Modified silicon dioxide aerogel thermal insulation coating as well as preparation method and application thereof

Abstract

The invention relates to a modified silica aerogel thermal insulation coating, which is composed of the following components by weight: 5-50 parts of a binder; 5-30 parts of a filling material; 10 to 50 parts of a solvent; 0-10 parts of an auxiliary agent; the modified silicon dioxide aerogel is prepared from isophorone diisocyanate modified silicon dioxide aerogel, due to the use of isophorone diisocyanate, the compatibility with organic resin is enhanced, meanwhile, the overall dispersion stability is kept, and in addition, the coating adopts a water-based system, and is non-toxic, safe and environment-friendly. The coating has excellent thermal insulation performance, is suitable for the field of building coatings, and provides a new thought and technical support for research and development of thermal insulation materials.

Description

Technical Field

[0001] The invention relates to the technical field of building coatings, in particular to a modified silica aerogel thermal insulation coating and a preparation method and application thereof. Background Art

[0002] Although the modified silica aerogel thermal insulation coatings currently on the market use silica aerogel as the core insulation material and organic resin as a binder, they still face many challenges in practical applications.

[0003] First, silica aerogel is not very compatible with organic resins, which leads to cracking after the coating is applied, affecting the overall performance and aesthetics of the coating; second, the aerogel used in some modified silica aerogel thermal insulation coatings on the market does not meet the quality standards and the performance fails to meet the requirements, resulting in poor thermal insulation effect; thirdly, due to the instability of the spatial structure of silica aerogel, it is easily corroded by organic matter in the coating, resulting in a significant decrease in thermal insulation performance after long-term storage.

[0004] Therefore, it is particularly important to develop a modified silica aerogel thermal insulation coating that can overcome the above-mentioned defects. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a modified silica aerogel thermal insulation coating and a preparation method and application thereof, aiming to solve the problems of poor compatibility between aerogel and resin, poor thermal insulation effect, and decreased long-term storage performance.

[0006] In the first aspect, the present application provides a modified silica aerogel thermal insulation coating, which adopts the following technical solution:

[0007] A modified silica aerogel thermal insulation coating, comprising the following components in parts by weight:

[0008] 5-50 parts of binder;

[0009] 5-30 parts of filling material;

[0010] 10-50 parts of solvent;

[0011] Additives 0-10 parts;

[0012] 10-40 parts of modified silica aerogel;

[0013] The preparation steps of the modified silica aerogel are as follows:

[0014] S1. First, mix the ethanol dispersion solution of isocyanate and the silica aerogel powder for 30-45 minutes until uniform, and then add glacial acetic acid to adjust the pH to 3-4;

[0015] S2, then adding sodium bicarbonate to the slurry obtained in S1, adjusting the pH to 8-9, and after forming a gel, performing freeze vacuum drying to obtain a modified silica aerogel.

[0016] More preferably, the mass percentage concentration of the ethanol dispersion solution of isocyanate is 10-25%.

[0017] Further preferably, the silica aerogel powder has a particle size of 0.1-0.5 µm, a density of 0.04-0.08 g / ml, and a porosity of 95-99%.

[0018] Further preferably, the auxiliary agent is at least one of a dispersant, a preservative, a wetting agent, a defoaming agent, an antifreeze agent, a pH regulator, a leveling agent, a rheological agent, a thickener and a thixotropic agent.

[0019] More preferably, the binder is an organic resin, specifically one or more selected from acrylic resin, polyurethane resin, epoxy resin, and silicone resin.

[0020] Further preferably, the filling material is a thermal insulation lightweight material, specifically selected from one or more of vacuum ceramic microspheres, hollow glass microspheres, white carbon black, fibers, and foaming materials.

[0021] In a second aspect, the present application provides a method for preparing the modified silica aerogel thermal insulation coating, and the preparation steps are as follows:

[0022] At room temperature, the modified silica aerogel is first mixed with a solvent, and then stirred evenly in a disperser to form a stable slurry, with a stirring speed of less than 800 r / min;

[0023] Then, the binder, the filler material and the auxiliary agent are sequentially added into the slurry, and the mixture is added while being stirred until the mixture is evenly mixed, and the mixture is filtered to obtain the modified silica aerogel thermal insulation coating.

[0024] In a third aspect, the present application provides the use of any of the above-mentioned silica aerogel thermal insulation coatings and / or coatings obtained by the preparation method in the field of building thermal insulation.

