Thermal barrier coating and method of making the same

Abstract

The application provides a kind of thermal insulation coating and preparation method thereof, according to mass fraction, the raw materials for preparing the thermal insulation coating include 50-100 parts of silicone-acrylate emulsion, 10-20 parts of thermal insulation filler, 1-10 parts of nano copper.The application can provide good thermal insulation performance and repair performance for metal frame or sunshade metal object by collocating silicone-acrylate emulsion, thermal insulation filler and nano copper.Although the reflectivity of nano copper to light is very low, but nano copper has the effect of repairing the worn surface of metal, after the metal parts emit heat due to friction, nano copper can be attached to the metal surface by its nano characteristics, repair the damaged part of the metal surface, and make the protective film formed on the metal surface more solid, thereby prolonging the service life of the metal device.Therefore, the application can control the light absorption effect of nano copper and the light reflection effect of thermal insulation filler, and then obtain a thermal insulation coating with good thermal insulation performance and repair performance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of coating, and particularly relates to a heat insulation coating and a preparation method thereof. BACKGROUND

[0002] Solar radiation refers to the energy transmitted by the sun in the form of electromagnetic waves, and the electromagnetic waves and particle flow emitted by the sun to the universe. The energy transmitted by the solar radiation is called solar radiation energy. Therefore, understanding the energy distribution of solar radiation helps to study the heat insulation performance. Among them, the ultraviolet region (0.2-0.4 μm) accounts for 5% of the total solar radiation energy, the visible light region (0.4-0.72 μm) accounts for 45% of the total solar radiation energy, and the infrared light region (0.72-2.5 μm) accounts for 50% of the total solar radiation energy. As can be seen, the solar radiation energy is mainly concentrated in the visible light region and the infrared light region. Therefore, when the heat insulation coating developed has a higher reflectivity to solar radiation in these two wavelength ranges, the heat insulation effect is better.

[0003] In addition, general objects at room temperature or lower temperature continuously radiate energy to the outside in the form of infrared light and electromagnetic waves with longer wavelengths, which can reduce the temperature of the object itself. The atmosphere has two windows for infrared radiation at 2.5-5 μm and 8-13.5 μm, that is, the atmospheric absorption capacity for infrared radiation in these two regions is weak, and the transmittance is generally above 80%. Therefore, to achieve continuous cooling of the object, the absorbed heat should be radiated to the outer space through these two windows as much as possible. This requires selecting appropriate fillers and binders to prepare heat insulation coatings so that the emissivity in these two regions is as high as possible, thereby achieving the purpose of rapid heat dissipation and cooling.

[0004] Therefore, in the prior art, fillers with high solar radiation reflectivity and high atmospheric window emissivity are used to prepare heat insulation coatings. SUMMARY

[0005] In order to improve the heat insulation performance of the metal surface, the present application provides a heat insulation coating and a preparation method thereof.

[0006] According to one aspect of the present application, a heat insulation coating is provided, and the raw materials for preparing the heat insulation coating include 50-100 parts of a silicone-acrylate emulsion, 10-20 parts of a heat insulation filler, 1-10 parts of nano-copper, and 1-10 parts of an anionic dispersant, in terms of mass fraction. The heat insulation filler includes hollow glass microspheres, titanium dioxide, and ceramic fibers.

[0007] In the present application, by introducing the three kinds of thermal insulation fillers (hollow glass microspheres, titanium dioxide, ceramic fiber), on the one hand, the ceramic fiber can block the heat transfer, the hollow glass microspheres and titanium dioxide can reflect visible light and infrared light to insulate solar energy, and the thermal insulation performance of the thermal insulation coating is synergistically enhanced; on the other hand, the hollow glass microspheres and titanium dioxide can block the light absorption of the nano-copper, and the ceramic fiber can block the heat caused by the light absorption of the nano-copper. Secondly, by introducing the anionic dispersant opposite to the charge on the surface of the nano-copper, the nano-copper is tightly combined together by the electrostatic space steric effect, so as to achieve the effect of uniformly dispersing the nano-copper around the thermal insulation filler, thereby reducing the light absorption effect of the nano-copper and enhancing the repair effect of the nano-copper. Thus, by utilizing the interaction between the thermal insulation filler and the nano-copper, the light absorption effect of the nano-copper is controlled, and the heat of the light is also blocked, and thus the thermal insulation coating provided by the present application has good thermal insulation performance and repair performance.

