A VCI bimetallic composite paint and VCI bimetallic composite coating for cable bridge

Abstract

The present application discloses a VCI bimetallic composite coating and a VCI bimetallic composite coating for cable trays. The VCI bimetallic composite coating comprises the following components in parts by weight: 20-40 parts of zinc powder, 10-20 parts of aluminum powder, 30-50 parts of a binder, and 5-15 parts of a VCI sustained-release agent. The binder is mainly a pre-hydrolyzed product of siloxane, which provides high bonding strength to the metal powder and the coating on the substrate. The residual siloxane groups allow the solid components of the coating to be densely accumulated during the loss of water and diluent, resulting in better salt spray corrosion resistance of the coating. The binder in the coating is a -Si-O-Si-crosslinked network with an increased degree of crosslinking, which has strong aging resistance under current fluctuations and skin effect. Therefore, the coating coated with the coating of the present application has excellent initial corrosion resistance and coating adhesion, is not easily aged under current fluctuations and skin effect, provides long-term protection for cable trays, and prolongs the service life of the cable trays.

Description

Technical Field

[0001] The present application relates to a cable tray, and in particular to a VCI bimetallic composite paint and a VCI bimetallic composite coating for a cable tray. Background Art

[0002] Cable trays are important infrastructure that support and protect cables. Their anti-corrosion performance is directly related to the safe and stable operation of the cable system. Traditional cable tray coatings mostly use organic coatings, such as epoxy resin coatings, polyacrylic acid coatings, etc.

[0003] Because cable trays are typically metal, they generate induced currents when the voltage and current fluctuate. Due to the skin effect, the charge on the cable trays is concentrated on the surface, causing the organic coating on the cable trays to age, become damaged, and lose its protective properties.

[0004] Therefore, the present application has developed a VCI bimetallic composite coating for cable trays, which can suppress the accelerated damage of cable trays caused by charges under the skin effect and extend the service life of the cable trays. Summary of the Invention

[0005] In order to reduce the damage of electric charges to the protective coating of cable bridges under the skin effect and extend the service life of cable bridges, a VCI bimetallic composite paint and a VCI bimetallic composite coating for cable bridges are provided.

[0006] The first object of the present invention is achieved by the following technical solutions:

[0007] A VCI bimetallic composite coating for cable trays, comprising the following components in parts by weight:

[0008] 20-40 parts of zinc powder;

[0009] 10-20 parts of aluminum powder;

[0010] 30-50 parts of binder;

[0011] 5-15 parts of VCI sustained-release agent;

[0012] The binder is obtained by pre-hydrolysis of siloxane.

[0013] By adopting the above technical solution, the binder in this application is mainly a siloxane pre-hydrolysis product, which not only has a cross-linked network of -Si-O-Si- but also has residual siloxane groups at the ends of the cross-linked network. As the cross-linked network of -Si-O-Si- formed by pre-hydrolysis, it is easier to combine with the active hydroxyl groups on the metal surface, so that the bonding strength between the binder and the metal powder in the coating and the coating on the substrate is higher, and the adhesion level of the coating is significantly improved. At the same time, the residual siloxane groups continuously affect and improve the surface tension of the coating during the curing process, so that the solid components of the coating can be densely accumulated in the process of losing water and diluent, and the coating has a higher density and better salt spray corrosion resistance.

[0014] In addition, the final cured coating bond is a cross-linked network of -Si-O-Si- with a further improved degree of cross-linking, which has strong resistance to accelerated aging caused by fluctuating current and magnetic fields and skin effect.

[0015] Therefore, the coating applied by the paint of the present application has excellent initial corrosion resistance and coating adhesion, and is not easy to age under the influence of fluctuating current magnetic field and skin effect. It can protect the cable tray for a long time and the cable tray has a long service life.

[0016] Optionally, the siloxane is a mixture of tetraethoxysiloxane, 3-glycidyloxyethyltrimethoxysiloxane and 3-aminopropyltriethoxysiloxane in a mass ratio of 7:2:1.