[0025] In a fourth aspect, the present application provides a modified silica aerogel, the preparation steps of which are as follows:

[0026] S1. First, mix the ethanol dispersion solution of isocyanate and the silica aerogel powder for 30-45 minutes until uniform, and then add glacial acetic acid to adjust the pH to 3-4;

[0027] S2, then adding sodium bicarbonate to the slurry obtained in S1, adjusting the pH to 8-9, and after forming a gel, performing freeze vacuum drying to obtain a modified silica aerogel.

[0028] In a fifth aspect, the present application provides a thermal insulation coating, which is formed by curing the modified silica aerogel thermal insulation coating described in any one of the above items.

[0029] Due to the adoption of the above technical solution, the present invention has the following beneficial effects:

[0030] 1. The present invention adopts isocyanate-modified silica aerogel, which is perfectly compatible with silicone resin to form a stable dispersion system. At the same time, a dense insulation layer is formed on the surface of the coated object to effectively isolate external heat and achieve excellent thermal insulation effect;

[0031] 2. The modified silica aerogel provided by the present invention has a stable spatial structure and is not corroded by organic matter in the coating, ensuring that the performance of the coating does not decrease after long-term storage;

[0032] 3. The modified silica aerogel thermal insulation coating provided by the present invention is thin and light, crack-resistant, has high bonding strength, and has no risk of falling off. It is a water-based system, non-toxic, safe and environmentally friendly, and has simple and convenient construction. It can be sprayed without removing the wall hanging or nailing or drilling.

[0033] 4. During the project construction period, the modified silica aerogel thermal insulation coating solution provided by the present invention can reduce the overall cost by about 15% and shorten the construction period by more than 50% compared with the traditional thermal insulation + decorative surface layer approach. During the project operation stage, by improving the thermal insulation performance of the building envelope structure, the indoor air conditioning power consumption can be reduced, achieving energy conservation and emission reduction. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0035] Preparation Example 1

[0036] A modified silica aerogel, the preparation steps are as follows:

[0037] S1. First, mix the ethanol dispersion solution of isocyanate with a mass percentage concentration of 10% and the silica aerogel powder for 30 minutes until uniform, and then add glacial acetic acid to adjust the pH to 3;

[0038] The particle size of silica aerogel powder is 0.1-0.5µm, the density is 0.04-0.08g / ml, and the porosity is 95-99%;

[0039] S2, then adding sodium bicarbonate to the slurry obtained in S1, adjusting the pH to 9, and after forming a gel, freeze-drying at -80°C in a vacuum for 24 hours to obtain a modified silica aerogel.

[0040] Preparation Example 2-5

[0041] A modified silica aerogel is different from Preparation Example 1 in that the use of the isocyanate ethanol dispersion solution or the silica aerogel powder is different, as shown in the following table:

[0042] Table: Comparison of raw material usage in preparation examples 2-5

[0043] Group Raw material usage comparison table Preparation Example 2 The mass percentage concentration of the ethanol dispersion solution of isocyanate is 5%. Preparation Example 3 The mass percent concentration of the isocyanate ethanol dispersion solution is 20%. Preparation Example 4 The mass percent concentration of the isocyanate ethanol dispersion solution is 25%. Preparation Example 5 The particle size of silica aerogel powder is 50-100µm, the density is 0.04-0.08g / ml, and the porosity is 95-99%.

[0044] Performance testing

[0045] The modified silica aerogel thermal insulation coatings prepared in the examples and comparative examples were respectively selected, and after being cured at room temperature for 48 hours to form a coating with a thickness of 2.0 mm, their adhesion and thermal insulation properties were tested respectively;

[0046] The adhesion is characterized by testing the adhesion strength using a microcomputer-controlled electronic universal testing machine;

[0047] The thermal conductivity was tested according to the standard GB / T10297-2015 "Hot wire method for determination of thermal conductivity of non-metallic solid materials". Each group was tested three times and the average value of the results was recorded in the table below.

[0048] Examples 1-5

[0049] A modified silica aerogel thermal insulation coating, the components and their corresponding weights of which are shown in the following table, is prepared by the following preparation method:

[0050] At room temperature, the modified silica aerogel is first mixed with a solvent, and then stirred evenly in a disperser to form a stable slurry, with a stirring speed of less than 800 r / min;

[0051] Then, the binder, the filler material and the auxiliary agent are sequentially added into the slurry, and the mixture is added while being stirred until the mixture is evenly mixed, and the mixture is filtered to obtain the modified silica aerogel thermal insulation coating.

