Corrosion-resistant and infrared-absorbing composite coating as well as preparation method and application thereof

Abstract

The invention discloses a corrosion-resistant and infrared-absorption composite coating which is composed of a component A and a component B, and the mass ratio of the component A to the component B is 7.5: 2.5. The component A is prepared from the following raw material components in percentage by mass: 50 to 60 percent of fluorine modified polyurethane resin, 13 to 20 percent of functional pigment / filler, 14 to 16 percent of anti-infrared radiation additive, 8 to 20 percent of auxiliary agent and 3.5 to 4.5 percent of coupling agent; the component B is prepared from the following raw material components in percentage by mass: 85 to 92 percent of polyisocyanate and 8 to 15 percent of xylene. The invention further provides a preparation method of the composite coating. The preparation method comprises the following steps: S1, preparing the component A; s2, preparing a component B; s3, mixing and dispersing the component A and the component B for 38-55 minutes to obtain a mixture; and S4, the mixture obtained in the step S3 is sprayed to the surface of a device, heat preservation is conducted for 4 h at the temperature of 65-95 DEG C, and the composite coating is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of coatings, and in particular relates to a corrosion-resistant and infrared-absorbing composite coating, a preparation method and application thereof. Background Art

[0002] Under modern conditions, ground vehicles need to serve in high salt fog and high humidity and heat environment all year round. Atmospheric corrosion and infrared characteristics caused by temperature have become one of the important issues affecting the survival of vehicle equipment. It is particularly important to study corrosion-resistant and infrared attenuation coatings that can resist atmospheric corrosion and reduce infrared emissivity.

[0003] Research shows that corrosion aging is the process in which the coating loses its original properties under the influence of the external environment. In order to study the application of coatings in projects such as submarine tunnels and cross-sea bridges, Japan has developed glass flake polyurethane coatings and fluorine coatings; in order to meet the needs of the development of aerospace technology, the United States has developed new heavy-duty anti-corrosion coatings, such as the fluorocarbon coating system launched by DuPont and the polysiloxane anti-corrosion coating system launched by Ameron. Organic fluorine coatings have excellent corrosion resistance, but can be cured at room temperature. The other types of organic fluorine resins have poor film-forming properties and need to be sintered at 230℃ to 380℃ to form films, which limits their application in large equipment. Inorganic-organic polymers also have excellent corrosion resistance, but are relatively expensive, and there are no reports on the use of this material in protection in China.

[0004] In addition, modern detection bands have expanded from visible light and radar waves to infrared bands. The infrared characteristics of equipment vehicles threaten the survivability of equipment. The coating applied on the surface of vehicle equipment may bring distinct infrared characteristics, making the equipment face severe challenges in multi-channel target detection, but it can also be adjusted and changed by applying coatings on the surface. Studies have shown that the greater the infrared emissivity, the more obvious the infrared characteristics of the equipment, and the lower the infrared emissivity, the less obvious the infrared characteristics of the equipment.

[0005] Based on the above analysis, the study proposes a new type of composite coating that has both excellent atmospheric corrosion resistance and low infrared emissivity, which has important scientific and technological value for the reliable survival of vehicle equipment in the atmospheric environment. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a corrosion-resistant and infrared-absorbing composite coating, a preparation method and its application. The composite coating provided by the present invention can not only ensure a long-life service environment for the vehicle, but also has a low infrared emissivity.

[0007] The first object of the present invention is to provide a corrosion-resistant and infrared-absorbing composite coating, which is composed of component A and component B, and the mass ratio of component A to component B is 7.5:2.5;

[0008] The A component is composed of the following raw material components in percentage by weight:

[0009] Fluorine-modified polyurethane resin 50-60%, functional color / filler 13-20%, infrared radiation protection additive 14-16%, auxiliary agent 8-20%, coupling agent 2.5-4.5%;

[0010] The B component is composed of the following raw material components in percentage by weight:

[0011] Polyisocyanate 85-92% and xylene 8-15%.

[0012] Preferably, the fluorine-modified polyurethane resin comprises the following raw material components in percentage by weight:

[0013] Polyurethane resin 50-55%, fluorocarbon resin 20-25%, isocyanate 10-15%, xylene 10-15%.

[0014] Preferably, the functional color / filler comprises the following raw material components in percentage by weight:

[0015] Fluorine-modified polyurethane resin 65-70%, indium powder 12-18% and infrared radiation protection additive 14-20%.

[0016] Preferably, the infrared radiation protection additive comprises the following raw material components in percentage by weight:

[0017] Graphene modified indium powder 90-95% and inert filler 5-10%.

[0018] Preferably, the graphene-modified indium powder comprises the following raw material components in percentage by mass:

[0019] Fluorine-modified polyurethane resin 70-75%, indium powder 22-25% and graphene 2-5%;

[0020] The inert filler comprises the following raw material components in percentage by weight:

[0021] Glass flakes 55-58% and nano calcium carbonate 42-45%.

