CN111218210A

CN111218210A - Composite coating, preparation method and application thereof

Info

Publication number: CN111218210A
Application number: CN202010018945.1A
Authority: CN
Inventors: 林棋; 陆畅; 夏建荣; 张于弛
Original assignee: Minjiang University
Current assignee: Minjiang University
Priority date: 2020-01-08
Filing date: 2020-01-08
Publication date: 2020-06-02

Abstract

The application discloses a composite coating and a preparation method and application thereof. The composite coating comprises the urushiol and the nano titanium dioxide, and the nano titanium dioxide is embedded into the urushiol. Polymerized urushiol and nano TiO₂The composite coating has compact and uniform structure and excellent corrosion resistance. Nano TiO 2₂The introduction of the coating improves the mechanical property, the thermal property and the like of the coating.

Description

Composite coating, preparation method and application thereof

Technical Field

The application relates to a composite coating, a preparation method and application thereof, and belongs to the technical field of coatings.

Background

Urushiol, the main component of raw lacquer, the content is 40-70%. The pyrocatechol is a mixture of several derivatives with unsaturated branched chains, has excellent corrosion resistance, acid and alkali resistance, heat resistance, self-drying property and the like, and has certain market on special anticorrosive paint.

Carbon steel materials are important structural materials due to their excellent mechanical properties and processability, and are used in the entire industrial field. However, carbon steel materials are susceptible to corrosion during use, particularly in acidic and neutral environments, which not only results in significant economic losses, but also poses a number of safety concerns. Corrosion protection of carbon steel materials is therefore becoming an increasingly important issue facing countries around the world. At present, various methods are used for delaying the corrosion of metal materials, such as the immersion treatment of corrosion inhibitors, the protection of surface coatings, the corrosion protection of sacrificial anodes and the like. The traditional preparation method of the organic anticorrosive film comprises dip coating, brush coating, spray coating and the like, and the traditional film preparation method often causes some air holes and cracks in the film, greatly influences the uniformity and compactness of the film layer and is not beneficial to corrosion protection of a metal substrate.

Disclosure of Invention

According to one aspect of the application, a composite coating is provided, the composite coating is compact and uniform in structure and has excellent corrosion resistance, and nano TiO₂The mechanical property, the thermal property and the like of the urushiol coating are improved by introducing the urushiol.

The electrochemical polymerization used in the method is an environment-friendly technology, has the characteristics of simple reaction conditions, easiness in control, wide monomer application range, mild polymerization conditions and the like, and can be used for preparing materials with new functions and characteristics. Researches find that the organic protective film is directly prepared on the surface of the metal substrate by utilizing an electric polymerization technology, so that the bonding force between the substrate and the organic protective film can be improved, and compared with the traditional dip-coating method, the organic protective film prepared by electric polymerization generally has higher compactness.

Nano TiO 2₂Has photocatalytic activity and can be applied to the field of self-cleaning surfaces. TiO 2₂The hydroxyl on the hydrated surface can react with the phenolic hydroxyl of urushiol and the oxygen atom in the molecule after urushiol polymerization, which is also beneficial to urushiol paint and nano TiO₂Are compatible. Therefore, if TiO can be mixed with₂Dispersing in paint liquid, and electroplating on steel plate to obtain compact and flat urushiol/nanometer TiO₂And (4) composite coating. The method can accelerate the drying of the paint film, simultaneously can improve the thermal property, the mechanical property and the like of the paint, and broadens the application range of the paint material.

The application provides a composite coating, including urushiol and nanometer titanium dioxide, nanometer titanium dioxide imbeds in the urushiol.

Optionally, the mass content of the nano titanium dioxide in the composite coating is 0.2-1.0%.

Optionally, the thickness of the composite coating is 0.13-0.15 mm.

In another aspect of the present application, there is also provided a method for preparing the above composite coating, comprising at least the following steps:

will contain urushiol and nano TiO₂And carrying out electrochemical polymerization on the composite solution to obtain the composite coating.

Optionally, the urushiol and the nano TiO₂The mass ratio of (A) to (B) is 10: 0.2-10: 1.

optionally, the composite liquid further contains an electrolyte; the electrolyte comprises at least one of water and an inorganic salt solution.

Optionally, the inorganic salt solution comprises at least one of a sodium chloride solution, a sodium sulfate solution.

Optionally, the composite liquid further contains a solvent A and a solvent B; the solvent A is an organic solvent;

the organic solvent is selected from at least one of ethanol and methanol;

the solvent B is at least one selected from water and ethanol.

Optionally, the composite liquid is prepared by at least the following steps:

a) obtaining a urushiol-containing solution A;

b) adding an ethanol water solution into the solution A to obtain a solution B;

c) adding TiO into the mixture₂Adding the sol into the solution B to obtain the composite liquid.

