An epoxy resin / mxene zinc-rich primer

Abstract

The present application relates to a kind of epoxy resin / MXene zinc-rich primer, belong to anticorrosive paint technical field.The zinc-rich primer includes independently stored A component and B component, by mass fraction, the raw material of A component includes: epoxy resin 31~48 parts, silane coupling agent modified MXene 0.5~3 parts, zinc powder 9~40 parts, defoaming agent 0.3~0.5 parts and inorganic filler 1~5 parts, the raw material of B component includes: curing agent 25~39 parts, wherein silane coupling agent modified MXene is added in the form of suspension liquid with solid content 0.5%~2%.The epoxy resin / MXene zinc-rich primer provided in the present application is in the epoxy resin zinc-rich coating system, join two-dimensional material MXene, use nanoscale zinc powder and micron grade zinc powder are used in combination, improve the electric contact between zinc powder and steel base plate, prolong the cathodic protection time of zinc powder, effectively improve the anticorrosive performance of coating, and construction method is simple and easy to operate, can be applied on a large scale.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of anticorrosive coatings, in particular to an epoxy resin / MXene zinc-rich primer. BACKGROUND

[0002] Zinc-rich epoxy coatings have been widely used as an effective method to protect steel from corrosion in marine environments. In marine environments, a galvanic system is formed between the zinc powder in the zinc-rich epoxy coating and the steel substrate, in which the zinc powder acts as a cathode and undergoes oxidation to prevent the corrosion of the steel substrate, thereby providing protection. Generally, the cathode coating of zinc-rich epoxy coatings requires a zinc content of up to 80% or more to ensure electrical contact between the zinc powder and the steel substrate. However, even with a zinc content of up to 90%, long-term cathodic protection has not been reported. This is because as the zinc powder is gradually sacrificed, non-conductive corrosion products of zinc hinder the contact between the zinc powder and the steel substrate, thereby affecting the cathodic protection of the zinc powder. As a result, the added zinc powder is not fully utilized, resulting in a much shorter protection time for zinc-rich epoxy coatings than expected.

[0003] Efforts have been made to address the problems caused by zinc powder corrosion. To this end, researchers have used inorganic fillers such as carbon nanotubes, nano-zinc, and polyaniline to improve the contact between the zinc powder and the steel substrate and enhance the barrier effect of the coating. Researchers have also used conductive fillers to partially replace zinc powder, maintaining the electrical conductivity of the coating at low zinc content. However, the aforementioned shortcomings have not been completely addressed. The contact between the conductive fillers and the zinc powder is still insufficient to ensure that zinc can provide optimal corrosion protection. SUMMARY

[0004] The present application aims to provide an epoxy resin / MXene zinc-rich primer that utilizes the excellent electrical conductivity and electrical properties of the two-dimensional material MXene and its unique layered structure in combination with zinc powder to solve the problem of zinc powder not being fully utilized due to cathodic corrosion, thereby greatly extending the protection time of the coating.

[0005] To achieve the above-mentioned purpose, the present application provides the following solutions:

[0006] One of the technical solutions of the present application is to provide an epoxy resin / MXene zinc-rich primer, which comprises independently stored A component and B component. The raw materials of the A component include, by mass fraction: epoxy resin 31-48 parts, silane coupling agent modified MXene 0.5-3 parts, zinc powder 9-40 parts, defoaming agent 0.3-0.5 parts, and inorganic filler 1-5 parts. The raw materials of the B component include: curing agent 25-39 parts. The silane coupling agent modified MXene is added in the form of a suspension with a solid content of 0.5%-2%.

[0007] Preferably, the silane coupling agent modification in the silane coupling agent modified MXene comprises KH560, KH570 or KH580, the size of the MXene is 0.2-50 mu m, and the number of layers of the MXene is 1-10 layers.

[0008] Preferably, the size of the zinc powder is nanoscale and microscale, and the nanoscale zinc powder accounts for no more than 20% of the total mass.

[0009] Preferably, the defoaming agent is BYK-A530 defoaming agent, the inorganic filler is titanium white and / or mica powder, and the curing agent is a polyamide curing agent.

