A method for preparing a coating with reduced infrared emissivity

Abstract

The application belongs to the technical field of optical coatings, and discloses a preparation method of a coating with reduced infrared emissivity. The preparation method comprises the following steps: mixing 40-70 parts of water-based hydroxyl acrylic resin, 10-30 parts of hydroxyl polydimethylsiloxane, 30-60 parts of modified filler, 2-8 parts of auxiliary agent, and 80-150 parts of solvent according to weight fractions to obtain the coating; the preparation process of the modified filler comprises the following steps: mixing mica powder, nano organic acid sodium salt and nano sodium silicate, calcining to obtain calcined substance, and then mixing the calcined substance, nano yttrium oxide, carbon nanotube, silane coupling agent, polyethylene oxide and water to obtain the modified filler. According to the preparation method, the selection of components and the amount of the components can not only significantly reduce the infrared emissivity of the coating formed by the coating, so that the stealth purpose is achieved, but also has good acid corrosion resistance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of optical coatings, and particularly relates to a preparation method of a coating with reduced infrared emissivity. BACKGROUND

[0002] Infrared technology is widely used, especially in the military field and the field of keeping warm. Objects that generate heat emit infrared, and infrared detection technology is used to detect targets by capturing infrared radiation energy.

[0003] The approach to target stealth is usually to reduce the infrared radiation energy signal of the target to achieve the purpose of stealth. For example, infrared stealth coating is applied to the surface of the target, and the low infrared emissivity of the coating is used to significantly reduce the thermal radiation of the target and greatly reduce the probability of the target being discovered by infrared detection instruments, so as to achieve the purpose of infrared stealth.

[0004] The working principle of the existing infrared thermal imaging detector is to distinguish and observe the target by using the difference in radiation intensity of the target and the background in the 3-5 mu m and 8-14 mu m wave bands.

[0005] In addition, when the infrared stealth coating is applied to the surface of a substance, it is inevitable to come into contact with rainwater, and acid rain also occurs in some places. Acid rain can easily corrode the coating, and the damaged coating can significantly reduce the stealth ability of the object. However, the existing coating pays little attention to acid corrosion resistance.

[0006] Therefore, there is an urgent need to provide a new infrared coating that not only greatly reduces the infrared emissivity but also has good acid corrosion resistance. SUMMARY

[0007] The application aims to provide a preparation method of a coating with reduced infrared emissivity. The coating prepared by the preparation method can significantly reduce the infrared emissivity, thereby achieving the purpose of stealth, and also has good acid corrosion resistance.

[0008] To achieve the above purpose, the application provides the following technical solutions:

[0009] A preparation method of a coating with reduced infrared emissivity, comprising the following steps:

[0010] Mix 40-70 parts of water-based hydroxyl acrylic resin, 10-30 parts of hydroxyl polydimethylsiloxane, 30-60 parts of modified filler, 2-8 parts of auxiliary agent, and 80-150 parts of solvent by weight to obtain the coating;

[0011] The preparation process of the modified filler comprises the following steps: mixing mica powder, nano organic acid sodium salt and nano sodium silicate, calcining to obtain calcined substance, and then mixing the calcined substance, nano yttrium oxide, carbon nanotube, silane coupling agent, polyethylene oxide and water to obtain the modified filler.

[0012] The coating is prepared by using water-based hydroxyl acrylic resin and hydroxyl polydimethylsiloxane as main film-forming materials, and the modified filler is uniformly dispersed in the space network structure formed after the water-based hydroxyl acrylic resin and hydroxyl polydimethylsiloxane are cured, so that the uniformity and structural stability of the coating layer are ensured, and the coating layer has good acid corrosion resistance. The modified filler is prepared by mixing mica powder, nano organic acid sodium salt and nano sodium silicate, and calcining to obtain calcined substance. In the environment of organic acid sodium salt, the calcined substance fuses the components of mica powder and nano sodium silicate. Then, the calcined substance is mixed with nano yttrium oxide, carbon nanotube, silane coupling agent and polyethylene oxide. While the silane coupling agent is hydrolyzed in water, the polyethylene oxide plays a surface modification role on the calcined substance, nano yttrium oxide and carbon nanotube, so that the compatibility of all inorganic and organic materials is significantly improved, and the modified filler can significantly reduce the infrared emissivity.

