A zinc-rich epoxy coating

Abstract

A zinc-rich epoxy coating, belonging to the field of anti-corrosion coating technology, comprises component A and component B. By weight, component A includes 24-26 parts of hyperbranched epoxy resin, 0.1-0.5 parts of water-based defoamer, 0.4-0.8 parts of dispersant, 60-70 parts of carbon nanotube-zinc powder composite, and 0.5-0.7 parts of organobentonite. Component B includes 3-5 parts of water-based epoxy curing agent, 0.4-0.6 parts of zinc phosphate, and 3-5 parts of deionized water. The zinc-rich epoxy coating prepared by this invention has a long service life and exhibits good corrosion resistance and adhesion.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to a zinc-rich epoxy coating. Background Technology

[0002] Zinc-rich epoxy coatings are widely used for surface anti-corrosion treatment and protection of various steel structures, bridges, ships, etc.

[0003] Water-based zinc-rich epoxy coatings have received increasing attention due to their significant environmental and safety advantages. However, because water-based zinc-rich epoxy coatings are greatly affected by temperature and humidity, long-term exposure to sun and rain can easily cause cracks on the coating surface, leading to accelerated failure of the protective coating and affecting the anti-corrosion effect.

[0004] Therefore, improving the durability of coatings and enhancing the long-term protective effect of water-based zinc-rich epoxy coatings is a technical challenge that urgently needs to be addressed. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides a zinc-rich epoxy coating.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A zinc-rich epoxy coating comprises component A and component B. By weight, component A comprises 24-26 parts of hyperbranched epoxy resin, 0.1-0.5 parts of water-based defoamer, 0.4-0.8 parts of dispersant, 60-70 parts of carbon nanotube-zinc powder composite and 0.5-0.7 parts of organobentonite, and component B comprises 3-5 parts of water-based epoxy curing agent, 0.4-0.6 parts of zinc phosphate and 3-5 parts of deionized water.

[0010] Furthermore, the preparation method of the carbon nanotube-zinc powder composite includes the following steps:

[0011] S1: By weight, place 0.8-1.2 parts of multi-walled carbon nanotubes in an Erlenmeyer flask, then add 30-50 parts of mixed acid solution. Sonicate the Erlenmeyer flask in a water bath at 40-60℃ for 10-20 minutes, cool to room temperature, add 100-200 parts of deionized water to the Erlenmeyer flask for dilution, filter, discard the filtrate, wash 2-3 times with 50-70% ethanol solution, and dry to obtain pretreated carbon nanotubes.

[0012] S2: By weight, 0.3-0.5 parts of polyethyleneimine and pretreated carbon nanotubes are added sequentially to 50-100 parts of deionized water, ultrasonically dispersed for 5-8 minutes, filtered, dried and ground, and passed through a 200-mesh sieve to obtain modified carbon nanotubes.

[0013] S3: By weight, mix 50 parts zinc powder and 25 parts xylene evenly, then add 8 parts polyethyleneimine, heat to 50°C, stir for 4 hours, filter and dry to obtain pretreated zinc powder;

[0014] S4: By weight, the modified carbon nanotubes obtained in S2 and the pretreated zinc powder obtained in S3 are added to 70 parts of ethanol, mixed evenly, and then 6 parts of isobutyraldehyde are added. The mixture is heated to 40°C, stirred for 6 hours, filtered, and dried to obtain the carbon nanotube-zinc powder composite.

[0015] Furthermore, the mixed acid is a mixture of concentrated sulfuric acid and concentrated nitric acid, with a volume ratio of 3:1.

[0016] Furthermore, the volume concentration of the concentrated sulfuric acid is 98%, and the volume concentration of the concentrated nitric acid is 67%.

[0017] Furthermore, the preparation method of the hyperbranched epoxy resin includes the following steps:

[0018] C1: Weigh 10-20 parts of triethylamine by weight and add it to 50 parts of epoxy resin. Stir until homogeneous. Under nitrogen protection, add 0.4-0.6 parts of 4-dimethylaminopyridine, heat to 70-80℃, stir for 0.5-1h, continue to heat to 100-110℃, keep the reaction at this temperature for 2-3h, and cool to room temperature to obtain the pretreated epoxy resin.