[0052] Table: Components and corresponding weights in Examples 1-5 (kg)

[0053] Example Ingredients 1 2 3 4 5 Modified silica aerogel 10 25 40 40 40 Binder 30 30 30 5 50 Filling material 20 20 20 5 30 Additives 0 0 0 0 0 Solvents 30 30 30 10 50

[0054] The modified silica aerogel in the above table is prepared by Preparation Example 1; the binder is the organic silicone resin ZY1053 produced by Kramar; the filling material is the hollow glass microspheres of 2-5 um; and the solvent is water.

[0055] Comparative Example 1

[0056] A silica aerogel thermal insulation coating, which differs from Example 1 in that the modified silica aerogel is replaced by an equal amount of silica aerogel;

[0057] The silica aerogel powder has a particle size of 0.1-0.5 µm, a density of 0.04-0.08 g / ml, and a porosity of 95-99%. Other preparation conditions and raw materials are the same as those in Example 1.

[0058] The silica aerogel thermal insulation coatings prepared in the above Examples 1-5 and Comparative Example 1 were sampled, and their adhesion and thermal insulation properties were tested according to the above measurement steps. The average values ​​of the test results were recorded in the following table.

[0059] Project Category Bond strength(Mpa) Thermal conductivity (w / mk) Example 1 0.8 0.050 Example 2 0.8 0.048 Example 3 0.8 0.042 Example 4 0.6 0.050 Example 5 1.0 0.032 Comparative Example 1 0.6 0.0065

[0060] It can be seen from the above table that the silica aerogel thermal insulation coatings prepared in Examples 1-5 have excellent adhesion and thermal insulation properties, with a bonding strength of ≥0.6MPa and a thermal conductivity of ≤0.050w / mk. Example 5 is a preferred example, which is improved to varying degrees compared with Comparative Example 1.

[0061] The possible reason is that the isocyanate-modified silica aerogel is perfectly compatible with silicone resin to form a stable dispersion system. At the same time, a dense insulation layer is formed on the surface of the coated object to effectively isolate external heat and achieve excellent thermal insulation effect. Obviously, the unmodified silica aerogel does not have the corresponding effect, so all performances are reduced.

[0062] In addition, combined with the data of Examples 1-5, it can be concluded that the preferred weight proportions of the components of the silica aerogel thermal insulation coating are as follows: 5-50 parts of binder; 5-30 parts of filler material; 10-50 parts of solvent; 0-10 parts of additive; 10-40 parts of modified silica aerogel. Any adjustment within this range can obtain a silica aerogel thermal insulation coating with relatively stable and uniform performance.

[0063] The selection and dosage of the bonding material and the filling material will affect the thermal conductivity, because hollow glass microspheres and silicone resins with low thermal conductivity are selected. In other embodiments, the filling material can also be one or more of vacuum ceramic microspheres, white carbon black, fibers, and foaming materials.

[0064] Those skilled in the art may replace the filler material and the binder according to the actual bonding strength and thermal conductivity, etc., and this should not be regarded as a limitation on the protection of this application. However, it should be noted that the replacement of components needs to take into account the compatibility of the filler material with the binder and the modified silica aerogel.

[0065] In addition, in other embodiments, the auxiliary agent can be selected from at least one of a dispersant, a preservative, a wetting agent, a defoaming agent, an antifreeze agent, a pH regulator, a leveling agent, a rheological agent, a thickener and a thixotropic agent. This application discards irrelevant variables to reduce the interference of the test performance of this application. However, since technicians in this field can add them according to actual needs, it should not be regarded as a limitation to this application.

[0066] Embodiment 6-9

[0067] A silica aerogel thermal insulation coating, which is different from Example 1 in that the usage of its modified silica aerogel is different, as shown in the following table:

[0068] Table: Comparison table of modified silica aerogel usage in Examples 6-9

[0069] Group Comparison table of modified silica aerogel usage Example 6 Modified silica aerogel was prepared by Preparation Example 2 Example 7 Modified silica aerogel was prepared by Preparation Example 3 Example 8 Modified silica aerogel was prepared by Preparation Example 4 Example 9 Modified silica aerogel was prepared by Preparation Example 5

[0070] The silica aerogel thermal insulation coatings prepared in the above Examples 6-9 were sampled, and their adhesion and thermal insulation properties were tested according to the above measurement steps. The average values ​​of the test results were recorded in the following table.

[0071] Project Category Bond strength(Mpa) Thermal conductivity (w / mk) Example 6 0.8 0.052 Example 7 0.8 0.045 Example 8 0.8 0.045 Example 9 0.8 0.050

[0072] It can be seen from the above table that the silica aerogel thermal insulation coatings prepared in Examples 6-9 also have excellent adhesion and thermal insulation properties, with a bonding strength of 0.8 MPa and a thermal conductivity of ≤0.052 w / mk, which are different from those in Example 1.