[0013] Preferably, 50-60 parts by weight of water-based hydroxyl acrylic resin, 15-25 parts by weight of hydroxyl polydimethylsiloxane, 35-50 parts by weight of modified filler, 2-8 parts by weight of auxiliary agent and 80-150 parts by weight of solvent are mixed to obtain the coating.

[0014] Preferably, the preparation process of the modified filler comprises the following steps: mixing 50 parts by weight of mica powder, 10-20 parts by weight of nano organic acid sodium salt and 5-20 parts by weight of nano sodium silicate, and calcining to obtain calcined substance, and then mixing the calcined substance, nano yttrium oxide, carbon nanotube, silane coupling agent, polyethylene oxide and water to obtain the modified filler. The weight ratio of the calcined substance, nano yttrium oxide, carbon nanotube, silane coupling agent, polyethylene oxide and water is 10:(0.5-2.5):(0.2-1.0):(8-20):(5-20):(25-40).

[0015] Preferably, the nano organic acid sodium salt comprises nano sodium citrate and / or nano sodium oxalate.

[0016] Preferably, the calcining temperature is 350-500℃, and more preferably 400-480℃.

[0017] Preferably, the calcining time is 1-3 hours, and more preferably 1.5-2.5 hours.

[0018] Preferably, the preparation process of the modified filler comprises the following steps: mixing mica powder 50 parts, nano-organic acid sodium salt 15-20 parts, nano-sodium silicate 8-15 parts by weight fraction, calcining at 350-500 DEG C for 1-3 hours to obtain calcine, then stirring and mixing the calcine, nano-yttrium oxide, carbon nanotube, silane coupling agent, polyethylene oxide and water, the weight ratio of the calcine, nano-yttrium oxide, carbon nanotube, silane coupling agent, polyethylene oxide and water being 10:(0.5-1.5):(0.4-0.8):(10-15):(6-20):(28-40), to obtain the modified filler.

[0019] Preferably, the auxiliary agent comprises isocyanate, dimethicone and sodium dodecyl sulfate.

[0020] Preferably, the isocyanate comprises at least one of hexamethylene diisocyanate, toluene diisocyanate and isophorone diisocyanate.

[0021] Preferably, in the preparation process of the modified filler, cerium oxide is added when the mica powder is added. Due to the unique electronic structure of cerium in cerium oxide, the addition of cerium oxide helps to further reduce the infrared emissivity of the coating formed by the coating.

[0022] Preferably, in the preparation process of the modified filler, 1-3 parts of cerium oxide is added when the mica powder is added.

[0023] A coating with reduced infrared emissivity is prepared by the above preparation method.

[0024] A use method of a coating with reduced infrared emissivity, comprising the following steps:

[0025] The coating is coated on the surface of the substrate and cured to obtain a coating.

[0026] Preferably, the material of the substrate comprises any one of iron, plastic and ceramic.

[0027] Preferably, the coating amount is 20-100 g / m 2 , and more preferably 40-80 g / m 2 .

[0028] Preferably, the curing temperature is 80-130 DEG C, and the curing time is 5-30 minutes.

[0029] The present application has the following beneficial effects:

[0030] The preparation method selects components and dosages, so that the coating formed by the coating has a uniform and stable space network structure, and the modified filler can significantly reduce the infrared emissivity, so that the coating formed by the coating can not only significantly reduce the infrared emissivity to achieve the purpose of stealth, but also has good acid corrosion resistance. DETAILED DESCRIPTION

[0031] In order to make the skilled in the art more clearly understand the technical solutions of the present application, the following examples are listed for illustration. It should be pointed out that the following examples do not constitute a limitation on the scope of protection required by the present application.

[0032] Example 1

[0033] A preparation method of a coating with reduced infrared emissivity, comprising the following steps:

[0034] Mix 50 parts by weight of water-based hydroxyl acrylic resin, 20 parts of hydroxyl polydimethylsiloxane, 40 parts of modified filler, 5 parts of auxiliary (3.5 parts of toluene diisocyanate, 1 part of polydimethylsiloxane, 0.5 part of sodium dodecyl sulfate), and 90 parts of water, the stirring speed during mixing is 500 rpm, and the mixing time is 20 minutes, to obtain the coating;

[0035] The preparation process of the modified filler comprises: mixing 50 parts by weight of mica powder, 16 parts of nano sodium citrate and 9 parts of nano sodium silicate, calcining at 450 DEG C for 2 hours to obtain calcined material, then stirring and mixing the calcined material, nano yttrium oxide, carbon nanotube, silane coupling agent, polyethylene oxide and water, the stirring speed during mixing is 600 rpm, and the mixing time is 15 minutes, wherein the weight ratio of the calcined material, nano yttrium oxide, carbon nanotube, silane coupling agent KH550, polyethylene oxide and water is 10:0.8:0.5:12:10:35, and the modified filler is prepared.