[0022] Preferably, the auxiliary agent is cellulose acetate butyrate, and the coupling agent is a fluorosilane coupling agent.

[0023] A second object of the present invention is to provide a method for preparing the above-mentioned corrosion-resistant and infrared-absorbing composite coating, comprising the following steps:

[0024] S1. Preparation of component A

[0025] Weigh 50-60% of fluorine-modified polyurethane resin, 13-20% of functional pigment / filler, 14-16% of infrared radiation protection additive, 8-20% of auxiliary agent, and 2.5-4.5% of coupling agent according to mass percentage, stir and mix evenly to obtain component A;

[0026] Preparation of S2 and B components

[0027] Weigh 85-92% of polyisocyanate and 8-15% of xylene by mass, add polyisocyanate into xylene, and stir evenly to obtain component B;

[0028] S3, mixing and dispersing the component A obtained in step S1 and the component B obtained in step S2 at a mass ratio of 7.5:2.5 for 38 to 55 minutes to obtain a mixture;

[0029] S4, spraying the mixture obtained in step S3 on the surface of the device, and keeping it at 65-95° C. for 4 hours to obtain a composite coating.

[0030] Preferably, step S1 specifically comprises the following steps:

[0031] S11. Preparation of fluorine-modified polyurethane resin

[0032] Weigh 50-55% of polyurethane resin, 20-25% of fluorocarbon resin, 10-15% of isocyanate, and 10-15% of xylene respectively by mass percentage, stir and mix evenly to obtain fluorine-modified polyurethane resin;

[0033] S12. Preparation of functional pigments / fillers

[0034] Weigh 65-70% of the fluorine-modified polyurethane resin obtained in step S11, 12-18% of indium powder, and 14-20% of the infrared radiation protection additive according to the mass percentage, mix and stir thoroughly, add a diluent, disperse until the indium powder is completely dissolved, and mix the fluorine-modified polyurethane resin and the indium powder evenly, and then adjust the non-volatile content to 38% to 40% with a diluent to obtain a functional pigment / filler;

[0035] S13. Preparation of infrared radiation protection additive

[0036] Weigh 90-95% of graphene-modified indium powder and 5-10% of inert filler by mass percentage, stir and mix them evenly to obtain an infrared radiation protection additive;

[0037] S14. Weigh 50-60% of the fluorine-modified polyurethane resin obtained in step S11, 13-20% of the functional color / filler obtained in step S12, 14-16% of the anti-infrared radiation additive obtained in step S13, 8-20% of the auxiliary agent, and 2.5-4.5% of the coupling agent according to their mass percentages, stir and mix them evenly, and filter to obtain component A.

[0038] Preferably, in step S13, the anti-infrared radiation additive is prepared by the following method:

[0039] S131, weighing 68-75% of the fluorine-modified polyurethane resin obtained in step S11, 23-38% of indium powder and 2.5-3.5% of graphene respectively according to weight percentage, and set aside;

[0040] S132, mixing and dispersing the weighed fluorine-modified polyurethane resin and indium powder, then adding the weighed graphene under stirring, grinding for 2 hours, and sieving to obtain graphene-modified indium powder;

[0041] S133, weighing 55-58% of glass flakes and 42-45% of nano calcium carbonate respectively by mass percentage, stirring and mixing evenly to obtain an inert filler;

[0042] S134. Weigh 90-95% of the graphene-modified indium powder obtained in step S132 and 5-10% of the inert filler obtained in step S133 according to their mass percentages, stir and mix them evenly to obtain an infrared radiation protection additive.

[0043] The third object of the present invention is to provide an application of the above-mentioned corrosion-resistant and infrared-absorbing composite coating in the preparation of surface coatings for vehicle equipment.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] (1) The corrosion-resistant and infrared-absorbing composite coating provided by the present invention designs the component composition of the composite coating based on the requirements of corrosion resistance and infrared protection, uses polyurethane resin as the base, and grafts the fluorocarbon resin into the polyurethane resin system through chemical reaction between the active groups in the fluorocarbon resin chain and the active groups in the polyurethane resin, so that the carbon-hydrogen bonds in the molecular structure are partially replaced by carbon-fluorine bonds;

[0046] (2) The present invention uses graphene with unique carrier properties to "bridge" indium metal pigments to improve the conductivity of the paint film, thereby reducing the emissivity of the paint film;

[0047] (3) The present invention forms a layered shielding structure inside the resin through glass flakes to produce a "maze effect", forming a barrier to the outside and making the invasion path of the corrosive medium complicated, thereby improving the corrosion resistance of the coating; by making nano-calcium carbonate compatible with the resin, reliable thermal stability is maintained to ensure the low emissivity of the coating; indium powder is oriented by cellulose acetate butyrate; the resin / filler interface is optimized by a coupling agent, and then a scientific spraying process is adopted to form an effective corrosion-resistant and infrared-compatible composite coating.

