阅读说明：本技术 一种水性纳米片复合涂料及其制备方法与应用 (Water-based nanosheet composite coating and preparation method and application thereof ) 是由 顾林 孙九龙 于 2021-08-10 设计创作，主要内容包括：本发明公开了一种水性纳米片复合涂料,属于水性涂料领域。本发明所述产品的原料组分中以漆酚衍生物作为改性剂,对二维纳米片进行锚定改性,使而二维纳米片在水性环氧树脂中得到有效分散,而改性后的纳米片可在涂料使用时充分发挥“迷宫效应”,起到很好的物理阻隔作用,大大延长了腐蚀性介质进入涂层内部的路径；此外漆酚衍生物含有的邻苯二酚基团可有效钝化保护的金属及合金,使其表面形成致密的氧化膜,从而对金属基底起到有效防护。本发明还公开了所述水性纳米片复合涂料的制备方法及应用。(The invention discloses a water-based nanosheet composite coating, and belongs to the field of water-based coatings. According to the invention, the urushiol derivative is used as a modifier in the raw material components of the product, and the two-dimensional nanosheets are subjected to anchoring modification, so that the two-dimensional nanosheets are effectively dispersed in the water-based epoxy resin, and the modified nanosheets can fully play a labyrinth effect when the coating is used, so that a good physical barrier effect is achieved, and the path of a corrosive medium entering the coating is greatly prolonged; in addition, the catechol group contained in the urushiol derivative can effectively passivate protected metal and alloy, so that a compact oxide film is formed on the surface of the urushiol derivative, and the urushiol derivative can effectively protect a metal substrate. The invention also discloses a preparation method and application of the water-based nanosheet composite coating.)

1. The water-based nanosheet composite coating is characterized by comprising the following raw materials in parts by weight:

0.07-0.08 part of two-dimensional nanosheet, 0.08-0.12 part of urushiol derivative, 2-3 parts of deionized water, 8-12 parts of waterborne epoxy resin and 3-8 parts of curing agent; and mixing the two-dimensional nanosheets, the urushiol derivative and deionized water, and then carrying out ultrasonic treatment to form a nanosheet dispersion liquid for preparing the water-based nanosheet composite coating.

2. The aqueous nanoplate composite coating of claim 1, wherein the two-dimensional nanoplates have a size of 0.5 to 50 μ ι η.

3. The aqueous nanoplatelet composite coating of claim 2 wherein the two-dimensional nanoplatelets comprise at least one of boron nitride, graphene, tungsten disulfide, molybdenum disulfide, borolene.

4. The aqueous nanoplate composite coating of claim 1, wherein the urushiol derivative has the structure:

5. the aqueous nanoplate composite coating of claim 1, wherein the epoxy resin comprises at least one of a bisphenol a type aqueous epoxy resin, a bisphenol F type aqueous epoxy resin.

6. The aqueous nanoplate composite coating of claim 1, wherein the curing agent is an amine curing agent; preferably, the amine curing agent includes at least one of a polyamide curing agent and a cardanol amine curing agent.

7. A method of preparing an aqueous nanoplate composite coating according to any of claims 1 to 6, comprising the steps of:

(1) mixing the two-dimensional nanosheets, the urushiol derivatives and deionized water according to a ratio, and then carrying out ultrasonic treatment for 3.5-4.5 hours to obtain a nano dispersion liquid;

(2) and adding waterborne epoxy resin into the nano dispersion liquid, stirring and mixing uniformly, adding a curing agent, continuously stirring, and then carrying out defoaming treatment for 12-18 min to obtain the waterborne nano sheet composite coating.

8. The method for preparing an aqueous nanosheet composite coating according to claim 7, wherein the defoaming treatment is performed by a defoaming machine having a set rotation speed of 1400 to 1600r/min and a vacuum degree of 95 to 96 kPa.

9. Use of the aqueous nanocomposite coating according to any one of claims 1 to 6 for metal corrosion protection.

10. The application of the water-based nano composite coating in metal corrosion prevention according to claim 9, wherein when the water-based nano composite coating is applied, the water-based nano composite coating is coated on the surface of a metal product by a wire rod coater after the surface of the metal product is subjected to polishing, cleaning and drying treatment for one time; when the water-based nanosheet composite coating is coated on the surface of a metal product, the thickness of a wet film is 65-75 micrometers, and the thickness of a cured dry film is 40-50 micrometers.

Technical Field

The invention relates to the field of water-based paint, in particular to water-based nanosheet composite paint and a preparation method and application thereof.