[0019] C2: By weight, add 4-6 parts of glycerol triglycidyl ether and 1-2 parts of phenol to the pretreated epoxy resin, place it in a hot water bath at 70-80℃, stir for 1.5-2.5 hours, then add 0.8-1.2 parts of tetrabutylammonium bromide, stir for 4-6 hours, and the hyperbranched epoxy resin is obtained.

[0020] Furthermore, the epoxy resin is epoxy resin E51.

[0021] Furthermore, the aqueous defoamer is Hemings Deqian DAPRO AP 7015.

[0022] Furthermore, the dispersant is Additol VXW6208.

[0023] Furthermore, the waterborne epoxy curing agent is Huntsman Aradur 38-1.

[0024] Furthermore, the preparation method of the zinc-rich epoxy coating includes the following steps:

[0025] Q1: Weigh each component in component A according to the weight percentage, stir the hyperbranched epoxy resin and dispersant evenly, control the stirring speed to 600~1000r / min, add the water-based defoamer and organic bentonite in sequence, stir for 10~20min, then add the carbon nanotube-zinc powder composite, and stir for 20~40min after the addition is complete to obtain component A.

[0026] Q2: Weigh each component in component B, mix the water-based epoxy curing agent, deionized water and zinc phosphate evenly, control the stirring speed to 600~1000r / min, stir for 20~40min, and you will get component B;

[0027] Q3: Mix component A and component B prepared in Q1 and Q2 evenly to obtain zinc-rich epoxy coating.

[0028] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0029] 1. This invention improves the compatibility and bonding ability between E51 epoxy resin and other components by hyperbranching the resin to give it a certain amount of amino groups and form a hyperbranched crosslinking system, thereby improving the weather resistance and crack resistance of the coating.

[0030] 2. By modifying multi-walled carbon nanotubes to achieve a high aspect ratio, and then combining them with pretreated zinc powder, the zinc powder can be coated and extended. The extended multi-walled carbon nanotubes are combined with hyperbranched epoxy resin to form a robust and complete conductive network system, giving the entire coating high integrity and crack resistance.

[0031] 3. This zinc-rich epoxy coating modifies E51 epoxy resin and combines it with a specific carbon nanotube-zinc powder composite. The resulting product has high adhesion and excellent aging resistance, thus broadening the anti-corrosion application range of zinc-rich epoxy coatings.

[0032] 4. This invention provides a zinc-rich epoxy coating that is highly environmentally friendly, weather-resistant, and also has excellent corrosion resistance and adhesion. Detailed Implementation

[0033] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0034] In the following examples and comparative examples: the epoxy resin is epoxy resin E51, the water-based defoamer is Hemings Deqian DAPRO AP 7015, the dispersant is Zhanxin Additol VXW6208, and the water-based epoxy curing agent is Huntsman Aradur 38-1.

[0035] The mixed acid is a mixture of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, with the volume concentration of concentrated sulfuric acid being 98% and the volume concentration of concentrated nitric acid being 67%.

[0036] Example 1

[0037] A zinc-rich epoxy coating comprises component A and component B. By weight, component A comprises 25 parts hyperbranched epoxy resin, 0.3 parts water-based defoamer, 0.6 parts dispersant, 65 parts carbon nanotube-zinc powder composite and 0.6 parts organobentonite, and component B comprises 4 parts water-based epoxy curing agent, 0.5 parts zinc phosphate and 4 parts deionized water.

[0038] The preparation method of carbon nanotube-zinc powder composite includes the following steps:

[0039] S1: By weight, 1.0 part of multi-walled carbon nanotubes were placed in an Erlenmeyer flask, and then 40 parts of mixed acid solution were added. The Erlenmeyer flask was ultrasonically treated in a 50°C water bath for 15 min, cooled to room temperature, and 150 parts of deionized water were added to the Erlenmeyer flask for dilution. The mixture was filtered, the filtrate was discarded, and the mixture was washed twice with a 60% ethanol solution. After drying, the pretreated carbon nanotubes were obtained.

[0040] S2: By weight, 0.4 parts of polyethyleneimine and pretreated carbon nanotubes were added to 80 parts of deionized water, ultrasonically dispersed for 6 minutes, filtered, dried and ground, and passed through a 200-mesh sieve to obtain modified carbon nanotubes.