[0017] By adopting the above technical solution, 3-glycidyloxyethyl trimethoxysiloxane and 3-aminopropyl triethoxysiloxane are used as one of the components of siloxane. During the curing process, the amino group reacts with the epoxy group to form a more complex -Si-O-Si- cross-linked network, which can improve the corrosion resistance and adhesion of the coating.

[0018] Therefore, the siloxane is a compound of tetraethoxysilane, 3-glycidyloxyethyltrimethoxysilane and 3-aminopropyltriethoxysilane. By controlling the appropriate proportion of 3-glycidyloxyethyltrimethoxysilane and 3-aminopropyltriethoxysilane, the synergistic effect brought by "amino groups reacting with epoxy groups to form a more complex cross-linked network during the curing process" can be made better than the loss of "amino groups and epoxy groups" under the action of fluctuating current magnetic field and skin effect, effectively improving the initial performance of the coating's corrosion resistance and adhesion, as well as the performance retention value after fluctuating current magnetic field simulation accelerated aging.

[0019] Optional: Tris(trimethylsiloxane) phosphate is also included.

[0020] Optionally, the amount of tris(trimethylsiloxane) phosphate is 3.1 to 5.0 parts.

[0021] By adopting the above technical solution, tris(trimethylsiloxane) phosphate is also added to the coating. Tris(trimethylsiloxane) phosphate is also hydrolyzed during the curing process of the coating. Its phosphate group can combine with the cross-linked network of -Si-O-Si-, thereby increasing the cross-linking degree of the cross-linked network of -Si-O-Si- and complicating its cross-linked network, thereby improving the corrosion resistance and adhesion of the coating, and having good aging resistance to the effects of fluctuating current and magnetic fields and skin effect.

[0022] Optional: the VCI sustained-release agent is 6-hydroxymethyl-aminobenzothiazole.

[0023] By adopting the above technical solution, the corrosion resistance of the coating is better.

[0024] The second object of the present invention is achieved by the following technical solutions:

[0025] A VCI bimetallic composite coating is obtained by coating and curing the cable bridge with a VCI bimetallic composite coating.

[0026] By adopting the above technical solution, the coating has good aging resistance under fluctuating current magnetic field and skin effect, which can effectively extend the service life of the cable tray.

[0027] Optionally, when the coating surface is dry but not completely cured, the coating surface is further coated with a surface treatment liquid for surface treatment, wherein the surface treatment liquid contains one or both of magnesium acetate and lithium acetate.

[0028] By adopting the above technical solution, when the coating surface is dry and not completely cured, a surface treatment liquid is further applied. The magnesium or lithium acetate in the surface treatment liquid penetrates into the pores of the coating and reacts with the active hydroxyl groups and is deposited on the surface of the pores, thereby sealing the pores on the coating surface and enhancing the corrosion resistance of the coating.

[0029] Optional: The concentration of magnesium acetate in the surface treatment solution is 8.2 g / L, and the concentration of lithium acetate mixed solution is 2.1 g / L.

[0030] By adopting the above technical solution, the corrosion resistance improvement effect is best.

[0031] In summary, this application has at least the following beneficial effects:

[0032] 1. The main body of the binder is a pre-hydrolyzed product of siloxane, which makes it have a high bonding strength with the metal powder and the coating to the substrate. The residual siloxane groups make the solid components of the coating densely accumulated during the loss of water and diluent, and the coating has better salt spray corrosion resistance. The binder in the coating is a -Si-O-Si- cross-linked network with an increased degree of cross-linking, which has strong aging resistance under current fluctuations and skin effect. Therefore, the coating coated with the coating of this application has excellent initial corrosion resistance and coating adhesion, and is not easy to age under current fluctuations and skin effect, providing long-term protection for cable trays and extending the service life of cable trays.

