CN112920697B

CN112920697B - Preparation method of super-hydrophobic low-infrared-emissivity coating

Info

Publication number: CN112920697B
Application number: CN202110363930.3A
Authority: CN
Inventors: 张伟钢; 吕丹丹
Original assignee: Chuzhou University
Current assignee: Chuzhou University
Priority date: 2021-04-02
Filing date: 2021-04-02
Publication date: 2022-04-26
Anticipated expiration: 2041-04-02
Also published as: CN112920697A

Abstract

The invention discloses a preparation method of a super-hydrophobic low-infrared-emissivity coating, which takes flaky Al powder as a functional pigment and nano SiO₂Is a micro-nano structure modifier containing hydrogen siliconThe preparation method comprises the following steps of taking oil (HCSO) modified Polyurethane (PU) as a binder, taking polyether polyol as a curing agent and absolute ethyl alcohol as a diluent, putting the raw materials into a disposable plastic cup, fully stirring the raw materials by a glass rod, fully dispersing the raw materials by ultrasonic waves, adjusting the viscosity by using a proper amount of the diluent until the paint can flow down linearly and continuously to obtain the super-hydrophobic low-infrared-emissivity paint, then coating 0.8-1.2 g of the paint on a prepared substrate by a glass rod scraping method, drying the paint for 5 hours at room temperature, and then placing the paint in an oven at 80 ℃ for 10 hours to obtain the super-hydrophobic low-infrared-emissivity paint. According to the preparation method of the super-hydrophobic low-infrared-emissivity coating, the prepared coating has low infrared emissivity, glossiness and adhesive force performance, has an infrared stealth effect and has outstanding super-hydrophobic and self-cleaning performances.

Description

Preparation method of super-hydrophobic low-infrared-emissivity coating

Technical Field

The invention relates to the technical field of fine chemical engineering, in particular to a preparation method of an ultra-hydrophobic low-infrared-emissivity coating.

Background

Due to the fact that various aircrafts such as warplanes and missiles can generate far higher infrared radiation intensity than the background at 8-14 mu m infrared atmospheric window wave bands through thermal and pneumatic heating, the aircrafts are easy to be discovered and destroyed by high-sensitivity infrared detection equipment and infrared guided weapons, and the safety of military targets is seriously threatened. Therefore, the infrared stealth technology for reducing and weakening the efficiency of enemy infrared detection equipment is an important means for improving the wartime survival capability of the aircraft, and has attracted wide attention of domestic and foreign scholars.

The adoption of the low infrared emissivity material is the most effective technical method which is recognized at present and can realize the infrared stealth of the target. Various types of low infrared emissivity materials have been reported, such as nanocomposite films, single (multilayer) film structure materials, core-shell structure composites, photonic crystals, and composite coating materials. The resin-based low-infrared-emissivity coating material is mainly prepared by taking Polyurethane (PU), epoxy resin and the like as resin matrixes and taking aluminum powder, copper powder, bronze powder and other metal pigments as functional fillers. The method has the outstanding advantages of low infrared emissivity, simple preparation process, convenient construction, no limitation of the shape of the target surface in use and the like, is a main technical measure for realizing infrared stealth of various aircrafts, and is expected to realize large-scale engineering application.

However, the traditional resin-based low-infrared-emissivity coating mainly uses strong-polarity resin matrixes such as polyurethane, epoxy resin and the like as an adhesive, and the resin matrixes can endow the coating with good bonding strength, stability and mechanical properties. However, the large amount of hydrophilic polar groups such as isocyanate group, amino group, hydroxyl group, ether bond and the like in the resin matrix can cause the overall surface energy of the coating to be higher, so that the coating is easy to be polluted by dust and dirt in the long-term use process, and the infrared stealth performance of the coating is weakened. In addition, the low-infrared-emissivity coating with high surface energy is very easy to corrode electrolyte in seawater or salt fog when used in a marine environment, so that the microstructure inside the coating is damaged, the functional characteristics of the coating are further reduced, the appearance structure is pulverized, and the coating is finally scrapped. The problems become the bottleneck of realizing essential breakthrough of the using efficiency of the infrared stealth coating of various aircrafts on the prior basis, and the effective solving of the difficult problems has important theoretical and practical significance for essentially improving the infrared stealth efficiency of various aircrafts.