[0041] S3: By weight, mix 50 parts zinc powder and 25 parts xylene evenly, then add 8 parts polyethyleneimine, heat to 50°C, stir for 4 hours, filter and dry to obtain pretreated zinc powder;

[0042] S4: By weight, the modified carbon nanotubes obtained in S2 and the pretreated zinc powder obtained in S3 are added to 70 parts of ethanol, mixed evenly, and then 6 parts of isobutyraldehyde are added. The mixture is heated to 40°C, stirred for 6 hours, filtered, and dried to obtain the carbon nanotube-zinc powder composite.

[0043] A method for preparing hyperbranched epoxy resin includes the following steps:

[0044] C1: Weigh 15 parts of triethylamine by weight and add it to 50 parts of epoxy resin. Stir well and under nitrogen protection, add 0.5 parts of 4-dimethylaminopyridine. Heat to 75°C and stir for 0.8 hours. Continue to heat to 105°C and keep the reaction at this temperature for 2 hours. Cool to room temperature to obtain the pretreated epoxy resin.

[0045] C2: By weight, add 5 parts of glycerol triglycidyl ether and 1.5 parts of phenol to the pretreated epoxy resin, place it in a 75°C hot water bath, stir for 1 hour, then add 1 part of tetrabutylammonium bromide, stir for 5 hours, and the hyperbranched epoxy resin is obtained.

[0046] A method for preparing a zinc-rich epoxy coating includes the following steps:

[0047] Q1: Weigh each component in component A according to the weight percentage, stir the hyperbranched epoxy resin and dispersant evenly, control the stirring speed to 800 r / min, add the water-based defoamer and organic bentonite in sequence, stir for 15 min, then add the carbon nanotube-zinc powder composite, and stir for 30 min after the addition is complete to obtain component A.

[0048] Q2: Weigh each component in component B, mix the water-based epoxy curing agent, deionized water and zinc phosphate evenly, control the stirring speed at 800 r / min, stir for 30 min, and you will get component B;

[0049] Q3: Mix component A and component B prepared in Q1 and Q2 evenly to obtain zinc-rich epoxy coating.

[0050] Example 2

[0051] A zinc-rich epoxy coating comprises component A and component B. By weight, component A comprises 24 parts hyperbranched epoxy resin, 0.1 parts water-based defoamer, 0.4 parts dispersant, 60 parts carbon nanotube-zinc powder composite and 0.5 parts organobentonite, and component B comprises 3 parts water-based epoxy curing agent, 0.4 parts zinc phosphate and 3 parts deionized water.

[0052] The preparation method of carbon nanotube-zinc powder composite includes the following steps:

[0053] S1: By weight, 0.8 parts of multi-walled carbon nanotubes were placed in an Erlenmeyer flask, and then 30 parts of mixed acid solution were added. The Erlenmeyer flask was ultrasonically treated in a 40°C water bath for 10 minutes, cooled to room temperature, and 100 parts of deionized water were added to the Erlenmeyer flask for dilution. The mixture was filtered, the filtrate was discarded, and the mixture was washed twice with a 50% ethanol solution. After drying, the pretreated carbon nanotubes were obtained.

[0054] S2: By weight, 0.3 parts of polyethyleneimine and pretreated carbon nanotubes were added to 50 parts of deionized water, ultrasonically dispersed for 5 minutes, filtered, dried and ground, and passed through a 200-mesh sieve to obtain modified carbon nanotubes.

[0055] S3: By weight, mix 50 parts zinc powder and 20 parts xylene evenly, then add 6 parts polyethyleneimine, heat to 40°C, stir for 3 hours, filter and dry to obtain pretreated zinc powder;

[0056] S4: By weight, the modified carbon nanotubes obtained in S2 and the pretreated zinc powder obtained in S3 are added to 60 parts of ethanol, mixed evenly, and then 5 parts of isobutyraldehyde are added. The mixture is heated to 35°C, stirred for 5 hours, filtered, and dried to obtain the carbon nanotube-zinc powder composite.