Optionally, in step a), the solution a further contains the solvent a;

the mass percentage of the urushiol in the solution A is 8-10.0 wt%.

Optionally, in the step b), the mass percentage of the ethanol in the ethanol aqueous solution is 18-20 wt%;

the mass ratio of the ethanol aqueous solution to the solution A is 1: 1.1-1: 1.2.

in step c), the TiO₂Nano TiO in sol₂The mass concentration is 2-10 wt%;

the TiO is₂The mass ratio of the sol to the solution B is 0.2: 10-1: 10.

optionally, the conditions of the electrochemical polymerization are: the electrochemical polymerization voltage is 130-300V; the electrochemical polymerization time is 6-12 min.

Preferably, the electrochemical polymerization is carried out under a constant pressure.

Preferably, the composite coating is electrochemically polymerized to the surface of the tinplate.

The application also provides an application of the composite coating and the composite coating prepared by the method in an anti-corrosion protective material.

The beneficial effects that this application can produce include:

1) the composite coating of the present application, Polyurushiol/Nano TiO₂Urushiol with good corrosion resistance is used as a matrix, so that the price is low;

2) in the present application, nano TiO is used₂Adding urushiol, electropolymerization of urushiol/nanometer TiO₂The composite coating has compact and uniform structure and excellent corrosion resistance;

3) this application is through nano TiO₂The mechanical property, the thermal property and the like of the urushiol coating are improved by introducing;

4) the application is realized by adjusting nano TiO₂The dosage is used for controlling the thermal property, the mechanical property and the corrosion resistance of the composite coating.

Drawings

FIG. 1 is a diagram of an experimental apparatus for electrochemical polymerization according to an embodiment of the present application;

FIG. 2 shows electrochemically polymerized urushiol/nano TiO of an embodiment of the present application₂A model of the composite coating;

FIG. 3 is an SEM image of samples UT0 and UT 1.0.

Detailed Description

The present application will be described in detail with reference to examples, but the present application is not limited to these examples.

The raw materials in the examples of the present application were all purchased commercially, unless otherwise specified.

The analysis method in the examples of the present application is as follows:

the paint film adhesion tester in the embodiment of the application adopts a QFH model; the paint film cylindrical bending instrument tester adopts a QTY-32 model; the paint film impacter adopts a QCJ-120 model; the paint film scratch tester adopts a CT-291 model;

the electrochemical polymerization urushiol/nano TiO₂The adhesion performance of the composite coating is tested by adopting a paint film adhesion tester, and is referred to the national standard GB/T5210-2006; the flexibility performance test adopts a paint film cylindrical bending instrument tester, and refers to the national standard GB/T6742-2007; the paint film impacter is used for testing impact performance, and is referred to the national standard GB/T1732-1993; the pencil hardness test is measured by a paint film scratch tester according to the national standard GB/T15184-; use of GermanyDSA25 surface contact Angle tester measured the contact angle of water on different sample coatings, the drop volume of the micro-syringe was 2 μ L, each sample surface was tested at 5 different locations, and the average was taken as the final contact angle value.

Comparative example 1

And (2) component A: urushiol 10g was dissolved in absolute ethanol (90g), component B: to absolute ethanol (90g) was added 20g of distilled water. And slowly dropwise adding the component B to the component A, and fully stirring for 120min to obtain urushiol mixed liquor, which is recorded as UT0.

Example 1

And (2) component A: urushiol 10g was dissolved in absolute ethanol (90g), component B: to absolute ethanol (90g) was added 20g of distilled water. Slowly dripping the component B into the component A, fully stirring for 20min, and then dropwise adding 10g of TiO₂Stirring the hydrosol at room temperature for 2h 15min to prepare urushiol/nano TiO₂And (4) compounding the liquid. Pouring the prepared complex liquid into a 100ml beaker for electrochemical polymerization (constant pressure 130V)Left and right) experiment, the electrochemical polymerization device is shown in figure 1, and the nano TiO with the structure shown in figure 2 is obtained₂0.2 percent of urushiol/TiO₂Composite coating, noted UT 0.2.

Example 2

And (2) component A: urushiol 10g was dissolved in absolute ethanol (90g), component B: to absolute ethanol (90g) was added 20g of distilled water. Slowly dripping the component B into the component A, fully stirring for 20min, and then dropwise adding 15g of TiO₂Stirring the hydrosol at room temperature for 2h 15min to prepare urushiol/nano TiO₂And (4) compounding the liquid. Pouring the prepared composite liquid into a 100ml beaker for carrying out an electrochemical polymerization (constant pressure about 130V) experiment to obtain the nano TiO₂0.5 percent of urushiol/TiO₂Composite coating, noted UT 0.5.