[0008] Preferably, the mass ratio of the thermal insulation filler to the nano-copper is 1:0.1-0.8.

[0009] Preferably, in the thermal insulation filler, the mass ratio of the hollow glass microspheres to the titanium dioxide to the ceramic fiber is (1-2):1:(0.5-1).

[0010] Preferably, the particle size of the hollow glass microspheres is 10-50 μm, and the wall thickness is 1-2 μm.

[0011] Preferably, the particle size of the titanium dioxide is 1-5 μm.

[0012] Preferably, the diameter of the ceramic fiber is 1-3 μm, and the length is 100-200 mm.

[0013] Preferably, the particle size of the nano-copper is 1-50 nm. The particle size of the nano-copper affects its performance, which is mainly due to the special physical and chemical effects of the size of the nano-materials, which are different from conventional materials. The nano-materials have unique physical and chemical properties different from macro-materials. Among them, the reflectivity of the ultrafine particle metal material to light is very low, which is usually lower than 1%, and the thickness of about several microns can completely extinguish. For example, compared with copper, the nano-copper has excellent light absorption performance, that is, the nano-copper has low reflectivity.

[0014] Preferably, the anionic dispersant includes at least one of dodecyl benzene sulfonic acid, sodium polyphosphate, and sodium silicate.

[0015] Preferably, the thermal insulation coating further comprises a non-ionic dispersant, the non-ionic dispersant comprising at least one of nonylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether. The non-ionic dispersant can improve the dispersion effect of the thermal insulation filler, and can further improve the thermal insulation performance and block the absorption of nano-copper light.

[0016] Preferably, the thermal insulation coating further comprises an emulsifier, the emulsifier comprising at least one of sodium dodecyl sulfate, alkyl diphenyl ether sodium sulfate.

[0017] According to a second aspect of the present application, a method for preparing the thermal insulation coating as described above is provided, the method comprising the following steps: S1. mixing the thermal insulation filler with a solvent to obtain solution A, and mixing the nano-copper with a solvent to obtain solution B; S2. mixing solution A and solution B, stirring for 25-120 minutes, then adding the silicone-acrylate emulsion to obtain the thermal insulation coating.

[0018] Preferably, solution B further comprises a dispersant.

[0019] Preferably, in S2, after mixing solution A and solution B, the emulsifier is added. DETAILED DESCRIPTION

[0020] In order to make the person skilled in the art better understand the technical solutions in the present application, the technical solutions of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the scope of protection of the present application.

[0021] Embodiment 1

[0022] (1) Raw materials for preparing the thermal insulation coating

[0023] The raw materials for preparing the thermal insulation coating in this embodiment are shown in Table 1.

[0024] Table 1. Raw materials for preparing the thermal insulation coating

[0025]

[0026] (2) Preparation of the thermal insulation coating

[0027] S1. mixing the thermal insulation filler with water to obtain solution A, and mixing the nano-copper, water, anionic dispersant, non-ionic dispersant to obtain solution B;

[0028] S2. mixing solution A and solution B, stirring for 60 minutes, then adding the emulsifier, continuing to stir for 30 minutes, subsequently adding the silicone-acrylate emulsion, stirring for 50 minutes to obtain the thermal insulation coating.

[0029] (3) Preparation of thermal insulation coating

[0030] 1. Pretreatment of steel plate substrate: Take ordinary steel plate, remove dust and dirt on the glass surface, wash with clean water, and dry after scrubbing with distilled water for standby use.

[0031] 2. Preparation of coating: The thermal insulation coating prepared above is coated on the surface of the pretreated steel plate with a size of 220*250*5 mm 3 at room temperature until the coating is dry, or after the coating surface is dry, put it into an oven to solidify into a film for standby use.