[0048] (4) The composite coating provided by the present invention can improve the corrosion resistance of the surface of the equipment structure to 10 years; the test results of the 5% NaCl salt spray test show that the continuous corrosion resistance time reaches 1008 hours; the infrared emissivity (mid-infrared (3μm~5μm), far infrared (8μm~14μm)) is not more than 0.4; the bonding strength of the coating is not less than 8MPa; the impact resistance is not less than 45kg·cm; therefore, the composite coating provided by the present invention can effectively improve the corrosion resistance and anti-infrared absorption ability of the surface of equipment in corrosive environment, and provide strong technical support for improving the long-life survivability of the surface of equipment structure to adapt to complex environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is the microstructure diagram of the corrosion-resistant and infrared-absorbing composite coating;

[0050] in, Figure 1 (a) is the original metal coating film; Figure 1 (b) is the original modified resin coating; Figure 1 (c) is a graphene modified coating; Figure 1 (d) is a coating with glass flakes (accounting for 55 wt% of the inert filler); Figure 1 (e) is a coating with nano calcium carbonate (accounting for 44 wt% of the inert filler); Figure 1 (f) is a coating with an additive CAB addition amount of 15 wt%; Figure 1 (g) is a coating with 0% coupling agent added; Figure 1 (h) is a coating with a coupling agent addition amount of 3 wt%;

[0051] Figure 2 The corrosion cycle and infrared emissivity life graph of JF-100 fluorocarbon and polyurethane resin coatings;

[0052] Figure 3 The corrosion cycle and infrared emissivity life of coatings with different indium contents before and after adding additives;

[0053] Figure 4 This is the effect of different coupling agent addition amounts on the emissivity-corrosion life of the corrosion-resistant and infrared-absorbing composite coating;

[0054] Figure 5 A graph showing the salt spray resistance test results of the corrosion-resistant and infrared-absorbing composite coating provided in an embodiment of the present invention;

[0055] in, Figure 5 (a) is the coating before salt spray corrosion; Figure 5 (b) After the coating is corroded by salt spray;

[0056] Figure 6 A diagram showing the results of a wet heat corrosion test of a corrosion resistant and infrared absorbing composite coating provided in an embodiment of the present invention;

[0057] in, Figure 6 (a) Before wet heat corrosion; Figure 6 (b) After wet heat corrosion. DETAILED DESCRIPTION

[0058] The following is a description of the embodiments of the present invention. Figures 1 to 6 , the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0059] Example 1

[0060] The embodiment of the present invention provides a corrosion-resistant and infrared-absorbing composite coating, which is composed of component A and component B, wherein component B is specifically a curing agent, and the mass ratio of component A to component B is 7.5:2.5;

[0061] The component A in the embodiment of the present invention is composed of the following raw material components in percentage by weight:

[0062] Fluorine-modified polyurethane resin 50%, functional color / filler 20%, infrared radiation protection additive 14%, auxiliary agent 12%, coupling agent 3%;

[0063] The component B in the embodiment of the present invention is composed of the following raw material components in percentage by weight:

[0064] Polyisocyanate 85% and solvent xylene 15%.

[0065] The fluorine-modified polyurethane resin in the embodiment of the present invention comprises the following raw material components in percentage by weight:

[0066] Polyurethane resin 55%, fluorocarbon resin 20%, isocyanate 15%, xylene 10%.

[0067] The functional pigment / filler in the embodiment of the present invention comprises the following raw material components in percentage by weight:

[0068] 65% fluorine-modified polyurethane resin, 15% indium powder and 20% infrared radiation protection additive.

[0069] The infrared radiation protection additive in the embodiment of the present invention comprises the following raw material components in percentage by weight:

[0070] Graphene modified indium powder 90% and inert filler 10%.

[0071] The graphene-modified indium powder in the embodiment of the present invention comprises the following raw material components in percentage by weight:

[0072] 70% fluorine-modified polyurethane resin, 25% indium powder and 5% graphene; the particle size of the indium (In) powder in this embodiment is 20-40 μm, and the structure is flaky; the graphene is flaky, with a particle size of 10-50 μm and a purity of not less than 90%;

[0073] The inert filler in the embodiment of the present invention comprises the following raw material components in percentage by weight:

[0074] Glass flakes 55% and nano calcium carbonate 45%. The particle size of the glass flakes in this embodiment is 30-40 μm;

[0075] The auxiliary agent in the embodiment of the present invention is cellulose acetate butyrate (CAB), and the coupling agent is a fluorosilane coupling agent.