Background

Epoxy coatings are widely used for corrosion protection of metals due to excellent corrosion resistance, electrical insulation and strong adhesion to metal substrates, and currently, epoxy coatings industrially used for corrosion protection of metals are mainly solvent-based epoxy coatings. However, the prior art solvent-based epoxy coatings contain a proportion of volatile materials that pose a significant environmental and human health hazard. In recent years, with the emphasis on human health and environmental protection, water-based epoxy coatings have attracted much attention and are considered as potential substitutes for solvent-based epoxy coatings. However, although waterborne epoxy coatings have been commercialized for more than 40 years, waterborne epoxy coatings do not provide long-term preservation of metal substratesProtection, especially in strongly corrosive environments, is less effective because waterborne epoxy systems typically contain hydrophilic groups or segments in the epoxy backbone or side chains, which accelerate H₂O、O₂And penetration of other corrosive media. Some current research schemes are that nano sheets such as graphene are added into a water-based paint, so that components of a corrosive medium reaching the metal surface can be effectively delayed, the defects are overcome, and efficient corrosion prevention is realized; however, nanosheet materials such as graphene are easy to agglomerate, and need to be dispersed efficiently, but an efficient dispersion technology for the water-based epoxy coating is still lacking at present.

Disclosure of Invention

Based on the defects of the prior art, the invention aims to provide the water-based nanosheet composite coating, and the high dispersibility of the nanosheets in the water-based epoxy resin is improved through the structural composition of anchoring the nanosheets by the urushiol derivative, so that the corrosion resistance of the nanosheets is greatly improved.

In order to achieve the purpose, the invention adopts the technical scheme that:

a water-based nanosheet composite coating comprises the following raw materials in parts by weight:

0.07-0.08 part of two-dimensional nanosheet, 0.08-0.12 part of urushiol derivative, 2-3 parts of deionized water, 8-12 parts of waterborne epoxy resin and 3-8 parts of curing agent; and mixing the two-dimensional nanosheets, the urushiol derivative and deionized water, and then carrying out ultrasonic treatment to form a nanosheet dispersion liquid for preparing the water-based nanosheet composite coating.

In the raw material components of the water-based nanosheet composite coating, a urushiol derivative is used as a modifier to anchor and modify the two-dimensional nanosheets, so that the two-dimensional nanosheets are effectively dispersed in the water-based epoxy resin, and the modified nanosheets can fully play a labyrinth effect when the coating is used, so that a good physical barrier effect is achieved, and a path of a corrosive medium entering the coating is greatly prolonged; in addition, the catechol group contained in the urushiol derivative can effectively passivate protected metal and alloy, so that a compact oxide film is formed on the surface of the urushiol derivative, and the urushiol derivative can effectively protect a metal substrate.

Preferably, the size of the two-dimensional nano sheet is 0.5-50 μm;

more preferably, the two-dimensional nanoplatelets comprise at least one of boron nitride, graphene, tungsten disulfide, molybdenum disulfide, borolene (two-dimensional boron).

The two-dimensional nanoplatelets are moderate in size and stable in property, and can be effectively and uniformly dispersed in a solvent and a resin matrix after being modified by the urushiol derivatives, so that an external corrosive medium can be effectively isolated.

Preferably, the urushiol derivative has the following structure:

the urushiol derivative is stable in property and can effectively assist the two-dimensional nanosheets in being stripped and dispersed in deionized water.

Preferably, the epoxy resin comprises at least one of bisphenol A type waterborne epoxy resin and bisphenol F type waterborne epoxy resin;

more preferably, the epoxy resin is bisphenol A type WTE-51 type high-solid content water-based epoxy resin.

Preferably, the curing agent is an amine curing agent;

more preferably, the amine curing agent comprises at least one of a polyamide curing agent and a cardanol amine curing agent;

more preferably, the curing agent is a WH115 type polyamide curing agent.

Another object of the present invention is to provide a preparation method of the aqueous nanosheet composite coating, including the steps of:

(1) mixing the two-dimensional nanosheets, the urushiol derivatives and deionized water according to a ratio, and then carrying out ultrasonic treatment for 3.5-4.5 hours to obtain a nano dispersion liquid;

(2) and adding waterborne epoxy resin into the nano dispersion liquid, stirring and mixing uniformly, adding a curing agent, continuously stirring, and then carrying out defoaming treatment for 12-18 min to obtain the waterborne nano sheet composite coating.

The preparation method of the nano-sheet composite coating has simple operation steps and can realize industrial large-scale production.

Preferably, the defoaming treatment is carried out by a defoaming machine, the set rotating speed of the defoaming machine is 1400-1600 r/min, and the vacuum degree is 95-96 kPa.

Still another object of the present invention is to provide the use of the aqueous nanocomposite coating in metal corrosion prevention.

Compared with the traditional resin anticorrosive paint, the water-based nanosheet composite paint provided by the invention has the advantages that the anticorrosive performance is remarkably improved, volatile toxic substances are not released through the synergistic effect of the urushiol derivative and the two-dimensional nanosheet material, and the water-based nanosheet composite paint can be effectively applied to the anticorrosive application of various metal products.