[0010] The second technical solution of the present application provides a preparation method of the above-mentioned epoxy resin / MXene zinc-rich primer, comprising the following steps:

[0011] The silane coupling agent modified MXene is prepared into an MXene suspension with a solid content of 0.5%-2%; the epoxy resin, zinc powder, defoaming agent and inorganic filler are sequentially added into the above-mentioned suspension, and stirred uniformly to obtain component A; component B is a curing agent, and component A and component B are independently stored, which is the above-mentioned epoxy resin / MXene zinc-rich primer.

[0012] Preferably, the dispersion medium used in the suspension is a mixture of dimethylbenzene and n-butanol with a volume ratio of 3:1.

[0013] The third technical solution of the present application provides an epoxy resin / MXene zinc-rich primer coating layer, which is obtained after the above-mentioned epoxy resin / MXene zinc-rich primer is applied on a substrate.

[0014] Preferably, the application method is brushing or spraying, and the coating thickness is 60-200 mu m.

[0015] The fourth technical solution of the present application provides that the above-mentioned epoxy resin / MXene zinc-rich primer is used for protecting steel parts used in marine environments.

[0016] The present application discloses the following technical effects:

[0017] The application adds two-dimensional material MXene with excellent electrical conductivity and conductivity in the zinc-rich epoxy coating, and improves the dispersibility and interface compatibility in the coating by silane coupling agent modification, increases the conductivity in the whole epoxy resin system, connects the zinc powder with the zinc powder by using MXene conductive material, fully improves the electrical contact between the zinc powder and the steel substrate, improves the effective content of the zinc for cathodic protection, and prolongs the protection time of the zinc-rich epoxy coating. The MXene material has a layered structure and a large specific surface area, and can reduce the porosity of the coating as an inorganic filler of the zinc-rich epoxy coating, and can also use the unique layered structure of MXene to prolong the channel of the external corrosion medium and water into the coating, and reduce the diffusion rate of the corrosion medium.

[0018] In the application, micron and nanometer zinc powder are used in combination, and the nanometer zinc powder can effectively improve the electrical connection of the zinc powder in the coating and prolong the duration of the cathodic protection effect of the zinc-rich epoxy coating. In addition, the nanometer zinc powder can fill the pores between the micron zinc powder and the epoxy resin in the coating, further improve the contact between the zinc powder and the zinc powder and between the zinc powder and MXene in the zinc-rich epoxy coating, not only improve the hindering effect of the external corrosion medium, but also improve the utilization rate of the zinc powder, thereby further prolonging the protection time of the zinc-rich epoxy coating. DETAILED DESCRIPTION

[0019] Various exemplary embodiments of the present application will now be described in detail, which should not be considered as limiting the present application, but rather as a more detailed description of certain aspects, characteristics and embodiments of the present application.

[0020] It should be understood that the terms described in the present application are only for describing the specific embodiments, and are not used to limit the present application. In addition, for the numerical range in the present application, it should be understood that each intermediate value between the upper limit and the lower limit of the range is also specifically disclosed. Each smaller range between any stated value or intermediate value within the stated range, and any other stated value or intermediate value within the stated range, is also included in the present application. The upper limit and the lower limit of these smaller ranges can be independently included or excluded from the range.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application pertains. Although preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials in connection with which the documents are concerned. In the event of any conflict between the content of this specification and any document incorporated by reference, the content of this specification will control.

[0022] Many modifications and variations of the present application described in the specification are possible without departing from the scope or spirit of the application. Other implementations of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. The specification and examples are illustrative only.

[0023] As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having,” and the like are open-ended terms that are intended to be synonymous, and are generally used to permit for the inclusion of additional elements, components, etc. without omitting other elements that are not expressly included.

[0024] The raw materials used in the following examples and comparative examples of the present application are as follows:

[0025] Silane coupling agent K560 modified MXene:

[0026] Preparation method of MXene: 3.2 g of LiF was dissolved in 40 mL of HCl solution (9 mol / L) and stirred at room temperature for 40 min. Then 2 g of Ti3AlC2 solid powder was slowly added to the above mixed solution and continuously stirred at 40°C for 48 h. The mixed solution was repeatedly washed and centrifuged, and the obtained solid after washing was freeze-dried in a freeze dryer (-60°C, 50 Pa). 20 mL of dimethyl sulfoxide (DMSO) was poured into a beaker containing 1 g of the above dried solid, stirred at 40°C for 12 h, and then repeatedly washed / centrifuged with deionized water. The obtained precipitate was dispersed in deionized water, and ultrasonically treated for 2 h under ice bath condition, centrifuged, and the supernatant was collected to obtain a MXene suspension, which was freeze-dried to obtain MXene nanosheets. The MXene prepared by other methods does not affect the technical effects of the present application.