[0033] 2. A suitable proportion of tetraethoxysiloxane, 3-glycidyloxyethyl trimethoxysiloxane, and 3-aminopropyl triethoxysiloxane as a binder can effectively improve the initial corrosion resistance and adhesion of the coating, as well as the performance retention value after accelerated aging simulated by fluctuating current and magnetic field;

[0034] 3. Tris(trimethylsiloxane) phosphate is also added to the coating to improve the corrosion resistance and adhesion of the coating, and has good aging resistance to fluctuating current magnetic fields and skin effect;

[0035] 4. When the coating surface is dry and not completely cured, further coating of surface treatment liquid can seal the pores on the coating surface, thereby enhancing the corrosion resistance of the coating. DETAILED DESCRIPTION

[0036] raw material:

[0037] Raw materials not further specified in this application are all commercially available products.

[0038] Preparation Example 1

[0039] The invention discloses an adhesive, which is obtained by pre-hydrolyzing siloxane. The siloxane used is tetraethoxysiloxane, 3-glycidyloxyethyltrimethoxysiloxane and 3-aminopropyltriethoxysiloxane.

[0040] Tetraethoxysiloxane, 3-glycidyloxyethyltrimethoxysiloxane, 3-aminopropyltriethoxysiloxane and water were mixed in a mass ratio of 7:2:1:20, the pH thereof was adjusted to 5 using acetic acid, and the mixture was hydrolyzed at 30° C. for 6 h to obtain a binder.

[0041] Preparation Example 2

[0042] A binder is obtained by uniformly mixing water and sodium silicate in a ratio of 1:2.

[0043] Preparation Example 3

[0044] A binder is obtained by uniformly mixing Nan Ya epoxy resin 128 and ethylenediamine in a mass ratio of 100:3.2, and can be used immediately after mixing.

[0045] Preparation Example 4

[0046] The invention discloses an adhesive, which is obtained by pre-hydrolyzing siloxane, wherein the siloxane used is tetraethoxysiloxane.

[0047] Tetraethoxysiloxane and water were mixed in a mass ratio of 1:2, the pH value thereof was adjusted to 5 using acetic acid, and the mixture was hydrolyzed at 30° C. for 6 h to obtain a binder.

[0048] Preparation Example 5

[0049] The invention discloses an adhesive, which is obtained by pre-hydrolyzing siloxane, wherein the siloxane used is 3-glycidyloxyethyltrimethoxysiloxane.

[0050] 3-Glycidyloxyethyltrimethoxysiloxane and water were mixed in a mass ratio of 1:2, the pH thereof was adjusted to 5 using acetic acid, and the mixture was hydrolyzed at 30° C. for 6 h to obtain a binder.

[0051] Preparation Example 6

[0052] The invention discloses an adhesive, which is obtained by pre-hydrolyzing siloxane, wherein the siloxane used is 3-aminopropyltriethoxysiloxane.

[0053] 3-Glycidyloxyethyltrimethoxysiloxane and water were mixed in a mass ratio of 1:2, the pH thereof was adjusted to 5 using acetic acid, and the mixture was hydrolyzed at 30° C. for 6 h to obtain a binder.

[0054] Example 1

[0055] A VCI bimetallic composite coating for cable bridges is prepared by mixing zinc powder, aluminum powder, a binder, a VCI slow-release agent and a diluent.

[0056] The dosage ratio of zinc powder, aluminum powder, binder, VCI slow-release agent and solvent is 38:19:46:14:6.

[0057] The particle size of zinc powder is 0.5 μm; the particle size of aluminum powder is 0.5 μm.

[0058] The binder is prepared in Preparation Example 1; the VCI corrosion inhibitor is 6-hydroxymethyl-aminobenzothiazole; and the solvent is ethylene glycol.

[0059] Solvents are used to adjust the viscosity of the paint and the paint needs to be stirred before use.

[0060] Comparative Example 1

[0061] A bimetallic composite coating is different from Example 1 in that the binder is prepared in Preparation Example 2.

[0062] Comparative Example 2

[0063] A bimetallic composite coating, which differs from Example 1 in that the binder is prepared in Preparation Example 3.

[0064] Example 2

[0065] The difference between a VCI bimetallic composite coating for cable trays and Example 1 is that the binder is prepared in Preparation Example 4.

[0066] Example 3

[0067] The difference between a VCI bimetallic composite coating for cable trays and Example 1 is that the binder is prepared in Preparation Example 5.