Preferably, when the water-based nanosheet composite coating is applied, the surface of a metal product is subjected to polishing, cleaning and drying treatment at one time, and then the water-based nanosheet composite coating is coated on the surface of the metal product by using a wire rod film coating device.

More preferably, the thickness of a wet film is 65-75 μm when the water-based nanosheet composite coating is coated on the surface of a metal product, and the thickness of a cured dry film is 40-50 μm.

The waterborne nanosheet composite coating with the thickness can passivate the metal surface to form an oxide film; meanwhile, the insulation effect of the coating can be guaranteed, and the appearance and the performance of the metal product cannot be influenced.

The invention has the beneficial effects that: the invention provides a water-based nanosheet composite coating, wherein a urushiol derivative is used as a modifier in raw material components of the product to anchor and modify a two-dimensional nanosheet, so that the two-dimensional nanosheet is effectively dispersed in water-based epoxy resin, and the modified nanosheet can fully play a labyrinth effect when the coating is used, so that a good physical barrier effect is achieved, and a path of a corrosive medium entering the coating is greatly prolonged; in addition, the catechol group contained in the urushiol derivative can effectively passivate protected metal and alloy, so that a compact oxide film is formed on the surface of the urushiol derivative, and the urushiol derivative can effectively protect a metal substrate. The invention also provides a preparation method and application of the water-based nanosheet composite coating.

Drawings

FIG. 1 is an EIS test chart of a waterborne nanosheet composite coating and a purely aqueous epoxy resin coating prepared in example 1 of the present invention after being applied and immersed in a 3.5 wt% NaCl aqueous solution for 15 days;

FIG. 2 is an EIS test chart of the waterborne nano-sheet composite coating and the pure water epoxy resin coating prepared in the embodiment 2 of the invention after being applied and soaked in a 3.5 wt% NaCl aqueous solution for 15 days;

FIG. 3 is an EIS test chart of the waterborne nano-sheet composite coating and the pure water epoxy resin coating prepared in the embodiment 3 of the invention after being applied and soaked in a 3.5 wt% NaCl aqueous solution for 15 days;

FIG. 4 is an EIS test chart of the waterborne nano-sheet composite coating and the pure water epoxy resin coating prepared in the embodiment 4 of the invention after being applied and soaked in a 3.5 wt% NaCl aqueous solution for 15 days;

fig. 5 is an EIS test chart of the waterborne nanosheet composite coating and the pure water epoxy resin coating prepared in embodiment 5 of the present invention after being applied and immersed in a 3.5 wt% NaCl aqueous solution for 15 days.

Detailed Description

For better illustrating the objects, technical solutions and advantages of the present invention, the present invention will be further described with reference to specific examples, which are intended to be understood in detail, but not intended to limit the present invention. The urushiol derivative used in each example has the following structure:

example 1

The preparation method of the water-based nano sheet composite coating comprises the following steps:

(1) respectively adding 75mg of two-dimensional nanosheet material boron nitride powder with the size of 0.5-50 mu m and 0.1g of urushiol derivative into 2.5g of deionized water, and carrying out ultrasonic treatment for 4h to obtain a boron nitride nanosheet dispersion liquid;

(2) adding 10g of WTE-51 type waterborne epoxy resin into the nanosheet dispersion liquid, and stirring the mixture uniformly through mechanical stirring; and finally, adding a 5Gwh115 type polyamide curing agent, stirring for 5min, quickly putting into a defoaming machine, setting the rotating speed to be 1500r/min and the vacuum degree to be 95.8kPa, and defoaming for 15min to obtain the water-based nanosheet composite coating.

The metal product used in this example was a 5cm × 5cm × 1mm Q235 carbon steel sheet, the surface of which was polished with 180-mesh and 600-mesh sandpaper to remove rust and stains, and then ultrasonically cleaned in acetone and alcohol for 30min and dried.

And then coating the prepared water-based nano composite coating on the surface of the processed Q235 carbon steel sheet by using a wire rod coating machine (the wet film thickness is about 75 microns), and curing to obtain a coating dry film thickness of about 45 microns.

Soaking a Q235 steel sheet sample coated with the water-based nano composite coating in 3.5 wt% NaCl solution for 15d, performing electrochemical impedance spectroscopy test by adopting a three-electrode system (a saturated AgCl electrode is used as a reference electrode, a platinum sheet is used as an auxiliary electrode, and the Q235 steel sheet coated with the water-based nano sheet composite coating is used as a working electrode), and performing a control test by adopting a WTE-51 type water-based epoxy resin coating as a control group, wherein the test result is shown in figure 1.