[0032] Example 2

[0033] In this example, the thermal insulation coating is prepared according to the formula and method provided in Example 1, and the difference from Example 1 is that the nano-copper added in the preparation of the thermal insulation coating is 1.5 parts by mass fraction. In addition to the above difference, the operation steps for preparing the thermal insulation coating and the thermal insulation coating in this example are strictly consistent with those in Example 1.

[0034] Example 3

[0035] In this example, the thermal insulation coating is prepared according to the formula and method provided in Example 1, and the difference from Example 1 is that the nano-copper added in the preparation of the thermal insulation coating is 12 parts by mass fraction. In addition to the above difference, the operation steps for preparing the thermal insulation coating and the thermal insulation coating in this example are strictly consistent with those in Example 1.

[0036] Example 4

[0037] In this example, the thermal insulation coating is prepared according to the formula and method provided in Example 1, and the difference from Example 1 is that the nano-copper added in the preparation of the thermal insulation coating is 15 parts by mass fraction. In addition to the above difference, the operation steps for preparing the thermal insulation coating and the thermal insulation coating in this example are strictly consistent with those in Example 1.

[0038] Example 5

[0039] In this example, the thermal insulation coating is prepared according to the formula and method provided in Example 1, and the difference from Example 1 is that the particle size of the nano-copper added in the preparation of the thermal insulation coating is 100 nm. In addition to the above difference, the operation steps for preparing the thermal insulation coating and the thermal insulation coating in this example are strictly consistent with those in Example 1.

[0040] Example 6

[0041] The present example is prepared according to the formula and method provided in Example 1, except that the hollow glass microspheres: titanium dioxide: ceramic fiber ratio in the present example is 1.5:1:0.6 by mass, and the total mass fraction of the thermal insulation fillers remains unchanged as provided in Example 1. Except for the above difference, the steps for preparing the thermal insulation coating in the present example are strictly consistent with those in Example 1.

[0042] Example 7

[0043] The present example is prepared according to the formula and method provided in Example 1, except that the hollow glass microspheres: titanium dioxide: ceramic fiber ratio in the present example is 2:1:1 by mass, and the total mass fraction of the thermal insulation fillers remains unchanged as provided in Example 1. Except for the above difference, the steps for preparing the thermal insulation coating in the present example are strictly consistent with those in Example 1.

[0044] Example 8

[0045] The present example is prepared according to the formula and method provided in Example 1, except that the anionic dispersant used in the present example is oleic acid. Except for the above difference, the steps for preparing the thermal insulation coating in the present example are strictly consistent with those in Example 1.

[0046] Example 9

[0047] The present example is prepared according to the formula and method provided in Example 1, except that no nonionic dispersant is added in the present example. Except for the above difference, the steps for preparing the thermal insulation coating in the present example are strictly consistent with those in Example 1.

[0048] Comparative Example 1

[0049] The present example is prepared according to the formula and method provided in Example 1, except that the hollow glass microspheres: titanium dioxide: ceramic fiber ratio in the present example is 1.5:1:0.6 by mass, and the total mass fraction of the thermal insulation fillers remains unchanged as provided in Example 1. Except for the above difference, the steps for preparing the thermal insulation coating in the present example are strictly consistent with those in Example 1.

[0050] Comparative Example 2

[0051] The comparative example 1 is prepared according to the formula and method provided in the example 1, except that the hollow glass microspheres and the ceramic fibers are replaced by titanium dioxide in equal mass fraction. The operation steps for preparing the thermal insulation coating and the thermal insulation coating layer of the comparative example 1 are strictly consistent with those of the example 1.

[0052] Comparative example 3

[0053] The comparative example 1 is prepared according to the formula and method provided in the example 1, except that the hollow glass microspheres and the ceramic fibers are replaced by titanium dioxide in equal mass fraction. The operation steps for preparing the thermal insulation coating and the thermal insulation coating layer of the comparative example 1 are strictly consistent with those of the example 1.

[0054] Comparative example 4

[0055] The comparative example 1 is prepared according to the formula and method provided in the example 1, except that the hollow glass microspheres and the ceramic fibers are replaced by titanium dioxide in equal mass fraction. The operation steps for preparing the thermal insulation coating and the thermal insulation coating layer of the comparative example 1 are strictly consistent with those of the example 1.