[0068] Example 4

[0069] The difference between a VCI bimetallic composite coating for cable trays and Example 1 is that the binder is prepared in Preparation Example 6.

[0070] Example 5

[0071] A VCI bimetallic composite coating for cable bridges is prepared by mixing zinc powder, aluminum powder, a binder, a VCI slow-release agent, tris(trimethylsiloxane) phosphate and a diluent.

[0072] The dosage ratio of zinc powder, aluminum powder, binder, VCI slow-release agent, tris(trimethylsiloxane) phosphate and diluent is 38:19:46:14:4.2:6.

[0073] The particle size of zinc powder is 0.5 μm; the particle size of aluminum powder is 0.5 μm.

[0074] The binder is prepared in Preparation Example 1; the VCI corrosion inhibitor is 6-hydroxymethyl-aminobenzothiazole; and the solvent is ethylene glycol.

[0075] The thinner is used to adjust the viscosity of the paint and the paint needs to be stirred before use.

[0076] Example 6

[0077] The difference between a VCI bimetallic composite coating for cable trays and Example 5 is that the ratio of zinc powder, aluminum powder, binder, VCI slow-release agent, tris(trimethylsiloxane) phosphate, and diluent is 38:19:46:14:3.1:6.

[0078] Example 7

[0079] The difference between a VCI bimetallic composite coating for cable trays and Example 5 is that the ratio of zinc powder, aluminum powder, binder, VCI slow-release agent, tris(trimethylsiloxane) phosphate, and diluent is 38:19:46:14:5:6.

[0080] Examples 8 to 14

[0081] A VCI bimetallic composite coating is obtained by coating and curing the coatings in Examples 1 to 6 on a cable tray, specifically:

[0082] Paint used Example 8 Example 1 Example 9 Example 2 Example 10 Example 3 Example 11 Example 4 Example 12 Example 5 Example 13 Example 6 Example 14 Example 7

[0083] The coating thickness is 0.2 to 0.8 mm, depending on the protection level required by the cable tray installation environment.

[0084] Example 15 Sealing treatment

[0085] A VCI bimetallic composite coating is further modified based on Example 13. When the original coating surface is dry and not completely cured, a surface treatment liquid is sprayed on the coating surface with a coating density of 10.6 g / m 2 .

[0086] The surface treatment solution is a mixed solution of magnesium acetate and lithium acetate, wherein the concentration of magnesium acetate is 0.057 mol / L and the concentration of lithium acetate is 0.032 mol / L.

[0087] Example 16

[0088] A VCI bimetallic composite coating, which differs from Example 13 in that the surface treatment liquid is a magnesium acetate solution with a concentration of 0.089 mol / L.

[0089] Example 17

[0090] A bimetallic composite coating, which differs from Example 13 in that the surface treatment liquid is a magnesium acetate solution with a concentration of 0.089 mol / L.

[0091] Example 18

[0092] A bimetallic composite coating, which differs from Example 13 in that the concentration of magnesium acetate in the surface treatment solution is 0.025 mol / L and the concentration of lithium acetate is 0.064 mol / L.

[0093] Example 19 Sealing Treatment-Compound Solution

[0094] A VCI bimetallic composite coating, which differs from Example 13 in that the concentration of magnesium acetate in the surface treatment liquid is 0.07 mol / L and the concentration of lithium acetate is 0.019 mol / L.

[0095] Comparative Example 3

[0096] A VCI bimetallic composite coating is obtained by coating with the coating of Comparative Example 1, which is different from Example 8.

[0097] Comparative Example 4

[0098] A VCI bimetallic composite coating is obtained by coating with the coating of Comparative Example 2, which is different from that of Example 8.

[0099] Comparative Example 5

[0100] A VCI bimetallic composite coating, which differs from Example 15 in that the surface treatment liquid is sprayed 24 hours after the coating is completely cured.

[0101] The coatings applied in Examples 7 to 19 were tested, and the coatings applied in Comparative Examples 3 to 4 were tested. The test samples used a galvanized iron plate with a length of 10 cm and a width of 10 cm as a substrate, on which a 0.5 mm thick coating was applied.