[0036] Example 2

[0037] A preparation method of a coating with reduced infrared emissivity, comprising the following steps:

[0038] Mix 65 parts by weight of water-based hydroxyl acrylic resin, 15 parts of hydroxyl polydimethylsiloxane, 55 parts of modified filler, 6 parts of auxiliary (4.5 parts of hexamethylene diisocyanate, 0.8 parts of polydimethylsiloxane, 0.7 parts of sodium dodecyl sulfate), and 100 parts of water, the stirring speed during mixing is 400 rpm, and the mixing time is 30 minutes, to obtain the coating;

[0039] The preparation process of the modified filler comprises the following steps: taking mica powder 50 parts, nano sodium oxalate 18 parts, and nano sodium silicate 15 parts by weight fraction, mixing, calcining at 480 DEG C for 1.5 hours, obtaining calcine, then stirring and mixing the calcine, nano yttrium oxide, carbon nanotube, silane coupling agent, polyethylene oxide, and water, the stirring speed during mixing is 550 rpm, the mixing time is 20 minutes, wherein the weight ratio of the calcine, nano yttrium oxide, carbon nanotube, silane coupling agent KH560, polyethylene oxide, and water is 10:1.5:0.8:15:15:40, and the modified filler is prepared.

[0040] Example 3

[0041] A preparation method of a coating with reduced infrared emissivity, comprising the following steps:

[0042] The water-based hydroxyl acrylic resin 50 powder, hydroxyl polydimethylsiloxane 20 parts, modified filler 40 parts, auxiliary agent 5 parts (toluene diisocyanate 3.5 parts, polydimethylsiloxane 1 part, sodium dodecyl sulfate 0.5 parts), and water 90 parts are mixed by weight fraction, the stirring speed during mixing is 500 rpm, the mixing time is 20 minutes, and the coating is obtained;

[0043] The preparation process of the modified filler comprises the following steps: taking mica powder 50 parts, cerium oxide 1.1 parts, nano sodium citrate 16 parts, and nano sodium silicate 9 parts by weight fraction, mixing, calcining at 450 DEG C for 2 hours, obtaining calcine, then stirring and mixing the calcine, nano yttrium oxide, carbon nanotube, silane coupling agent, polyethylene oxide, and water, the stirring speed during mixing is 600 rpm, the mixing time is 15 minutes, wherein the weight ratio of the calcine, nano yttrium oxide, carbon nanotube, silane coupling agent KH550, polyethylene oxide, and water is 10:0.8:0.5:12:10:35, and the modified filler is prepared.

[0044] Comparative Example 1

[0045] Comparative Example 1 is different from Example 1 only in that an equal amount of water-based hydroxyl acrylic resin is used instead of hydroxyl polydimethylsiloxane in Example 1, and the rest of the components and processes are the same as in Example 1.

[0046] Comparative Example 2

[0047] Comparative Example 2 is different from Example 1 only in that the calcination process is not performed in the preparation process of the modified filler, and the rest of the components and processes are the same as in Example 1.

[0048] Comparative Example 3

[0049] The difference between Comparative Example 3 and Example 1 is that graphene is used instead of nanometer yttrium oxide and carbon nanotube in the preparation of the modified filler in Comparative Example 3, and the rest of the components and processes are the same as in Example 1.

[0050] Comparative Example 4

[0051] The difference between Comparative Example 4 and Example 1 is that polyethylene glycol is used instead of polyethylene oxide in the preparation of the modified filler in Comparative Example 4, and the rest of the components and processes are the same as in Example 1.

[0052] Product effect test

[0053] 1. Infrared emissivity effect test

[0054] The paint prepared in Examples 1-3 and Comparative Examples 1-4 is coated on the surface of a cleaned and dried tinplate at a coating amount of 80 g / m 2 , and then cured in an oven at 100°C for 30 minutes to form a coating. Then, the infrared emissivity of the coating is tested according to GB / T7287-2008, and the adhesion of the coating is tested according to the grid method of GB / T9286-1998, and the results are shown in Table 1.