[0057] A method for preparing hyperbranched epoxy resin includes the following steps:

[0058] C1: Weigh 10 parts of triethylamine by weight and add it to 50 parts of epoxy resin. Stir well and add 0.4 parts of 4-dimethylaminopyridine under nitrogen protection. Heat to 70°C and stir for 0.5 h. Continue to heat to 100°C and keep the reaction at this temperature for 2 h. Cool to room temperature to obtain pretreated epoxy resin.

[0059] C2: By weight, add 4 parts of glycerol triglycidyl ether and 1 part of phenol to the pretreated epoxy resin, place it in a 70°C hot water bath, stir for 1.5 h, then add 0.8 parts of tetrabutylammonium bromide, stir for 4 h, and the hyperbranched epoxy resin is obtained.

[0060] A method for preparing a zinc-rich epoxy coating includes the following steps:

[0061] Q1: Weigh each component in component A according to the weight parts, stir the hyperbranched epoxy resin and dispersant evenly, control the stirring speed to 600 r / min, add the water-based defoamer and organic bentonite in sequence, stir for 10 min, then add the carbon nanotube-zinc powder composite, and stir for 20 min after the addition is complete to obtain component A.

[0062] Q2: Weigh each component in component B, mix the water-based epoxy curing agent, deionized water and zinc phosphate evenly, control the stirring speed to 600 r / min, stir for 20 min, and you will get component B;

[0063] Q3: Mix component A and component B prepared in Q1 and Q2 evenly to obtain zinc-rich epoxy coating.

[0064] Example 3

[0065] A zinc-rich epoxy coating comprises component A and component B. By weight, component A comprises 26 parts hyperbranched epoxy resin, 0.5 parts water-based defoamer, 0.8 parts dispersant, 70 parts carbon nanotube-zinc powder composite and 0.7 parts organobentonite, and component B comprises 5 parts water-based epoxy curing agent, 0.6 parts zinc phosphate and 5 parts deionized water.

[0066] The preparation method of carbon nanotube-zinc powder composite includes the following steps:

[0067] S1: By weight, 1.2 parts of multi-walled carbon nanotubes were placed in an Erlenmeyer flask, and then 50 parts of mixed acid solution were added. The Erlenmeyer flask was ultrasonically treated in a 60°C water bath for 20 minutes, cooled to room temperature, and 200 parts of deionized water were added to the Erlenmeyer flask for dilution. The mixture was filtered, the filtrate was discarded, and the mixture was washed three times with a 70% ethanol solution. After drying, the pretreated carbon nanotubes were obtained.

[0068] S2: By weight, 0.5 parts of polyethyleneimine and pretreated carbon nanotubes were added to 100 parts of deionized water, ultrasonically dispersed for 8 minutes, filtered, dried and ground, and passed through a 200-mesh sieve to obtain modified carbon nanotubes.

[0069] S3: By weight, mix 50 parts zinc powder and 30 parts xylene evenly, then add 10 parts polyethyleneimine, heat to 60°C, stir for 5 hours, filter and dry to obtain pretreated zinc powder;

[0070] S4: By weight, the modified carbon nanotubes obtained in S2 and the pretreated zinc powder obtained in S3 are added to 80 parts of ethanol, mixed evenly, and then 7 parts of isobutyraldehyde are added. The mixture is heated to 45°C, stirred for 7 hours, filtered, and dried to obtain the carbon nanotube-zinc powder composite.

[0071] A method for preparing hyperbranched epoxy resin includes the following steps:

[0072] C1: Weigh 20 parts of triethylamine and add it to 50 parts of epoxy resin by weight. Stir well and add 0.6 parts of 4-dimethylaminopyridine under nitrogen protection. Heat to 80°C and stir for 1 hour. Continue to heat to 110°C and keep the reaction at this temperature for 3 hours. Cool to room temperature to obtain the pretreated epoxy resin.

[0073] C2: By weight, add 6 parts of glycerol triglycidyl ether and 2 parts of phenol to the pretreated epoxy resin, place it in an 80°C hot water bath, stir for 2.5 h, then add 1.2 parts of tetrabutylammonium bromide, stir for 6 h, and the hyperbranched epoxy resin is obtained.

[0074] A method for preparing a zinc-rich epoxy coating includes the following steps:

[0075] Q1: Weigh each component in component A according to the weight percentage, stir the hyperbranched epoxy resin and dispersant evenly, control the stirring speed to 1000 r / min, add the water-based defoamer and organic bentonite in sequence, stir for 20 min, then add the carbon nanotube-zinc powder composite, and stir for 40 min after the addition is complete to obtain component A.