[0076] The embodiment of the present invention also provides a method for preparing the above-mentioned corrosion-resistant and infrared-absorbing composite coating, which specifically comprises the following steps:

[0077] S1. Preparation of component A

[0078] Weigh 50% of fluorine-modified polyurethane resin, 20% of functional pigment / filler, 14% of infrared radiation protection additive, 12% of auxiliary agent, and 3% of coupling agent according to mass percentage, stir and mix evenly to obtain component A;

[0079] Step S1 specifically includes the following steps:

[0080] S11. Preparation of fluorine-modified polyurethane resin

[0081] Weigh 55% polyurethane resin, 20% fluorocarbon resin, 15% isocyanate, and 10% xylene respectively by mass percentage, stir and mix evenly to obtain fluorine-modified polyurethane resin;

[0082] S12. Preparation of functional pigments / fillers

[0083] Weigh 65% of the fluorine-modified polyurethane resin, 15% of indium powder and 20% of the anti-infrared radiation additive obtained in step S11 according to their mass percentages, mix and stir thoroughly, add xylene, disperse at a low speed until the indium powder is completely dissolved, and mix the fluorine-modified polyurethane resin, indium powder and anti-infrared radiation additive evenly, and then adjust the non-volatile matter content to 38% to 40% with xylene to obtain a functional color / filler; the preparation method of the anti-infrared radiation additive in this embodiment is the same as the preparation method of the anti-infrared radiation additive in step S13.

[0084] S13. Preparation of infrared radiation protection additive

[0085] Weigh 90% of graphene-modified indium powder and 10% of inert filler by mass to obtain an infrared radiation protection additive;

[0086] Step S13 specifically includes the following steps:

[0087] S131, weigh 70% of the fluorine-modified polyurethane resin obtained in step S11, 25% of indium powder and 5% of graphene respectively according to weight percentage, and set aside;

[0088] S132, mixing the weighed fluorine-modified polyurethane resin and indium powder and dispersing them at a low speed, then adding the weighed graphene under stirring, grinding for 2 hours, adding xylene solvent for dispersion according to the viscosity, and finally filtering with a 100-mesh filter to obtain graphene-modified indium powder;

[0089] S133, weigh 55% of glass flakes and 45% of nano calcium carbonate by mass percentage, mix and grind for 1 hour, the fineness is not greater than 40 μm, add xylene to disperse according to the viscosity, and finally filter with a 100-mesh filter to obtain an inert filler;

[0090] S134. Weigh 90% of the graphene-modified indium powder obtained in step S132 and 10% of the inert filler obtained in step S133 respectively according to their mass percentages, stir and mix them evenly, and obtain an infrared radiation protection additive.

[0091] S14. Weigh 50% of the fluorine-modified polyurethane resin obtained in step S11, 20% of the functional color / filler, 14% of the infrared radiation protection additive, 12% of the auxiliary agent, and 3% of the coupling agent according to their mass percentages, stir and mix them evenly, and filter through a 100-mesh filter to obtain component A.

[0092] Preparation of S2 and B components

[0093] Weigh 85% of polyisocyanate and 15% of solvent xylene according to their mass percentages, add the polyisocyanate into the xylene, and stir evenly to obtain component B;

[0094] S3, mixing and dispersing the component A obtained in step S1 and the component B obtained in step S2 in a mass ratio of 7.5:2.5 for 38 to 55 minutes at a dispersing speed of 100 r / min to 1000 r / min to obtain a mixture;

[0095] S4. Use a spray gun to spray the mixture obtained in step S3 on the surface of the equipment, wherein the spraying pressure is 0.25-0.35 MPa, the spraying distance is 20 cm-30 cm, the gun speed is 25 cm / s-35 cm / s, and then keep it at 65-95° C. for 4 hours to obtain a composite coating.

[0096] Example 2

[0097] The embodiment of the present invention provides a corrosion-resistant and infrared-absorbing composite coating, which is composed of component A and component B, wherein component B is specifically a curing agent, and the mass ratio of component A to component B is 7.5:2.5;

[0098] The component A in the embodiment of the present invention is composed of the following raw material components in percentage by weight:

[0099] Fluorine-modified polyurethane resin 50%, functional color / filler 13%, infrared radiation protection additive 14%, auxiliary agent 20%, coupling agent 3%;

[0100] The component B in the embodiment of the present invention is composed of the following raw material components in percentage by weight:

[0101] Polyisocyanate 92% and solvent xylene 8%.

[0102] The fluorine-modified polyurethane resin in the embodiment of the present invention comprises the following raw material components in percentage by weight:

[0103] Polyurethane resin 50%, fluorocarbon resin 25%, isocyanate 10%, xylene 15%.

[0104] The functional pigment / filler in the embodiment of the present invention comprises the following raw material components in percentage by weight:

[0105] Fluorine-modified polyurethane resin 70%, indium powder 12% and infrared radiation protection additive 18%.

[0106] The infrared radiation protection additive in the embodiment of the present invention comprises the following raw material components in percentage by weight:

[0107] Graphene modified indium powder 95% and inert filler 5%.

[0108] The graphene-modified indium powder in the embodiment of the present invention comprises the following raw material components in percentage by weight:

[0109] 75% fluorine-modified polyurethane resin, 22% indium powder and 3% graphene; the particle size of the indium (In) powder in this embodiment is 20-40 μm, and the structure is flaky; the graphene is in the form of flakes, with a particle size of 10-50 μm and a purity of not less than 90%;

[0110] The inert filler in the embodiment of the present invention comprises the following raw material components in percentage by weight:

[0111] Glass flakes 58% and nano calcium carbonate 42%. The particle size of the glass flakes in this embodiment is 30-40 μm;

[0112] The auxiliary agent in the embodiment of the present invention is cellulose acetate butyrate (CAB), and the coupling agent is a fluorosilane coupling agent.