[0102] The test contents include initial salt spray corrosion resistance test, coating bonding strength test, salt spray corrosion resistance test after fluctuating current and magnetic field simulation accelerated aging, and coating bonding strength test after fluctuating current and magnetic field simulation accelerated aging.

[0103] The salt spray corrosion resistance test is carried out according to GB / T1771, using neutral salt spray at a temperature of 25°C. The test results are expressed as salt spray corrosion resistance time. The longer the salt spray corrosion resistance time, the better the salt spray corrosion resistance performance.

[0104] The coating adhesion test is carried out using the cross-hatch method in GB / T10610. The test results are expressed as adhesion grades, which are divided into 0 to 5 levels, with 0 being the best and 5 being the worst. The closer the adhesion grade is to 0, the better the coating adhesion.

[0105] Fluctuating current and magnetic field simulation accelerated aging method: The sample is suspended horizontally with an iron wire directly below the cable, with a distance of 5 cm from the outside of the cable. The cable voltage is sinusoidal with a peak value of 10 kV and a valley value of 5 kV. The fluctuation period is 30 minutes and lasts for 24 days.

[0106] The test results are shown in Table 1 below.

[0107] Table 1. Coating test results of Examples 7 to 17 and Comparative Examples 3 to 4

[0108]

[0109] Combined with the above table, comparing the test results of Example 8 and Comparative Examples 3 to 4, the coating of Example 7 is similar to Comparative Example 4 in initial salt spray corrosion resistance and coating adhesion, and is better than Comparative Example 3;

[0110] After accelerated aging simulated by fluctuating current magnetic field, Example 8 showed almost no change, Comparative Example 3 showed a slight decrease, and the salt spray corrosion resistance and coating adhesion level of Comparative Example 4 showed a significant decrease.

[0111] This is because the coating used in Comparative Example 4 is Comparative Example 2, in which the main binder is epoxy resin. Under the action of the fluctuating current magnetic field and the skin effect, the charge on the sample corresponding to the cable bridge armor is transferred to the coating surface. Under the action of the charge and the fluctuating magnetic field, the aging of the epoxy resin is accelerated, resulting in damage to the internal structure of the coating and a decrease in adhesion.

[0112] The coating used in Comparative Example 3 is similar to that in Comparative Example 1, in which the main binder is silicic acid and sodium silicate, which has poor adhesion to the galvanized iron plate, more holes in the coating, and poor resistance to neutral salt spray corrosion; but it has little effect under the action of fluctuating current magnetic field and skin effect.

[0113] The coating used in Example 8 is Example 1, in which the binder body is a siloxane pre-hydrolysis product, which not only has a cross-linked network of -Si-O-Si- but also has residual siloxane groups at the ends of the cross-linked network. The cross-linked network of -Si-O-Si- formed by pre-hydrolysis is more easily combined with the active hydroxyl groups on the metal surface, so that the binding strength of the binder to the metal powder in the coating and the coating to the substrate is higher, and the adhesion level of the coating is significantly improved. At the same time, the residual siloxane groups continuously affect and improve the surface tension of the coating during the curing process, so that the solid components of the coating can be densely accumulated in the process of losing water and diluent, and the coating has a higher density and better salt spray corrosion resistance.

[0114] In addition, the final cured coating bond is a cross-linked network of -Si-O-Si- with a further improved degree of cross-linking, which has strong resistance to accelerated aging caused by fluctuating current and magnetic fields and skin effect.

[0115] Therefore, the coating applied by the paint of the present application has excellent initial corrosion resistance and coating adhesion, and is not easy to age under the influence of fluctuating current magnetic field and skin effect. It can protect the cable tray for a long time and the cable tray has a long service life.

[0116] It can be seen from Examples 8 to 11 that when pre-hydrolyzed siloxane is used in the coating, different siloxanes have an impact on the performance of the final coating.

[0117] Among Examples 8 to 11, Example 8 is significantly superior to Examples 9 to 11 in terms of initial salt spray corrosion resistance and coating adhesion, as well as salt spray corrosion resistance and coating adhesion after accelerated aging simulated by fluctuating current and magnetic field.