[0073] It can be seen that the change in the characteristics of the modified silica aerogel does not affect the bonding strength of the coating, but only affects its thermal insulation performance, i.e., thermal conductivity;

[0074] A specific analysis of Examples 1 and 6-8 shows that the mass percentage concentration of the ethanol dispersion solution of isocyanate will affect the final thermal conductivity, which is related to the modification degree of the silica aerogel, and is preferably 10-25%, which should not be too low. There is no obvious improvement in performance beyond this range.

[0075] A specific analysis of Examples 1 and 9 also shows that the specifications of the silica aerogel powder are preferably: a particle size of 0.1-0.5µm, a density of 0.04-0.08g / ml, and a porosity of 95-99%. The larger the porosity, the less favorable it is for its thermal insulation performance. The analysis may be related to the compatibility of the silicone resin.

[0076] In summary, the modified silica aerogel thermal insulation coating is applied on the facade of the building wall to form a thermal insulation coating, which can play a heat barrier effect in both winter and summer, making the room warm in winter and cool in summer. The modified silica aerogel thermal insulation coating has a high application value in the field of building thermal insulation coatings.

[0077] Although the specific embodiments of the present invention are described in detail above, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the purpose of the present invention, and modifications or deformations without creative labor are still within the protection scope of the present invention.

Claims

1. A modified silica aerogel thermal insulation coating, characterized in that: It is composed of the following components in parts by weight: 5-50 parts of binder; 5-30 parts of filling material; 10-50 parts of solvent; Additives 0-10 parts; 10-40 parts of modified silica aerogel; The preparation steps of the modified silica aerogel are as follows: S1. First, mix the ethanol dispersion solution of isophorone diisocyanate and the silica aerogel powder for 30-45 minutes until they are uniform. During the mixing process, add glacial acetic acid to adjust the pH to 3-4; S2, then adding calcium hydroxide to the slurry obtained in S1, adjusting the pH to 8-9, and after forming a gel, performing freeze vacuum drying to obtain modified silica aerogel.

2. The modified silica aerogel thermal insulation coating according to claim 1, characterized in that: The mass percentage concentration of the ethanol dispersion solution of isophorone diisocyanate is 10-25%.

3. The modified silica aerogel thermal insulation coating according to claim 1, characterized in that: The silica aerogel powder has a particle size of 0.1-0.5 µm, a density of 0.04-0.08 g / ml, and a porosity of 95-99%.

4. The modified silica aerogel thermal insulation coating according to claim 1, characterized in that: The auxiliary agent is at least one of a dispersant, a preservative, a wetting agent, a defoaming agent, an antifreeze agent, a pH regulator, a leveling agent, a rheological agent, a thickener and a thixotropic agent.

5. The modified silica aerogel thermal insulation coating according to claim 1, characterized in that: The binder is an organic resin, specifically selected from one or more of acrylic resin, polyurethane resin, epoxy resin and silicone resin.

6. The modified silica aerogel thermal insulation coating according to claim 1, characterized in that: The filling material is a heat-insulating lightweight material, specifically selected from one or more of vacuum ceramic microspheres, hollow glass microspheres, white carbon black, fibers, and foaming materials.

7. The method for preparing the modified silica aerogel thermal insulation coating according to claim 1, characterized in that: The preparation steps are as follows: At room temperature, the modified silica aerogel is first mixed with a solvent, and then stirred evenly in a disperser to form a stable slurry, with a stirring speed of less than 800 r / min; Then, the binder, the filler material and the auxiliary agent are sequentially added into the slurry, and the mixture is added while being stirred until the mixture is evenly mixed, and the mixture is filtered to obtain the modified silica aerogel thermal insulation coating.

8. Use of the silica aerogel thermal insulation coating according to any one of claims 1 to 6 and / or the coating obtained by the preparation method according to claim 7 in the field of building thermal insulation.

9. A modified silica aerogel, characterized in that: Prepared by the preparation steps in claim 1, specifically as follows: S1. First, mix the ethanol dispersion solution of isophorone diisocyanate and the silica aerogel powder for 30-45 minutes until uniform, and then add glacial acetic acid to adjust the pH to 3-4; S2, then adding calcium hydroxide to the slurry obtained in S1, adjusting the pH to 8-9, and after forming a gel, performing freeze vacuum drying to obtain modified silica aerogel.

10. A thermal insulation coating, characterized in that: The coating is formed by curing the modified silica aerogel thermal insulation coating according to any one of claims 1 to 6.