[0027] Modification process of MXene: 2 g of MXene was added to 250 ml of 95% (v / v) ethanol / water mixed solution and stirred at room temperature for 60 min to obtain a MXene suspension. At the same time, 3 ml of KH550 was hydrolyzed in a mixture of 3 ml of water and 15.3 ml of ethanol for 60 min. The hydrolyzed KH550 was added to the above MXene suspension and stirred under nitrogen atmosphere for 8 h to obtain the product, which was washed twice with ethanol and then repeatedly washed with deionized water, filtered, and the filter cake was freeze-dried to obtain KH550 modified MXene.

[0028] Epoxy resin: Epoxy resin 6101

[0029] Defoaming agent: BYK-A530 defoaming agent

[0030] Zinc powder: The particle size of the nano-sized zinc powder is 100 nm, and the particle size of the micron-sized zinc powder is 500 mesh

[0031] Curing agent: low molecular 650 polyamide curing agent

[0032] Example 1

[0033] The silane coupling agent KH550 modified MXene was added to a mixed solvent of xylene and n-butanol in a volume ratio of 3:1, ultrasonic dispersion, and a MXene suspension with a solid content of 1% was prepared; to the above MXene suspension, epoxy resin, zinc powder, defoaming agent and titanium white were sequentially added, wherein the nano zinc powder accounted for 5% of the total zinc powder mass, and the remaining 95% was micron zinc powder, and the mass fractions of the silane coupling agent modified MXene, epoxy resin, zinc powder, defoaming agent and titanium white were 3 parts, 47 parts, 9 parts, 0.3 parts and 2.7 parts respectively. After high-speed stirring at 1800 rpm for 30 min, component A was obtained; component A was prepared according to the preset concentration, 38 parts of component B polyamide curing agent was added, and stirring was carried out at a stirring speed of 1800 rpm for 60 min to disperse and mature for 30 min. A primer coating layer with a thickness of 100 μm was uniformly sprayed on a Q235 steel plate, and after curing, an epoxy resin / MXene zinc-rich primer coating layer was obtained, and then the intermediate paint and topcoat were applied according to the standard.

[0034] Example 2

[0035] The silane coupling agent KH550 modified MXene was added to a mixed solvent of xylene and n-butanol in a volume ratio of 3:1, ultrasonic dispersion, and a MXene suspension with a solid content of 0.8% was prepared; to the above MXene suspension, epoxy resin, zinc powder, defoaming agent and titanium white were sequentially added, wherein the nano zinc powder accounted for 5% of the total zinc powder mass, and the remaining 95% was micron zinc powder, and the mass fractions of the silane coupling agent modified MXene, epoxy resin, zinc powder, defoaming agent and titanium white were 2 parts, 42 parts, 20 parts, 0.5 parts and 2.5 parts respectively. After high-speed stirring at 1800 rpm for 30 min, component A was obtained; component A was prepared according to the preset concentration, 33 parts of polyamide curing agent was added, and stirring was carried out at a stirring speed of 1800 rpm for 60 min to disperse and mature for 30 min. A primer coating layer with a thickness of 100 μm was uniformly sprayed on a Q235 steel plate, and after curing, an epoxy resin / MXene zinc-rich primer coating layer was obtained, and then the intermediate paint and topcoat were applied according to the standard.