The super-hydrophobic coating is a coating with a water contact angle of more than 150 degrees and a rolling angle of less than 10 degrees, and has outstanding self-cleaning performance and corrosion resistance. The method mainly forms a special micro-nano structure on the surface of a coating by using low surface energy resin and nano powder materials to generate good hydrophobic property. If hydrogen-containing silicone oil (HCSO) with low surface energy characteristic is used as the adhesive, the surface energy of the coating can be obviously reduced. By using nano SiO₂When the coating is modified by the light hydrophobic nano-particles, a micro-nano rough structure can be formed on the surface of the coating, so that the coating has outstanding hydrophobic characteristics. Therefore, the design concept of the super-hydrophobic coating is introduced into the design of the coating with low infrared emissivity, the surface energy of the coating is obviously reduced through reasonable coating formula design and interface structure construction, and the coating has the super-hydrophobic characteristic on the premise of keeping low emissivity, so that the method is an effective way for solving the problems.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a preparation method of a super-hydrophobic low-infrared-emissivity coating, and solves the technical problem that the existing low-infrared-emissivity coating does not have super-hydrophobic and self-cleaning properties.

(II) technical scheme

In order to achieve the purpose, the invention is realized by the following technical scheme: a preparation method of a super-hydrophobic low-infrared-emissivity coating comprises the following specific operation steps:

s1, using a standard tin plate, an aluminum alloy plate and a titanium alloy plate as a substrate, polishing the substrate with sand paper to make the substrate have roughness of 3-10 μm, washing the substrate with tap water, drying the substrate in an oven at 80 ℃ for 30min, and wiping the substrate clean with a piece of cotton cloth dipped with alcohol for later use;

s2, mixing the components in a mass ratio of 1: 9-3: 7, fully mixing HCSO and PU to obtain blended modified PU, and then using the HCSO modified PU as an adhesive to prepare a coating, wherein polyether polyol is used as a curing agent, and the using amount of the polyether polyol is 25% of the mass of the modified resin;

s3, flaky Al powder and nano SiO₂The mass ratio of (A) to (B) is 5.5: 4.5-6.5: 3.5, weighing a proper amount of HCSO modified PU and functional filler in a clean disposable plastic cup according to the mass ratio of 7: 3-5: 5;

s4, adding absolute ethyl alcohol serving as a diluent in the plastic cup, wherein the weight of the absolute ethyl alcohol is 10-20% of that of HCSO modified PU, and fully stirring by using a glass rod to uniformly disperse the absolute ethyl alcohol until no obvious particles are seen in the coating;

s5, further ultrasonically dispersing the paint for 10min by using ultrasonic waves with the frequency of 25KHz to further uniformly disperse the paint, and then adding a small amount of absolute ethyl alcohol to adjust the viscosity of the paint to a proper range until the paint can continuously flow downwards in a straight line shape;

s6, coating 0.8-1.2 g of the coating on the prepared substrate by a glass rod blade coating method, drying for 5h at room temperature, and then placing in an oven at 80 ℃ for 10h to obtain the super-hydrophobic low-infrared-emissivity coating.

Preferably, the particle size of the flaky Al powder is 20-50 μm; the nano SiO₂The purity of the product is more than 99.5%, and the particle size is 20-40 nm; the solid content of the PU is 50-60 percent; the solid content of the HCSO is 90-97%, and the viscosity is 18-22.

(III) advantageous effects

1. The coating prepared by the invention has good infrared stealth effect, excellent adhesive force and low gloss performance, and outstanding super-hydrophobic and self-cleaning performances.

2. The coating prepared by the invention can be used on the surfaces of various carriers such as fabrics, tinplate, aluminum alloy plates, titanium alloy plates and the like, so that the coating has super-hydrophobic and self-cleaning properties while achieving an infrared stealth effect.