[0076] Q2: Weigh each component in component B, mix the water-based epoxy curing agent, deionized water and zinc phosphate evenly, control the stirring speed at 1000 r / min, stir for 40 min, and you will get component B;

[0077] Q3: Mix component A and component B prepared in Q1 and Q2 evenly to obtain zinc-rich epoxy coating.

[0078] Example 4

[0079] A zinc-rich epoxy coating comprises component A and component B. By weight, component A comprises 24.5 parts hyperbranched epoxy resin, 0.2 parts water-based defoamer, 0.5 parts dispersant, 63 parts carbon nanotube-zinc powder composite and 0.55 parts organobentonite, and component B comprises 3.5 parts water-based epoxy curing agent, 0.45 parts zinc phosphate and 3.5 parts deionized water.

[0080] The preparation method of carbon nanotube-zinc powder composite includes the following steps:

[0081] S1: By weight, 0.9 parts of multi-walled carbon nanotubes were placed in an Erlenmeyer flask, and then 35 parts of mixed acid solution were added. The Erlenmeyer flask was ultrasonically treated in a 45°C water bath for 13 minutes, cooled to room temperature, and 120 parts of deionized water were added to the Erlenmeyer flask for dilution. The mixture was filtered, the filtrate was discarded, and the mixture was washed twice with a 55% ethanol solution. After drying, the pretreated carbon nanotubes were obtained.

[0082] S2: By weight, 0.35 parts of polyethyleneimine and pretreated carbon nanotubes were added to 60 parts of deionized water, ultrasonically dispersed for 6 minutes, filtered, dried and ground, and passed through a 200-mesh sieve to obtain modified carbon nanotubes.

[0083] S3: By weight, mix 50 parts zinc powder and 23 parts xylene evenly, then add 7 parts polyethyleneimine, heat to 45°C, stir for 3.5 hours, filter and dry to obtain pretreated zinc powder;

[0084] S4: By weight, the modified carbon nanotubes obtained in S2 and the pretreated zinc powder obtained in S3 are added to 65 parts of ethanol, mixed evenly, and then 5.5 parts of isobutyraldehyde are added. The mixture is heated to 38°C, stirred for 5.5 hours, filtered, and dried to obtain the carbon nanotube-zinc powder composite.

[0085] A method for preparing hyperbranched epoxy resin includes the following steps:

[0086] C1: Weigh 12 parts of triethylamine by weight and add it to 50 parts of epoxy resin. Stir well and under nitrogen protection, add 0.45 parts of 4-dimethylaminopyridine. Heat to 72°C and stir for 0.6 h. Continue to heat to 102°C and keep the reaction at this temperature for 2.2 h. Cool to room temperature to obtain the pretreated epoxy resin.

[0087] C2: By weight, add 4.5 parts of glycerol triglycidyl ether and 1.2 parts of phenol to the pretreated epoxy resin, place it in a 73°C hot water bath, stir for 1.8 h, then add 0.9 parts of tetrabutylammonium bromide, stir for 4.5 h to obtain hyperbranched epoxy resin.

[0088] A method for preparing a zinc-rich epoxy coating includes the following steps:

[0089] Q1: Weigh each component in component A according to the weight percentage, stir the hyperbranched epoxy resin and dispersant evenly, control the stirring speed to 800 r / min, add the water-based defoamer and organic bentonite in sequence, stir for 13 min, then add the carbon nanotube-zinc powder composite, and stir for 25 min after the addition is complete to obtain component A.

[0090] Q2: Weigh each component in component B, mix the water-based epoxy curing agent, deionized water and zinc phosphate evenly, control the stirring speed at 700 r / min, stir for 25 min, and you will get component B;

[0091] Q3: Mix component A and component B prepared in Q1 and Q2 evenly to obtain zinc-rich epoxy coating.

[0092] Comparative Example 1

[0093] The difference from Example 1 is that the hyperbranched epoxy resin is replaced with epoxy resin E51.