[0036] Example 3

[0037] The silane coupling agent KH550 modified MXene is added to a mixed solvent with a volume ratio of xylene to n-butanol of 3:1, ultrasonic dispersion, and a MXene suspension with a solid content of 0.5% is prepared; the epoxy resin, zinc powder, defoaming agent and titanium white are sequentially added to the above MXene suspension, wherein the nano zinc powder accounts for 5% of the total mass of zinc powder, and the remaining 95% is micron zinc powder, and the mass fraction of the silane coupling agent modified MXene, epoxy resin, zinc powder, defoaming agent and titanium white is 0.5 parts, 31 parts, 40 parts, 0.5 parts and 3 parts respectively, and after 1800 rpm high-speed stirring for 30 min, the A component is obtained; the A component is prepared according to the preset concentration, 25 parts of polyamide curing agent is added, and stirring is carried out at a stirring speed of 1800 rpm for 60 min to disperse and mature for 30 min, and then a primer coating with a thickness of 100 μm is uniformly sprayed on a Q235 steel plate, and after curing, an epoxy resin / MXene zinc-rich primer coating is obtained, and then the intermediate paint and topcoat are constructed according to the standard.

[0038] Comparative Example 1

[0039] The silane coupling agent KH550 modified MXene is added to a mixed solvent with a volume ratio of xylene to n-butanol of 3:1, ultrasonic dispersion, and a MXene suspension with a solid content of 0.5% is prepared; the epoxy resin, zinc powder, defoaming agent and titanium white are sequentially added to the above MXene suspension, wherein the nano zinc powder accounts for 5% of the total mass of zinc powder, and the remaining 95% is micron zinc powder, and the mass fraction of the silane coupling agent modified MXene, epoxy resin, zinc powder, defoaming agent and titanium white is 0.5 parts, 31 parts, 40 parts, 0.5 parts and 3 parts respectively, and after 1800 rpm high-speed stirring for 30 min, the A component is obtained; the A component is prepared according to the preset concentration, 25 parts of polyamide curing agent is added, and stirring is carried out at a stirring speed of 1800 rpm for 60 min to disperse and mature for 30 min, and then a primer coating with a thickness of 100 μm is uniformly sprayed on a Q235 steel plate, and after curing, an epoxy resin / MXene zinc-rich primer coating is obtained, and then the intermediate paint and topcoat are constructed according to the standard.

[0040] Example 4

[0041] The silane coupling agent KH550 modified MXene is added to a mixed solvent with a volume ratio of xylene to n-butanol of 3:1, ultrasonic dispersion is performed, and a MXene suspension with a solid content of 1% is prepared; the epoxy resin, zinc powder, defoaming agent and titanium white are sequentially added to the above-mentioned MXene suspension, wherein the nano-scale zinc powder accounts for 20% of the total mass of the zinc powder, and the remaining 80% is micron-scale zinc powder, and the mass fractions of the silane coupling agent modified MXene, the epoxy resin, the zinc powder, the defoaming agent and the titanium white are 3 parts, 47 parts, 9 parts, 0.3 parts and 2.7 parts respectively, and after high-speed stirring at 1800 rpm for 30 min, the A component is obtained; the A component is prepared according to the preset concentration, 38 parts of the B component polyamide curing agent is added, stirring is performed at a stirring speed of 1800 rpm for 60 min, and aging is performed for 30 min, a primer coating with a thickness of 100 μm is uniformly sprayed on a Q235 steel plate, and after curing, an epoxy resin / MXene zinc-rich primer coating is obtained, and then the intermediate paint and the topcoat are applied according to the standards.

[0042] Comparative Example 2

[0043] In this comparative example, the silane coupling agent modified MXene is omitted compared with Example 1.

[0044] Comparative Example 3

[0045] In this comparative example, the modification of the MXene by the silane coupling agent is omitted compared with Example 1.

[0046] Comparative Example 4

[0047] In this comparative example, all the zinc powder used is micron-scale compared with Example 1.

[0048] The results of the coating test items of the groups of Examples 1-3 and Comparative Examples 1-4 are shown in Table 1.

[0049] Detection method: The adhesion grade of the coating is determined according to GB / T 9286-98, and the salt spray resistance of the coating is tested according to GB / T 1771-2007.

[0050] Table 1 Results of coating test items of groups of Examples 1-3 and Comparative Examples 1-4

[0051]

[0052] As can be seen from Table 1, the epoxy resin / MXene zinc-rich primer coating obtained in Examples 1-3 has a smooth and flat appearance, the salt spray resistance is more than 1800 h, and there is no delamination after storage, which further indicates that the epoxy resin / MXene zinc-rich primer provided in the application has good corrosion resistance within the limited range.