Example 3

And (2) component A: urushiol 10g was dissolved in absolute ethanol (90g), component B: to absolute ethanol (90g) was added 20g of distilled water. Slowly dripping the component B into the component A, fully stirring for 20min, and then dropwise adding 20g of TiO₂Stirring the hydrosol at room temperature for 2h 15min to prepare urushiol/nano TiO₂And (4) compounding the liquid. Pouring the prepared composite liquid into a 100ml beaker for carrying out an electrochemical polymerization (constant pressure about 130V) experiment to obtain the nano TiO₂1% of urushiol/TiO₂Composite coating, noted UT 1.0.

Example 4

The mechanical properties and the dielectric resistance of comparative example 1 and examples 1 to 3 were respectively tested, and the results of the mechanical properties are shown in Table 1, which shows that with the nano TiO₂Constantly introduced of Polyurushiol/Nano TiO₂The mechanical properties of the composite coating are improved to a certain degree, and super-hydrophobicity can be achieved; the results of the medium resistance test are shown in table 2, and the solvent resistance of the coating and the corrosion grade of the surface of the coating in the NaCl solution are evaluated by the immersion method. Firstly, the stainless steel samples with different coatings are subjected to chemical medium resistance analysis, the different samples are respectively soaked in different media for 3 days at room temperature, and whether the coatings have wrinkling, discoloration and cracking or not and whether the coatings fall off from the surfaces of the stainless steel are observed, so that the chemical medium resistance of the different coatings is measuredThe quality performance. As can be seen from the table, the UT1.0 sample exhibited good dielectric resistance, TiO₂The incorporation of (a) improves the medium resistance of the urushiol.

TABLE 1 mechanical Properties of comparative example 1 and examples 1 to 3

TABLE 2 comparative example 1, examples 1 to 3 Medium resistance test

Chemical media	UT0	UT0.2	UT0.5	UT1.0
					30％H₂SO₄	+	+	+	+
10％H₂SO₄	+	+	+	+
					30％NaOH	-	-	-	+
10％NaOH	-	-	-	+
					15％NaCl	+	+	+	+
C₂H₅OH	+	+	+	+
					H₂0	+	+	+	+

Note: + indicates that the paint film does not appear wrinkling, discoloration or cracking; indicates that the paint film is wrinkled, discolored or cracked.

Example 5 topography characterization

The topography of comparative example 1 and examples 1 to 3, respectively, as represented by samples UT0 and UT1.0, is shown in FIG. 3, where the UT0 sample of FIG. 3 (A) had a dense and smooth surface, while the "white dots" visible on the UT1.0 sample of FIG. 3 (B) were embedded in the urushiol coating and were uniformly distributed in micron dimensions.

Although the present application has been described with reference to a few embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the application as defined by the appended claims.

Claims

1. The composite coating is characterized by comprising the urushiol and the nano titanium dioxide, wherein the nano titanium dioxide is embedded in the urushiol.

2. The composite coating of claim 1, wherein the mass content of the nano titanium dioxide in the composite coating is 0.2-1.0%;

preferably, the thickness of the composite coating is 0.13-0.15 mm.

3. Method for the preparation of a composite coating according to any of claims 1 to 2, characterized in that it comprises at least the following steps:

4. The method according to claim 3, wherein the urushiol and the nano TiO are mixed together₂The mass ratio of (A) to (B) is 10: 0.2-10: 1;

preferably, the composite liquid also contains an electrolyte; the electrolyte includes at least one of water and an inorganic salt solution.

5. The preparation method according to claim 3, wherein the composite liquid further contains a solvent A and a solvent B; the solvent A is an organic solvent;

the organic solvent is selected from at least one of ethanol and methanol;

the solvent B is at least one selected from water and ethanol.

6. The preparation method according to claim 3, wherein the composite liquid is prepared by at least the following steps:

a) obtaining a urushiol-containing solution A;

b) adding an ethanol water solution into the solution A to obtain a solution B;

7. The method according to claim 6, wherein in step a), the solution A further contains the solvent A;

the mass percentage of the urushiol in the solution A is 8-10.0 wt%.

8. The preparation method according to claim 6, wherein in the step b), the mass percentage of the ethanol in the ethanol aqueous solution is 18-20 wt%;

the mass ratio of the ethanol aqueous solution to the solution A is 1: 1.1-1: 1.2;

preferably, in step c), the TiO is₂Nano TiO in sol₂The mass concentration is 2-10 wt%;

the TiO is₂The mass ratio of the sol to the solution B is 0.2: 10-1: 10.

9. the method according to claim 3, wherein the conditions of the electrochemical polymerization are: the electrochemical polymerization voltage is 130-300V; the electrochemical polymerization time is 6-12 min;

preferably, the electrochemical polymerization is carried out at constant pressure;

10. Use of the composite coating according to any one of claims 1 to 2, the composite coating produced by the method according to any one of claims 3 to 9 in corrosion-resistant protective materials.