[0118] The siloxanes in Example 1 of the coating used in Example 8 are tetraethoxysilane, 3-glycidyloxyethyltrimethoxysilane, and 3-aminopropyltriethoxysilane. During the curing process, the amino group reacts with the epoxy group to form a more complex -Si-O-Si- cross-linked network, which can improve the corrosion resistance and adhesion of the coating.

[0119] By controlling the appropriate proportions of 3-glycidyloxyethyltrimethoxysilane and 3-aminopropyltriethoxysilane, the synergistic benefit brought about by the "reaction of amino groups with epoxy groups during the curing process to promote the formation of a more complex -Si-O-Si- cross-linked network" can be made better than the loss of "amino groups and epoxy groups" under the action of fluctuating current magnetic field and skin effect. Therefore, the salt spray corrosion resistance and coating adhesion of Examples 10 to 11 after accelerated aging simulated by fluctuating current magnetic field show a greater decline than that of Example 9, while Example 8 shows a smaller decline.

[0120] Comparing Example 8 with Examples 12 to 14, compared with Example 8, Examples 12 to 14 further add tri(trimethylsiloxane) phosphate to the coating used. Tri(trimethylsiloxane) phosphate also hydrolyzes during the coating curing process, and its phosphate group can combine with the cross-linked network of -Si-O-Si-, thereby increasing the cross-linking degree of the cross-linked network of -Si-O-Si- and complicating its cross-linked network, thereby improving the corrosion resistance and adhesion of the coating, and having good aging resistance to the effects of fluctuating current and magnetic fields and skin effect.

[0121] In combination with Example 13, Examples 15 to 19 and Comparative Example 5, when the coating surface of Examples 15 to 19 is dry and not completely cured, a surface treatment liquid is further applied. The magnesium or lithium acetate in the surface treatment liquid penetrates into the pores of the coating and reacts with the active hydroxyl groups and is deposited on the surface of the pores, thereby blocking the pores on the coating surface and enhancing the corrosion resistance of the coating. Therefore, the corrosion resistance of Examples 15 to 19 before and after is better than that of Example 13.

[0122] This treatment process needs to be carried out when the coating is fully cured. After the coating is fully cured, the H+ concentration of the residual liquid in it is reduced, and the number of active hydroxyl groups on the surface of the pores is reduced, and the effect of blocking the tiny pores on the surface cannot be achieved. Therefore, Example 5 does not show corrosion resistance that is significantly better than Example 13.

[0123] Further comparison of Examples 15 to 19 shows that the best corrosion resistance improvement effect is achieved when the surface treatment solution is a mixed solution of magnesium acetate and lithium acetate with a magnesium acetate concentration of 8.2 g / L and a lithium acetate mixed solution of 2.1 g / L.

[0124] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed. However, as long as the modifications are within the scope of protection required by the present invention, they will be protected by patent law.

Claims

1. A VCI bimetallic composite coating, characterized in that: It is obtained by coating and curing the cable bridge with VCI bimetallic composite coating; VCI bimetallic composite coating for cable trays, comprising the following components in parts by weight: 20-40 parts of zinc powder; 10-20 parts of aluminum powder; 30~50 parts of adhesive; 5-15 parts of VCI sustained-release agent; 3.1-5.0 parts of tris(trimethylsiloxane) phosphate; The binder is obtained by pre-hydrolysis of siloxane; The siloxane is a compound of tetraethoxysiloxane, 3-glycidyloxyethyl trimethoxysiloxane and 3-aminopropyl triethoxysiloxane in a mass ratio of 7:2:1; The VCI sustained-release agent is 6-hydroxymethyl-aminobenzothiazole; When the coating surface is dry and not completely cured, the coating surface is also coated with a surface treatment liquid for surface treatment. The surface treatment liquid contains one or both of magnesium acetate and lithium acetate. The concentration of magnesium acetate in the surface treatment liquid is 8.2 g / L and the lithium acetate mixed solution is 2.1 g / L.

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