[0053] By comparing the test item results of the coatings of Example 1, Comparative Example 1 and Example 4, it can be seen that when the amount of nano-zinc powder is less than 20% of the total mass of zinc powder, the salt water resistance time and salt spray resistance of the prepared coating are improved, but when the amount of nano-zinc powder is more than 20% of the total mass of zinc powder, the salt water resistance time and salt spray resistance of the prepared coating are reduced. This is because when the amount of nano-zinc powder is too large, the micron-sized zinc powder is blocked by the nano-zinc powder, and since the nano-zinc powder has higher reactivity than the micron-sized zinc powder, it can be covered by corrosion products in a short time, losing the electrical connection with the steel matrix and failing to provide long-term cathodic protection, which is not conducive to the realization of the corrosion resistance of the epoxy zinc-rich coating.

[0054] By comparing the test item results of the coatings of Example 1, Comparative Example 2 and Comparative Example 3, it can be seen that omitting the addition of the silane coupling agent modified MXene or omitting the modification process of the MXene will result in a decrease in the salt water resistance time and salt spray resistance of the coating. This shows that the addition of the silane coupling agent modified MXene and the modification of the MXene can effectively improve the corrosion resistance of the coating. This is because the MXene can increase the electrical conductivity in the entire epoxy resin system, and its special structure can also reduce the porosity of the coating and prolong the channel for the entry of external corrosive medium and water into the coating; the modification of the MXene can also improve its dispersibility in the epoxy resin matrix.

[0055] By comparing the test item results of the coatings of Example 1 and Comparative Example 4, it can be seen that the use of both nano-sized and micron-sized zinc powder in the present application can improve the corrosion resistance of the coating. This is because the nano-zinc powder can improve the electrical connection of the zinc powder and fill the pores between the micron-sized zinc powder and the epoxy resin in the coating, thereby further improving the contact between the zinc powder and the zinc powder, the zinc powder and the MXene in the epoxy zinc-rich coating, improving the utilization rate of the zinc powder and prolonging the cathodic protection time of the zinc powder.

[0056] The above-described examples are only used to describe the preferred modes of the present application and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. An epoxy resin / MXene zinc-rich primer, characterized in that, The raw materials of the A component are epoxy resin 31-48 parts, silane coupling agent modified MXene 0.5-3 parts, zinc powder 9-40 parts, defoaming agent 0.3-0.5 parts and inorganic filler 1-5 parts by mass fraction, and the raw materials of the B component are curing agent 25-39 parts, and the silane coupling agent modified MXene is added in the form of a suspension with a solid content of 0.5%-2%; The silane coupling agent in the silane coupling agent modified MXene includes KH550, KH560, KH570 or KH580, the size of the MXene is 0.2-50 μm, and the number of layers is 1-10 layers; The size of the zinc powder is nanoscale and microscale, and the nanoscale zinc powder accounts for no more than 20% of the total mass; The defoaming agent is BYK-A530 defoaming agent, the inorganic filler is titanium white, and the curing agent is a polyamide curing agent; The preparation method of the epoxy resin / MXene zinc-rich primer includes the following steps: The silane coupling agent modified MXene is made into a suspension with a solid content of 0.5%-2%, and the epoxy resin, zinc powder, defoaming agent and inorganic filler are sequentially added to the suspension and stirred uniformly to obtain the A component; the curing agent is used as the B component, the A component and the B component are independently stored, and the epoxy resin / MXene zinc-rich primer is obtained. The dispersion medium used in the suspension is a mixture of dimethylbenzene and n-butanol with a volume ratio of 3:

1.

2. An epoxy resin / MXene zinc-rich primer coating, characterized by, The epoxy resin / MXene zinc-rich primer coating is obtained after the epoxy resin / MXene zinc-rich primer of claim 1 is applied on a substrate.

3. The epoxy resin / MXene zinc-rich primer coating of claim 2, wherein, The application method is brushing or spraying, and the coating thickness is 60-200 μm.

4. Application of the epoxy resin / MXene zinc-rich primer of claim 1 as a corrosion-resistant coating for steel parts.

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