[0113] The embodiment of the present invention also provides a method for preparing the above-mentioned corrosion-resistant and infrared-absorbing composite coating, which specifically comprises the following steps:

[0114] S1. Preparation of component A

[0115] Weigh 50% of fluorine-modified polyurethane resin, 13% of functional pigment / filler, 14% of infrared radiation protection additive, 20% of auxiliary agent, and 3% of coupling agent according to mass percentage, stir and mix evenly to obtain component A;

[0116] Step S1 specifically includes the following steps:

[0117] S11. Preparation of fluorine-modified polyurethane resin

[0118] Weigh 53% polyurethane resin, 25% fluorocarbon resin, 12% isocyanate, and 10% xylene according to mass percentage, stir and mix evenly to obtain fluorine-modified polyurethane resin;

[0119] S12. Preparation of functional pigments / fillers

[0120] 70% of fluorine-modified polyurethane resin, 12% of indium powder and 18% of infrared radiation protection additive were weighed respectively by mass percentage, mixed and stirred thoroughly, xylene was added, and dispersed at a low speed until the indium powder was completely dissolved, and the fluorine-modified polyurethane resin, indium powder and infrared radiation protection additive were mixed evenly, and then the non-volatile content was adjusted to 38% to 40% with xylene to obtain a functional pigment / filler;

[0121] S13. Preparation of infrared radiation protection additive

[0122] Weigh 95% of graphene-modified indium powder and 5% of inert filler by mass to obtain an infrared radiation protection additive;

[0123] Step S13 specifically includes the following steps:

[0124] S131, weighing 70% of the fluorine-modified polyurethane resin obtained in step S11, 12% of indium powder and 18% of the infrared radiation protection additive respectively according to weight percentage, and set aside;

[0125] S132, mixing the weighed fluorine-modified polyurethane resin and indium powder and dispersing them at a low speed, then adding the weighed graphene under stirring, grinding for 2 hours, adding xylene solvent for dispersion according to the viscosity, and finally filtering with a 100-mesh filter to obtain graphene-modified indium powder;

[0126] S133, weigh 58% of glass flakes and 42% of nano calcium carbonate by mass percentage, mix and grind for 1 hour, the fineness is not greater than 40 μm, add xylene to disperse according to the viscosity, and finally filter with a 100-mesh filter to obtain an inert filler;

[0127] S134. Weigh 95% of the graphene-modified indium powder obtained in step S132 and 5% of the inert filler obtained in step S133 respectively according to their mass percentages, stir and mix them evenly, and obtain an infrared radiation protection additive.

[0128] S14. Weigh 50% of the fluorine-modified polyurethane resin obtained in step S11, 13% of functional pigments / fillers, 14% of infrared radiation protection additives, 20% of auxiliary agents, and 3% of coupling agents according to their mass percentages, stir and mix them evenly to obtain component A.

[0129] Preparation of S2 and B components

[0130] Weigh 92% of polyisocyanate and 8% of solvent xylene according to their mass percentages, and dilute to obtain component B;

[0131] S3, mixing and dispersing the component A obtained in step S1 and the component B obtained in step S2 in a mass ratio of 7.5:2.5 for 38 to 55 minutes at a dispersing speed of 100 r / min to 1000 r / min to obtain a mixture;

[0132] S4. Use a spray gun to spray the mixture obtained in step S3 on the surface of the equipment, wherein the spraying pressure is 0.25-0.35 MPa, the spraying distance is 20 cm-30 cm, the gun speed is 25 cm / s-35 cm / s, and then keep it at 65-95° C. for 4 hours to obtain a composite coating.

[0133] Example 3

[0134] The embodiment of the present invention provides a corrosion-resistant and infrared-absorbing composite coating, which is composed of component A and component B, wherein component B is specifically a curing agent, and the mass ratio of component A to component B is 7.5:2.5;

[0135] The component A in the embodiment of the present invention is composed of the following raw material components in percentage by weight:

[0136] Fluorine-modified polyurethane resin 55%, functional color / filler 18%, infrared radiation protection additive 15%, auxiliary agent 8%, coupling agent 4%;

[0137] The component B in the embodiment of the present invention is composed of the following raw material components in percentage by weight:

[0138] Polyisocyanate 88% and solvent xylene 12%.

[0139] The fluorine-modified polyurethane resin in the embodiment of the present invention comprises the following raw material components in percentage by weight:

[0140] Polyurethane resin 55%, fluorocarbon resin 23%, isocyanate 10%, xylene 12%.

[0141] The functional pigment / filler in the embodiment of the present invention comprises the following raw material components in percentage by weight:

[0142] Fluorine-modified polyurethane resin 68%, indium powder 15% and infrared radiation protection additive 17%.