3. The invention has simple preparation process, convenient construction, small weight increment to the target and low use cost.

Drawings

FIG. 1 is a surface topography and water contact angle plot of a superhydrophobic low infrared emissivity coating prepared in accordance with the invention;

FIG. 2 is a diagram illustrating the self-cleaning effect of the ultra-hydrophobic low IR emissivity coating prepared in the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-2, an embodiment of the present invention provides a technical solution: a preparation method of a super-hydrophobic low-infrared-emissivity coating comprises the following specific operation steps:

s3, flaky Al powder and nano SiO₂The mass ratio of (A) to (B) is 5.5:4.5 to 65:3.5, weighing a proper amount of HCSO modified PU and functional filler in a clean disposable plastic cup according to the mass ratio of 7: 3-5: 5;

In a further improvement, the particle size of the flaky Al powder is 20-50 μm; the nano SiO₂The purity of the product is more than 99.5%, and the particle size is 20-40 nm; the solid content of the PU is 50-60 percent; the solid content of the HCSO is 90-97%, and the viscosity is 18-22.

The emissivity of the coating in a wave band of 8-14 mu m can be as low as 0.675 measured by an IR-2 type dual-wave-band infrared emissivity tester developed by Shanghai technical and physical research institute of Chinese academy of sciences; the glossiness of the coating can be measured to be as low as 2.7 by using a JKGZ-60 mirror-oriented glossiness meter produced by Tianjin Jingkejie materials testing machine, Inc.; the water contact angle of the coating measured by a JC2000D7 contact angle measuring instrument produced by Shanghai Zhongchen resin technology equipment Co., Ltd is 155 degrees, the rolling angle is 8 degrees, and good super-hydrophobic performance is embodied. The adhesion of the coating was evaluated as described in GB 1720-79 to grade 1.

The prepared coating has low infrared emissivity, glossiness and outstanding super-hydrophobic, self-cleaning and adhesive force performances, and can be coated on the surfaces of various equipment such as fighters, missiles, warships, tanks, combat vehicles and the like, so that the coating has an infrared stealth effect and outstanding infrared stealth performanceThe invention adopts hydrogen-containing silicone oil (HCSO) modified Polyurethane (PU) as adhesive, flaky Al powder as functional filler and nano SiO₂The invention has wide application prospect in the field of infrared stealth design and modification of various equipment and has important significance for improving the combat effectiveness of various equipment in China.

Example 1:

according to the mass ratio of 1: 9, fully mixing HCSO and PU to obtain blended modified PU, and then using the HCSO modified PU as an adhesive to prepare a coating, wherein polyether polyol is used as a curing agent, and the using amount of the polyether polyol is 25% of the mass of the modified resin;

flaky Al powder and nano SiO₂The mass ratio of (A) is 6.5:3.5, and a proper amount of HCSO modified PU and functional filler (flaky Al powder + nano SiO) are weighed in a clean disposable plastic cup according to the mass ratio of 7:3₂)；

Adding absolute ethyl alcohol serving as a diluent into a plastic cup, wherein the weight of the absolute ethyl alcohol is 20% of the mass of the HCSO modified PU, and fully stirring by using a glass rod to uniformly disperse the absolute ethyl alcohol until no obvious particles are seen in the coating;

further ultrasonically dispersing the coating for 10min by using ultrasonic waves with the frequency of 25KHz to further uniformly disperse the coating, and then adding a small amount of absolute ethyl alcohol to adjust the viscosity of the coating to a proper range until the coating can continuously flow downwards in a straight line shape;

coating 1.2g of the coating on a prepared substrate by a glass rod blade coating method, drying at room temperature for 5 hours, and then placing in an oven at 80 ℃ for 10 hours to obtain a super-hydrophobic low-infrared-emissivity coating;

the infrared emissivity of the obtained coating is 0.650, the glossiness is 3.4, the water contact angle is 152 degrees, the rolling angle is 9 degrees, and the adhesive force is 1 grade.