[0055] Table 1

[0056]

[0057] As can be seen from Table 1, the infrared emissivity of the coating of the examples is significantly lower than that of the comparative examples. As can be seen from the results of Example 1 and Example 3, the addition of cerium oxide significantly helps to reduce the infrared emissivity of the coating, so that the coating has better stealth effect.

[0058] As can be seen from Examples 1 and Comparative Examples 1-4, the use of water-based hydroxyl acrylic resin and hydroxyl polydimethylsiloxane in the preparation of the paint can make the coating structure more stable, the adhesion to the substrate better, and help the uniform dispersion of the modified filler, so that a coating with uniform and good performance is obtained. In the preparation of the modified filler, the calcination process, nanometer yttrium oxide and carbon nanotube, and polyethylene oxide cannot be omitted or replaced at will, otherwise the modified filler obtained will have a significant adverse effect on the infrared emissivity of the paint. The reason is that the electronic interaction or compatibility of the components in the preparation of the modified filler needs to be maintained by appropriate component matching, and good compatibility with the main film-forming material is maintained, so that the coating has good infrared emissivity reduction effect.

[0059] 2. Acid corrosion resistance effect test

[0060] The coating prepared in Example 1 and Comparative Example 4 was coated on the surface of a ceramic according to the above method to form a coating layer, which was placed in 0.5 mol / L hydrochloric acid at 30℃, and the time required for cracks to appear on the surface of the coating layer was observed, and the results are shown in Table 2.

[0061] Table 2

[0062] Time (hours) required for cracks to appear on the surface of the coating Example 1 72 Comparative Example 4 24

[0063] As can be seen from Table 2, the coating layer of Example 1 has better acid corrosion resistance than that of Comparative Example 4, and it can also be seen that polyethylene oxide has a significant promoting effect on the improvement of the acid corrosion resistance of the coating layer during the preparation of the modified filler.

[0064] A stealth equipment coated with the coating of Example 1 on the surface.

[0065] The above describes the basic principles and main features of the present application and the advantages of the present application. It should be understood by those skilled in the art that the scope of protection of the present application is not limited by the above examples. Various changes and improvements can be made to the present application without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. A method for preparing a coating that reduces infrared emissivity, characterized in that, Includes the following steps: The coating is prepared by mixing 40-70 parts of waterborne hydroxyl acrylic resin powder, 10-30 parts of hydroxyl polydimethylsiloxane, 30-60 parts of modified filler, 2-8 parts of additives, and 80-150 parts of solvent by weight. The preparation process of the modified filler includes: taking 50 parts by weight of mica powder, 15-20 parts by weight of nano-organic acid sodium salt, and 8-15 parts by weight of nano-sodium silicate, and calcining at 350-500℃ for 1-3 hours to obtain a calcined product; then stirring and mixing the calcined product, nano-yttrium oxide, carbon nanotubes, silane coupling agent, polyethylene oxide, and water, wherein the weight ratio of the calcined product, nano-yttrium oxide, carbon nanotubes, silane coupling agent, polyethylene oxide, and water is 10:(0.5-1.5):(0.4-0.8):(10-15):(6-20):(28-40) to obtain the modified filler; The nano-organic acid sodium salt includes nano-sodium citrate and / or nano-sodium oxalate; The additives include isocyanate, polydimethylsiloxane, and sodium dodecyl sulfate.

2. The preparation method according to claim 1, characterized in that, The coating is prepared by mixing 50-60 parts by weight of waterborne hydroxyl acrylic resin powder, 15-25 parts by weight of hydroxyl polydimethylsiloxane, 35-50 parts by weight of modified filler, 2-8 parts by weight of additives and 80-150 parts by weight.

3. The preparation method according to claim 1, characterized in that, In the preparation process of the modified filler, cerium oxide is added along with mica powder.

4. A coating for reducing infrared emissivity, characterized in that, It is prepared by any one of claims 1-3.

5. A method for using a coating that reduces infrared emissivity, characterized in that, Includes the following steps: The coating described in claim 4 is applied to the surface of the substrate and cured to obtain a coating layer.

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