[0056] Comparative example 5

[0057] The comparative example 1 is prepared according to the formula and method provided in the example 1, except that the hollow glass microspheres and the ceramic fibers are replaced by titanium dioxide in equal mass fraction. The operation steps for preparing the thermal insulation coating and the thermal insulation coating layer of the comparative example 1 are strictly consistent with those of the example 1.

[0058] Comparative example 6

[0059] The comparative example 1 is prepared according to the formula and method provided in the example 1, except that the hollow glass microspheres and the ceramic fibers are replaced by titanium dioxide in equal mass fraction. The operation steps for preparing the thermal insulation coating and the thermal insulation coating layer of the comparative example 1 are strictly consistent with those of the example 1.

[0060] Comparative example 7

[0061] The comparative example 1 is prepared according to the formula and method provided in the example 1, except that the hollow glass microspheres and the ceramic fibers are replaced by titanium dioxide in equal mass fraction. The operation steps for preparing the thermal insulation coating and the thermal insulation coating layer of the comparative example 1 are strictly consistent with those of the example 1.

[0062] Test example

[0063] 1. Test object

[0064] The samples prepared in Examples 1-9 and Comparative Examples 1-7 and a blank steel plate (not coated, control group) were used as test objects.

[0065] 2. Test method

[0066] (1) Spectral analysis of the coating film: The reflectivity of the sample was calculated according to the industry standard JG / T 235-2014 "Building Reflective Heat-Insulating Coatings".

[0067] (2) Heat-insulating performance test: A 300 W iodine tungsten lamp was used to simulate a solar light source at a distance of 40 cm above the test object (the spectrum of the iodine tungsten lamp is similar to that of sunlight). After irradiation for 30 minutes, the surface temperature of the sample was measured, and the heat-insulating performance was analyzed.

[0068] (3) Light ray aging resistance test: The samples were subjected to aging treatment in a light aging test chamber at a constant temperature of 60°C under irradiation in the ultraviolet-visible light range. Each ultraviolet aging sample was placed at a distance of 20 cm from the light source (500 W, 340 nm), and the light source was rotated at a constant speed to ensure uniform irradiance of the sample. Then, the appearance of the coating film was observed, and the aging degree of each sample was determined.

[0069] (4) Repair performance: After the steel plate was scratched, the scratch area S1 was observed and recorded using an optical microscope. Then, an appropriate amount of sample was coated on the surface of the scratched steel plate, and the area S2 of the steel plate surface still having scratches after 24 hours was recorded. The repair rate was calculated, where the repair rate = (S1-S2) x 100%.

[0070] 3. Test results and analysis

[0071] The test results of the test example are shown in Table 2. Among them, by comparing the experimental data in the test example, it can be found that in Comparative Examples 1-3, the introduction of only one heat insulation filler will cause the heat insulation performance of the corresponding heat insulation coating to decline, and will also cause the dispersion effect of nano-copper, thereby affecting the repair performance of the heat insulation filler. In addition, in Comparative Example 3, since only ceramic fibers are added, without introducing visible light and infrared light reflecting and solar energy insulating, the light aging resistance of the heat insulation coating is declined. In Comparative Example 4, since no heat insulation filler is added, the heat insulation performance is significantly reduced, and the light aging resistance is also reduced, which shows that the introduction of the heat insulation filler can further enhance the heat insulation performance and light aging resistance of the silicone-acrylate emulsion. In Comparative Example 5, it can be found that since no anionic dispersant is introduced, nano-copper is easy to form large agglomerates in the preparation process, causing the heat insulation performance and repair performance of the coating prepared in Comparative Example 5 to decline. In Comparative Example 6, since no nano-copper is added, although the heat insulation performance of the coating is improved, the coating prepared does not have the ability to repair the steel plate, and the repair ability is similar to that of the control group without coating. In addition, through the comprehensive implementation of Example 1 and Comparative Examples 1-6, it can be proved that although nano-copper has a repair effect on metal materials, due to the high absorbance and easy agglomeration of nano-copper, it will not only reduce the heat insulation performance of the heat insulation coating, but also affect its repair effect. In Comparative Example 7, by replacing the silicone-acrylate emulsion with the styrene-acrylate emulsion, it can be found by comparing the experimental data that the heat insulation performance and light aging resistance of the silicone-acrylate emulsion are better than those of the styrene-acrylate emulsion.