[0143] The infrared radiation protection additive in the embodiment of the present invention comprises the following raw material components in percentage by weight:

[0144] Graphene modified indium powder 92% and inert filler 8%.

[0145] The graphene-modified indium powder in the embodiment of the present invention comprises the following raw material components in percentage by weight:

[0146] 74% fluorine-modified polyurethane resin, 24% indium powder and 2% graphene; the particle size of the indium (In) powder in this embodiment is 20-40 μm, and the structure is flaky; the graphene is in the form of flakes, with a particle size of 10-50 μm and a purity of not less than 90%;

[0147] The inert filler in the embodiment of the present invention comprises the following raw material components in percentage by weight:

[0148] Glass flakes 56% and nano calcium carbonate 44%. The particle size of the glass flakes in this embodiment is 30-40 μm;

[0149] The auxiliary agent in the embodiment of the present invention is cellulose acetate butyrate (CAB), and the coupling agent is a fluorosilane coupling agent.

[0150] The embodiment of the present invention also provides a method for preparing the above-mentioned corrosion-resistant and infrared-absorbing composite coating, which specifically comprises the following steps:

[0151] S1. Preparation of component A

[0152] Weigh 55% of fluorine-modified polyurethane resin, 18% of functional pigment / filler, 15% of infrared radiation protection additive, 8% of auxiliary agent, and 4% of coupling agent according to mass percentage, stir and mix evenly to obtain component A;

[0153] Step S1 specifically includes the following steps:

[0154] S11. Preparation of fluorine-modified polyurethane resin

[0155] Weigh 55% polyurethane resin, 23% fluorocarbon resin, 10% isocyanate, and 12% xylene according to mass percentage, stir and mix evenly to obtain fluorine-modified polyurethane resin;

[0156] S12. Preparation of functional pigments / fillers

[0157] Weigh 68% of fluorine-modified polyurethane resin, 15% of indium powder and 17% of infrared radiation protection additive according to the mass percentage, mix and stir thoroughly, add xylene, disperse at a low speed until the indium powder is completely dissolved, and mix the fluorine-modified polyurethane resin, indium powder and infrared radiation protection additive evenly, and then adjust the non-volatile content to 38% to 40% with xylene to obtain a functional pigment / filler;

[0158] S13. Preparation of infrared radiation protection additive

[0159] 92% of graphene-modified indium powder and 8% of inert filler were weighed respectively according to mass percentage to obtain an infrared radiation protection additive;

[0160] Step S13 specifically includes the following steps:

[0161] S131, weigh 74% of the fluorine-modified polyurethane resin obtained in step S11, 24% of indium powder and 2% of graphene respectively according to weight percentage, and set aside;

[0162] S132, mixing the weighed fluorine-modified polyurethane resin and indium powder and dispersing them at a low speed, then adding the weighed graphene under stirring, grinding for 2 hours, adding xylene solvent for dispersion according to the viscosity, and finally filtering with a 100-mesh filter to obtain graphene-modified indium powder;

[0163] S133, weigh 56% of glass flakes and 44% of nano calcium carbonate by mass percentage, mix and grind for 1 hour, the fineness is not greater than 40 μm, add xylene to disperse according to the viscosity, and finally filter with a 100-mesh filter to obtain an inert filler;

[0164] S134. Weigh 92% of the graphene-modified indium powder obtained in step S132 and 8% of the inert filler obtained in step S133 respectively according to their mass percentages, stir and mix them evenly, and obtain an infrared radiation protection additive.

[0165] S14. Weigh 55% of the fluorine-modified polyurethane resin obtained in step S11, 18% of the functional pigment / filler, 15% of the infrared radiation protection additive, 8% of the auxiliary agent, and 4% of the coupling agent according to their mass percentages, stir and mix them evenly to obtain component A.

[0166] Preparation of S2 and B components

[0167] Weigh 88% of polyisocyanate and 12% of solvent xylene according to mass percentage, and dilute to obtain component B;

[0168] S3, mixing and dispersing the component A obtained in step S1 and the component B obtained in step S2 at a mass ratio of 7.5:2.5 for 38 to 55 minutes at a dispersing speed of 100 r / min to 1000 r / min to obtain a mixture;

[0169] S4. Use a spray gun to spray the mixture obtained in step S3 on the surface of the equipment, wherein the spraying pressure is 0.25-0.35 MPa, the spraying distance is 20 cm-30 cm, the gun speed is 25 cm / s-35 cm / s, and then keep it at 65-95° C. for 4 hours to obtain a composite coating.

[0170] The specific process parameters of step S4 in Examples 1-3 of the present invention are shown in Table 1 below:

[0171] Table 1 Corrosion-resistant and infrared composite coatings and coating preparation process parameters

[0172]

[0173] The properties of the composite coating prepared by the present invention are studied as follows.