[0094] A zinc-rich epoxy coating comprises component A and component B. By weight, component A comprises 25 parts epoxy resin E51, 0.3 parts water-based defoamer, 0.6 parts dispersant, 65 parts carbon nanotube-zinc powder composite and 0.6 parts organobentonite, and component B comprises 4 parts water-based epoxy curing agent, 0.5 parts zinc phosphate and 4 parts deionized water.

[0095] A method for preparing a zinc-rich epoxy coating, characterized by comprising the following steps:

[0096] Q1: Weigh each component in component A according to the weight percentage, mix epoxy resin E51 and dispersant evenly, control the stirring speed to 800 r / min, add water-based defoamer and organic bentonite in sequence, stir for 15 min, then add carbon nanotube-zinc powder composite, stir for 30 min after the addition is complete, and you will get component A.

[0097] Q2: Weigh each component in component B, mix the water-based epoxy curing agent, deionized water and zinc phosphate evenly, control the stirring speed at 800 r / min, stir for 30 min, and you will get component B;

[0098] Q3: Mix component A and component B prepared in Q1 and Q2 evenly to obtain zinc-rich epoxy coating.

[0099] Comparative Example 2

[0100] The difference from Example 1 is that the multi-walled carbon nanotubes were not modified in the preparation of the carbon nanotube-zinc powder composite.

[0101] The preparation method of carbon nanotube-zinc powder composite includes the following steps:

[0102] S1: By weight, mix 50 parts zinc powder and 25 parts xylene evenly, then add 8 parts polyethyleneimine, heat to 50°C, stir for 4 hours, filter and dry to obtain pretreated zinc powder;

[0103] S3: By weight, 1.0 part of multi-walled carbon nanotubes and the pretreated zinc powder obtained in S2 were added to 70 parts of ethanol, mixed evenly, and then 6 parts of isobutyraldehyde were added. The mixture was heated to 40°C, stirred for 6 hours, filtered, and dried to obtain the carbon nanotube-zinc powder composite.

[0104] Comparative Example 3

[0105] The difference from Example 1 is that no pretreatment of zinc powder was performed in the preparation of the carbon nanotube-zinc powder composite.

[0106] The preparation method of carbon nanotube-zinc powder composite includes the following steps:

[0107] S1: By weight, 1.0 part of multi-walled carbon nanotubes were placed in an Erlenmeyer flask, and then 40 parts of mixed acid solution were added. The Erlenmeyer flask was ultrasonically treated in a 50°C water bath for 15 min, cooled to room temperature, and 150 parts of deionized water were added to the Erlenmeyer flask for dilution. The mixture was filtered, the filtrate was discarded, and the mixture was washed twice with a 60% ethanol solution. After drying, the pretreated carbon nanotubes were obtained.

[0108] S2: By weight, 0.4 parts of polyethyleneimine and pretreated carbon nanotubes were added to 80 parts of deionized water, ultrasonically dispersed for 6 minutes, filtered, dried and ground, and passed through a 200-mesh sieve to obtain modified carbon nanotubes.

[0109] S3: By weight, the modified carbon nanotubes obtained in S2 and 50 parts of zinc powder were added to 70 parts of ethanol, mixed evenly, and then 6 parts of isobutyraldehyde were added. The mixture was heated to 40°C, stirred for 6 hours, filtered, and dried to obtain the carbon nanotube-zinc powder composite.

[0110] Comparative Example 4

[0111] The difference from Example 1 is that in the preparation of the carbon nanotube-zinc powder composite, the multi-walled carbon nanotubes were not modified, and the zinc powder was not pretreated.

[0112] The preparation method of carbon nanotube-zinc powder composite includes the following steps:

[0113] By weight, 1.0 part of multi-walled carbon nanotubes and 50 parts of zinc powder were added to 70 parts of ethanol, mixed evenly, and then 6 parts of isobutyraldehyde were added. The mixture was heated to 40°C, stirred for 6 hours, filtered, and dried to obtain the carbon nanotube-zinc powder composite.

[0114] The adhesion, salt spray resistance, and aging resistance of the coatings obtained in the examples and comparative examples were tested respectively, and the specific results are shown in Table 1:

[0115] The resistance to neutral salt spray was tested in accordance with GB / T 1771-2007 "Determination of resistance to neutral salt spray of paints and varnishes".