Example 2:

according to the mass ratio of 2: 8, fully mixing HCSO and PU to obtain blended modified PU, and then using the HCSO modified PU as an adhesive to prepare a coating, wherein polyether polyol is used as a curing agent, and the using amount of the polyether polyol is 25% of the mass of the modified resin;

flaky Al powder and nano SiO₂The mass ratio of (A) is 5.5:4.5, and a proper amount of HCSO modified PU and functional filler (flaky Al powder + nano SiO) are weighed in a clean disposable plastic cup according to the mass ratio of 5:5₂)；

Adding absolute ethyl alcohol serving as a diluent in a plastic cup, wherein the weight of the absolute ethyl alcohol is 15% of the mass of the HCSO modified PU, and fully stirring by using a glass rod to uniformly disperse the absolute ethyl alcohol until no obvious particles are seen in the coating;

coating 1.0g of the coating on a prepared substrate by a glass rod blade coating method, drying at room temperature for 5 hours, and then placing in an oven at 80 ℃ for 10 hours to obtain a super-hydrophobic low-infrared-emissivity coating;

the infrared emissivity of the obtained coating is 0.675, the glossiness is 2.7, the water contact angle is 155 degrees, the rolling angle is 8 degrees, and the adhesive force is 1 grade.

Example 3:

according to the mass ratio of 3: 7, fully mixing HCSO and PU to obtain blended modified PU, and then using the HCSO modified PU as an adhesive to prepare a coating, wherein polyether polyol is used as a curing agent, and the using amount of the polyether polyol is 25% of the mass of the modified resin;

flaky Al powder and nano SiO₂The mass ratio of (A) to (B) is 6:4, weighing a proper amount of HCSO modified PU and functional filler (flaky Al powder + nano SiO) in a clean disposable plastic cup in a mass ratio of 6:4₂)；

Adding absolute ethyl alcohol serving as a diluent in a plastic cup, wherein the weight of the absolute ethyl alcohol is 10% of the mass of the HCSO modified PU, and fully stirring by using a glass rod to uniformly disperse the absolute ethyl alcohol until no obvious particles are seen in the coating;

coating 0.8g of the coating on a prepared substrate by a glass rod blade coating method, drying at room temperature for 5 hours, and then placing in an oven at 80 ℃ for 10 hours to obtain a super-hydrophobic low-infrared-emissivity coating;

the infrared emissivity of the obtained coating is 0.638, the glossiness is 3.9, the water contact angle is 153 degrees, the rolling angle is 9 degrees, and the adhesive force is 2-grade.

While there have been shown and described what are at present considered the fundamental principles and essential features of the invention and its advantages, it will be apparent to those skilled in the art that the invention is not limited to the details of the foregoing exemplary embodiments, but is capable of other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. A preparation method of a super-hydrophobic low-infrared-emissivity coating is characterized by comprising the following specific operation steps:

s2, mixing the components in a mass ratio of 1: 9-3: 7, fully mixing hydrogen-containing silicone oil and PU to obtain blended modified PU, and then using the hydrogen-containing silicone oil modified PU as an adhesive to prepare a coating, wherein polyether polyol is used as a curing agent, and the using amount of the polyether polyol is 25% of the mass of the modified resin;

s3, flaky Al powder and nano SiO₂The mass ratio of (A) to (B) is 5.5: 4.5-6.5: 3.5, weighing a proper amount of hydrogen-containing silicone oil modified PU and functional filler in a clean disposable plastic cup in a mass ratio of 7: 3-5: 5, wherein the particle size of the flaky Al powder is 20-50 mu m, and the nano SiO is₂The purity of the PU is more than 99.5%, the particle size is 20-40 nm, and the solid content of the PU is 50-60%; the solid content of the hydrogen-containing silicone oil is 90-97%, and the viscosity is 18-22;

s4, adding absolute ethyl alcohol serving as a diluent in the plastic cup, wherein the weight of the absolute ethyl alcohol is 10% -20% of the weight of the hydrogen-containing silicone oil modified PU, and fully stirring the mixture by using a glass rod to uniformly disperse the mixture until no obvious particles can be seen in the coating;