[0174] 1. Microstructure of coating before and after modification

[0175] Scanning electron microscopy was used to observe the microstructure of the coatings under different environments. Figure 1 As shown, through Figure 1 It can be seen that after the coupling agent is added to the coating, the fluorocarbon resin matrix on the surface wraps the indium powder modified particles very well, providing a basis for the long-life survival of the coating in the corrosive medium.

[0176] 2. Corrosion life of corrosion-resistant and infrared-absorbing composite coatings - infrared emissivity test

[0177] GB / T 7287.9 ​​and GJB 150.11A were used, respectively, with an infrared emissivity tester and a salt spray corrosion test chamber, and the test was conducted once every 24 hours until the coating fell off. The corrosion life-infrared emissivity curves of the corrosion-resistant and infrared-absorbing composite coatings were obtained in the test, among which the corrosion cycle and infrared emissivity life curves of the JF-100 fluorocarbon and polyurethane resin coatings were ( Figure 2 ), the corrosion cycle and infrared emissivity life of the coating before and after adding additives ( Figure 3 ) and the effect of different coupling agent addition amounts on the emissivity-corrosion life of the corrosion-resistant and infrared-absorbing composite coating ( Figure 4 ).pass Figure 2-Figure 4 It can be clearly seen that in a 5% NaCl salt spray environment (temperature 40°C, humidity 95%), the corrosion resistance life of the unmodified coating is 12 days (288 hours); after adding the CAB additive, the emissivity of the coating is still less than 0.4, and the coating loses its low emissivity performance on the 30th day; after further adding the coupling agent, the corrosion resistance life of the coating reaches 42 days (1008 hours), and the infrared emissivity of the coating is less than 0.4.

[0178] 3. Mechanical properties of corrosion-resistant and infrared-absorbing composite coatings

[0179] According to GB / T 5210-2006 standard, the adhesion ability of the prepared coating was optimized in succession according to the test process. Coating 0 was the control group, i.e., the original coating; coating 1 was fluorine-modified polyurethane resin; coating 2 was based on coating 1, with graphene-modified indium powder (accounting for 90% of the infrared radiation protection additive); coating 3 was based on coating 2, with glass flakes (accounting for 55% of the inert filler); coating 4 was based on coating 3, with nano calcium carbonate (accounting for 44% of the inert filler); coating 5 was based on coating 4, with additives (accounting for 15% of the total amount of coating 4); coating 6 was based on coating 5, with coupling agents (accounting for 3% of the total amount of coating 5), and the adhesion strength tested was shown in Table 2 below. It can be seen from the results in Table 2 that the mechanical properties of the coating are improved after adding additives. Among them, on the basis of the above, coating 2 with graphene-modified indium powder added, the strength of the coating reached 12MPa. After the subsequent addition of glass flakes, nano-calcium carbonate, cellulose acetate butyrate and coupling agent, the coating maintained the secondary adhesion test strength level.

[0180] Table 2 Mechanical properties of corrosion-resistant and infrared-absorbing composite coatings

[0181]

[0182] 4. Corrosion resistance mechanism of corrosion-resistant and infrared-absorbing coatings

[0183] The anti-corrosion and infrared coatings used in the marine atmospheric environment need to adapt to the high humidity and high salt spray environment of the ocean, so they must have good salt spray corrosion resistance.

[0184] The salt spray corrosion test chamber was used at a temperature of 50°C and a humidity of 80%. The salt spray and wet heat corrosion resistance tests were conducted on the anti-corrosion and infrared coating according to GJB 150.11A (salt spray corrosion resistance), GJB 150.9A test (wet heat corrosion resistance) and GB / T 1865-2009 (ultraviolet corrosion resistance). The results are as follows: Figure 5 and Figure 6 As shown, through Figure 5 and Figure 6 It can be seen from the results that there is no blistering or falling off on the coating surface.

[0185] It can be seen from the above test analysis that the corrosion-resistant and infrared-absorbing composite coating prepared by the present invention has a continuous corrosion resistance time of 1008 hours in a 5% NaCl salt spray test; the infrared emissivity (mid-infrared (3μm~5μm), far infrared (8μm~14μm)) is not greater than 0.4; the bonding strength of the coating is not less than 8MPa; and the impact resistance is not less than 45kg·cm.

[0186] In summary, the composite coating provided by the embodiments of the present invention can effectively improve the corrosion resistance and anti-infrared absorption ability of the surface of equipment in corrosive environments, and provide strong technical support for improving the long-life survivability of the surface of equipment structures to adapt to complex environments.

[0187] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A composite coating that is corrosion resistant and infrared absorbing. It is characterized in that It is composed of component A and component B, and the mass ratio of component A to component B is 7.5:2.5; The A component is composed of the following raw material components in percentage by weight: Fluorine-modified polyurethane resin 50-60%, functional color / filler 13-20%, infrared radiation protection additive 14-16%, auxiliary agent 8-20%, coupling agent 2.5-4.5%; The B component is composed of the following raw material components in percentage by weight: Polyisocyanate 85-92% and xylene 8-15%.