[0116] The adhesion test was conducted in accordance with the standard GB / T 5210-2006 "Paints and Varnishes - Pull-off Adhesion Test".

[0117] The aging resistance performance was tested according to the standard GB / T 14522-2008 "Artificial Climate Aging Test Method for Plastics, Coatings and Rubber Materials for Mechanical Industry Products - Fluorescent Ultraviolet Lamp" for 360 hours. After aging, the adhesion was tested and the adhesion retention rate was calculated. In addition, the number of fine lines on the coating surface was counted. The method for counting the number of fine lines was as follows: three groups of specimens were selected, and the number of fine lines in a fixed area of ​​the specimen was observed with a magnifying glass. The average number of fine lines in the three areas was calculated.

[0118] Table 1

[0119]

[0120] The data on salt spray resistance, adhesion, and aging resistance of the zinc-rich epoxy coatings in Examples 1-4 show that the zinc-rich epoxy coatings prepared by the technical solution of this invention have good corrosion resistance and excellent adhesion, and also have a long service life.

[0121] The difference between Comparative Example 1 and Example 1 is that the hyperbranched epoxy resin was replaced with epoxy resin E51.

[0122] The salt spray resistance and adhesion of the zinc-rich epoxy coating prepared in Comparative Example 1 were lower than those of the zinc-rich epoxy coating in Example 1. The aging resistance of the zinc-rich epoxy coating in Comparative Example 1 was also lower than that of the zinc-rich epoxy coating in Example 1.

[0123] The above results indicate that hyperbranched epoxy resins can improve the corrosion resistance, adhesion, and aging resistance of zinc-rich epoxy coatings, thereby extending their service life.

[0124] The difference between Comparative Example 2 and Example 1 is that the multi-walled carbon nanotubes were not modified in the preparation of the carbon nanotube-zinc powder composite.

[0125] The zinc-rich epoxy coating prepared in Comparative Example 2 exhibited lower salt spray resistance and adhesion than the zinc-rich epoxy coating in Example 1. The aging resistance of the zinc-rich epoxy coating in Comparative Example 2 was also lower than that of the zinc-rich epoxy coating in Example 1.

[0126] The above indicates that the modification treatment of pretreated carbon nanotubes can improve the corrosion resistance, adhesion and aging resistance of zinc-rich epoxy coatings, thereby increasing their service life.

[0127] The difference between Comparative Example 3 and Example 1 is that no pretreatment of zinc powder was performed in the preparation of the carbon nanotube-zinc powder composite.

[0128] The salt spray resistance and adhesion of the zinc-rich epoxy coating prepared in Comparative Example 3 were lower than those of the zinc-rich epoxy coating in Example 1. The aging resistance of the zinc-rich epoxy coating in Comparative Example 3 was also lower than that of the zinc-rich epoxy coating in Example 1.

[0129] The above indicates that pretreatment with zinc powder can improve the corrosion resistance, adhesion, and aging resistance of zinc-rich epoxy coatings, thereby extending their service life.

[0130] The difference between Comparative Example 4 and Example 1 is that in the preparation of the carbon nanotube-zinc powder composite, the multi-walled carbon nanotubes were not modified and the zinc powder was not pretreated.

[0131] The zinc-rich epoxy coating prepared in Comparative Example 4 exhibited lower salt spray resistance and adhesion than the zinc-rich epoxy coating in Example 1. The aging resistance of the zinc-rich epoxy coating in Comparative Example 4 was also lower than that of the zinc-rich epoxy coating in Example 1.

[0132] Combined with Comparative Examples 2 and 3, the modified pretreated carbon nanotubes and the pretreated zinc powder have a synergistic effect on improving the corrosion resistance and aging resistance of zinc-rich epoxy coatings.

