example 6, it can be seen that when the weight ratio of the polysilazane to the organic solvent is 0.1-5:1, preferably 3.5-4.5:1, it has a lower powder loss rate and a higher hydrophobicity, and the aerogel felt has a significantly better effect.

[0083] By comparing the results of Example 3 and Example 7, it can be seen that when the weight ratio of the polysilazane to the silane coupling agent is 10-40:1, preferably 20-30:1, it has a lower powder loss rate and a higher water repellency, and the aerogel felt has a significantly better effect.

[0084] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A coating composition, It is characterized in that The coating composition comprises polysilazane and a silane coupling agent.

2. The coating composition according to claim 1, in, The polysilazane and the silane coupling agent are stored independently; and / or, the polysilazane is selected from one or more of methylpolysilazane, phenylpolysilazane, vinylpolysilazane, propenylpolysilazane and perhydropolysilazane, preferably perhydropolysilazane; And / or, the weight average molecular weight of the polysilazane is 500-1500 g / mol.

3. The coating composition according to claim 1, in, The coating composition further comprises an organic solvent selected from the group consisting of 1 -C 12 Alkanes, C 6 -C 10 Aromatics and C 4 -C 8 One or more of the alkyl ethers, preferably one or more selected from n-hexane, xylene, anisole, decalin, cyclohexane, cyclohexene, methylcyclohexane, ethylcyclohexane, limonene, octane, nonane and decane; Preferably, the weight ratio of the polysilazane to the organic solvent is 0.1-5:1, preferably 3.5-4.5:

1.

4. The coating composition according to claim 1, in, The silane coupling agent is selected from one or more of alkyl silane, amino silane, epoxy silane and acyloxy silane, preferably selected from one or more of ethyl triethoxy silane, octadecyl triethoxy silane, trifluoropropyl trimethoxy silane, γ-aminopropyl triethoxy silane, γ-glycidyloxypropyl trimethoxy silane and γ-methacryloxypropyl trimethoxy silane.

5. A coating composition according to any one of claims 1 to 4, in, The weight ratio of the polysilazane to the silane coupling agent is 10-40:1, preferably 20-30:

1.

6. Use of the coating composition according to any one of claims 1 to 5 in improving the hydrophobic properties of aerogel felt.

7. A method for preparing a coated aerogel felt, It is characterized in that The preparation method comprises the following steps: coating the coating composition described in any one of claims 1 to 5 on the surface of the aerogel felt, and then curing it.

8. The preparation method according to claim 7, in, The preparation steps of the coating composition are as follows: (1) mixing polysilazane with an organic solvent to obtain a mixed solution; (2) adding a silane coupling agent to the mixed solution to obtain the coating composition; Wherein, the polysilazane, organic solvent and silane coupling agent are the same as those in the coating composition according to any one of claims 1 to 5.

9. The preparation method according to claim 7 or 8, in, The coating is selected from one or more of spray coating, brush coating and spin coating; Preferably, the curing temperature is 60-120° C. and the curing time is 8-12 hours.

10. The preparation method according to any one of claims 7 to 9, in, The amount of the coating composition applied is 200-500 g / m 2 ; And / or, the aerogel felt is made of silica aerogel felt.

11. A coated aerogel felt, It is characterized in that The coated aerogel felt comprises an aerogel felt and a coating attached to the surface of the aerogel felt, wherein the coating is obtained by curing the coating composition according to any one of claims 1 to 5.

12. The aerogel felt according to claim 11, in, The room temperature thermal conductivity of the coated aerogel felt is 0.021-0.025 W / m·K, the powder loss rate is 0.2-1.1%, and the hydrophobicity is 96-99.8%; Preferably, the coating has a thickness of 50-200 nm.

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