2. The corrosion-resistant and infrared-absorbing composite coating according to claim 1, It is characterized in that The fluorine-modified polyurethane resin comprises the following raw material components in percentage by weight: Polyurethane resin 50-55%, fluorocarbon resin 20-25%, isocyanate 10-15%, xylene 10-15%.

3. The corrosion-resistant and infrared-absorbing composite coating according to claim 1, It is characterized in that The functional pigment / filler comprises the following raw material components in percentage by weight: Fluorine-modified polyurethane resin 65-70%, indium powder 12-18% and infrared radiation protection additive 14-20%.

4. The corrosion-resistant and infrared-absorbing composite coating according to claim 1 or 3, It is characterized in that The infrared radiation protection additive comprises the following raw material components in percentage by weight: Graphene modified indium powder 90-95% and inert filler 5-10%.

5. The corrosion-resistant and infrared-absorbing composite coating according to claim 4, It is characterized in that The graphene-modified indium powder comprises the following raw material components in percentage by mass: Fluorine-modified polyurethane resin 70-75%, indium powder 22-25% and graphene 2-5%; The inert filler comprises the following raw material components in percentage by weight: Glass flakes 55-58% and nano calcium carbonate 42-45%.

6. The corrosion-resistant and infrared-absorbing composite coating according to claim 1, It is characterized in that The auxiliary agent is cellulose acetate butyrate, and the coupling agent is a fluorosilane coupling agent.

7. A method for preparing the corrosion-resistant and infrared-absorbing composite coating according to any one of claims 1 to 6, It is characterized in that The following steps are involved: S1. Preparation of component A Weigh 50-60% of fluorine-modified polyurethane resin, 13-20% of functional pigment / filler, 14-16% of infrared radiation protection additive, 8-20% of auxiliary agent, and 2.5-4.5% of coupling agent according to mass percentage, stir and mix evenly to obtain component A; Preparation of S2 and B components Weigh 85-92% of polyisocyanate and 8-15% of xylene by mass, add polyisocyanate into xylene, stir evenly, and obtain component B; S3, mixing and dispersing the component A obtained in step S1 and the component B obtained in step S2 at a mass ratio of 7.5:2.5 for 38 to 55 minutes to obtain a mixture; S4, spraying the mixture obtained in step S3 on the surface of the device, and keeping it at 65-95° C. for 4 hours to obtain a composite coating.

8. The method for preparing the corrosion-resistant and infrared-absorbing composite coating according to claim 7, It is characterized in that Step S1 specifically includes the following steps: S11. Preparation of fluorine-modified polyurethane resin Weigh 50-55% of polyurethane resin, 20-25% of fluorocarbon resin, 10-15% of isocyanate, and 10-15% of xylene respectively by mass percentage, stir and mix evenly to obtain fluorine-modified polyurethane resin; S12. Preparation of functional pigments / fillers Weigh 65-70% of the fluorine-modified polyurethane resin obtained in step S11, 12-18% of indium powder, and 14-20% of the infrared radiation protection additive according to the mass percentage, mix and stir thoroughly, add a diluent, disperse until the indium powder is completely dissolved, and mix the fluorine-modified polyurethane resin and the indium powder evenly, and then adjust the non-volatile content to 38% to 40% with a diluent to obtain a functional pigment / filler; S13. Preparation of infrared radiation protection additive Weigh 90-95% of graphene-modified indium powder and 5-10% of inert filler by mass percentage, stir and mix them evenly to obtain an infrared radiation protection additive; S14. Weigh 50-60% of the fluorine-modified polyurethane resin obtained in step S11, 13-20% of the functional color / filler obtained in step S12, 14-16% of the anti-infrared radiation additive obtained in step S13, 8-20% of the auxiliary agent, and 2.5-4.5% of the coupling agent according to their mass percentages, stir and mix them evenly, and filter to obtain component A.

9. The method for preparing the corrosion-resistant and infrared-absorbing composite coating according to claim 8, It is characterized in that In step S13, the anti-infrared radiation additive is prepared by the following method: S131, weighing 68-75% of the fluorine-modified polyurethane resin obtained in step S11, 23-38% of indium powder and 2.5-3.5% of graphene respectively according to weight percentage, and set aside; S132, mixing and dispersing the weighed fluorine-modified polyurethane resin and indium powder, then adding the weighed graphene under stirring, grinding for 2 hours, and sieving to obtain graphene-modified indium powder; S133, weighing 55-58% of glass flakes and 42-45% of nano calcium carbonate respectively by mass percentage, stirring and mixing evenly to obtain an inert filler; S134. Weigh 90-95% of the graphene-modified indium powder obtained in step S132 and 5-10% of the inert filler obtained in step S133 according to their mass percentages, stir and mix them evenly to obtain an infrared radiation protection additive.

10. Use of the corrosion-resistant and infrared-absorbing composite coating according to claim 1 in preparing surface coatings for vehicle equipment.

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