[0133] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A zinc-rich epoxy coating, characterized by: The A component comprises 24-26 parts by weight of hyperbranched epoxy resin, 0.1-0.5 parts by weight of water-based defoamer, 0.4-0.8 parts by weight of dispersant, 60-70 parts by weight of carbon nanotube-zinc powder composite and 0.5-0.7 parts by weight of organic bentonite, and the B component comprises 3-5 parts by weight of water-based epoxy curing agent, 0.4-0.6 parts by weight of zinc phosphate and 3-5 parts by weight of deionized water; The preparation method of the carbon nanotube-zinc powder composite comprises the following steps: S1: 0.8-1.2 parts by weight of multi-walled carbon nanotubes are placed in a conical flask, then 30-50 parts by weight of mixed acid solution is added, the conical flask is ultrasonically treated in a 40-60 DEG C water bath for 10-20 min, cooled to room temperature, 100-200 parts by weight of deionized water is added for dilution in the conical flask, filtered, the filtrate is discarded, washed with ethanol solution for 2-3 times, dried to obtain pretreated carbon nanotubes; S2: 0.3-0.5 parts by weight of polyethyleneimine and the pretreated carbon nanotubes obtained in S1 are sequentially added into 50-100 parts by weight of deionized water, ultrasonically dispersed for 5-8 min, filtered, dried, ground, and then passed through a 200-mesh sieve to obtain modified carbon nanotubes; S3: 50 parts by weight of zinc powder and 20-30 parts by weight of dimethylbenzene are uniformly mixed, then 6-10 parts by weight of polyethyleneimine is added, heated to 40-60 DEG C, stirred for 3-5 h, filtered and dried to obtain pretreated zinc powder; S4: the modified carbon nanotubes prepared in S2 and the pretreated zinc powder prepared in S3 are added into 60-80 parts by weight of ethanol, uniformly mixed, then 5-7 parts by weight of isobutyraldehyde is added, heated to 35-45 DEG C, stirred for 5-7 h, filtered and dried to obtain the carbon nanotube-zinc powder composite; The preparation method of the hyperbranched epoxy resin comprises the following steps: C1: 10-20 parts by weight of triethylamine is weighed and added into 50 parts by weight of epoxy resin, uniformly stirred, 0.4-0.6 parts by weight of 4-dimethylaminopyridine is added under nitrogen protection, heated to 70-80 DEG C, stirred for 0.5-1 h, continuously heated to 100-110 DEG C, kept for 2-3 h, cooled to room temperature to obtain pretreated epoxy resin; C2: 4-6 parts by weight of glycerol triglycidyl ether and 1-2 parts by weight of phenol are added into the pretreated epoxy resin, placed in a 70-80 DEG C hot water bath, stirred for 1.5-2.5 h, then 0.8-1.2 parts by weight of tetrabutylammonium bromide is added, stirred for 4-6 h to obtain the hyperbranched epoxy resin.

2. The zinc-rich epoxy coating of claim 1, wherein: The mixed acid is a mixture of concentrated sulfuric acid and concentrated nitric acid, and the volume ratio of the concentrated sulfuric acid to the concentrated nitric acid is 3:

1.

3. The zinc-rich epoxy coating of claim 2, wherein: The volume concentration of the concentrated sulfuric acid is 98%, and the volume concentration of the concentrated nitric acid is 67%.

4. The zinc-rich epoxy coating of claim 1, wherein: The epoxy resin is epoxy resin E51.

5. The zinc-rich epoxy coating of claim 1, wherein: The water-based defoamer is HENKEL DAPRO AP 7015.

6. The zinc-rich epoxy coating of claim 1, wherein: The dispersant is ZANNING Additol VXW6208.

7. The zinc-rich epoxy coating of claim 1, wherein: The water-based epoxy curing agent is HENKEL Aradur 38-1.

8. The zinc-rich epoxy coating according to any one of claims 1 to 7, characterized in that: The preparation method of the zinc-rich epoxy coating comprises the following steps: Q1: each component in A group is weighed according to the weight part, the hyperbranched epoxy resin and the dispersing agent are stirred and mixed uniformly, the stirring speed is controlled to be 600-1000 r / min, the water-based defoaming agent and the organic bentonite are sequentially put in, stirring is carried out for 10-20 min, then the carbon nanotube-zinc powder composite is added, after the addition is completed, stirring is carried out for 20-40 min, A group is obtained; Q2: each component in B group is weighed, the water-based epoxy curing agent, deionized water and zinc phosphate are mixed uniformly, the stirring speed is controlled to be 600-1000 r / min, stirring is carried out for 20-40 min, B group is obtained; Q3: A group prepared in Q1 and B group prepared in Q2 are mixed uniformly, a zinc-rich epoxy coating is obtained.

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