[0072] The experimental data of Examples 1-4 show that the mass ratio of heat insulation filler to nano-copper will affect the heat insulation performance of the coating. This is mainly because nano-copper has good light absorption performance. In order to balance the repair performance and heat insulation performance of the coating, the heat insulation filler and nano-copper with a mass ratio of 1:0.1-0.8 prepared have good performance.

[0073] In addition, by comparing Example 1 with Example 5, it can be found that the particle size of nano-copper will affect the repair performance and heat insulation performance of the heat insulation coating. This is mainly because nano-materials have unique properties due to their nano structure. When the nano size is changed, the performance will also change.

[0074] It can be found in Embodiment 1 and Embodiments 6-7 that the combination and mass ratio of the thermal insulation fillers (hollow glass microspheres, titanium dioxide, ceramic fibers) can affect the thermal insulation performance of the coating. The present application can further improve the thermal insulation effect of the coating by combining the ceramic fibers capable of blocking heat transfer, the hollow glass microspheres capable of reflecting visible light and infrared light to achieve solar energy insulation, and the titanium dioxide, and the thermal insulation effect of the coating can be changed with the mass ratio of the three. When the mass ratio of the three satisfies hollow glass microspheres: titanium dioxide: ceramic fibers = (1-2): 1: (0.5-1), the coating has good thermal insulation performance.

[0075] In Embodiment 8, although the introduced oleic acid also belongs to an anionic dispersant, it can be found that the dispersibility of the nano-copper in the silicone-acrylate emulsion is reduced due to the poor water solubility of the oleic acid compared with the dodecyl benzene sulfonic acid, thus leading to the decline of the thermal insulation performance of the coating prepared in Embodiment 8.

[0076] In Embodiment 9, it can be found that the dispersing effect of the thermal insulation filler is reduced due to the absence of the non-ionic dispersant, thus leading to the decline of the thermal insulation performance of the coating prepared in Embodiment 9.

[0077] Table 2. Test results of the test example

[0078]

[0079] The above embodiments are only used to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A thermal barrier coating characterized by, The raw materials for preparing the heat insulation coating include 50-100 parts of a silicone-acrylate emulsion, 10-20 parts of a heat insulation filler, 1-10 parts of nano-copper, and 1-10 parts of an anionic dispersant, in terms of mass fraction; The nano-copper has a particle size of 1-50 nm; In the heat insulation coating, the heat insulation filler:nano-copper = 1:0.1-0.8, in terms of mass ratio; The heat insulation filler includes hollow glass microspheres, titanium dioxide, and ceramic fibers. In the heat insulation filler, the hollow glass microspheres:titanium dioxide:ceramic fibers = (1-2):1:(0.5-1), in terms of mass ratio.

2. The thermal barrier coating of claim 1, wherein, The hollow glass microspheres have a particle size of 10-50 μm and a wall thickness of 1-2 μm.

3. The thermal barrier coating of claim 1, wherein, The titanium dioxide has a particle size of 1-5 μm.

4. The thermal barrier coating of claim 1, wherein, The ceramic fibers have a diameter of 1-3 μm and a length of 100-200 mm.

5. The thermal barrier coating of claim 1, wherein, The anionic dispersant includes at least one of dodecyl benzene sulfonic acid, sodium polyphosphate, and sodium silicate.

6. The thermal barrier coating of claim 1, wherein, The heat insulation coating further includes a non-ionic dispersant, which includes at least one of nonylphenol polyoxyethylene ether and fatty alcohol polyoxyethylene ether, in terms of mass fraction.

7. A process for the preparation of a thermal barrier coating according to any one of claims 1 to 6, characterized in that The method includes the following steps: S1. Mixing the heat insulation filler with a solvent to obtain solution A, and mixing the nano-copper and the anionic dispersant with a solvent to obtain solution B; S2. Mixing the solution A and solution B, stirring for 25-120 minutes, and then adding the silicone-acrylate emulsion to obtain the heat insulation coating.

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