As can be seen from FIG. 1, the pure waterborne epoxy resin coating was immersed in a 3.5 wt% NaCl aqueous solution for 15 days, and then | Z_f＝0.01HzIs 1.33X 10⁷Ω·cm²After the urushiol derivative modified boron nitride nanosheet/water-based composite coating is soaked in 3.5 wt% NaCl aqueous solution for 15 days, | Z | Y_f＝0.01HzIs 7.28 multiplied by 10⁸Ω·cm²And the corrosion resistance of the coating is obviously improved.

In addition, in order to verify the synergistic effect of the urushiol derivative and the two-dimensional nanosheet in the aqueous nanosheet composite coating, the urushiol derivative modified aqueous coating without the two-dimensional nanosheet (namely, the two-dimensional nanosheet material boron nitride powder is not added in the step (1), and the rest steps are the same) is prepared according to the preparation method and subjected to the same test, and the obtained urushiol derivative modified aqueous coating is immersed in 3.5 wt% of NaCl aqueous solution for 15 days, and then the | Z & ltEn & gt & lt & gt_f＝0.01HzIs 3.25X 10⁸Ω·cm²The corrosion resistance of the paint product can be improved only by means of the urushiol derivative, but the effect is far less than that of the boron nitride nanosheet/water-based composite coating modified by the urushiol derivative.

Example 2

According to the embodiment of the water-based nanosheet composite coating, the preparation method and the application thereof, the difference between the embodiment and the embodiment 1 is that the two-dimensional nanosheet material is graphene with the size of 0.5-50 μm.

The application and the test of the aqueous nanosheet composite coating obtained in the present embodiment are the same as those in embodiment 1, and the test results are shown in fig. 2.

As can be seen from FIG. 2, | Z! Y cells after the coating layer of the pure waterborne epoxy resin coating material was immersed in a 3.5 wt% NaCl aqueous solution for 15 days_f＝0.01HzIs 1.33X 10⁷Ω·cm²After the urushiol derivative modified boron nitride nanosheet/water-based composite coating is soaked in 3.5 wt% NaCl aqueous solution for 15 days, | Z | Y_f＝0.01HzIs 1.77X 10⁸Ω·cm²And the corrosion resistance of the coating is obviously improved.

Example 3

According to the embodiment of the water-based nanosheet composite coating, the preparation method and the application thereof, the only difference between the embodiment and the embodiment 1 is that the two-dimensional nanosheet material is tungsten disulfide with the size of 0.5-50 μm.

The application and the test of the aqueous nanosheet composite coating obtained in the present embodiment are the same as those in embodiment 1, and the test results are shown in fig. 3.

As can be seen from FIG. 3, | Z! Y cells after the coating layer of the pure aqueous epoxy resin coating material was immersed in a 3.5 wt% NaCl aqueous solution for 15 days_f＝0.01HzIs 1.33X 10⁷Ω·cm²After the urushiol derivative modified boron nitride nanosheet/water-based composite coating is soaked in 3.5 wt% NaCl aqueous solution for 15 days, | Z | Y_f＝0.01HzIs 7.08X 10⁸Ω·cm²And the corrosion resistance of the coating is obviously improved.

Example 4

According to the embodiment of the water-based nanosheet composite coating, the preparation method and the application thereof, the difference between the embodiment and the embodiment 1 is that the two-dimensional nanosheet material is molybdenum disulfide with the size of 0.5-50 μm.

The application and the test of the aqueous nanosheet composite coating obtained in the present embodiment are the same as those in embodiment 1, and the test results are shown in fig. 4.

As can be seen from FIG. 4, | Z! Y cells after the coating layer of the pure waterborne epoxy resin coating material was immersed in a 3.5 wt% NaCl aqueous solution for 15 days_f＝0.01HzIs 1.33X 10⁷Ω·cm²After the urushiol derivative modified boron nitride nanosheet/water-based composite coating is soaked in 3.5 wt% NaCl aqueous solution for 15 days, | Z | Y_f＝0.01HzIs 2.99X 10⁸Ω·cm²And the corrosion resistance of the coating is obviously improved.

Example 5

According to the embodiment of the water-based nanosheet composite coating, the preparation method and the application thereof, the difference between the embodiment and the embodiment 1 is that the two-dimensional nanosheet material is a borolene with the size of 0.5-50 μm.

The application and the test of the aqueous nanosheet composite coating obtained in the present embodiment are the same as those in embodiment 1, and the test results are shown in fig. 5.

As can be seen from FIG. 5, | Z! Y cells after the coating layer of the pure waterborne epoxy resin coating was immersed in a 3.5 wt% NaCl aqueous solution for 50 days_f＝0.01HzIs 1.33X 10⁷Ω·cm²After the urushiol derivative modified boron nitride nanosheet/water-based composite coating is soaked in 3.5 wt% NaCl aqueous solution for 50 days, | Z | Y_f＝0.01HzIs 9.57X 10⁷Ω·cm²And the corrosion resistance of the coating is obviously improved.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the protection scope of the present invention, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.